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  Subjects -> ENGINEERING (Total: 2268 journals)
    - CHEMICAL ENGINEERING (190 journals)
    - CIVIL ENGINEERING (183 journals)
    - ELECTRICAL ENGINEERING (103 journals)
    - ENGINEERING (1201 journals)
    - ENGINEERING MECHANICS AND MATERIALS (380 journals)
    - HYDRAULIC ENGINEERING (55 journals)
    - INDUSTRIAL ENGINEERING (67 journals)
    - MECHANICAL ENGINEERING (89 journals)

CIVIL ENGINEERING (183 journals)                     

Showing 1 - 183 of 183 Journals sorted alphabetically
ACI Structural Journal     Full-text available via subscription   (Followers: 17)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 2)
Acta Structilia : Journal for the Physical and Development Sciences     Open Access   (Followers: 2)
Advances in Civil Engineering     Open Access   (Followers: 35)
Advances in Structural Engineering     Full-text available via subscription   (Followers: 28)
Ambiente Construído     Open Access   (Followers: 1)
American Journal of Civil Engineering and Architecture     Open Access   (Followers: 30)
Architectural Engineering     Open Access   (Followers: 4)
Archives of Civil and Mechanical Engineering     Full-text available via subscription   (Followers: 1)
Archives of Civil Engineering     Open Access   (Followers: 10)
Archives of Hydro-Engineering and Environmental Mechanics     Open Access   (Followers: 2)
ATBU Journal of Environmental Technology     Open Access   (Followers: 4)
Australian Journal of Structural Engineering     Full-text available via subscription   (Followers: 6)
Baltic Journal of Road and Bridge Engineering     Full-text available via subscription   (Followers: 1)
BER : Building and Construction : Full Survey     Full-text available via subscription   (Followers: 10)
BER : Building Contractors' Survey     Full-text available via subscription   (Followers: 4)
BER : Building Sub-Contractors' Survey     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Building and Construction : An Executive Summary     Full-text available via subscription   (Followers: 4)
Bioinspired Materials     Open Access   (Followers: 5)
Bridge Structures : Assessment, Design and Construction     Hybrid Journal   (Followers: 15)
Building and Environment     Hybrid Journal   (Followers: 15)
Building Women     Full-text available via subscription  
Built Environment Project and Asset Management     Hybrid Journal   (Followers: 15)
Bulletin of Pridniprovsk State Academy of Civil Engineering and Architecture     Open Access   (Followers: 6)
Canadian Journal of Civil Engineering     Hybrid Journal   (Followers: 12)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 8)
Case Studies in Nondestructive Testing and Evaluation     Open Access   (Followers: 11)
Case Studies in Structural Engineering     Open Access   (Followers: 9)
Cement and Concrete Composites     Hybrid Journal   (Followers: 17)
Challenge Journal of Concrete Research Letters     Open Access   (Followers: 2)
Challenge Journal of Structural Mechanics     Open Access   (Followers: 5)
Change Over Time     Full-text available via subscription   (Followers: 2)
Civil and Environmental Engineering     Open Access   (Followers: 7)
Civil And Environmental Engineering Reports     Open Access   (Followers: 5)
Civil and Environmental Research     Open Access   (Followers: 19)
Civil Engineering = Siviele Ingenieurswese     Full-text available via subscription   (Followers: 4)
Civil Engineering and Architecture     Open Access   (Followers: 17)
Civil Engineering and Environmental Systems     Hybrid Journal   (Followers: 3)
Civil Engineering and Technology     Open Access   (Followers: 10)
Civil Engineering Dimension     Open Access   (Followers: 8)
Cohesion and Structure     Full-text available via subscription   (Followers: 2)
Composite Structures     Hybrid Journal   (Followers: 265)
Computer-aided Civil and Infrastructure Engineering     Hybrid Journal   (Followers: 11)
Computers & Structures     Hybrid Journal   (Followers: 36)
Concrete Research Letters     Open Access   (Followers: 6)
Construction Economics and Building     Open Access   (Followers: 2)
Construction Engineering     Open Access   (Followers: 9)
Construction Management and Economics     Hybrid Journal   (Followers: 22)
Construction Science     Open Access   (Followers: 4)
Constructive Approximation     Hybrid Journal  
Curved and Layered Structures     Open Access   (Followers: 2)
DFI Journal : The Journal of the Deep Foundations Institute     Hybrid Journal   (Followers: 1)
Earthquake Engineering and Structural Dynamics     Hybrid Journal   (Followers: 16)
Enfoque UTE     Open Access   (Followers: 4)
Engineering Project Organization Journal     Hybrid Journal   (Followers: 7)
Engineering Structures     Hybrid Journal   (Followers: 13)
Engineering Structures and Technologies     Hybrid Journal   (Followers: 2)
Engineering, Construction and Architectural Management     Hybrid Journal   (Followers: 14)
Environmental Geotechnics     Hybrid Journal   (Followers: 5)
European Journal of Environmental and Civil Engineering     Hybrid Journal   (Followers: 9)
Fatigue & Fracture of Engineering Materials and Structures     Hybrid Journal   (Followers: 16)
Frattura ed Integrità Strutturale : Fracture and Structural Integrity     Open Access  
Frontiers in Built Environment     Open Access  
Frontiers of Structural and Civil Engineering     Hybrid Journal   (Followers: 6)
Geomaterials     Open Access   (Followers: 4)
Geosystem Engineering     Hybrid Journal   (Followers: 1)
Geotechnik     Hybrid Journal   (Followers: 3)
Géotechnique Letters     Hybrid Journal   (Followers: 6)
HBRC Journal     Open Access   (Followers: 2)
Hormigón y Acero     Full-text available via subscription  
HVAC&R Research     Hybrid Journal  
Indoor and Built Environment     Hybrid Journal   (Followers: 2)
Infrastructure Asset Management     Hybrid Journal   (Followers: 2)
Infrastructures     Open Access  
Ingenio Magno     Open Access   (Followers: 1)
Insight - Non-Destructive Testing and Condition Monitoring     Full-text available via subscription   (Followers: 22)
International Journal for Service Learning in Engineering     Open Access  
International Journal of 3-D Information Modeling     Full-text available via subscription   (Followers: 3)
International Journal of Advanced Structural Engineering     Open Access   (Followers: 16)
International Journal of Civil, Mechanical and Energy Science     Open Access   (Followers: 1)
International Journal of Concrete Structures and Materials     Open Access   (Followers: 14)
International Journal of Condition Monitoring     Full-text available via subscription   (Followers: 2)
International Journal of Construction Engineering and Management     Open Access   (Followers: 9)
International Journal of Geo-Engineering     Open Access   (Followers: 3)
International Journal of Geosynthetics and Ground Engineering     Full-text available via subscription   (Followers: 4)
International Journal of Masonry Research and Innovation     Hybrid Journal   (Followers: 1)
International Journal of Pavement Research and Technology     Open Access   (Followers: 5)
International Journal of Protective Structures     Hybrid Journal   (Followers: 6)
International Journal of Steel Structures     Hybrid Journal   (Followers: 2)
International Journal of Structural Engineering     Hybrid Journal   (Followers: 10)
International Journal of Structural Integrity     Hybrid Journal   (Followers: 2)
International Journal of Structural Stability and Dynamics     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Built Environment     Open Access   (Followers: 4)
International Journal of Sustainable Construction Engineering and Technology     Open Access   (Followers: 8)
International Journal on Pavement Engineering & Asphalt Technology     Open Access   (Followers: 6)
International Journal Sustainable Construction & Design     Open Access  
Journal of Bridge Engineering     Full-text available via subscription   (Followers: 15)
Journal of Building Engineering     Hybrid Journal   (Followers: 1)
Journal of Building Materials and Structures     Open Access   (Followers: 2)
Journal of Building Performance Simulation     Hybrid Journal   (Followers: 6)
Journal of Civil Engineering and Construction Technology     Open Access   (Followers: 12)
Journal of Civil Engineering and Management     Hybrid Journal   (Followers: 7)
Journal of Civil Engineering and Science     Open Access   (Followers: 7)
Journal of Civil Engineering Research     Open Access   (Followers: 6)
Journal of Civil Society     Hybrid Journal   (Followers: 4)
Journal of Civil Structural Health Monitoring     Hybrid Journal   (Followers: 4)
Journal of Composites for Construction     Full-text available via subscription   (Followers: 13)
Journal of Computing in Civil Engineering     Full-text available via subscription   (Followers: 24)
Journal of Construction Engineering     Open Access   (Followers: 7)
Journal of Construction Engineering and Management     Full-text available via subscription   (Followers: 19)
Journal of Constructional Steel Research     Hybrid Journal   (Followers: 8)
Journal of Earth Sciences and Geotechnical Engineering     Open Access   (Followers: 4)
Journal of Fluids and Structures     Hybrid Journal   (Followers: 6)
Journal of Frontiers in Construction Engineering     Open Access   (Followers: 2)
Journal of Green Building     Full-text available via subscription   (Followers: 11)
Journal of Highway and Transportation Research and Development (English Edition)     Full-text available via subscription   (Followers: 13)
Journal of Infrastructure Systems     Full-text available via subscription   (Followers: 21)
Journal of Legal Affairs and Dispute Resolution in Engineering and Construction     Full-text available via subscription   (Followers: 5)
Journal of Marine Science and Engineering     Open Access   (Followers: 1)
Journal of Materials and Engineering Structures     Open Access   (Followers: 5)
Journal of Materials in Civil Engineering     Full-text available via subscription   (Followers: 10)
Journal of Nondestructive Evaluation     Hybrid Journal   (Followers: 11)
Journal of Performance of Constructed Facilities     Full-text available via subscription   (Followers: 4)
Journal of Pipeline Systems Engineering and Practice     Full-text available via subscription   (Followers: 7)
Journal of Rehabilitation in Civil Engineering     Open Access   (Followers: 3)
Journal of Solid Waste Technology and Management     Full-text available via subscription   (Followers: 1)
Journal of Structural Engineering     Full-text available via subscription   (Followers: 40)
Journal of Structural Fire Engineering     Full-text available via subscription   (Followers: 6)
Journal of Sustainable Architecture and Civil Engineering     Open Access   (Followers: 3)
Journal of Sustainable Design and Applied Research in Innovative Engineering of the Built Environment     Open Access   (Followers: 1)
Journal of the Civil Engineering Forum     Open Access  
Journal of the South African Institution of Civil Engineering     Open Access   (Followers: 4)
Jurnal Spektran     Open Access   (Followers: 1)
Jurnal Teknik Sipil dan Perencanaan     Open Access   (Followers: 1)
Konstruksia     Open Access  
KSCE Journal of Civil Engineering     Hybrid Journal   (Followers: 2)
Latin American Journal of Solids and Structures     Open Access   (Followers: 4)
Materiales de Construcción     Open Access  
Mathematical Modelling in Civil Engineering     Open Access   (Followers: 3)
Nondestructive Testing And Evaluation     Hybrid Journal   (Followers: 17)
Obras y Proyectos     Open Access   (Followers: 1)
Open Journal of Civil Engineering     Open Access   (Followers: 7)
Photonics and Nanostructures - Fundamentals and Applications     Hybrid Journal   (Followers: 2)
Practice Periodical on Structural Design and Construction     Full-text available via subscription   (Followers: 4)
Proceedings of the Institution of Civil Engineers - Bridge Engineering     Hybrid Journal   (Followers: 7)
Proceedings of the Institution of Civil Engineers - Civil Engineering     Hybrid Journal   (Followers: 11)
Proceedings of the Institution of Civil Engineers - Management, Procurement and Law     Hybrid Journal   (Followers: 8)
Proceedings of the Institution of Civil Engineers - Municipal Engineer     Hybrid Journal   (Followers: 3)
Proceedings of the Institution of Civil Engineers - Structures and Buildings     Hybrid Journal   (Followers: 4)
Random Structures and Algorithms     Hybrid Journal   (Followers: 5)
Research in Nondestructive Evaluation     Hybrid Journal   (Followers: 7)
Revista IBRACON de Estruturas e Materiais     Open Access   (Followers: 1)
Road Materials and Pavement Design     Hybrid Journal   (Followers: 10)
Russian Journal of Nondestructive Testing     Hybrid Journal   (Followers: 6)
Science and Engineering of Composite Materials     Hybrid Journal   (Followers: 61)
Selected Scientific Papers - Journal of Civil Engineering     Open Access   (Followers: 3)
Slovak Journal of Civil Engineering     Open Access   (Followers: 2)
Soils and foundations     Full-text available via subscription   (Followers: 4)
Steel Construction - Design and Research     Hybrid Journal   (Followers: 3)
Structural and Multidisciplinary Optimization     Hybrid Journal   (Followers: 9)
Structural Concrete     Hybrid Journal   (Followers: 11)
Structural Control and Health Monitoring     Hybrid Journal   (Followers: 9)
Structural Engineering International     Full-text available via subscription   (Followers: 11)
Structural Safety     Hybrid Journal   (Followers: 7)
Structural Survey     Hybrid Journal  
Structure     Full-text available via subscription   (Followers: 23)
Structure and Infrastructure Engineering: Maintenance, Management, Life-Cycle Design and Performance     Hybrid Journal   (Followers: 13)
Structures     Hybrid Journal   (Followers: 1)
Study of Civil Engineering and Architecture     Open Access   (Followers: 8)
Superlattices and Microstructures     Hybrid Journal   (Followers: 2)
Surface Innovations     Hybrid Journal  
Technical Report Civil and Architectural Engineering     Open Access  
Teknik     Open Access  
The IES Journal Part A: Civil & Structural Engineering     Hybrid Journal   (Followers: 6)
The Structural Design of Tall and Special Buildings     Hybrid Journal   (Followers: 6)
Thin Films and Nanostructures     Full-text available via subscription   (Followers: 2)
Thin-Walled Structures     Hybrid Journal   (Followers: 4)
Transactions of the VŠB - Technical University of Ostrava. Construction Series     Open Access   (Followers: 1)
Transportation Geotechnics     Full-text available via subscription   (Followers: 1)
Transportation Infrastructure Geotechnology     Hybrid Journal   (Followers: 8)
Underground Space     Open Access  
Water Science & Technology     Partially Free   (Followers: 25)
Water Science and Technology : Water Supply     Partially Free   (Followers: 22)

           

Journal Cover International Journal of Structural Stability and Dynamics
  [SJR: 0.613]   [H-I: 19]   [7 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0219-4554 - ISSN (Online) 1793-6764
   Published by World Scientific Homepage  [118 journals]
  • Axisymmetric Vibration of Rotating Annular Plate with Variable Thickness
           Subjected to Tensile Centrifugal Body Force
    • Authors: Jae-Hoon Kang
      Abstract: International Journal of Structural Stability and Dynamics, Volume 17, Issue 09, November 2017.
      This paper is concerned with the axisymmetric free vibration analysis of a rotating annular plate with variable thickness by using the Ritz method. The rotating plate has a constant angular speed and subjected to a tensile centrifugal body force. The annular plate is fixed at the inner edge and free at the outer edge. Exact stresses, strains, and radial displacement of the rotating annular plate are obtained via plane elasticity. Presented herein are the natural frequencies and modes shapes for the rotating, nonuniform annular plate with various angular speeds and different ratios of the inner radius to the outer radius.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-10-23T07:44:06Z
      DOI: 10.1142/S0219455417501012
       
  • Probabilistic Solutions of a Nonlinear Plate Excited by Gaussian White
           Noise Fully Correlated in Space
    • Authors: G. K. Er, V. P. Iu
      Abstract: International Journal of Structural Stability and Dynamics, Volume 17, Issue 09, November 2017.
      This paper addresses the nonlinear random vibration of a rectangular von Kármán plate excited by uniformly distributed Gaussian white noise which is fully correlated in space. The state-space-split method and exponential polynomial closure method are jointly utilized to analyze the probabilistic solutions of the plate. The computational efficiency and numerical accuracy of the methodology for analyzing the nonlinear random vibration of the plate are verified by comparing the computational effort and numerical results with those obtained by Monte Carlo simulation and equivalent linearization, respectively. Meanwhile, the convergence of the probabilistic solution in the sense of Galerkin’s approximation is examined by analyzing the plate modeled as single-degree-of-freedom and multi-degree-of-freedom systems. Some phenomena are discussed after numerically studying the behaviors of probabilistic solutions of the deflection at different locations of the plate.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-10-23T07:44:02Z
      DOI: 10.1142/S0219455417500973
       
  • Mechanics of Collapse of WTC Towers Clarified by Recent Column Buckling
           Tests of Korol and Sivakumaran
    • Authors: Jia-Liang Le, Zdeněk P. Bažant
      Abstract: International Journal of Structural Stability and Dynamics, Volume 17, Issue 09, November 2017.
      The previously formulated model of the gravity-driven collapse of the twin towers of the World Trade Center (WTC) on September 11, 2011 was shown to match all the existing observations, including the video record of the crush-down motion of the top part of tower during the first few seconds, the seismically recorded duration of collapse, the size distribution of particles caused by impact comminution of concrete floor slabs, the loud booms due to near-sonic lateral ejection velocity of air and dust, and precedence of the crush-down collapse mode before the crush-up. Nevertheless, different degrees of ductility, fracturing and end support flexibility of WTC columns could lead to an equally good match of these observations and remained uncertain, due to lack of test data. Recently, Korol and Sivakumaran reported valuable experiments that allow clarifying this uncertainty. They revealed that, under the simplifying assumptions of rigid end supports and unlimited ductility (or no fracturing) of unheated columns, the energy dissipation of the WTC columns would have been at maximum 3.5-times as large as that calculated by the plastic hinge mechanism normally considered for small-deflection buckling. This increase would still allow close match of all the aforementioned observations except for the first two seconds of the video. The proper conclusion from Korol and Sivakumaran’s tests, based on close matching of the video record, is that the fracturing of unheated columns and the flexibility of their end restraints must have significantly reduced the energy dissipation in columns calculated under the assumptions of no fracture and no end restraint flexibility.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-10-23T07:43:58Z
      DOI: 10.1142/S0219455417710110
       
  • Nonlinear Dynamic Thermal Buckling of Sandwich Spherical and Conical
           Shells with CNT Reinforced Facesheets
    • Authors: A. Sankar, S. Natarajan, T. Merzouki, M. Ganapathi
      Abstract: International Journal of Structural Stability and Dynamics, Volume 17, Issue 09, November 2017.
      Owing to their superior mechanical and thermal properties, carbon nanotube (CNT) reinforced composite materials have wide range of applications in various technical areas such as aerospace, automobile, chemical, structural and energy. In this paper, the nonlinear axisymmetric dynamic behavior of sandwich spherical and conical shells made up of CNT reinforced facesheets is studied. The shell is subjected to thermal loads and discretized with three-noded axisymmetric curved shell element based on field consistency approach. The in-plane and the rotary inertia effects are included within the transverse shear deformation theory in the element formulation. The present model is validated with the available analytical solutions from the literature. A detailed parametric study is carried out to showcase the effects of the shell geometry, the volume fraction of the CNT, the core-to-face sheet thickness and the environment temperature on the dynamic buckling thermal load of spherical caps.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-10-23T07:43:53Z
      DOI: 10.1142/S0219455417501000
       
  • Vibration and Stability Analysis of DWCNT-Based Spinning Nanobearings
    • Authors: Rohollah Dehghani Firouz-Abadi, Hassan Mohammad-Khani, Mohammad Rahmanian
      Abstract: International Journal of Structural Stability and Dynamics, Volume 17, Issue 09, November 2017.
      This paper aims at investigating free vibrations and stability of double-walled carbon nanotube (DWCNT)-based spinning nanobearings. The so-called nanobearing consists of two coaxial carbon nanotubes (CNTs) where either of the two CNTs can be a rotor while the other takes the role of stator. Euler–Bernoulli beam model along with the Eringen’s nonlocal theory of elasticity are employed to obtain governing equations of transverse vibrations for the CNTs. The coupling of the two CNTs originates from the van-der-Waals (vdW) forcing present in the interface of the two CNTs. The coupling is taken into account as distributed spring foundation with an equivalent elastic stiffness. Based on the obtained model, effects of small-scale parameter, vdW interaction between CNTs and the diameter ratio of CNTs on the critical spinning speed are investigated. Finally, the stability margins of the nanobearings are determined and some general conclusions are drawn.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-10-23T07:43:51Z
      DOI: 10.1142/S0219455417501024
       
  • Derailment and Dynamic Analysis of Tilting Railway Vehicles Moving Over
           Irregular Tracks Under Environment Forces
    • Authors: Yung-Chang Cheng, Chern-Hwa Chen, Chin-Te Hsu
      Abstract: International Journal of Structural Stability and Dynamics, Volume 17, Issue 09, November 2017.
      Utilizing a nonlinear creep model, the dynamic behavior of tilting railway vehicles moving over curved tracks with rail irregularities and under earthquakes and wind loads is studied. The car model adopted consists of 28 degrees of freedom, capable of simulating the lateral, vertical, roll and yaw motions for the wheelsets, truck frames and car body. The derailment quotient is investigated to analyze the running safety of a tilting railway vehicle using the linear and nonlinear creep models, while considering the rail irregularities and environmental forces for various tilting angles. Generally, the derailment risk of the tilting railway vehicle is higher than that of non-tilting railway vehicle with or without rail irregularities and environmental forces. The derailment quotients calculated by the linear creep model are underestimated for a tilting railway vehicle. In addition, the derailment quotients evaluated for rough rails and under environmental forces are higher than those obtained for smooth rails with no environmental forces. It is confirmed that rail irregularities and each type of environmental forces have decisive effects on derailment quotients. They are compared and ranked according to their significance.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-10-23T07:43:43Z
      DOI: 10.1142/S0219455417500985
       
  • Inelastic Buckling of FGM Cylindrical Shells Subjected to Combined Axial
           and Torsional Loads
    • Authors: Huaiwei Huang, Yongqiang Zhang, Qiang Han
      Abstract: International Journal of Structural Stability and Dynamics, Volume 17, Issue 09, November 2017.
      A semi-analytical procedure is presented to solve the elastoplastic buckling problem of cylindrical shells made of functionally groded materials (FGMs) under combined axial and torsional loads. The elastoplastic properties are assumed to vary smoothly according to the power law distribution rule, introduced in the J2 deformation theory for formulation of the constitutive relation of FGMs in the framework of the Tamura–Tomota–Ozawa (TTO) model, which is a volume fraction-based material model. The critical condition is deduced by the Ritz method. Assuming the uniform prebuckling strain, a biaxial stress state analysis is conducted to determine the analytical position of the elastoplastic interface, which is used in the integration of the elastoplastic internal force and all the material-related structural parameters. Finally, an iterative procedure is adopted to find the exact elastoplastic critical load. Numerical results indicate the effects of the inhomogeneous parameter and the elastoplastic material properties of their constituents on the stability region and plastic flow region of the materials.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-10-23T07:43:41Z
      DOI: 10.1142/S0219455417710109
       
  • Modeling of Longitudinal Human Walking Force Using Self-Sustained
           Oscillator
    • Authors: Prakash Kumar, Anil Kumar, Vitomir Racic
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The paper proposes a self-sustained single-degree-of-freedom oscillator to accurately generate the longitudinal contact force between a pedestrian’s feet and the supporting flat rigid surface. The model is motivated from the self-sustained nature of pedestrian walking, i.e. a pedestrian produces the required internal energy to maintain a repetitive body motion. It is derived by adding two nonlinear terms to the conventional Rayleigh oscillator to yield odd as well as even harmonics, as observed in experimentally recorded longitudinal force data. For the dynamic analysis of the oscillator, two methods are adopted: the energy balance method and the Lindstedt–Poincare perturbation technique. Moreover, the least-squares identification procedure is used to identify values of the oscillator parameters from the force records of 12 different pedestrians walking on an instrumented treadmill at 10 walking speeds. The results generated by the proposed oscillator agree well with the experimental data.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-11-10T02:43:11Z
      DOI: 10.1142/S0219455418500803
       
  • A Multi-Scale Wavelet Finite Element Model for Damage Detection of Beams
           Under a Moving Load
    • Authors: Wen-Yu He, Songye Zhu, Zhi-Wei Chen
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The resolution of structural finite element model (FEM) determines the computation cost and accuracy in dynamic analysis. This study proposes a novel wavelet finite element model (WFEM), which facilitates adaptive mesh refinement, for the dynamic analysis and damage detection of beam structures subjected to a moving load (ML). The multi-scale equations of motion for the beam under the ML are derived using the second-generation cubic Hermite multi-wavelets as the shape functions. Then an adaptive-scale analysis strategy is established, in which the scales of the wavelet beam elements are dynamically changed according to the ML position. The performance of the multi-scale WFEM is examined in both dynamic analysis and damage detection problems. It is demonstrated that the multi-scale WFEM with a similar number of degrees of freedom can achieve much higher accuracy than the traditional FEM. In particular, the multi-scale WFEM enables the detection of sub-element damage with a progressive model updating process. The advantage in computation efficiency and accuracy makes the proposed method a promising tool for multi-scale dynamic analysis or damage detection of structures.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-11-10T02:43:10Z
      DOI: 10.1142/S0219455418500785
       
  • Buckling Analysis of Laminated Composite Plate on Tensionless Elastic
           Foundations Under Uniaxial Compression
    • Authors: Jianghui Dong, Xing Ma, Yan Zhuge, Julie E. Mills
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper addresses the compressive local buckling behavior of an infinitely long laminated composite plate resting on a tensionless elastic foundation (Winkler foundation). The analytical solution to the contact buckling coefficient of a laminated composite plate is derived using a one-dimensional analytical method. Numerical examples are considered to investigate the influence of the ply angle and foundation stiffness on the contact buckling coefficients of laminated composite plates under uniaxial compression. The lateral boundary conditions including clamped and simply-supported edges are treated. Finally, finite element (FE) analysis is conducted to provide an independent check on the analytical solutions.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-11-10T02:43:08Z
      DOI: 10.1142/S0219455418500797
       
  • Modified Harmonic Balance Method for Nonlinear Aeroelastic Analysis of Two
           Degree-of-Freedom Airfoils in Supersonic Flow
    • Authors: Niu Yaobin, Wang Zhongwei
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In this paper, a new modified harmonic balance method is presented for the nonlinear aeroelastic analysis of two degree-of-freedom airfoils. Using this method, the nonlinear problem is first translated into a minimization problem, and the Particle Swarm Optimization which has high calculation efficiency is adopted to solve the problem. The proposed method is used to solve the nonlinear aeroelastic behavior of supersonic airfoil, with the unsteady aerodynamic load evaluated by the piston theory. Three examples of nonlinear aeroelasticity with significantly different coefficients are prepared, in which the frequencies and amplitudes of the limit cycles are obtained. The results show that the present current method is computationally more efficient.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-11-07T09:20:47Z
      DOI: 10.1142/S0219455418710062
       
  • Free Vibration of MDOF Systems with Nonperiodically Time-Varying Mass
    • Authors: Seyed Mojtaba Hozhabrossadati, Ahmad Aftabi Sani
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper deals with the free vibration response of MDOF mass-spring systems with time-variable mass and constant stiffness. To show the necessity of this study, a review on the related published articles is presented. After formulating the governing initial value problem which is a coupled system of differential equations with variable coefficients, the differential transform method (DTM) is employed to obtain an analytical solution. The proposed solutions are verified against exact results available in the literature. It is demonstrated that the effect of time-variable mass is equivalent to viscous damping. This viscous damping can be positive or negative depending on the sign of the mass change rate. This role is thoroughly investigated via numerical examples.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-10-26T04:01:08Z
      DOI: 10.1142/S0219455418500773
       
  • Impact Response of Flying Objects Modeled by Positional Finite Element
           Method
    • Authors: João Paulo de Barros Cavalcante, Daniel Nelson Maciel, Marcelo Greco
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper analyzes the dynamic response of space and plane trusses with geometrical and material nonlinear behaviors using different time integration algorithms, considering an alternative Finite Element Method (FEM) formulation called positional FEM. Each algorithm is distinguished from each other by its specific form of position, velocity, acceleration and equilibrium equation concerning the stability, consistency, accuracy and efficiency of solution. Particularly, the impact problems against rigid walls are analyzed considering Null-Penetration Condition. This formulation is based on the minimum potential energy theorem written according to the nodal positions, instead of the structural displacements. It has the advantage of simplicity when compared with the classical counterparts, since it does not necessarily reply on the corotational axes. Moreover, the performance of each temporal integration algorithm is evaluated by numerical simulations.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-10-26T04:01:06Z
      DOI: 10.1142/S0219455418500761
       
  • A Simplified Method for Evaluating the Dynamic Properties of Structures
           Considering Soil–Pile–Structure Interaction
    • Authors: Hao-Yun Deng, Xin-Yang Jin, Ming Gu
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      A simplified method is presented for evaluating the dynamic properties of structures considering the effects of soil–pile–structure interaction (SPSI). A substructure method is used to establish the model of the soil–pile–structure system which is characterized by several dimensionless parameters. The shear-type structure is modeled as a generalized single-degree-of-freedom system using the virtual displacement principle, and the impedance functions of the floating pile-foundation are formulated by the thin-layer method. A number of coupled systems are analyzed and the results are used as the statistical base to obtain the mathematical relations between the dimensionless parameters and the dynamic properties. The dynamic properties solved by the equations are compared with those of the field experiment, shaking-table test and other analytical methods. The results indicated that the proposed equations are of high accuracy and can be used to obtain the dynamic properties of piles directly without performing complex analysis.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-10-17T09:23:19Z
      DOI: 10.1142/S0219455418710050
       
  • FBGs Real-Time Impact Damage Monitoring System of GFRP Beam Based on
           CC-LSL Algorithm
    • Authors: E. Vorathin, Z. M. Hafizi, S. A. Che Ghani, J. P. Siregar, K. S. Lim
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Glass-fiber reinforced polymer (GFRP) composite materials have an undisputed dominance over conventional metallic materials. However, susceptibility to barely visible or invisible internal damage due to impact has increased the demand for these composite materials in robust real-time structural health monitoring (SHM) system since they are capable of localizing the source of impact. Thus, in this paper, an in situ FBG sensor was embedded in a GFRP beam, providing an online real-time monitoring system and with the knowledge of cross-correlation linear source location (CC-LSL) algorithm, the impact location was capable of being determined in a split second. The consistency of cross-correlation function in providing repeatable results for all trials estimated a consistent time difference for all the impact points. The CC-LSL algorithm also revealed that the highest percentage of error was only 4.21% away from the actual hit. In the meantime, FBGs also showed good results as a dynamic strain measuring device in capturing frequency response at certain orientations compared to the AE sensor.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-10-17T09:23:18Z
      DOI: 10.1142/S021945541850075X
       
  • Simplified Approach Based on the Natural Period of Vibration for
           Considering Second-Order Effects on Reinforced Concrete Frames
    • Authors: Daniel G. Reis, Gustavo H. Siqueira, Luiz C. M. Vieira, Ronald D. Ziemian
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Recent studies have demonstrated the existence of a relationship between a structures susceptibility to second-order effects and its natural period of vibration ([math]) given that both these properties are fundamentally dependent on the structure stiffness and mass properties. The main advantage of the use of this characteristic is that [math] can be obtained easily by the existing structural analysis software. In this study, different formulations are developed in order to propose an amplification factor ([math]) to multiply first-order analysis results and satisfactorily obtain results of a second-order analysis. These formulations are based on D’Alembert’s principle, Rayleighs method, and the use of generalized coordinates to represent the dynamic displacement of flexible structures. It is observed that [math] provides values closer to and in fact, more conservatively than, those obtained by the conventional simplified methods currently used by structural design engineers. Thus, the amplification factor [math], which is based on the natural period of vibration, is proposed to be used as (i) an indicator of a structure susceptibility to second-order effects and (ii) an amplification factor to describe the second-order effects on reinforced concrete frames.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-10-11T07:48:59Z
      DOI: 10.1142/S0219455418500748
       
  • Passive Winglet Control of Flutter and Buffeting Responses of Suspension
           Bridges
    • Authors: Duc-Huynh Phan
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The passive control using winglets has been considered to be an alternative solution for control of flutter and buffeting responses of long suspension bridges. This method is aimed at not only developing lightweight, reduced-cost stiffening girders without adding stiffness for aerodynamic stability, but also avoiding problems from malfunctions caused by the control and energy supply systems of active control devices by winglets. This paper presented a mechanically controlled approach using the winglets, for which a two-dimensional bridge deck model was numerically and experimentally studied. In addition, numerical research on the flutter and buffeting passive control of a 3000[math]m span suspension bridge was carried out. The result showed that the flutter speed of the suspension bridge increases, whereas the buffeting response decreases, through the implementation of the winglets.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-10-11T07:48:58Z
      DOI: 10.1142/S0219455418500724
       
  • Isogeometric Stress, Vibration and Stability Analysis of In-Plane
           Laminated Composite Structures
    • Authors: S. Faroughi, E. Shafei, D. Schillinger
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      We present a computational study that develops isogeometric analysis based on higher-order smooth NURBS basis functions for the analysis of in-plane laminated composites. Focusing on the stress, vibration and stability analysis of angle-ply and cross-ply 2D structures, we compare the convergence of the strain energy error and selected stress components, eigen-frequencies and buckling loads according to overkill solutions. Our results clearly demonstrate that for in-plane laminated composite structures, isogeometric analysis is able to provide the same accuracy at a significantly reduced number of degrees of freedom with respect to standard [math] finite elements. In particular, we observe that the smoothness of spline basis functions enables high-quality stress solutions, which are superior to the ones obtained with conventional finite elements.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-10-11T07:48:56Z
      DOI: 10.1142/S0219455418500700
       
  • Dynamic Analysis of an Integrated Train–Bridge–Foundation–Soil
           System by the Substructure Method
    • Authors: Hong Qiao, He Xia, Xianting Du
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The substructure method is applied to the dynamic analysis of a train–bridge system considering the soil–structure interaction. With this method, the integrated train–bridge–foundation–soil system is divided into the train–bridge subsystem and the soil–foundation subsystem. Further, the train–bridge subsystem is divided into the train and bridge components. The frequency-dependent impedance function of the soil–foundation subsystem is transformed into time domain by rational approximation and simulated by a high-order lumped-parameter model with masses. The equations of motion of the train and bridge components are established by the rigid-body dynamics method and the modal superposition method, respectively. Finally, the dynamic responses of the two subsystems are obtained by iterative procedures, with the influence of the soil shear velocity studied. The case study reveals that it is important to consider the effect of soil–foundation interaction in the dynamic analysis of train–bridge systems, but with the increase of the shear velocity of the soil, such influence becomes weaker.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-10-11T07:48:54Z
      DOI: 10.1142/S0219455418500694
       
  • Contact-Point Response for Modal Identification of Bridges by a Moving
           Test Vehicle
    • Authors: Y. B. Yang, Bin Zhang, Yao Qian, Yuntian Wu
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The response of the contact point of the vehicle with the bridge, rather than the vehicle itself, is proposed for modal identification of bridges by a moving test vehicle. To begin, approximate closed-form solutions were derived for the vehicle and contact-point responses, and they were verified by finite element solutions. The contact-point acceleration is born to be free of the vehicle frequency, an annoying effect that may overshadow the bridge frequencies in case of rough surface. From the frequency response function (FRF) of the vehicle with respect to the contact point, it was shown that the contact-point response generally outperforms the vehicle response in extracting the bridge frequencies because it could identify more frequencies. In the numerical simulations, the contact-point response was compared with the vehicle response for various scenarios. It is concluded that in each case, say, for varying vehicle speeds or frequencies, for smooth or rough road surfaces, with or without existing traffic, the contact-point response outperforms the vehicle response in extracting either the frequencies or mode shapes of the bridge.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-10-11T07:48:54Z
      DOI: 10.1142/S0219455418500736
       
  • GBT-Based Vibration Analysis Using the Exact Element Method
    • Authors: Rui Bebiano, Moshe Eisenberger, Dinar Camotim, Rodrigo Gonçalves
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Generalized Beam Theory (GBT), intended to analyze the structural behavior of prismatic thin-walled members and structural systems, expresses the member deformed configuration as a combination of cross-section deformation modes multiplied by the corresponding longitudinal amplitude functions. The determination of the latter, often the most computer-intensive step of the analysis, is almost always performed by means of GBT-based “conventional” 1D (beam) finite elements. This paper presents the formulation, implementation and application of the so-called “exact element method” in the framework of GBT-based elastic free vibration analyses. This technique, originally proposed by Eisenberger (1990), uses the power series method to solve the governing differential equations and obtains the vibration eigenvalue problem from the boundary terms. A few illustrative numerical examples are presented, focusing mainly on the comparison between the combined accuracy and computational effort associated with the determination of vibration solutions with the exact and conventional GBT-based (finite) elements. This comparison shows that the GBT-based exact element method may lead to significant computational savings, particularly when the vibration modes exhibit large half-wave numbers.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-10-11T07:48:53Z
      DOI: 10.1142/S0219455418500682
       
  • Vibration Analysis of Third-Order Shear Deformable FGM Beams with Elastic
           Support by Chebyshev Collocation Method
    • Authors: Nuttawit Wattanasakulpong, Tinh Quoc Bui
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In this paper, we present new results of natural frequencies for the functionally graded beams based on Chebyshev collocation method and the third-order shear deformation theory (TSDT), without requiring any shear correction factors. The beams are assumed to be elastically supported by translational and rotational springs, or simply known as elastically restrained ends. The material compositions of the beams across the gradient direction are described by different mathematical models including the simple power law, exponential and Mori–Tanaka models, and their effects on the response of beams are analyzed. We first present the Chebyshev collocation formulation of the coupled differential equations of motion for free vibration of FGM beams considering different boundary conditions, and then verify the results obtained by the proposed approach against reference ones. A parametric study is also performed for parameters such as thickness, spring constant factor, material volume fraction index, etc. The present numerical results reveal that the proposed method can offer accurate frequency results for the FGM beams as compared with those available in the literature. The results also indicate that the spring constant factors have a significant effect on the frequencies of the beams.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-10-11T07:48:53Z
      DOI: 10.1142/S0219455418500712
       
  • Subspace Flexibility Identification Adaptive to Different Types of Input
           Forces
    • Authors: P. J. Li, Q. Xia, J. Zhang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Impact testing is an effective means of identifying structural flexibility. However, most flexibility identification methods have strict requirements on the type of input forces. For instance, methods operated in the frequency domain may generate incorrect flexibility identification results when double or multiple clicks occur in an impact test. This article proposes a method to estimate the structural modal scaling coefficients and flexibility characteristics using a subspace identification algorithm in the time domain. The advantage of the proposed method is that it adapts to the input force type and thus has the potential to be widely used in engineering practice. Numerical and experimental examples are presented to illustrate the effectiveness and robustness of the proposed method.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-10-06T01:52:38Z
      DOI: 10.1142/S0219455418500670
       
  • Element-Independent Pure Deformational and Co-Rotational Methods for
           Triangular Shell Elements in Geometrically Nonlinear Analysis
    • Authors: Y. Q. Tang, Y. P. Liu, S. L. Chan
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Proposed herein is a novel pure deformational method for triangular shell elements that can decrease the element quantities and simplify the element formulation. This approach has computational advantages over the conventional finite element method for linear and nonlinear problems. In the element level, this method saves time for computing stresses, internal forces and stiffness matrices. A flat shell element is formed by a membrane element and a plate element, so that the pure deformational membrane and plate elements are derived and discussed separately in this paper. Also, it is very convenient to incorporate the proposed pure deformational method into the element-independent co-rotational (EICR) framework for geometrically nonlinear analysis. Thus, on the basis of the pure deformational method, a novel EICR formulation is proposed which is simpler and has more clear physical characteristics than the traditional formulation. In addition, a triangular membrane element with drilling rotations and the discrete Kirchhoff triangular plate element are used to verify the proposed pure deformational method, although several benchmark problems are employed to verify the robustness and accuracy of the proposed EICR formulations.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-10-06T01:52:37Z
      DOI: 10.1142/S0219455418500657
       
  • Dynamic Response of a Nonuniform Timoshenko Beam with Elastic Supports,
           Subjected to a Moving Spring-Mass System
    • Authors: Guojin Tan, Wensheng Wang, Yongchun Cheng, Haibin Wei, Zhigang Wei, Hanbing Liu
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper is concerned with the dynamic response of a nonuniform Timoshenko beam with elastic supports subjected to a moving spring-mass system. The modal orthogonality of nonuniform Timoshenko beams and the corresponding overall matrix of undetermined coefficients are derived. Then the natural frequencies and mode shapes of nonuniform Timoshenko beams are obtained by the Runge–Kutta method and cubic spline interpolation method. By using the Newmark-[math] method and the mode summation method, the vibration equation of Timoshenko beams subjected to a moving spring-mass system was established. A comparison of results between the proposed method and finite element method reveals that this method possesses favorable accuracy for dynamic response analysis. In numerical examples, the effects of the support spring and moving spring-mass system on Timoshenko beams have been examined in detail.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-09-26T03:21:38Z
      DOI: 10.1142/S0219455418500669
       
  • Feedback Control for Structural Health Monitoring in a Smart Aggregate
           Based Sensor Network
    • Authors: Jian Chen, Peng Li, Gangbing Song, Zhang Ren, Yu Tan, Yongjun Zheng
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The concept of smart aggregates, a distributed intelligent multi-purpose sensor network for civil structures, has been implemented to address three important issues including early-age concrete strength monitoring, impact detection and evaluation, and structural health monitoring. This paper presents mainly the employment of smart aggregates’ active sensing property to form feedback in a sensor network to reduce damage-location detection time for lower power cost. Firstly, the concept of smart aggregates and the principle of a smart-aggregate-based sensor network are outlined. Next, the data pretreatment methods, including the sensor observation estimation model and the wavelet-packet-based signal processing algorithm, are proposed. A crucial concept using the damage index is also introduced. Moreover, the concept of the geometry structure matching method with the knowledge of an expert system is presented to determine which sensor is the optimal actuator. Finally, the data pretreatment algorithm and the geometry structure matching method are evaluated for a two-story concrete frame instrumented with smart aggregates as a testing object by means of actual experiments. The testing results demonstrate that the proposed algorithms are feasible and perform well in selecting optimal actuators of the sensor network for detecting damage locations.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-09-26T03:21:37Z
      DOI: 10.1142/S0219455418500645
       
  • Soft Computing Based Force Recovery Technique for Hypersonic Shock Tunnel
           Tests
    • Authors: Ramesh Babu Pallekonda, Soumya Ranjan Nanda, Santosha K. Dwivedy, Vinayak Kulkarni, Viren Menezes
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      A hemispherical model equipped with a three component accelerometer force balance has been tested in a shock tunnel at Mach 8.0 freestream conditions. A novel technique has been devised using the Artificial Neuro-Fuzzy Inference System (ANFIS) for recovering the forces experienced by the model during the experiments. Implementation of this methodology in calibration of the force balance showed encouraging agreement with the impulse forces recovered from the calibration tests. The same recovery procedure is then adopted to obtain the time history of the forces for 0[math] and 15[math] angle of attack experiments. The drag recovered in steady state is found to agree well with the conventional methods with minor discrimination for the lift and pitching moment. In light of the limitation of the accelerometer force balance theory due to the unaccountability of model dynamics, the force recovery technique proposed herein is found simple to implement and can be opted as a tool for prediction of the aerodynamic coefficients and force time histories.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-09-26T03:21:37Z
      DOI: 10.1142/S0219455418710049
       
  • Nonlinear Characteristics Analysis of a Rotor-Bearing-Brush Seal System
    • Authors: Yuan Wei, Zhaobo Chen, Earl H. Dowell
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The vibration response and nonlinear dynamic behavior of a rotor-bearing-brush seal system were investigated with a new seal force model of the brush seal. The nonlinear oil–film force model was adopted based on a short bearing assumption. The dimensionless equation of motion was solved using the fourth order Runge–Kutta method. The effects of key parameters including rotor speed, installation spacing of the brush seal, disk eccentricity, disk mass, and journal mass on the nonlinear dynamic characteristics of rotor-bearing-brush seal system were determined and compared under different operating conditions with a bifurcation diagram, time history, axis orbit, poincaré map, frequency spectrum, and spectrum cascade. The results showed that the system response contained various nonlinear phenomena, such as periodic motion, multi-periodic motion, and quasi-periodic motion. The interaction of the rotor speed, installation spacing of the brush seal, disk eccentricity, disk mass, and journal mass could seriously affect the stability and working condition of the system. This study provides a theoretical support for the selection of key design parameters and further understanding of the nonlinear characteristics of rotor-bearing-seal systems with a brush seal.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-09-26T03:21:36Z
      DOI: 10.1142/S0219455418500633
       
  • Buckling and Free Vibration of a Single Pile Considering the Effect of
           Soil–Structure Interaction
    • Authors: Jianjun Ma, Fengjun Liu, Xiaojuan Gao, Mengqiang Nie
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The buckling response and free vibration characteristics of a single pile in the elastic foundation are investigated. Considering the effect of soil–structure interaction and geometric nonlinearity, the nonlinear equation of motion for a single pile is derived by Hamilton’s principle. Then, closed-form solutions of the critical load and buckled configuration of the pile are obtained analytically, and the natural frequencies of the pre- and post-buckling pile are examined. Finally, the effect of elastic foundation parameter on the critical load of the pile is discussed, and the effect of axial load on the natural frequencies of the pile is also explored. Numerical results show that the effect of elastic foundation parameter plays a dominant role on the critical load and buckled configuration of the pile, and the shear parameter affects the critical load directly. The axial load effect on the dynamic characteristics of the pre-buckling pile is significant, meanwhile, it may contribute very small to the post-buckling pile when the axial load exceeds some specific values.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-09-14T08:15:07Z
      DOI: 10.1142/S021945541850061X
       
  • Probabilistic Solutions of the In-Plane Nonlinear Random Vibrations of
           Shallow Cables Under Filtered Gaussian White Noise
    • Authors: G. K. Er, K. Wang, V. P. Iu
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The probabilistic solutions of the responses of shallow cable are studied when the cable is excited by filtered Gaussian white noise. The nonlinear multi-degree-of-freedom system is formulated which governs the random vibration of cable. The state-space-split (SSS) method and exponential polynomial closure (EPC) method are adopted to analyze the probabilistic solutions of cable systems in order to study the effectiveness and computational efficiency of SSS-EPC procedure in analyzing the probabilistic solutions of the cable systems under the excitation of filtered Gaussian white noise. Numerical results obtained by SSS-EPC method, Monte Carlo simulation, and equivalent linearization method are compared to examine the computational efficiency and numerical accuracy of SSS-EPC method in this case. Thereafter, the behaviors of probabilistic solutions of the cable systems are studied with different values of peak frequency and seismic intensity of excitation when the cable is excited by Kanai–Tajimi seismic force. Some observations and discussions are given by introducing a probabilistic quantity to show the influence of excitations on the probabilistic solutions.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-09-14T08:15:06Z
      DOI: 10.1142/S0219455418500621
       
  • Buckling Behavior of Non-Uniformly Heated Tapered Laminated Composite
           Plates with Ply Drop-Off
    • Authors: Shushanth Ashok, Jeyaraj Pitchaimani
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The thermal buckling characteristics of non-uniformly heated tapered laminated composites plates with ply drop-off have been investigated numerically. Detailed parametric studies have been carried out for the effects of taper configuration, temperature variation, aspect ratio and structural boundary conditions on critical buckling temperatures and buckling mode shapes. It is found that the nature of taper as well as the applied temperature field have considerable effects on the critical buckling temperatures of laminated composite tapered plates. Square plates buckle at the highest temperature when subjected to the decreasing temperature profile. Additionally, it is noted that Taper B and Taper C plates show the best behavior under buckling for most structural boundary conditions. Moreover, the change in buckling mode shapes with respect to temperature profile and taper configuration is significant for rectangular plates in comparison with square plates.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-09-14T08:15:05Z
      DOI: 10.1142/S0219455418500591
       
  • Wave Propagation Analysis of Piezoelectric Nanoplates Based on the
           Nonlocal Theory
    • Authors: Li-Hong Ma, Liao-Liang Ke, Yi-Ze Wang, Yue-Sheng Wang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Based on the nonlocal theory, this paper develops the Kirchhoff nanoplate and Mindlin nanoplate models for the wave propagation analysis of piezoelectric nanoplates. The effects of small scale parameter and thermo-electro-mechanical loads are incorporated in the nanoplate models. The Hamilton’s principle is employed to derive the governing equations of the nanoplate, which are solved analytically to obtain the dispersion relation for piezoelectric nanoplates. The results show that the nonlocal parameter, temperature change, mechanical load and external electric potential have significant influence on the wave propagation characteristics of the piezoelectric nanoplates. The cut-off wave number is observed to exist for piezoelectric nanoplates subjected to positive electric potential, axial tensile force and temperature rise.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-09-11T07:51:55Z
      DOI: 10.1142/S0219455418500608
       
  • Longitudinal Vibration and Its Suppression of a Railway Cable-Stayed
           Bridge Under Vehicular Loads
    • Authors: Long Lu, Jianzhong Li
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The paper is aimed at investigating the longitudinal vibration and vibration reduction of a cable-stayed bridge under vehicular loads with emphasis on the longitudinal resonance. To investigate the phenomenon of longitudinal resonant vibration, the equivalent longitudinal excitation for the bridge deck due to moving vertical loads is approximately expressed as longitudinal loads with a sine-wave form. A formula for estimating the longitudinal resonant speed of the cable-stayed bridge is developed. A long-span cable-stayed railway bridge is considered in the case study to calculate the longitudinal response of the bridge under moving loads at different speeds. The numerical results indicate that the longitudinal resonance for the cable-stayed bridge occurs when the speeds of the moving loads approach the resonant speed predicted by the analytical formula. A fluid viscous damper (FVD) is employed to reduce the longitudinal vibration of the bridge under moving loads. The results show that the longitudinal resonant responses of the cable-stayed bridge can be effectively mitigated by the FVD adopted.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-09-08T10:01:15Z
      DOI: 10.1142/S0219455418500529
       
  • Enhanced Sensitivity for Structural Damage Detection Using Incomplete
           Modal Data
    • Authors: Akbar Esfandiari, Maryam Vahedi
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The necessity of detecting structural damages in an early stage has led to the development of various procedures for structural model updating. In this regard, sensitivity-based model updating methods utilizing mode shape data are known as effective tools. For this purpose, accurate estimation of the mode shape changes is desired to achieve successful model updating. In this paper, Wang’s method is improved by including measured natural frequencies of the damaged structure in derivation of the sensitivity equation. The sensitivity equation is then solved using an incomplete subset of mode shape data in evaluation of the changes of the structural parameters. A comparative study of the results obtained by the proposed method with those by the modal method for a truss and a frame model indicated that the former is significantly more effective for damage detection than the latter. Furthermore, the capability of the proposed method for model updating in the presence of measurement and mass modeling errors is investigated.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-08-29T06:40:23Z
      DOI: 10.1142/S0219455418500542
       
  • Effect of Reinforced Cutouts and Ply-Orientations on Buckling Behavior of
           Composite Panels Subjected to Non-Uniform Edge Loads
    • Authors: T. Rajanna, Sauvik Banerjee, Yogesh M. Desai, D. L. Prabhakara
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Buckling loads of laminated panels calculated by analytical approaches are usually based on the assumptions that the panels are subjected to uniform in-plane edge loads without cutouts, despite of the fact that real structural components are subjected to various kinds of non-uniform in-plane edge loads along with different sized cutouts. The main objective of this paper is to study the effects of reinforced/unreinforced circular cutouts and non-uniform in-plane edge loads on the buckling behavior of composite panels with different ply-orientations by the finite element technique. Furthermore, it addresses the effects of different boundary conditions and thickness of panels. To carry out the analyses, a nine-noded heterosis plate element and a compatible three-noded beam element are developed, including the effect of shear deformation and rotary inertia for both the plate and the stiffeners. In structural modeling, the plate and the stiffener elements are treated separately, with their displacement compatibility maintained using transformation matrices. It has been illustrated in this study that presence of larger-sized reinforced cutouts predominantly increases the buckling strength of the panel as compared to those with smaller sized cutouts.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-08-29T06:40:22Z
      DOI: 10.1142/S021945541850058X
       
  • A New Analytical Approach for Free Vibration, Buckling and Forced
           Vibration of Rectangular Nanoplates Based on Nonlocal Elasticity Theory
    • Authors: Dalun Rong, Junhai Fan, C. W. Lim, Xinsheng Xu, Zhenhuan Zhou
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In this paper, an analytical Hamiltonian-based model for the dynamic analysis of rectangular nanoplates is proposed using the Kirchhoff plate theory and Eringen’s nonlocal theory. In a symplectic space, the dynamic problem is reduced to solving a unified Hamiltonian dual equation formed by a total unknown vector consisting of displacements, rotation angles, bending moments and generalized shear forces. The exact solutions for free vibration, buckling and steady state forced vibration are established by the eigenvalue analysis and expansion of eigenfunction without any trial functions. In addition, the explicit expressions of the characteristic equations, mode functions and steady state response of the nanoplate with two opposite edges that are simply supported or guided supported are obtained. To verify the accuracy and reliability of the present method, numerical results are compared with published solutions and excellent agreement is obtained. Comprehensive benchmark results that consider the nonlocal effect on the dynamic behaviors of rectangular nanoplates are also presented in dimensionless tabular and graphical forms.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-08-29T06:40:21Z
      DOI: 10.1142/S0219455418500554
       
  • Two-Mass Vehicle Model for Extracting Bridge Frequencies
    • Authors: Judy P. Yang, Bo-How Chen
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The dynamic response of a moving vehicle has been utilized to extract the frequencies of the supporting bridge. In most previous studies, the vehicle was modeled as a single-degree-of-freedom sprung mass moving over a simple beam, which suffers from the drawback that the sprung mass may be affected by the vehicle motion. To overcome this drawback, this paper presents a two-mass vehicle model for extracting the bridge frequencies, which contains a sprung mass (vehicle body) and an unsprung mass (axle mass). By using the response of the unsprung mass, the bridge response can be more realistically extracted. The main findings of the present study are as follows: (1) the use of unsprung mass in the vehicle model can faithfully reveal the dynamic responses of both the vehicle and bridge, (2) the increase in the unsprung mass can effectively help the extraction of bridge frequencies, including the second frequency, (3) under high levels of road roughness, the proposed model can identify the bridge frequencies, while the single-mass model cannot, and (4) in the presence of vehicle damping, the proposed model can identify the bridge frequencies under high levels of road roughness without additional techniques of processing.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-08-24T08:52:22Z
      DOI: 10.1142/S0219455418500566
       
  • Critical Buckling of Prestress-Stable Tensegrity Structures Solved by
           Real-Coded Genetic Algorithm
    • Authors: Pei Zhang, Jian Feng
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Tensegrity structures are classified as kinematically determinate ones with two subcases and kinematically indeterminate ones with three subcases in view of their respective stability properties. How the stiffness of a tensegrity structure changes as the level of prestress changes is explored for different scenarios using six carefully chosen samples. For a tensegrity structure merely satisfying the prestress-stability condition, a new optimization model is presented to determine its critical buckling state corresponding to zero stiffness. A real-coded genetic algorithm (RCGA) is then developed to solve this problem, featured by the fact that a special sign-control technique is embedded in the fundamental genetic operations, making the individuals generated in each step fall into the admissible region automatically. The stability of the neutral equilibrium state for tensegrity structures violating the prestress-stability condition is also discussed. Several numerical examples are tested to validate the efficiency of the present approach.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-08-24T08:52:20Z
      DOI: 10.1142/S0219455418500487
       
  • Constrained-Energy Dynamic Cross-Well Motion of Bistable Structures
           Subjected to Noise Disturbance
    • Authors: Masoud Zarepoor, Onur Bilgen
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Bistable structures have two stable equilibrium positions and can be utilized to maintain a static shape with no energy consumption. This paper focuses on the minimum energy required for performing snap-through of a bistable structure subjected to noise disturbance. This paper uses the Duffing–Holmes equation as a one-degree-of-freedom representative model of a bistable structure. This equation is numerically solved to calculate the energy required for cross-well oscillation under different system and forcing conditions. The paper shows how the energy required for cross-well transfer varies as a function of damping ratio and frequency ratio at specific harmonic force amplitude when the system is externally disturbed with a band-limited noise signal. A magneto-elastic bistable beam is fabricated and tested to validate the used mathematical model. Various nondimensional parameters are used to highlight interesting phenomena. The relationships between signal-to-noise ratio (SNR), dynamic-to-static force ratio, and damping ratio to the response behavior are shown. It is found that the domain of low energy regions decreases by increasing the level of noise. Additionally, underactuated bistable and linear systems behave similarly for high levels of noise. This paper specifically identifies the critical force ratio, which allows for snap-through as a function of critical nondimensional system parameters.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-08-24T08:52:19Z
      DOI: 10.1142/S0219455418500475
       
  • Concrete Curved Box Girders Interacted with Vehicles in Braking or
           Acceleration
    • Authors: Xinyi Huang, Chung C. Fu, Weidong Zhuo, Quanzhe Yan, Ying Sun
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In this study, an experimentally validated spatial analysis method for the vehicle–bridge interaction system was modified to include the features of vehicle braking and accelerating. The effect of braking or accelerating was considered as external force acting on the vehicular center of gravity and was quasi-statically distributed to every tandem, for which the formulae of load redistribution were derived. The effect of centrifugal force was also incorporated in the model. Based on the modified spatial analysis method, the dynamic responses of a three-span continuous concrete box girder bridge due to vehicle braking and accelerating were studied. Impact factors, including deflection, bending moment, torsional moment and shear force, were examined. The results show that vehicle braking has considerable effect on dynamic responses and the impact factors are related to braking rise time and braking position, but cases of vehicle braking do not always cause larger effects. While the increase in initial speed can produce higher maximum dynamic responses and corresponding impact factors, the dynamic responses in the first span of a multi-span bridge are smaller than those in other spans due to vehicle accelerating.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-08-24T08:52:19Z
      DOI: 10.1142/S0219455418500530
       
  • Delamination of Multilayered Functionally Graded Beams with Material
           Nonlinearity
    • Authors: V. Rizov
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Delamination fracture in multilayered functionally graded, split cantilever beams is analyzed with account taken of the nonlinear behavior of the material. The fracture is studied analytically in terms of the strain energy release rate. The mechanical behavior of the material is described by a power-law stress–strain relation that is not symmetric for tension and compression. The beam can have an arbitrary number of vertical layers of different thickness. Each layer can have different material properties. Besides, the material in each layer is functionally graded along the layer thickness. Also, the delamination fracture can occur at any interface. The strain energy release rate is derived by analyzing the complementary strain energy of the beam. The solution obtained is applied to elucidating the effects of crack location, material gradient and material nonlinearity on the delamination fracture behavior of multilayered functionally graded beam configuration. It is found that the material nonlinearity leads to increase of the strain energy release rate, which implies that the material nonlinearity should be taken into account in the fracture mechanics based safety design of multilayered functionally graded structural members and components.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-08-24T08:52:18Z
      DOI: 10.1142/S0219455418500517
       
  • Nonlinear Vibration of Size Dependent Microresonators with an
           Electrostatically Actuated Proof Mass
    • Authors: Ehsan Sharifinsab, Mahdi Mojahedi
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In this paper, the dynamic and nonlinear vibration responses of a microresonator containing a microbridge with a proof mass located at its middle are studied. The proof mass of the microresonator is actuated by the electrostatic field in such a way that a direct voltage finds a certain equilibrium position and then be prompted to vibration under the alternative voltage. Due to the importance of the size dependency effect in analysis of the performance of microelectromechanical systems, the size dependent theory is used in the modeling of the microstructure. By adopting the modified couple stress theory and considering electrostatic actuation, the dynamic equation of motion is derived using the extended Hamilton’s principle. Further, with the approximation by Galerkin’s method, the governing equation for the static and oscillatory motion is reduced and the resultant equation is solved by analytical (multiple-scales) and numerical methods. In the analytical and numerical results, the effects of various parameters on the system response, including the midplane stretching and size dependent effects, and dependency of vibration response to initial conditions, are analyzed in detail.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-08-24T08:52:13Z
      DOI: 10.1142/S0219455418500578
       
  • Free Vibration and Buckling Analysis of Functionally Graded Plates Resting
           on Elastic Foundation Using Higher Order Theory
    • Authors: Smita Parida, Sukesh Chandra Mohanty
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper deals with the free vibration and buckling analysis of functionally graded material (FGM) plates, resting on the Winkler–Pasternak elastic foundation. The higher order shear deformation plate theory (HSPT) is adopted for the realistic variation of transverse displacement through the thickness, using the power law distribution to describe the variation of the material properties. Both the effects of shear deformation and rotary inertia are considered. In the present model, the plate is discretised into [math] eight noded serendipity quadratic elements with seven nodal degrees of freedom (DOFs). The validation study is carried out by comparing the calculated values with those given in the literature. The effects of various parameters like the Winkler and Pasternak modulus coefficients, volume fraction index, aspect ratio, thickness ratio and different boundary conditions on the behaviour of the FGM plates are studied.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-08-24T08:52:12Z
      DOI: 10.1142/S0219455418500499
       
  • Improved Performance-Based Plastic Design for RC Moment Resisting Frames:
           Development and a Comparative Case Study
    • Authors: Jiulin Bai, T. Y. Yang, Jinping Ou
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The performance-based plastic design (PBPD) method employs the global yield mechanism and target drift to design reinforced concrete moment resisting frames (RC-MRFs), which satisfies both the drift and strength limits without iterations. However, different structural systems have different hysteretic behaviors and the influence on the energy balance equation has not been dealt with in a quantitative manner. Moreover, the gravity loads are not considered in the plastic design procedure, which makes the beam design not within the safe margin for low and moderate seismic regions. In this paper, an improved PBPD method for RC-MRF is developed. Furthermore, a case study of seven-story RC-MRF is designed using both the improved PBPD and conventional equivalent static force design (ESFD) approaches. Comprehensive comparative analyses are performed in terms of nonlinear static pushover analysis, nonlinear dynamic analysis and seismic loss estimation. The results illustrate that the PBPD procedure can reduce the seismic losses. Hence, it is proved that PBPD is a viable and more robust design procedure as compared to the conventional ESFD procedure.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-08-23T07:53:30Z
      DOI: 10.1142/S0219455418500505
       
  • Fatigue Life Evaluation of Linear Structures with Uncertain-But-Bounded
           Parameters Under Stochastic Excitations
    • Authors: Ying Zhu, Yuji Tian
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This study presents two hybrid methods, the full combination method and the simplified expression, for evaluating the fatigue life of linear structures with uncertain-but-bounded parameters subjected to stochastic excitations. First, approximate expressions of the spectral moments and spectral bandwidth parameters are derived based on the improved interval analysis via extra unitary interval and the interval Taylor expansion. Then, the lower and upper bounds of the interval expected fatigue damage rate and fatigue life are evaluated by fully or properly combining the two bounds of the spectral moments and spectral bandwidth parameters by the Tovo–Benasciutti method. Through the numerical study, the full combination method is recommended for the accurate assessment of the interval fatigue life, and the simplified expression is recommended for rapid evaluation of the two bounds of the interval fatigue life using the explicit expression. Finally, three numerical examples are adopted to illustrate the accuracy and efficiency of the proposed methods via comparison of the present results with the exact ones.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-08-11T03:01:36Z
      DOI: 10.1142/S0219455418500451
       
  • Stability Analysis of Initially Curved Beams Mechanically Coupled in a
           Parallel Arrangement
    • Authors: Hassen M. Ouakad
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper investigates the stability behavior of a mechanically coupled bi-stable mechanism made of two parallel and initially curved microbeams with focus on the influence of the coupled beams’ initial curvatures on the system. First, the nonlinear and coupled force–displacement equation is derived. Then, a parametric study of the coupled beams system is studied with the system categorized into different structural compartment types according to the initial curvature of the coupled beams. It is concluded that the snap-through of such a coupled bi-stable system is governed by the beams’ initial curvatures difference. The simulation results showed that these two parameters (the beams’ initial curvatures) essentially govern the structural behavior of the coupled system in satisfying the necessary structural stability condition. It is found that the smallest (critical) value of the minimum force amplitude occurs only when both initial beams’ mid-point elevations are equal to each other. Furthermore, it is shown that any probability to increase or decrease the curvature of any beam will alter the nonlinear behavior of the coupled beam system from a simple regular snap-through to a constrained-snap-through, and even to the disappearance of the snap-through. Finally, a finite element method is conducted to investigate the stability of the coupled mechanism, of which the results show a good agreement with the analytical results of this paper.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-08-11T03:01:35Z
      DOI: 10.1142/S0219455418500414
       
  • New Explicit Integration Algorithms with Controllable Numerical
           Dissipation for Structural Dynamics
    • Authors: Xiaoqiong Du, Dixiong Yang, Jilei Zhou, Xiaoliang Yan, Yongliang Zhao, Shi Li
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper presents a new family of explicit time integration algorithms with controllable numerical dissipation for structural dynamic problems by utilizing the discrete control theory. Firstly, the equilibrium equation of the implicit Yu-[math] algorithm is adopted, and the recursive formulas of velocity and displacement for the explicit CR algorithm are used in the algorithms. Then, the transfer function and characteristic equation of the algorithms with integration coefficients are obtained by the [math] transformation. Furthermore, their integration coefficients are derived according to the poles condition. It was indicated that the proposed algorithms possess the advantages of second-order accuracy, self-starting, and unconditional stability for linear systems and nonlinear systems with softening stiffness. The numerical dissipation of the algorithms is controlled by the spectral radius at infinity [math]. It was also shown that the proposed algorithms have the same poles as the Yu-[math] algorithm, and thus the same numerical properties. Compared with the implicit Yu-[math] algorithm, the proposed algorithms are explicit in terms of both the displacement and velocity formulas. Finally, the effectiveness of the proposed algorithms in reducing the undesired participation of higher modes for solving the dynamic responses of linear and nonlinear systems has been demonstrated.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-08-11T03:01:34Z
      DOI: 10.1142/S021945541850044X
       
  • Hencky Bar-Net Model for Vibration of Rectangular Plates with Mixed
           Boundary Conditions and Point Supports
    • Authors: H. Zhang, Y. P. Zhang, C. M. Wang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper is concerned with the development of the Hencky bar-net model (HBM) for free vibration analyses of rectangular plates with mixed boundary conditions and point supports. The HBM is a two-dimensional discrete net system composed of rigid segments connected by frictionless hinges and rotational springs. In the model, bending is accommodated by rotational springs at each joint while the twisting by a diagonal spring system in each grid cell. The total mass of the plate is distributed as lumped mass at each joint and the continuous boundary stiffness of plate is simulated by springs located at the edge joints. Owing to the discrete property of HBM, it is able to readily handle any boundary conditions of plates including mixed boundary conditions and point supports. The HBM is herein used to solve some vibration problems of rectangular plates with mixed boundary conditions and point supports to demonstrate its accuracy and convenience for plate analyses.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-08-11T03:01:33Z
      DOI: 10.1142/S0219455418500463
       
  • A New Procedure for Nonlinear Dynamic Analysis of Structures Under Seismic
           Loading Based on Equivalent Nodal Secant Stiffness
    • Authors: Tzu-Ying Lee, Kun-Jun Chung, Hao Chang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper presents a dynamic analysis procedure for predicting the responses of large, highly nonlinear, discontinuous structural systems subjected to seismic loading. The concept of equivalent nodal secant stiffness is adopted to diagonalize the conventional stiffness matrix of the structure. With the lumped-mass idealization, the decoupled equilibrium equations of the structure are then solved by the implicit Newmark integration method. Additionally, an incremental-iterative procedure is performed to ensure that the equilibrium conditions are satisfied at the end of each time step. The proposed analysis procedure has the advantages of both the conventional explicit and implicit integration procedures, but with their disadvantages removed. Through extensive applications, the results demonstrate that the proposed procedure is simple and robust for analyzing practical structural systems in terms of computational efficiency and stability.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-08-03T08:03:33Z
      DOI: 10.1142/S0219455418500438
       
  • An Analytical Solution for Free Flexural Vibration of a Thin Cylindrical
           Shell Submerged in Acoustic Half-Space Bounded by a Free Surface
    • Authors: Peng Wang, Tian-Yun Li, Xiang Zhu, Wen-Jie Guo, Rui Nie
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      An analytical solution is proposed for the free flexural vibration of a finite cylindrical shell submerged in half-space bounded by a free surface in the low frequency range. The motion of the shell is described by the Flügge shell theory and the fluid surrounding the shell is assumed to be an acoustic media. The free surface effect is considered by satisfying the pressure release boundary condition. The accuracy of the present method is verified through comparison with the finite element solution. To throw light on the influence mechanism of free surface on the coupled modal frequencies, a modal added mass is introduced and calculated. Numerical results show that when the shell is close to the free surface, the presence of free surface will make a negative contribution to the modal added mass and finally result in the corresponding increase of the coupled modal frequencies. But the free surface effect will decrease when the immersion depth of the cylindrical shell increases. Finally, the free surface effect can be neglected if the immersion depth is higher than four times the shell radius. This conclusion is helpful to select proper test environment for an experiment on the dynamic characteristics of submerged cylindrical shells.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-07-31T07:49:40Z
      DOI: 10.1142/S0219455418500426
       
  • Buckling of Graphene Platelet Reinforced Composite Cylindrical Shell with
           Cutout
    • Authors: Yu Wang, Chuang Feng, Zhan Zhao, Jie Yang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper investigates the buckling behavior of graphene platelets (GPL) reinforced composite cylindrical shells with cutouts via finite element method (FEM) simulation. Young’s modulus of the composites is determined by the modified Halpin–Tsai micromechanics model while the mass density and Poisson’s ratio of the composites are approximated by the rule of mixture. Comprehensive parametric study is conducted to investigate the effects of the weight fraction and the shape of GPL fillers, the geometry of the shell and the position and orientation of the cutout on the buckling behaviors of the cylindrical structures. The results demonstrate that the addition of GPLs can significantly increase the load bearing capacity of the cylindrical shells. Larger sized GPLs with fewer single graphene layers are favorable reinforcing fillers in enhancing the buckling performances of the structures. The buckling load is sensitive to the location of the cutout with larger aspect ratio. Moreover, the orientation of the cutout is found to have significant effects on the buckling load when the orientation angle [math] is falling within the ranges – [math]/2 [math] – [math]/4 and [math]/4 [math]/2.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-07-20T05:45:00Z
      DOI: 10.1142/S0219455418500402
       
  • Dynamic Behavior of Transmission Tower-Line Systems Subjected to Insulator
           Breakage
    • Authors: Jia-Xiang Li, Hong-Nan Li, Xing Fu
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Ice loads attached to a transmission tower-line system can not only increase the vertical loads on the insulators, but also cause flashover to occur more easily. Both effects can lead to an increased probability of insulator breakage. In this paper, a finite-element model of a transmission tower-line system with three towers and four span lines under the ice loads is established. Dynamic analyses of the tower-line system after insulator breakage are performed to study the dynamic responses of the system and its failure process. In addition, a parametric analysis is conducted to investigate the influence of span length and insulator length on the vibration of the system and the failure mode. The results show that a larger ice load can lead to more severe vibration of the tower-line system due to the insulator breakage. Moreover, as the span length increases, the insulator breakage can result in more serious consequences and even the cascading collapse of the transmission tower-line system. This study provides crucial reference for preventing the failure of transmission tower-line systems in heavy ice regions.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-07-20T05:44:59Z
      DOI: 10.1142/S0219455418500360
       
  • Fast Frequency-Domain Algorithm for Estimating the Dynamic Wind-Induced
           Response of Large-Span Roofs Based on Cauchy’s Residue Theorem
    • Authors: Ning Su, Zhenggang Cao, Yue Wu
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Wind-induced response analysis is an important process in the design of large-span roofs. Conventional time-domain methods are computationally more expensive than frequency-domain algorithms; however, the latter are not as accurate because of the ill-treatment of the modal coupling effects. This paper revisited the derivations of the frequency-domain algorithm and proposed a fast algorithm for estimating the dynamic wind-induced response considering duly the modal coupling effects. With the wind load cross-spectra modeled by rational functions, closed-form solutions to the frequency-domain integrals can be calculated by Cauchy’s residue theorem, rather than by numerical integration, thereby reducing the truncation errors and enhancing the efficiency of computation. The algorithm is applied to the analysis of a grandstand roof and a spherical dome. Through comparison with time domain analyses results, the algorithm is proved to be reliable. A criterion of the coupling modal combination was suggested based on the cumulative modal contribution rate of over 70%.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-07-20T05:44:59Z
      DOI: 10.1142/S0219455418500372
       
  • An Approximate Analytical Formulation for the Rise-Time Effect on Dynamic
           Structural Response Under Column Loss
    • Authors: Meng-Hao Tsai
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Dynamic progressive collapse analysis of building structures is usually conducted under sudden column loss conditions. The time length required for disabling the failed column is defined as the rise time. The rise-time effect on the maximum dynamic response of building frames under column loss is investigated in this study. Based on the work-energy principle, an approximate analytical formulation for the maximum dynamic response is derived considering the rise-time effect. The force- and displacement-based dynamic increase factors (DIFs) of a single degree-of-freedom model and a clamped steel beam are used to assess the accuracy and validity of the proposed formulation. Analysis results indicate that the DIFs decrease with increased rise time. Also, the rise-time effect decreases with increased ductility demand. Practical application of the analytical formulation to regular building frames subjected to column loss is illustrated. Primary factors related to the extent of the rise-time effect on the column-loss response are identified for design consideration.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-07-20T05:44:58Z
      DOI: 10.1142/S0219455418500384
       
  • Bayesian Prediction of Structural Response Under Crowd-Induced Walking
           Load
    • Authors: Lu Dai, Na Yang, Qingshan Yang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Research on modeling the walking-induced dynamic load and its effects on structures has been increasing in recent years. Existing standards for estimating the acceleration response excited by crowd takes [math] ([math] is the number of walking persons in a crowd) times the single pedestrian load as the crowd load, neglecting uncertainties in the related parameters. This paper proposes a method for predicting the crowd-induced structural acceleration response based on the Bayesian theory. Parameters of the crowd include the distribution of stepping frequency, the interval of arriving time and the weight of pedestrians. By combining the existing methods for calculating the structural response to a pedestrian load and the Bayesian theory, the root-mean-square acceleration along with the crowd parameters are obtained. A field investigation is conducted to study the walking characteristics of pedestrians, including the distribution of stepping frequency, walking velocity and step length. The case of a crowd moving across a simply supported beam bridge is taken for illustration. The acceleration response under the crowd load with different stepping frequencies is calculated. A comparison between the results from the Bayesian method and the design standards is conducted. The proposed method is found to yield acceptable results, and is then applied to estimating the acceleration response of a typical Tibetan heritage building, with the result compared with a field measurement.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-07-14T06:50:10Z
      DOI: 10.1142/S0219455418500396
       
  • Non-Stationary Random Vibration Analysis of Railway Bridges Under Moving
           Heavy-Haul Trains
    • Authors: Zhihui Zhu, Lidong Wang, Zhiwu Yu, Wei Gong, Yu Bai
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper presents a non-stationary random vibration analysis of railway bridges under moving heavy-haul trains by the pseudo-excitation method (PEM) considering the train-track-bridge coupling dynamics. The train and the ballasted track-bridge are modeled by the multibody dynamics and finite element (FE) method, respectively. Based on the linearized wheel-rail interaction model, the equations of motion of the train-ballasted track-bridge coupling system are then derived. Meanwhile, the excitations between the rails and wheels caused by the random track irregularity are transformed into a series of deterministic pseudo-harmonic excitation vectors by the PEM. Then, the random vibration responses of the coupling system are obtained using a step-by-step integration method and the maximum responses are estimated using the 3[math] rule for the Gaussian stochastic process. The proposed method is validated by the field measurement data collected from a simply-supported girder bridge (SSB) for heavy-haul trains in China. Finally, the effects of train speed, grade of track irregularity, and train type on the random dynamic behavior of six girder bridges for heavy-haul railways are investigated. The results show that the vertical acceleration and dynamic amplification factor (DAF) of the midspan of the SSB girders are influenced significantly by the train speed and track irregularity. With the increase in the vehicle axle-load, the vertical deflection-to-span ratio ([math]) of the girders increases approximately linearly, but the DAF and vertical acceleration fail to show clear trend.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-07-12T07:53:57Z
      DOI: 10.1142/S0219455418500359
       
  • Nonlinear Vibration Analysis of a Cable Carrying Moving Mass-Spring-Damper
    • Authors: M. Ghadiri, M. Kazemi
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In this study, nonlinear dynamics and vibrations of a mass, spring and damper system with constant and variable velocities have been investigated. One end of the large-sag cable is fixed and the other one can be varied using different heights with respect to the first end. The oscillator can be accelerated by the tangential component of the weight force. The governing equations of motion are derived with regard to the mutual influence of the cable movement and vertical motion of attached mass. The Galerkin’s method is employed in the displacement field in conjunction with the average acceleration method in the time domain to solve the governing equations. The parametric study is performed on the vertical movement of the oscillator, the displacement of the cable and the velocity of the moving oscillator.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-06-30T08:39:26Z
      DOI: 10.1142/S021945541850030X
       
  • Experimental and Numerical Study on the Dynamic Stability of
           Vortex-Induced Vibration of Bridge Decks
    • Authors: Kun Xu, Yaojun Ge, Lin Zhao, Xiuli Du
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The dynamic stability of vortex-induced vibration (VIV) of circular cylinders has been well investigated. However, there have been few studies on this topic for bridge decks. To fill this gap, this study focuses on the dynamic stability of a VIV system for bridge decks. Some recently developed techniques for nonlinear dynamics are adopted, for example, the state space reconstruction and Poincare mapping techniques. The dynamic stability of the VIV system is assessed by combining analytical and experimental approaches, and a typical bridge deck is analyzed as a case study. Results indicate that the experimentally observed hysteresis phenomenon corresponds to the occurrence of saddle-node bifurcation of the VIV system. Through the method proposed in this study, the evolution of dynamic stability of the VIV system versus wind velocity is established. The dynamic characteristics of the system are further clarified, which offers a useful clue to understanding the VIV system for bridge decks, while providing valuable information for mathematical modeling.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-06-30T08:39:26Z
      DOI: 10.1142/S0219455418500335
       
  • Nonlinear Dynamics of a Translational FGM Plate with Strong Mode
           Interaction
    • Authors: Yan Qing Wang, Jean W. Zu
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper examines the nonlinear dynamics of a translational functionally graded material (FGM) plate. The plate is composed of nickel and stainless steel, and its property is graded in the thickness direction that obeys a power-law distribution. By adopting the Kármán nonlinear geometrical relations, the equation of motion is derived from the D’Alembert’s principle by considering the dynamic equilibrium relationships for the out-of-plane vibration of the plate. The equation of motion is discretized by using the Galerkin method and thus a series of ordinary differential equations with mode-coupling terms are obtained. These ordinary differential equations are then solved by utilizing the method of harmonic balance. The analytical results are verified by the adaptive step-size fourth-order Runge–Kutta technique. The stability analysis of analytical solutions is also carried out by introducing small perturbation for steady state solutions. Both natural frequency and nonlinear frequency-amplitude characteristics are presented. In the translational FGM plate, strong nonlinear mode interaction phenomenon has been detected. The nonlinear frequency response shows intensive hardening-spring characteristics. Moreover, various system parameters such as power-law distribution, translating speed of the plate, in-plane tension force, damping coefficient and external excitation amplitude are selected as the controlled variables to present parametric study. Their effects on the nonlinear dynamical response of the translational FGM plate are highlighted.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-06-30T08:39:21Z
      DOI: 10.1142/S0219455418500311
       
  • Magneto-Elastic Combination Resonance of Rotating Circular Plate with
           Varying Speed Under Alternating Load
    • Authors: Hu Yuda, Li Zhe, Du Guojun, Wang Yanan
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Nonlinear magneto-elastic combined resonance of parametric and forced excitations is investigated for a rotating circular plate with a variable speed under alternating load. According to the magneto-elastic vibration equations of a conductive rotating thin circular plate, the axisymmetric vibration differential equations of the rotating circular plate under transverse magnetic field are obtained through the application of the Galerkin integral method. The method of multiple scales is applied to solve the differential equations of the circular plate under alternating magnetic field, and the resonance states of the system under combined parametric and forced excitations are obtained by analyzing secular terms. The respective amplitude–frequency response equations are also derived, as well as the necessary and sufficient conditions of the system to make it stable. A numerical method is adopted to acquire amplitude–frequency response curves, bifurcation diagrams of amplitude and the variation pattern of amplitude with magnetic induction intensity and radial force. The influence of parameter variation on stability of the system is also investigated. Based on the global bifurcation diagram of the system, the influence of the change of bifurcation parameters on the system dynamics is discussed.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-06-27T07:56:56Z
      DOI: 10.1142/S0219455418500323
       
  • Damage Assessment of Subway Station Columns Subjected to Blast Loadings
    • Authors: Q. S. Yan
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      With the increasing threat of terrorism attack, the probability of explosion inside the subway is very large. Reinforced concrete columns are the main supporting members of subway stations. If the columns of a subway station were subjected to near-field explosions, their damages can affect the safety of the subway after explosion. By using the finite element method, this paper established a coupling “explosive-air-concrete” model and verified the feasibility of the model through experiments. This model can be used in the damage assessment of subway station columns in terms of the bearing capacity, by which the damage of a reinforced concrete column can be divided into different levels. Furthermore, the effect of different parameters on the damage and bearing capacity of the subway station is discussed. The results demonstrate that the stirrup reinforcement ratio of a reinforced concrete is the key factor in determining the column damage under blast loadings. The present study therefore provides a key reference for assessing the damage of subway structures after terrorist attack.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-06-22T09:31:31Z
      DOI: 10.1142/S0219455418500347
       
  • Cuckoo Search-Based Least Squares Support Vector Machine Models for
           Optimum Tuning of Tuned Mass Dampers
    • Authors: Sadegh Etedali, Nader Mollayi
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Tuned mass dampers (TMDs) have been widely used to suppress or absorb vibration. Optimum tuning of the TMD parameters using metaheuristic algorithms demands numerous numerical analyses which is a tedious and time-consuming task. Recent advances in data processing systems have attracted great attention towards the creation of intelligent systems to evolve models in engineering applications. The present paper implements the least squares support vector machine (LS-SVM) to build up models which predict the optimum TMD parameters. The performance of the proposed models is largely dependent on the quantity and the accuracy of databases used for training the models. Therefore, a wide-range numerical tuning of the TMD system, attached to a single-degree-of freedom (SDOF) main system, is done using a novel metaheuristic algorithm, called the cuckoo search (CS), to obtain the tuning frequency and damping ratio of the TMD system for a main system subjected to three types of excitations: external white-noise force, harmonic base acceleration and white-noise base acceleration. The superior performance of the LS-SVM models in prediction of optimum TMD parameters is proved in comparison to other studies in the literature. Furthermore, it is found that the optimum TMD parameters are not influenced by the predominant frequency of the filtered white-noise excitation.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-06-16T07:12:17Z
      DOI: 10.1142/S0219455418500281
       
  • Effect of Eccentric Lateral Bracing Stiffness on Lateral Torsional
           Buckling Resistance of Wooden Beams
    • Authors: Ye Hu, Magdi Mohareb, Ghasan Doudak
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      An energy-based solution is developed for the lateral torsional buckling (LTB) analysis of wooden beams with flexible mid-span lateral bracing offset from section mid-height and subjected to uniformly distributed or mid-span point load. The study shows that such beams are prone to two potential buckling modes; symmetric or anti-symmetric. The symmetric mode is shown to govern the capacity of the beam for low bracing stiffness while the anti-symmetric mode governs the capacity when the bracing stiffness exceeds a threshold value. Using the present formulation, the threshold bracing stiffness required to suppress the symmetric mode and maximize the critical moments is directly obtained by solving a special eigenvalue problem in the unknown bracing stiffness. The technique thus eliminates the need for trial and error in standard solutions. A parametric study is conducted to investigate the effect of bracing height, load height, and bracing stiffness on the critical moments. A large database of runs is generated and used to develop simple expressions for determining the threshold bracing stiffness required to maximize the elastic LTB resistance.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-06-15T03:48:33Z
      DOI: 10.1142/S021945541850027X
       
  • Nonlinear Structural Damage Detection Based on Adaptive Volterra Filter
           Model
    • Authors: J. Prawin, A. Rama Mohan Rao
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The majority of the existing damage diagnostic techniques are based on linear models. Changes in the state of the dynamics of these models, before and after damage in the structure based on the vibration measurements, are popularly used as damage indicators. However, the system may initially behave linearly and subsequently exhibit nonlinearity due to the incipience of damage. Breathing cracks that exhibit bilinear behavior are one such example of the damage induced due to nonlinearity. Further many real world structures even in their undamaged state are nonlinear. Hence, in this paper, we present a nonlinear damage detection technique based on the adaptive Volterra filter using the nonlinear time history response. Three damage indices based on the adaptive Volterra filter are proposed and their sensitiveness to damage and noise is assessed through two numerically simulated examples. Numerical investigations demonstrate the effectiveness of the adaptive Volterra filter model to detect damage in nonlinear structures even with measurement noise.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-06-15T03:48:31Z
      DOI: 10.1142/S0219455418710037
       
  • Multi-Scale Failure Analysis of Transmission Towers Under Downburst
           Loading
    • Authors: F. Y. Wang, Y. L. Xu, W. L. Qu
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Collapse of transmission towers due to downbursts is often initiated by local failure of key structural members, while the local failure of key structural members is related to local material and geometrical nonlinearities. This paper presents a multi-scale finite element (FE) model for the failure analysis of transmission towers under downburst-induced wind loading. The potential local failure areas of the tower are modeled by shell or solid elements, and the remaining parts by beam elements. In this way, the failure of the tower can be accurately simulated on the one hand and the computational effort can be reduced on the other hand. This paper first introduces how to determine the downburst-induced wind loading on transmission towers. Both the conventional beam and multi-scale FE models of the transmission tower are then developed and used in the failure analysis. A comparison of the failure results obtained by the two FE models show that the multi-scale FE model can effectively simulate the stress concentration of angle members around the bolt connections and the cross-section plastic collapse of key structural members, leading to a different failure pattern for the tower from the conventional FE method. It is suggested that the multi-scale FE model should be used for better accuracy in the failure analysis of transmission towers under downburst loading.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-06-14T07:17:34Z
      DOI: 10.1142/S0219455418500293
       
  • Cylindrical Shells with Tunable Postbuckling Features Through Non-Uniform
           Patterned Thickening Patches
    • Authors: Nan Hu, Rigoberto Burgueño
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The research reported herein follows the increased interest in buckling-induced functionality for novel materials and devices with a focus on cylindrical shells as a suitable structural prototype. The paper proposes the concept of using patterned thickening patches on the surface of cylindrical shells to modify and control their elastic postbuckling response. Cylindrical shells with non-uniform thickness distributions (NTD) were fabricated through 3D printing to understand rules for pattern designs and then tested under loading-unloading cycles. Strategic thickening patches act as governing imperfections that modify the response type, the number, the location and the sequence of the localized buckling events. The use of patterned thickening patches and their layout provides diverse design opportunities for a desired elastic postbuckling response and can be potentially used in design materials and structures with switchable functionalities.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-06-02T06:55:20Z
      DOI: 10.1142/S0219455418500268
       
  • Power Spectral Density Function for Individual Jumping Load
    • Authors: Jiecheng Xiong, Jun Chen
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Modern slender structures such as long-span floors and cantilever stands are sensitive to jumping-induced vibrations. A conventional deterministic Fourier series model for the human jumping load may overestimate a structure’s responses in resonance condition. This paper suggests a power spectral density (PSD) function for the individual jumping load, which was treated as a narrowband stationary stochastic process. Experiments were conducted on individual jumping loads resulting in 334 records from 73 subjects. Statistical analysis of the records led to experimental PSD curves on which a symmetrical bilinear function was suggested. The proposed PSD function is centered on the given jumping frequency and its integer multiples. The function’s parameters were determined by equating the total energy of the proposed PSD with that of the experimental PSD. Application of the proposed PSD for predicting a floor’s peak response via the stochastic vibration theory was then presented. The predictions for an experimental floor model subjected to individual jumping were compared with the measured peak responses. The comparisons demonstrated that the proposed PSD function was applicable for predicting the floor’s response to individual jumping. Finally, the framework for calculating crowd-induced structure vibrations using the suggested PSD was also discussed.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-05-25T06:59:39Z
      DOI: 10.1142/S0219455418500232
       
  • State-of-the-Art Review on Modal Identification and Damage Detection of
           Bridges by Moving Test Vehicles
    • Authors: Y. B. Yang, Judy P. Yang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In 2004, Yang and co-workers proposed the extraction of bridge frequencies from the dynamic response of a moving test vehicle [Y. B. Yang, C. W. Lin and J. D. Yau, Extracting bridge frequencies from the dynamic response of a passing vehicle, J. Sound Vib. 272 (2004) 471–493] and verified the technique by a field test [C. W. Lin and Y. B. Yang, Use of a passing vehicle to scan the bridge frequencies — An experimental verification, Eng. Struct. 27(13) (2005) 1865–1878]. This technique was extended to construction of mode shapes [Y. B. Yang, Y. C. Li and K. C. Chang, Constructing the mode shapes of a bridge from a passing vehicles: A theoretical study, Smart Struct. Syst. 13(5) (2014) 797–819] and damage identification of bridges. It was referred to as the indirect method for bridge measurement because no vibration sensors are needed for installation on the bridge, but it only requires one or few vibration sensors on the test vehicle. When compared with the conventional direct method that relies fully on the response of the bridge fitted with vibration sensors, the advantage of the indirect method is clear: mobility, economy, and efficiency. Over the past years, many research studies were conducted along the lines of the indirect method for bridge measurement. Significant advances have been made on various aspects of application. This paper represents a state-of-the-art review of the related research works conducted worldwide. Comments and recommendations will be made at proper places, while concluding remarks including future research directions will be presented at the end of the paper.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-05-25T06:59:38Z
      DOI: 10.1142/S0219455418500256
       
  • Explicit Determination of Pinned–Pinned Beams with a Finite Number
           of Given Buckling Loads
    • Authors: Antonino Morassi, Martina Pressacco, Anastasia Vrech
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      We present an analytical procedure for the exact, explicit construction of Euler–Bernoulli beams with given values of the first [math] buckling loads. The result is valid for pinned–pinned (P–P) end conditions and for beams with regular bending stiffness. The analysis is based on a reduction of the buckling problem to an eigenvalue problem for a vibrating string, and uses recent results on the exact construction of Sturm–Liouville operators with prescribed natural frequencies.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-05-25T06:59:36Z
      DOI: 10.1142/S0219455418500189
       
  • Free Vibration Analysis of Rotating Euler–Bernoulli Beam with
           Exponentially Varying Cross-Section by Differential Transform Method
    • Authors: Mostafa Nourifar, Ali Keyhani, Ahmad Aftabi Sani
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In this paper, the free vibration analysis of non-uniform rotating Euler–Bernoulli beam is carried out. It is assumed that the beam has exponentially decaying circular cross-section. In order to solve the problem, the differential transform method (DTM) is utilized. Based on our knowledge, we claim that the recurrence relation presented herein is an elaborate recurrence relation which has been obtained for ordinary differential equations. Non-dimensional natural frequencies of the beam are obtained and tabulated for different values of the beam parameters such as taper ratio and rotating speed. Furthermore, the finite element method (FEM) is employed to solve the problem. Comparison of the results obtained by DTM and FEM indicates the accuracy of proposed solutions.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-05-25T06:59:36Z
      DOI: 10.1142/S0219455418500244
       
  • Development of a Novel Dual-Belt Van Doorne’s Continuously Variable
           Transmission for Automobiles — a Preliminary Study
    • Authors: Pak Kin Wong, Zhengchao Xie, Yueqiao Chen, Lap Mou Tam
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The continuously variable transmission (CVT) is one of the prevailing automotive transmissions. Nowadays, the most popular design is Van Doorne’s CVT with single metal pushing V-belt. However, it is only applicable to low-power passenger cars because of its low torque capacity. To overcome this limitation of traditional single-belt Van Doorne’s CVT, this research proposes a novel parallel Van Doorne’s dual-belt CVT system which can be applied to heavy-duty vehicles. As the first attempt, an analytical model for both torque capacity and power efficiency based on effective radii instead of traditional working radii for the single-belt CVT is developed for this novel CVT system, and this newly developed model is experimentally validated. Evaluation result reveals that the new analytical model based on effective radii is more accurate than that based on working radii. Experimental and simulation results show that the proposed dual-belt CVT system can greatly improve the torque capacity as compared with the single-belt CVT. Moreover, the newly proposed analytical model can provide a foundation for further study of multi-belt CVTs.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-05-25T06:59:35Z
      DOI: 10.1142/S0219455418500165
       
  • Stochastic Stability of Gyroscopic Systems Under Bounded Noise Excitation
    • Authors: Jian Deng
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Dynamic stochastic stability of a two-degree-of-freedom gyroscopic system under bounded noise parametric excitation is studied in this paper through moment Lyapunov exponent and the largest Lyapunov exponent. A rotating shaft subject to stochastically fluctuating thrust is taken as a typical example. To obtain these two exponents, the gyroscopic differential equation of motion is first decoupled into Itô stochastic differential equations by using the method of stochastic averaging. Then mathematical transformations are used in these Itô equation to obtain a partial differential eigenvalue problem governing moment Lyapunov exponents, the slope of which at the origin is equal to the largest Lyapunov exponent. Depending upon the numerical relationship between the natural frequency and the excitation frequencies, the gyroscopic system may fall into four types of parametric resonance, i.e. no resonance, subharmonic resonance, combination additive resonance, and combination differential resonance. The effects of noise and frequency detuning parameters on the parametric resonance are investigated. The results pave the way to utilize or control the vibration of gyroscopic systems under stochastic excitation.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-05-25T06:59:35Z
      DOI: 10.1142/S0219455418500220
       
  • A New Approach to the Rigid Finite Element Method in Modeling Spatial
           Slender Systems
    • Authors: Iwona Adamiec-Wójcik, Łukasz Drąg, Stanisław Wojciech
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The static and dynamic analysis of slender systems, which in this paper comprise lines and flexible links of manipulators, requires large deformations to be taken into consideration. This paper presents a modification of the rigid finite element method which enables modeling of such systems to include bending, torsional and longitudinal flexibility. In the formulation used, the elements into which the link is divided have seven DOFs. These describe the position of a chosen point, the extension of the element, and its orientation by means of the Euler angles Z[math]Y[math]X[math]. Elements are connected by means of geometrical constraint equations. A compact algorithm for formulating and integrating the equations of motion is given. Models and programs are verified by comparing the results to those obtained by analytical solution and those from the finite element method. Finally, they are used to solve a benchmark problem encountered in nonlinear dynamic analysis of multibody systems.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-05-23T07:12:50Z
      DOI: 10.1142/S0219455418500177
       
  • Analysis and Optimal Design of Stress Wave Intensity Attenuation in
           Layered Structures
    • Authors: R. Rafiee-Dehkharghani, Dipanshu Bansal, Amjad J. Aref, Gary F. Dargush
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Within the framework of linear two-dimensional elastodynamics, stress wave intensity attenuators are studied under material and boundary condition discontinuities collectively. The influence of various parameters on the efficiency of stress wave attenuators is investigated thoroughly and a comprehensive understanding of the response is developed under dynamic loadings for a wide range of frequencies. In particular, the effect of in-plane and out-of-plane dimensions, incident wave frequencies (wavelength), rigidity of the host structure, and impedance mismatch between different layers have been examined. The dependence of stress wave attenuator efficiency and robustness are found to be a complex function of all relevant parameters, and performance is observed to vary significantly for various combinations. To illustrate the significance of combined effects of various parameters on the potential efficiency of the stress wave intensity attenuators, an optimization problem is solved. An optimal material set-up of a 12-layered structure, subjected to transient loadings with varying durations and wide range of frequency contents, is presented. A coupled genetic algorithm-finite element methodology is developed specifically for the optimal design of layered structures. This methodology is highly suitable for investigating the solution space that is too large to be explored by an exhaustive parametric study. The results of the optimal designs evidently show that the efficiency of the stress wave attenuators depends significantly on the duration of transient loading, and high efficiency can be attained for short durations.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-05-23T01:00:42Z
      DOI: 10.1142/S0219455418500153
       
  • A Nonlinear Oscillator Model to Generate Lateral Walking Force on a Rigid
           Flat Surface
    • Authors: Prakash Kumar, Anil Kumar, Silvano Erlicher
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This study proposes a single degree of freedom nonlinear oscillator to model the lateral movement of the body center of mass of a pedestrian walking on a flat rigid surface. Experimentally recorded ground reaction force of a dozen of pedestrians in the lateral direction is used to develop the model. In detail, the hardening and softening effects are observed in the stiffness curve as well as higher odd harmonics are present in the frequency spectrum of the lateral force signals. The proposed oscillator is a modification of the Rayleigh and the Van der Pol oscillators with additional nonlinear softening and hardening terms. To obtain an approximation of the limit cycle of the oscillator and its stability, two methods are studied: the energy balance method and the Lindstedt–Poincare perturbation technique. The experimental force signals of pedestrians at four different walking speeds are used for the identification of the values of the model parameters. The results obtained from the proposed model show a good agreement with the experimental ones.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-05-17T09:09:11Z
      DOI: 10.1142/S0219455418500207
       
  • A Shell Element for Buckling Analysis of Thin-Walled Composite-Laminated
           Members
    • Authors: R. Emre Erkmen, Bram Gottgens
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper introduces a new shell element formulation and investigates the buckling behavior of thin-walled beams composed of fiber-reinforced polymer composite-laminates, which is a primary design concern for thin-walled beams composed of fiber-reinforced polymer composite-laminates due to their slenderness. Although global buckling behavior can be captured using beam-column type two-node simple finite element formulations, shell-type more sophisticated elements are needed in order to be able to capture the effects due to cross-sectional deformations. Pursuit of an efficient shell element formulation continues to date and in this study, a new flat rectangular shell element formulation is developed for the buckling analysis of thin-walled composite-laminated members. The plate component of the shell is locking-free and based on the twist-Kirchhoff theory. For the membrane component of the shell element, variational formulation employing drilling degrees of freedom is adopted. Convergence studies were presented to illustrate the numerical performances of the element. A broad class of problems including distortional as well as global buckling cases were solved and compared with solutions from the literature to validate the use of the developed shell element for the buckling analysis of thin-walled composite-laminated members.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-05-17T09:09:10Z
      DOI: 10.1142/S0219455418500219
       
  • Flexural Behavior of Pultruded GFRP Deck Panels with Snap-Fit Connections
    • Authors: Mário F. Sá, Augusto M. Gomes, João R. Correia, Nuno Silvestre
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper presents experimental, analytical and numerical investigations about the flexural behavior of glass fiber reinforced polymer (GFRP) pultruded panels for footbridge decks. The analyzed panels, made of isophthalic polyester and E-glass fibers, comprise a multicellular thin-walled cross-section with panel-to-panel vertical snap-fit connections at their lateral edges. As part of a comprehensive study about the mechanical and structural behavior of this type of footbridge decks, the experimental study presented here addresses: (i) the mechanical characterization of the laminated material, and (ii) the quasi-static flexural behavior of the panels for both service and failure conditions. The experimental data obtained is used to validate and assess the accuracy of three-dimensional shell finite element (FE) models and analytical formulae. Particular focus is given to the serviceability and failure performance of the panels, in terms of their deformability and susceptibility to buckling phenomena, respectively. Regarding the serviceability behavior, the results obtained in this study demonstrate the importance of duly specifying the shear coefficient of the multicellular cross-section on Timoshenko beam theory, in order to obtain accurate deflection predictions. In terms of failure performance, both the flexural tests and the analytical formulae indicate that the local buckling of the compressive flanges seems to have triggered the collapse of the tested panels, thus limiting their load carrying capacity. The geometrically nonlinear FE analyses allowed understanding in further depth the ultimate behavior of the panels, providing further insights about their failure mechanisms.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-05-11T08:36:13Z
      DOI: 10.1142/S0219455418500190
       
  • Post-Buckling, Limit Point, and Bifurcation Analyses of Shallow
           Nano-Arches by Generalized Displacement Control and Finite Difference
           Considering Small-Scale Effects
    • Authors: Parvaneh Mortazavi, Hamid Reza Mirdamadi, Ali Reza Shahidi
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Post-buckling of shallow nano-arches is examined numerically in this study. The small-scale effect is taken into account by using the nonlocal theory. The variational formulation is employed to derive the equilibrium equations of the arch based on the Euler–Bernoulli beam hypothesis. Moderate rotations are considered by including the von Karman nonlinear strains. The governing equations are discretized by the finite difference method and are solved iteratively by the generalized displacement control algorithm. In the buckling analysis, the effects of different factors, such as load distribution, initial height, arch span, and nonlocal parameter, on the buckling loads are investigated. The behavioral analysis of the arch with respect to its initial height follows and detailed analyses for the limit point and bifurcation buckling are presented. It is concluded that the value of nonlocal parameters can influence the arch model in two ways: apparently changing its initial rise and switching its buckling mechanism. There is also a comparison between the use of secant and tangent stiffness moduli for tracing the equilibrium paths.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-05-11T08:36:11Z
      DOI: 10.1142/S0219455418500141
       
  • Geometrically Nonlinear Transient Response of Laminated Plates with
           Flexible Supports
    • Authors: Shao-Chong Yang, Qing-Sheng Yang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Laminated plates are loading-bearing components that are generally connected to flexible pads and exhibit complicated mechanical responses. To investigate the geometrically nonlinear transient responses of a laminated plate with flexible pad supports, a varied constraint reaction model and a systematic numerical procedure are presented in this paper. The flexible pad supports of the plate were treated as viscoelastic boundary conditions, wherein the strip-type pad per unit length was modeled as a cantilever beam. The nonlinear Kelvin–Voigt model was developed to simulate the nonlinear viscoelastic behaviors of the flexible pads. The dynamically varied constraint reactions generated by the viscoelastic supports, which depend upon the displacement and velocity of the nodes along the plate edge, were determined by the deflection and slope equations of the beam theory used, and they were applied on the plate edges by using the nonlinear load functions. Thus, the dynamical responses of the laminated plate with viscoelastic supports were obtained. Numerical results show that the present method can effectively treat the geometrically nonlinear transient response of the laminated plate with viscoelastic supports, and it is essential to consider the effects of non-ideal boundary conditions in the nonlinear transient analysis.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-05-05T06:15:54Z
      DOI: 10.1142/S0219455418710025
       
  • Influence of Porosity on the Flexural and Free Vibration Responses of
           Functionally Graded Plates in Thermal Environment
    • Authors: Ankit Gupta, Mohammad Talha
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper examines the influence of porosities on the flexural and free vibration response of functionally graded material (FGM) plates based on the authors’ recently developed non-polynomial higher-order shear and normal deformation theory. The theory accommodates the nonlinear variation in the in-plane and transverse displacements in the thickness coordinates. It also contains the hyperbolic shear strain shape function in the displacement field with only four unknowns. A new mathematical model has also been proposed to incorporate the effects of porosity in the FGM plate. Various numerical examples have been solved to ascertain the accuracy, efficiency, and applicability of the present formulation. The effects of porosity, volume fraction index, plate thickness, aspect ratio, boundary conditions and temperature have been discussed in details. The obtained results can be treated as a benchmark for future studies.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-05-04T03:14:00Z
      DOI: 10.1142/S021945541850013X
       
  • A Theoretical Treatment of Crowd–Structure Interaction
    • Authors: Yan-an Gao, Qing-shan Yang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      A vertical crowd–structure interaction model including the interaction amongst pedestrians is developed to study the structural performances of the supporting structure with social force effect. This model can be used to analyze the vibration problem of footbridge under a large crowd excitation. The social force is firstly introduced to describe the dynamic interaction amongst the bipedal models with damping-spring legs modeling pedestrian movement on a three-dimensional plate structure. The social force determines the walking direction and velocity of pedestrian. Numerical studies show that the structural dynamic performances can be remarkably changed under the crowd action. The natural frequency of structure is decreased and is time-varying with an increase in the crowd density. However, the damping ratio of structure is increased. The proposed model could well describe the crowd–structure dynamic interaction.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-04-28T07:14:01Z
      DOI: 10.1142/S0219455418710013
       
  • An Approach to Partial Quadratic Eigenvalue Assignment of Damped Vibration
           Systems Using Static Output Feedback
    • Authors: Jiafan Zhang, Yongxin Yuan, Hao Liu
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper addresses the problem of the partial eigenvalue assignment for second-order damped vibration systems by static output feedback. The presented method uses the combined acceleration, velocity and displacement output feedback and works directly on second-order system models without the knowledge of the unassigned eigenpairs. It allows the input and output matrices to be prescribed beforehand in a simple form. The real-valued spectral decomposition of the symmetric quadratic pencil is adopted to derive a homogeneous matrix equation of output feedback gain matrices that assure the no spillover eigenvalue assignment. The method is validated by some illustrative numerical examples.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-04-28T07:13:56Z
      DOI: 10.1142/S0219455418500128
       
  • Multiple Parametric Resonances of Taut Inclined Cables Excited by Deck
           Vibration
    • Authors: Chang-Zhao Qian, Chang-Ping Chen
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      A mechanical model is proposed to describe the vibration of a taut inclined cable excited by a deck. The dynamic system is simplified into a one-degree-of-freedom nonlinear system with non-dimensional parameters by using the Galerkin and non-dimensional analysis methods. The periodicity ratio (PR) method is improved and applied to the parameter analysis for the cable system. The frequency ratio between the natural frequency of the cable and the vibration frequency of the deck and the amplitude of deck vibration are the main variable parameters, and nonlinear motion is diagnosed for a large range of parameters. Several forms of motion are distinguished, and the evolution between the forms is studied. Meanwhile, several types of parametric resonance are revealed in different ranges of parameters. The results indicate that the parametric resonance in the case of a 3:2 frequency ratio is significant and should be given more attention.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-04-28T07:13:51Z
      DOI: 10.1142/S0219455418500098
       
  • Dynamic Responses of Interspersed Railway Tracks to Moving Train Loads
    • Authors: Sakdirat Kaewunruen, Tomasz Lewandrowski, Kritditorn Chamniprasart
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper investigates novel dynamic phenomena of interspersed railway tracks. The interspersed method is commonly carried out by spot-replacing old timber sleepers with new concrete sleepers. Although this interspersed approach provides a short-term solution, such method has a negative effect on the long-term performance of railway tracks. It is evident that the performance of interspersed tracks can quickly deteriorate after some years. As a result, this paper is the first to evaluate dynamic responses of the interspersed track caused by a moving train load in order to understand the root cause of swift track deterioration. Interspersed track models in three-dimensional space have been developed using a finite element package, STRAND7. The model was validated earlier with experimental results. Parametric studies have been conducted to evaluate dynamic responses of the interspersed railway tracks, including dynamic displacement, frontal uplift, rear uplift and accelerations of rail over sleeper, rail at midspan, sleeper at rail seat, and sleeper at midspan. Dynamic amplification phenomena are highlighted as they convey a new insight into dynamic phenomena identifying the real source of track deterioration.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-04-24T02:23:48Z
      DOI: 10.1142/S0219455418500116
       
  • Field Testing of Fence Type Blast Wall for Blast Load Mitigation
    • Authors: Yifei Hao, Hong Hao, Yanchao Shi, Zhongqi Wang, Ruiqing Zong
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      To protect structures from external explosions, solid protective barriers have been demonstrated by experimental and numerical studies to be able to effectively mitigate blast loads on structures behind them. However, to protect against blast loads, barriers normally need to be designed to have high structural resistance and ductility. This often requires bulky and heavy protective barriers which are not only highly costly but also often not appropriate for application in downtown areas as they are not friendly to city planning or appearance. Fence type blast wall consisting of structural columns was recently proposed and its effectiveness in mitigating blast loads was investigated through numerical simulations. It was found that the wave–fence interaction and interference of waves significantly reduced the wave energy when the blast wave passed through the fence blast wall. To further investigate the effectiveness and applicability of fence type blast wall as a highly potential technology for structural protection in an urban area, field tests have been conducted and results are reported in this paper. Columns with circular and triangular cross-sections were adopted to build fence blast walls. In addition, a masonry wall was also constructed as solid barrier for comparison. Hemispherical TNT explosive weighing 1.0[math]kg with different stand-off distances was detonated on the ground to generate the blast load. Blast overpressures in free air, behind the fence blast wall and behind the masonry wall were recorded by pressure sensors. The effectiveness of the fence blast wall in reducing blast wave and protecting structures was demonstrated by the test data.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-04-13T01:56:48Z
      DOI: 10.1142/S0219455417500997
       
  • Damping Effect of a Passing Vehicle for Indirectly Measuring Bridge
           Frequencies by EMD Technique
    • Authors: Judy P. Yang, Wei-Chun Lee
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The indirect approach for measuring bridge frequencies from a passing vehicle has become an attractive method recently because it provides mobility, reliability, and safety for setting up sensors in comparison with the traditional method for measurement. In the vehicle–bridge interaction system, it is realized that the bridge frequencies can be identified from the spectral analysis of the passing vehicle. However, there exist many factors affecting the identified results of bridge frequencies, and one key factor is the vehicle damping. This study investigates the effect of vehicle damping on the identification of the first bridge frequency for three different levels of road surface roughness by the empirical mode decomposition (EMD) technique. The numerical experimentation shows the following properties that can be utilized in a field measurement: (1) higher vehicle damping tends to suppress the vehicle frequency, and (2) the use of vehicle damping helps to suppress the effect of rough surface roughness and make the first bridge frequency visible.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-04-13T01:56:48Z
      DOI: 10.1142/S0219455418500086
       
  • Dynamic Response of a Railway Bridge to Heavy Axle-Load Trains Considering
           Vehicle–Bridge Interaction
    • Authors: Ladislao R. Ticona Melo, Tulio N. Bittencourt, Diogo Ribeiro, Rui Calçada
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Railway bridges can be particularly sensitive to dynamic effects induced by trains owing to the resonance phenomena originated by periodic loading associated with the passage of regularly spaced train’s axles groups. The increase of these dynamic effects in bridges located in freight railway lines, due to heavy axle-loads, higher circulation speeds, and the existence of track irregularities or wheel defects, can lead to excessive bridge vibrations, that can put in risk the structural safety, mainly due to the fatigue phenomena, and wheel–rail contact stability. In this study, the dynamic response of the Suaçuí railway bridge to heavy axle-load trains (HAL) considering the vehicle–structure interaction was analyzed. For this purpose, three-dimensional finite element models of the truss bridge, including the track, and train were developed. The dynamic response was obtained using ABAQUS[math] software based on an iterative uncoupled method for the vehicle–structure interaction and considering track irregularities. The validation of the numerical models was performed through a comparison between the numerical and experimental dynamic responses, in terms of displacements and accelerations of the bridge for the passage of DASH 9[math]W Locomotives and GDE wagons. The experimental response obtained from a dynamic test under railway traffic revealed a good agreement with the numerical response.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-04-13T01:56:48Z
      DOI: 10.1142/S0219455418500104
       
  • Vibration Analysis of Functionally Graded Timoshenko Beams
    • Authors: Wei-Ren Chen, Heng Chang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The vibration behavior of a functionally graded Timoshenko beam is investigated by applying the transformed-section method. The material properties of a functionally graded (FG) beam are assumed to vary across the thickness according to a simple power law. The cross section of FG beam with two constituents is first transformed into an equivalent cross section of the material on the top. Then, the lateral and longitudinal vibration equations of a homogeneous Timoshenko beam are separately applied to the beam with the transformed section. The bending natural frequencies of FG beam are evaluated using the Chebyshev collocation method, and the longitudinal natural frequencies are also obtained from the known closed-form solutions. Some of the analytical results are compared with the existing numerical data to validate the present model accuracy. Good agreement has been observed between the analytical and numerical data. The effects of aspect ratio, volume fraction, and boundary conditions on the free-vibration behavior of FG beam are discussed. The present analytical solutions provide an insight to the effects of various parameters on the vibration behavior of the beam. They also serve as benchmarks for testing the vibration results obtained by other analytical or approximate methods.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-04-07T03:58:09Z
      DOI: 10.1142/S0219455418500074
       
  • Horizontal Resonance of a 13 Story Building Under External Machine
           Vibrations
    • Authors: Pei Liu, Peng-Yu Lian, Wei-Guo Yang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Excessive vibrations seriously affected the comfort of residents living on the upper floors of a high-rise shear walled building in Beijing. The ambient vibration tests were conducted to measure the floor acceleration responses, which were found to contain almost periodic signals likely to be excited by vibration sources with frequency of about 1.5[math]Hz. The transverse vibration levels of the building above the 8th floor are not acceptable as revealed by the one-third octave spectra and weighted acceleration levels according to the ‘Standard for Allowable Vibration of Building Engineering’ of China. The modal properties of the building are identified by a Bayesian FFT method, indicating that the resonance between the building and the vibration sources caused the excessive vibrations. For comparison, the vibration test of an adjacent building with the same structural design was also conducted, together with modal analysis by the finite element method. It is found that as the story level increases, different trends of amplification in floor root mean square (RMS) acceleration and mode shape component of the two buildings cause different vibration levels. After tests outside the residence community, the main vibration sources were identified to be the working machines in two stone processing factories a few hundred meters away from the building. The vibration tests with measurements in the building and near the vibration sources with different number of machines in the two factories were also conducted. The results show that the vibration levels of the building can be controlled below the acceptance value by reducing the number of machines.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-04-06T04:09:59Z
      DOI: 10.1142/S0219455418500050
       
  • Numerical Studies of Vibration of Four-Span Continuous Plate with Rails
           Excited by Moving Car with Experimental Validation
    • Authors: Jing Yang, Huajiang Ouyang, Dan Stancioiu
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The vibration of a four-span continuous plate with two rails on top and four extra elastic supports excited by a moving model car is studied through numerical simulations and experiments. Modal testing is carried out to identify the Young’s moduli of the plate material and the rail material. Shell elements and beam elements are adopted for the plate and the rails of their Finite Element (FE) model, respectively. An offset is required to connect the rails and the plate in the FE model and the offset ratio of the shell element is updated to bring the numerical frequencies of the structure (plate with rails) closest to its experimental frequencies. Modal Superposition (MS) method with numerical modes of the structure and an iterative method are combined to predict the vibration of the structure subjected to the moving car. The displacements of four points of the plate are measured during the crossing of the car and compared with predicted results. The two sets of results agree well, which validates the model of the system. Parametric analysis is then made using the validated system model.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-04-06T04:09:54Z
      DOI: 10.1142/S021945541750119X
       
  • Nonlinear In-Plane Stability of Deep Parabolic Arches Using Geometrically
           Exact Beam Theory
    • Authors: Aditya Sabale, K. V. Nagendra Gopal
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In this paper, we investigate the in-plane stability and post-buckling response of deep parabolic arches with high slenderness ratios subjected to a concentrated load on the apex, using the finite element implementation of a geometrically exact rod model and the cylindrical version of the arc-length continuation method enabled with pivot-monitored branch-switching. The rod model used here includes geometrically exact kinematics of the cross-section, exact kinetics, and a linear elastic constitutive law; and advantageously employs quaternion parameters to treat the cross-sectional rotations and to compute the exponential map in the configurational update of rotations. The evolution of the Frenet frame along the centroidal curve is used to determine the initial curvature of the rod. Three sets of boundary conditions, i.e. fixed–fixed (FF), fixed–pinned (FP) and pinned–pinned (PP), are considered, and arches with a wide range of rise-to-span ratios are analyzed for each set. Complete post-buckling response has been derived for all cases. The results reveal that although all the PP arches and all the FF arches (with the exception of FF arches with rise-to-span ratio less than 0.3) considered in this study buckle via bifurcation, the nature of stability of the different solution branches in the post-buckling regime differs from case to case. All FP slender parabolic arches exhibit limit-point buckling, again with several markedly different post-buckling behaviors. Also, some arches in the FF and PP case are shown to exhibit a clear bistable behavior in the post-buckled state.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-04-03T08:03:02Z
      DOI: 10.1142/S0219455418500062
       
  • Linear Buckling Analysis of Perforated Cold-Formed Steel Storage Rack
           Columns by Means of the Generalised Beam Theory
    • Authors: M. Casafont, J. Bonada, M. M. Pastor, F. Roure, A. Susín
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The investigation attempts to adapt a beam finite element procedure based on the Generalized Beam Theory (GBT) to the analysis of perforated columns. The presence of perforations is taken into account through the use of two beam elements with different properties for the non-perforated and perforated parts of the member. Each part is meshed with its corresponding finite element and, afterwards, they are linked by means of constraint equations. Linear buckling analyses on steel storage rack columns are carried out to demonstrate how the proposed procedure should be applied. Some practical issues are discussed, such as the GBT deformation modes to be included in the analyses, or the optimum finite element discretization. The resulting buckling loads are validated by comparison with the values obtained in analyses performed using shell finite element models. Finally, it is verified that the buckling loads produced with the proposed method are rather accurate.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-03-29T03:14:18Z
      DOI: 10.1142/S0219455418500049
       
  • Flutter Instability of Cracked Rotating Non-Uniform Beams Subjected to
           Distributed Follower Force
    • Authors: A. Karimi-Nobandegani, S. A. Fazelzadeh, E. Ghavanloo
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In this paper, the effect of an open edge crack on the instability of rotating non-uniform beams subjected to uniform distributed tangential compressive load is studied. The local stiffness due to the presence of crack is considered in the global stiffness matrix of the structure using the finite element method. The cracked beam element is modeled as two equal sub-beam elements connected by a massless rotational spring. Based on the fracture mechanics, the strain energy release rate and the stress intensity factors are employed to investigate the stiffness of the rotational spring. Then, the modified shape functions are developed to reflect the crack stiffness in the finite element analysis. To validate the accuracy of the finite element model and results obtained, comparisons have been made between the results obtained and those available in the literature. The effects of several parameters, including the linear and nonlinear thickness variations, angular velocity, crack location and size, on the instability of cracked rotating non-uniform cantilevers are also examined. The results show that the location of crack significantly influences the critical magnitude of the follower force that destabilizes the cantilevers. In addition, geometric non-uniformity reduces the stability of the cracked cantilevers. For the same amount of cantilever mass, different patterns of mass distribution result in different stability diagrams.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-03-29T03:14:16Z
      DOI: 10.1142/S0219455418500013
       
  • Dynamic Modeling and Analysis of a Rotating Piezoelectric Smart Beam
    • Authors: En Lu, Wei Li, Xuefeng Yang, Yuqiao Wang, Yufei Liu
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In active vibration control study, piezoelectric actuators and sensors are bonded on the surface of a beam. They can change the frequency and modal characteristics of the system. This paper presents an analysis of the frequency response to a rotating piezoelectric smart beam. Hamilton’s principle along with the assumed mode method are employed to derive the governing equations of the first-order approximate coupling model for the piezoelectric smart beam. The coupling is taken into account as the second-order coupling effect of the axial elongation caused by the transverse displacement of the beam. Then, the equations are transformed into a dimensionless form after identifying the necessary parameters. The dimensionless natural frequencies of the piezoelectric smart beam corresponding to the bending and stretching vibrations are obtained through a numerical simulation, with comparison made of those of the beam with no actuator or sensor. Furthermore, the implication is investigated of the structural parameters and bond location on the piezoelectric actuators and sensors. Besides, the common case of a smart beam bonded with multiple pairs of piezoelectric actuators and sensors is studied, and the effects of the first natural frequency and tip deformation are analyzed. The research provides a theoretical reference for the optimization of structural parameters and location of piezoelectric actuators and sensors, thereby preventing the resonance when the excitation frequency is approximately equal to the natural frequency of the beam.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-03-29T03:14:16Z
      DOI: 10.1142/S0219455418500037
       
  • Exact Solutions of Fully Nonstationary Random Vibration for Rectangular
           Kirchhoff Plates Using Discrete Analytical Method
    • Authors: Dixiong Yang, Guohai Chen, Jilei Zhou
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper proposes the discrete analytical method (DAM) to determine exactly and efficiently the fully nonstationary random responses of rectangular Kirchhoff plates under temporally and spectrally nonstationary acceleration excitation of earthquake ground motions. First, the fully nonstationary power spectral density (PSD) model is suggested by replacing the filtered frequency and damping of Gaussian filtered white-noise model with the time-variant ones. The exact solutions of free vibration of thin plates with two opposite edges simply supported boundary conditions are introduced. Then, the full analytical procedure for random vibration analysis of the plate is established by using a pseudo excitation method (PEM) that can consider all modal auto-correlation and cross-correlation terms. Owing to involving a series of Duhamel time integrals of single degree of freedom systems, it is difficult to fully analytically evaluate the PSD of time-variant responses such as the transverse deflection, velocity, acceleration and stress components. Thus, DAM that combines the PEM with precise integration technique is developed to enhance the computational efficiency. Finally, comparison of the results by the DAM with Monte Carlo simulations and the analytical stationary random vibration analysis demonstrates the high efficiency and accuracy of DAM. Moreover, the fully nonstationary excitation imposes a remarkable effect on the response PSD of rectangular Kirchhoff plates.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-03-29T03:14:15Z
      DOI: 10.1142/S0219455417501267
       
  • GBT-Based Buckling Analysis Using the Exact Element Method
    • Authors: Rui Bebiano, Moshe Eisenberger, Dinar Camotim, Rodrigo Gonçalves
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Generalized Beam Theory (GBT), intended to analyze the structural behavior of prismatic thin-walled members and structural systems, expresses the member deformed configuration as a combination of cross-section deformation modes multiplied by the corresponding longitudinal amplitude functions. The determination of the latter, usually the most computer-intensive step of the analysis, is almost always performed by means of GBT-based conventional 1D (beam) finite elements. This paper presents the formulation, implementation and application of the so-called “exact element method” in the framework of GBT-based linear buckling analyses. This method, originally proposed by Eisenberger (1990), uses the power series method to solve the governing differential equation and obtains the buckling eigenvalue problem from the boundary terms. A few illustrative numerical examples are presented, focusing mainly on the comparison between the combined accuracy and computational effort associated with the determination of buckling solutions with the exact and standard GBT-based (finite) elements. This comparison shows that the GBT-based exact element method may lead to significant computational savings, particularly when the buckling modes exhibit larger half-wave numbers.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-03-27T10:12:13Z
      DOI: 10.1142/S0219455417501255
       
  • The Response and Instability of Cross-Rope Suspension Towers Under
           Harmonic Excitation
    • Authors: Zhitao Yan, Yu Zhu, Yi You, Jing Wang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The galloping or vortex-induced vibration of transmission lines will lead to a periodic excitations to the masts of the cross-rope suspension tower (CRST). The mast of the CRST is modeled as a straight beam with an elastic support subjected to a pulsating axial force on the top, which will change the stiffness of the mast, thereby resulting in produce harmonic excitation and instability. The dynamic characteristics of the system are investigated, which show that the bending frequency of the CRST decreases linearly with increase in axial static load, while it increases nonlinearly with the increase in boundary stiffness. Then, the method of multiple scales is adopted to analyze the vibration. It is found that the wind load on the mast brings primary resonance, but has no effects on instability. In addition, the steady state solution of the primary resonance is obtained by the polar form of the reduced amplitude modulation equations (RAMEs), with the effects of the following parameters on the vibration amplitude of the mast studied: the prestressing load in the guy, magnitude of the dynamic force, detuning parameter and wind load. Finally, the instability regions of two cases ([math] near [math] and [math] near [math]) are studied by the Cartesian form of the RAMEs, with focus on the influence of the axial harmonic load produced by the galloping of the transmission lines on the instability area. It is observed that the magnitude of excitation frequency of the dynamic force in the range of instability region becomes larger until the spring stiffness is increased up to a certain value.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-03-27T10:12:11Z
      DOI: 10.1142/S0219455417501243
       
  • Effects of Temperature Variation on Vibration of a Cable-Stayed Beam
    • Authors: Yaobing Zhao, Zhiqian Wang, Xiaoyu Zhang, Lincong Chen
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper is concerned with the temperature effect on the vibration of a cable-stayed beam. The thermal effect is considered by using two non-dimensional factors for the cable tension force and sag. The nonlinear in-plane and out-of-plane vibration equations of motion of the cable-stayed beam with thermal effect are derived by using the extended Hamilton’s principle. Eigenvalue analysis is performed to obtain closed-form eigenvalue solutions. It is shown that the effect of temperature variation plays a dominant role on the vibration behavior of the cable-stayed beam, and the effect is closely related with the initial tension force and the stiffness ratio. As to the in-plane motion, both positive and negative correlations between the temperature variations and natural frequencies are found, which depend on the mode order and the stiffness ratio of the cable-stayed beam. However, as to the out-of-plane motion, there only exist negative correlations between the temperature variation and natural frequencies, and the effect of temperature dropping condition seems more obvious. Moreover, both for the in-plane and out-of-plane motions, the locations of veering points between two natural frequencies are shifted under the thermal effect, which can significantly affect the internal resonance between different modes of the cable-stayed beam.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-03-21T08:18:49Z
      DOI: 10.1142/S0219455417501231
       
  • Resonance of a Quasi-Zero Stiffness Vibration System Under Base Excitation
           with Load Mismatch
    • Authors: Chun Cheng, Shunming Li, Yong Wang, Xingxing Jiang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The primary resonance and 1/3 subharmonic resonance of a quasi-zero stiffness (QZS) vibration system under base excitation with load mismatch are studied in this research. The incremental harmonic balance (IHB) method is applied to obtain highly accurate solutions involving more dynamic behaviors. The effect of the offset displacement mainly caused by overloading on the primary resonance and displacement transmissibility is investigated. The results indicate that the system exhibits a softening characteristic under certain conditions. Although the isolation performance of the QZS system deteriorates, it still outperforms the equivalent linear system for excitation amplitudes that are not too large. The parametric analysis of the 1/3 subharmonic resonance shows that the response is unbounded, and interesting dynamic behaviors can be observed, such as the jump phenomenon. Moreover, the 1/3 subharmonic resonance can be avoided by applying a larger damping or reducing the excitation amplitude to a lower level.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-03-16T04:05:24Z
      DOI: 10.1142/S0219455418500025
       
  • Seismic Analysis of Single-Layer Latticed Domes Composed of Welded Round
           Pipes Considering Low Cycle Fatigue
    • Authors: Da-bin Yang, Chun-yang Liu, Ming-na Hu, Xin Zhang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Member failure due to low cycle fatigue may occur for steel structures under strong earthquakes. In this paper, the seismic response of single-layer latticed domes composed of welded round pipes is analyzed by the software Open System for Earthquake Engineering Simulation (OpenSees) incorporating low cyclic fatigue, in which the equations of initial camber for members are obtained from the buckling coefficient curve of compression members in Chinese codes. Single-layer latticed domes composed of welded round pipes with different parameters are modeled, and the seismic responses of the domes with and without material fatigue are compared by the incremental dynamic analysis. The results show that under strong earthquakes, the seismic responses including the maximum displacements and plastic development of the domes with fatigue are larger than those of the domes without fatigue. The collapsed PGAs decrease by 10–25% if low cycle fatigue is incorporated. Therefore, the low cycle fatigue of material should be taken into account in the seismic analyses of single-layer latticed domes under strong earthquakes.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-03-16T04:05:23Z
      DOI: 10.1142/S021945541750122X
       
  • Reliability-Based Design of Tuned Mass Damper Using Monte Carlo Simulation
           Under Artificial Earthquake Records
    • Authors: Amin Gholizad, Seyyed Davood Ojaghzadeh Mohammadi
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Displacement- and reliability-based designs of tuned mass damper (TMD) for a shear building are studied herein. Different sources of uncertainties such as earthquake records and their peak ground accelerations (PGA), masses of floors, cross-sectional dimensions of structural members, damping of the structure and modulus of elasticity are considered. Monte Carlo simulation (MCS) is used for evaluating the performance of the designed TMD. A method for generating artificial earthquake record by using wavelet packet transform (WPT) and particle swarm optimization (PSO) is proposed to generate artificial records for areas without sufficient strong ground motion records. An illustrative example is used to study the displacement- and reliability-based designs of TMD, which are related to minimizing the structural displacement and maximizing the performance of TMD, respectively. In addition, the performance of TMD on mitigating the response of structure and its reliability under uncertain parameters of loading and structural properties are investigated. The results show that a displacement-based designed TMD could reduce the lateral displacement of a structure. Furthermore, it illustrates that the reliability-based designed TMD has a better performance in real condition of loading and structural parameters.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-03-16T04:05:20Z
      DOI: 10.1142/S0219455417501218
       
  • Damage-Based Inelastic Seismic Spectra
    • Authors: Rita Greco, Giuseppe Carlo Marano, Alessandra Fiore
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Current inelastic seismic spectra suffer from a conceptual limitation: they are significant only on the maximum demand of ductility and they do not include any influence of the number of response cycles, yield excursions, stiffness and strength degradation and damage potential to structures. This paper presents a stochastic approach for obtaining damage-based inelastic seismic spectra. In order to consider the cumulative damage phenomenon in structural systems under strong ground motions, the authors adopt the Park and Ang damage model that includes the displacement ductility and the hysteretic energy. The novelty is that the peak theory of random processes is adopted to achieve damage-based seismic spectra. This approach has some advantages compared with the standard statistical approaches based on a large number of recorded accelerograms. First, it drastically reduces the computational effort, while allowing us to typify the seismic motion by some parameters such as the frequency content, peak acceleration, energy content and strong motion duration, i.e. all the parameters that affect the structural response under seismic actions. Besides, it allows to obtain the following stochastic inelastic seismic response spectra: damage-based (i) displacement and acceleration inelastic spectra, (ii) response modification factor spectra, (iii) yield strength demand spectra, and (iv) damage-based inelastic displacement ratio spectra.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-03-14T06:29:05Z
      DOI: 10.1142/S0219455417501152
       
  • An Explicit Fourth-Order Runge–Kutta Method for Dynamic Force
           Identification
    • Authors: Tao Lai, Ting-Hua Yi, Hong-Nan Li, Xing Fu
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper presents a new technique for input reconstruction based on the explicit fourth-order Runge–Kutta (RK4) method. First, the state-space representation of the dynamic system is discretized by the explicit RK4 method under the assumption of linear interpolation for the dynamic load, leading to a recurrence equation between the current state and the previous state. Then, the mapping from the sequences of input to output is established through the recursive operation of the system equation and observation equation. Finally, the stabilized force information is recovered using the Tikhonov regularization method. This approach makes use of the good stability and high precision of the RK4 method; in addition, the computational efficiency is enhanced by avoiding the computation of the inverse stiffness matrix. The proposed method is numerically illustrated and validated with various excitations on a simple four-story shear building and a more complicated 2D truss structure, along with a detailed parametric study. The simulation studies show that the external loads can be reconstructed with high efficiency and accuracy under a low noise environment.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-03-09T08:59:24Z
      DOI: 10.1142/S0219455417501206
       
  • Alpha-Modification of Cubic B-Spline Direct Time Integration Method
    • Authors: Sobhan Rostami, Saeed Shojaee
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Recently, a conditionally stable explicit time integration scheme using the cubic B-spline function was proposed for solving the structural dynamic problems. This paper presents a new unconditionally stable version of the previous algorithm, based on the uniform cubic B-spline piecewise polynomial approximations and collocation method. First, the method is implemented to solve the differential equation of motion for the single-degree-of-freedom (SDOF) systems. Then, it is generalized for the multi-degree-of-freedom (MDOF) systems. In this paper, a simple step-by-step algorithm is presented for the proposed method, with the stability and accuracy analyses carried out. The unconditional stability of the method is achieved through use of an adjustable collocation parameter [math]. The computational accuracy and efficiency of the proposed method are demonstrated in three numerical examples.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-03-09T08:59:12Z
      DOI: 10.1142/S0219455417501188
       
  • Dynamic Pull-In Instability of a Thermoelectromechanically Loaded
           Micro-Beam Based on “Symmetric Stress” Gradient Elasticity Theory
    • Authors: L. Yang, F. Fang, J.S. Peng, J. Yang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The dynamic pull-in instability of a thermoelectromechanically loaded micro-beam is investigated based on the “symmetric stress” gradient elasticity theory and Euler–Bernoulli beam theory. The beam is subjected to the combined action of an electric voltage, axial static force and a uniform temperature change. By employing Galerkin’s method, the nonlinear partial differential governing equation is decoupled into a set of nonlinear ordinary differential equations, which are then solved using Runge–Kutta method. Numerical results show that compared with the size-dependent micro-beam model, the classical elasticity theory in which the size effect is ignored underestimates the pull-in voltage. The effects of size, temperature change, axial force, geometric nonlinearity, fringe effect, initial gap, beam length and width on the pull-in instability of the micro-beam are discussed in detail.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-03-03T06:42:30Z
      DOI: 10.1142/S0219455417501176
       
  • Axial-Delayed Control of Nonlinear Resonance of Nanobeams with Graphene
           Sensor
    • Authors: Canchang Liu, Qian Ding, Qingmei Gong, Chicheng Ma, Shuchang Yue, Lu Liu
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Nonlinear resonance response of an electrostatic-actuated nanobeam is controlled by using a delayed axial electrostatic force with near-half the natural frequency. A graphene sensor pasted on the surface of the nanobeam is used to extract the vibration voltage signal. An axial-delayed capacitive controller is designed to produce delayed axial force to control the nonlinear vibration of the nanobeam. The vibration voltage signal from the graphene sensor is input to the axial-delayed capacitive controller to attenuate the nonlinear vibration of the nanobeam. The dynamic response of the resonator is investigated by using the method of multiple scales directly. The sufficient conditions of guaranteeing the system stability and the saddle-node bifurcation are studied. The attenuation ratio is defined as the ratio of the peak amplitude of the nonlinear vibration system with control to that without control. A critical feedback gain is given, which can shift the frequency–amplitude curves from the nonlinear vibration to a linear vibration. An optimal method in which the attenuation ratio is taken as objective function and the aforementioned sufficient conditions as the constraint conditions is given to calculate the optimal feedback gains. Numerical simulations are conducted for uniform nanobeams.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-03-01T09:25:17Z
      DOI: 10.1142/S0219455417501164
       
  • Free Vibration of a Rotating Sandwich Plate with Viscoelastic Core and
           Functionally Graded Material Constraining Layer
    • Authors: Shince. V. Joseph, S. C. Mohanty
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Free vibration analysis of a sandwich plate with viscoelastic material core and functionally graded material (FGM) constraining layer under centrifugal force field is investigated herein. One edge of the sandwich plate is fixed to a rotating hub. The first-order shear deformation theory (FSDT) is used in the finite element modeling of the problem. The effects of strains due to the longitudinal and transverse deformations are also considered in addition to the shear deformation of the core. Various parametric studies are carried out to examine the effects of volume fraction index, setting angle, hub radius and rotational speed on the vibration characteristics of the sandwich plate. It is found that the fundamental frequency of the plate decreases with an increase in the volume fraction index of the FGM layer, viscoelastic core thickness and setting angle. The first mode loss factor increases with respect to the increasing volume fraction index. Increase in rotational speed and hub radius lead to an increase in the natural frequencies and a decrease in the modal loss factors.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-02-22T08:42:56Z
      DOI: 10.1142/S0219455417501140
       
  • Vibration Behavior of Gravity-Loaded Whirling Micro-Scale Shafts
           Influenced by an Axial Magnetic Field
    • Authors: K. B. Mustapha, Z. W. Zhong, S. B. A. Kashem
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Some high-speed rotating micro-machines and micro-vibration devices rely on the use of whirling micro-shafts subject to the effect of gravity and magnetic fields. At present, the consequences of the interaction between the elastic deformation of such shafts and the magnetic/gravitational field effects remain unresolved. Focusing on micro-scale whirling shafts with very high torsional rigidity, this study presents a theoretical treatment grounded in the theory of micro-continuum elasticity to examine the ramification of this interaction. The differential transformation method (DTM) is used to obtain extensive numerical results for qualitative assessments of the magnetic-gravitational effects interaction on standing, hanging and horizontally positioned spinning micro-scale shafts. The influence of bearing-support flexibility on the response of the whirling micro-shaft is also considered with rotational and translational springs. The gravitational sag reduces the stability of whirling standing micro-shafts and increases that of the hanging micro-shafts. Further, for all the micro-shafts configurations investigated, the magnetic field is observed to stiffen the response of the shaft and favorably shifts the critical points of vibration of the whirling shafts forward.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-02-14T02:24:06Z
      DOI: 10.1142/S0219455417501103
       
  • Free Vibration of Damaged Frame Structures Considering the Effects of
           Axial Extension, Shear Deformation and Rotatory Inertia: Exact Solution
    • Authors: Ugurcan Eroglu, Ekrem Tufekci
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In this paper, a procedure based on the transfer matrix method for obtaining the exact solution to the equations of free vibration of damaged frame structures, considering the effects of axial extension, shear deformation, rotatory inertia, and all compliance components arising due to the presence of a crack, is presented. The crack is modeled by a rotational and/or translational spring based on the concept of linear elastic fracture mechanics. Only the in-plane motion of planar structures is considered. The formulation is validated through some examples existing in the literature. Additionally, the mode shapes and natural frequencies of a frame with pitched roof are provided. The variation of natural frequencies with respect to the crack location is presented. It is concluded that considering the axial compliance, and axial-bending coupling due to the presence of a crack results in different dynamic characteristics, which should be considered for problems where high precision is required, such as for the crack identification problems.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-02-14T02:24:05Z
      DOI: 10.1142/S0219455417501115
       
  • Vibrational Analysis of Size-Dependent Rotating Micro-Rings
    • Authors: A. Karimzadeh, M. T. Ahmadian, K. Firoozbakhsh, M. Rahaeifard
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The size-dependent dynamic behavior and flexural vibration of rotating micro-rings are investigated in this paper. Using the modified couple stress theory and Hamilton’s principle, the governing equations of motion of the rotating micro-ring are derived. The natural frequencies for both extensional and inextensional micro-rings are obtained in closed form along with the forward and backward traveling waves derived. The results indicate that the natural frequencies of the rotating micro-ring are clearly size dependent, but the size dependency decreases as the speed of rotation of the ring increases, while it decreases when the radius-to-thickness ratio of the ring increases. A comparison between the natural frequencies of the extensional and inextensional micro-rings is performed. Moreover, the effect of the radius-to-thickness ratio of the ring on the behavior of the micro-ring is investigated. Good agreement is found between the natural frequencies obtained and the experimental results reported in the literature.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-02-08T03:20:40Z
      DOI: 10.1142/S0219455417710122
       
  • Semi-Active Vortex Induced Vibration Control of an Elastic Elliptical
           Cylinder with Energy Regeneration Capability
    • Authors: Seyyed M. Hasheminejad, Amir H. Rabiee, Miad Jarrahi
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The concept of energy-regenerative damping is adopted in semi-active vortex-induced vibration (VIV) suppression of an elastically supported inclined impenetrable elliptical cylinder modeled as a two degree-of-freedom (DOF) system in laminar cross-flow at low Reynolds numbers (Re [math] 210). It is based on the intelligent (model free) adaptive fuzzy sliding mode control (AFSMC) strategy in conjunction with switch-based energy regenerating circuit of a tunable electromagnetic (EM) damper. The semi-active damper is linked to the plant model in a multi-field co-simulation framework via MATLAB/Simulink coupled with a user defined function in a CFD package. The AFSM controller initially calculates the desired transverse control force for suppression of the cylinder VIV. Consequently, by smart adjustment of the variable circuit load resistance, the current flow through EM damper circuit is adaptively modulated in such a way that the damping force continually tracks its active counterpart in a semi-active manner. Furthermore, when the damper is operating in the regeneration mode, the mechanical vibration energy that is traditionally dissipated as heat in conventional viscous dampers will be stored as electric charge in a capacitor. Numerical simulations demonstrate that the regenerative semi-active EM-based VIV control system can effectively suppress the cylinder motion while recovering a certain portion of mechanical vibration energy through the cooperative action of two distinct operation modes of the EM damper. Unlike conventional active control systems, the proposed system does not require a large external power supply, and at least part of the required power may be provided by the recovered energy.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-02-08T03:20:37Z
      DOI: 10.1142/S0219455417501073
       
  • Dynamic Optimization of Functionally Graded Thin-Walled Box Beams
    • Authors: Karam Y. Maalawi
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper introduces a mathematical model for optimizing the dynamic performance of thin-walled functionally graded box beams with closed cross-sections. The objective function is to maximize the natural frequencies and place them at their target values to avoid the occurrence of large amplitudes of vibration. The variables considered include fiber volume fraction, fiber orientation angle and ply thickness distributions. Various power-law expressions describing the distribution of the fiber volume fraction have been implemented, where the power exponent was taken as the main optimization variable. The mass of the beam is kept equal to that of a known reference beam. Side constraints are also imposed on the design variables in order to avoid having unacceptable optimal solutions. The mathematical formulation is carried out in dimensionless quantities, enabling the generalization to include models with different cross-sectional types and beam configurations. The optimization problem is solved by invoking the MatLab optimization ToolBox routines, along with structural dynamic analysis and eigenvalue calculation routines. A case study on the optimization of a cantilevered, single-cell spar beam made of carbon/epoxy composite is considered. The results for the basic case of uncoupled bending motion are given. Conspicuous design charts are developed, showing the optimum design trends for the mathematical models implemented in the study. It is concluded that the natural frequencies, even though expressed in implicit functions, are well-behaved, monotonic and can be treated as explicit functions in the design variables. Finally, the developed models can be suitably used in the global optimization of typical composite, functionally graded, thin-walled beam structures.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-02-08T03:20:36Z
      DOI: 10.1142/S0219455417501097
       
  • Performance of Semi-Active Base Isolation Systems under External Explosion
    • Authors: M. Mohebbi, H. D. Dadkhah
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Structures designed against earthquake loads based on using control systems may experience explosions during their lifetime. In this paper, the performance of a hybrid control system composed of a low-damping base isolation and a supplemental magneto-rheological (MR) damper under external explosion has been studied. Base isolation system has the ability of decreasing the maximum structural response under blast loadings by shifting the period of the structure. In addition, MR damper improves the base isolation system performance by controlling the base drift of the structure. Hence, in this paper, the capability of a hybrid base isolation system equipped with an MR damper at the base has been evaluated in reducing the maximum structural response and base drift under external blast loadings. To determine the voltage of the semi-active MR damper, the H2/Linear Quadratic Gaussian (LQG) and clipped-optimal control algorithms have been applied. For numerical simulations, a 10-storey shear frame subjected to blast loadings applied on different floors has been considered and the performance of the hybrid isolation system and MR damper has been studied. The results have proven the effectiveness of the hybrid control system in controlling the maximum response and base drift of the isolated structure against spherical external explosion. Furthermore, comparing the performance of the hybrid passive and semi-active base isolation systems indicates that the semi-active hybrid base isolation system is more effective in reducing the root-mean-square (RMS) value of the base drift. Similarly, it has been found that the semi-active hybrid base isolation system also performs better than the high-damping base isolation system.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-02-08T03:20:31Z
      DOI: 10.1142/S0219455417501127
       
  • Vibro-Acoustic Analysis of the Railway Tracks with Fractional Railpads and
           Nonlinear Ballast
    • Authors: Ali Hosseinkhani, Davood Younesian
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Noise and vibration from the railway tracks with fractional railpads are studied in this paper. The track system is modeled by a beam on a viscoelastic foundation including the fractional railpads and nonlinear ballast. The nonlinear fractional governing equation is obtained in the time domain by use of the fractional finite element formulation. The Newmark’s method is combined with the Adomian decomposition method (ADM) to solve the nonlinear fractional equation. The acoustical pressure field around the vibrating beam is obtained by the Rayleigh integral approach. The effects of the fractional parameters, load speed and condition on the track responses are investigated. It is found that the dynamic deflection and stress alongside the railways are more influenced by the loading condition, while the acoustical pressure is remarkably influenced by the load speed.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-02-08T03:20:27Z
      DOI: 10.1142/S021945541750105X
       
  • A New Reliability Method Combining Kriging and Probability Density
           Evolution Method
    • Authors: Zhongming Jiang, Jie Li
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Stochastic dynamic analysis of structures with random parameters continues to be an open question in the field of civil engineering. As a newly developed method, the probability density evolution method (PDEM) can provide the probability density function (PDF) of the dynamic responses of highly nonlinear structures. In this paper, a new method based on PDEM and the kriging surrogate model, named the K-PDEM, is proposed to study the stochastic response of a structure. Being an exact interpolation method, the Gaussian process regression or the so-called kriging method is capable of producing highly accurate results. Unlike the traditional PDEM numerical method whose numerical precision is strongly influenced by the number of representative points, the K-PDEM employs the kriging method at each instant to generate additional time histories. Then, the PDEM, which is capable of capturing the instantaneous PDF of a dynamic response and its evolution, is employed in nonlinear stochastic dynamic systems. Because of the decoupling properties of the K-PDEM, the numerical precision of the result is improved by the enrichment of the generalized density evolution equations without increasing the computation time. The result shows that the new method is capable of calculating the stochastic response of structures with efficiency and accuracy.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-02-08T03:20:25Z
      DOI: 10.1142/S0219455417501139
       
  • Consistent Multilevel RDT-ERA for Output-Only Ambient Modal Identification
           of Structures
    • Authors: Zhouquan Feng, Wenai Shen, Zhengqing Chen
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper presents an improved method called the consistent multilevel random decrement technique in conjunction with eigensystem realization algorithm (RDT-ERA) for modal parameter identification of linear dynamic systems using the ambient vibration data. The conventional RDT-ERA is briefly revisited first and the problem of triggering level selection in the RDT is thoroughly studied. Due to the use of a single triggering level by the conventional RDT-ERA, an inappropriate triggering level may produce poor random decrement (RD) functions, thereby yielding a poor estimate of modal parameters. In the proposed consistent multilevel RDT-ERA, multiple triggering levels are used and a consistency analysis is proposed to sift out the RD functions that deviate largely from the majority of the RD functions. Then the ERA is applied to the retained RD functions for modal parameter identification. Subsequently, a similar consistency analysis is conducted on the identified modal parameters to sift out the outliers. Finally, the final estimates of the modal parameters are calculated using weighted averaging with the weights set proportional to the number of RD segments extracted from the corresponding triggering levels. The proposed method is featured by the fact that the information from the signal is fully utilized using multiple triggering levels and the outliers are sifted out using consistency analysis, thus making the identified result more accurate and reliable. The effectiveness and accuracy of the method have been demonstrated in the examples using the simulated data and experimental data.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-01-25T08:49:37Z
      DOI: 10.1142/S0219455417501061
       
  • Damage and Risk Assessment for Single-Layer Reticulated Domes Subject to
           Explosive Blast Loads
    • Authors: X. D. Zhi, M. G. Stewart
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In order to provide a better understanding of the dynamic behavior of single-layer reticulated domes subjected to explosive blast loads, a number of analyses are carried out on structures with different standoff distances ([math], explosive weights ([math], rise–span ratios ([math] and other parameters. An equation for a structural damage factor is proposed to evaluate structural damage quantitatively. The damage states for single-layer reticulated domes are defined based on their structural dynamic performance and corresponding damage factors. Structural reliabilities for different standoff distances are obtained using the Monte-Carlo Analysis. A typical protective measure is bollards which are used to help ensure a minimum standoff distance. To illustrate the cost-effectiveness of such a protective measure, structural damage states and various losses, including direct and indirect economic loss and maimed and fatality loss, are considered for assessing the risk reduction, costs and benefits. It was found that the bollards significantly reduce the likelihood of structural progressive collapse or severe damage, and the optimal standoff distance can be determined.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-01-25T08:49:36Z
      DOI: 10.1142/S0219455417501085
       
  • Analytical and Finite Element Buckling Solutions of Fixed–Fixed
           Anisotropic Laminated Composite Columns Under Axial Compression
    • Authors: Rund Al-Masri, Hayder A. Rasheed
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      A generalized analytical formula is developed to predict buckling of anisotropic laminated composite fixed–fixed thin columns by using the Rayleigh–Ritz displacement field approximation. Based on the generalized constitutive relationship, the effective extensional, coupling and flexural stiffness coefficients of the anisotropic layup are determined using dimensional reduction by static condensation of the 6[math][math][math]6 composite stiffness matrix. The resulting explicit formula is expressed in terms of the flexural stiffness since the coupling and extensional stiffness coefficients drop out of the formulation for this boundary condition when following the standard Rayleigh–Ritz formulation steps. This formula is similar to the Euler buckling formula in which the flexural rigidity is expressed in terms of the flexural stiffness coefficient of laminated composites. Motivated by reducing some of the discrepancy with the finite element results, the pre-buckling solution was substituted into the bifurcation expression to yield an updated formula that includes the coupling and extensional stiffness coefficients. The analytical results are verified against finite element Eigen value solutions for a wide range of anisotropic laminated layups yielding high accuracy. A parametric study is then conducted to examine the effect of ply orientation and material properties including hybrid carbon/glass fiber composites. Relevance of the numerical and analytical results is discussed for all these cases. In addition, comparisons with an earlier buckling solution for cross-ply laminated columns are made.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-01-23T08:40:32Z
      DOI: 10.1142/S0219455417501036
       
  • Correlation and Combination Factors of Wind Forces on Cylindrical Roof
           Structures
    • Authors: Bo Chen, Pengpeng Zhong, Weihua Cheng, Xinzhong Chen, Qingshan Yang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The correlations among wind pressures on roof and walls are examined for the cylindrical roof buildings with different rise-span ratios based on wind tunnel data. Wind-induced dynamic response is also analyzed with a parametric study concerning span length, rise-span ratio, stiffness of supporting frames and connection type between roof and supporting frames, where the roof system is a single-layer cylindrical reticular shell. For both roof and supporting frames, the responses induced by vertical wind loads on the roof and by horizontal wind loads on the walls are investigated. The correlation coefficients of these response components are examined. The results showed that the fluctuating wind pressure on the roof is strongly correlated with the wind pressure on the side wall and the leeward wall, but weakly correlated with the wind pressure on the windward wall. The response of roof and supporting frames caused by the wind loads on the roof is much larger than that of wind loads on the walls. On the bases of a comprehensive parameter study and complete quadratic combination (CQC) rule, a practical simplified combination rule is suggested for estimating response of roof and supporting frames. It is given as sum of response component caused by wind load on roof and that of wind load on walls multiplied with a combination factor of [math].
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2017-01-19T08:12:18Z
      DOI: 10.1142/S0219455417501048
       
 
 
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