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  Subjects -> ENGINEERING (Total: 2515 journals)
    - CHEMICAL ENGINEERING (210 journals)
    - CIVIL ENGINEERING (219 journals)
    - ELECTRICAL ENGINEERING (120 journals)
    - ENGINEERING (1320 journals)
    - ENGINEERING MECHANICS AND MATERIALS (403 journals)
    - HYDRAULIC ENGINEERING (57 journals)
    - INDUSTRIAL ENGINEERING (84 journals)
    - MECHANICAL ENGINEERING (102 journals)

CIVIL ENGINEERING (219 journals)                  1 2 | Last

Showing 1 - 200 of 219 Journals sorted alphabetically
ACI Structural Journal     Full-text available via subscription   (Followers: 20)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 3)
Acta Structilia : Journal for the Physical and Development Sciences     Open Access   (Followers: 3)
Advances in Civil Engineering     Open Access   (Followers: 43)
Advances in Structural Engineering     Full-text available via subscription   (Followers: 34)
Agregat     Open Access   (Followers: 1)
Ambiente Construído     Open Access   (Followers: 1)
American Journal of Civil Engineering and Architecture     Open Access   (Followers: 36)
Architectural Engineering     Open Access   (Followers: 5)
Architecture and Engineering     Open Access  
Architecture, Civil Engineering, Environment     Open Access   (Followers: 1)
Archives of Civil and Mechanical Engineering     Full-text available via subscription   (Followers: 3)
Archives of Civil Engineering     Open Access   (Followers: 13)
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: 7)
Baltic Journal of Road and Bridge Engineering     Open Access   (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: 2)
BER : Building Sub-Contractors' Survey     Full-text available via subscription   (Followers: 2)
BER : Survey of Business Conditions in Building and Construction : An Executive Summary     Full-text available via subscription   (Followers: 3)
Berkeley Planning Journal     Open Access   (Followers: 6)
Bioinspired Materials     Open Access   (Followers: 5)
Bridge Structures : Assessment, Design and Construction     Hybrid Journal   (Followers: 14)
Building & Management     Open Access   (Followers: 2)
Building and Environment     Hybrid Journal   (Followers: 16)
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: 14)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 6)
Case Studies in Nondestructive Testing and Evaluation     Open Access   (Followers: 11)
Case Studies in Structural Engineering     Open Access   (Followers: 10)
Cement and Concrete Composites     Hybrid Journal   (Followers: 20)
Challenge Journal of Concrete Research Letters     Open Access   (Followers: 3)
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: 8)
Civil and Environmental Engineering Reports     Open Access   (Followers: 8)
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: 24)
Civil Engineering and Environmental Systems     Hybrid Journal   (Followers: 3)
Civil Engineering and Technology     Open Access   (Followers: 13)
Civil Engineering Dimension     Open Access   (Followers: 12)
Civil Engineering Infrastructures Journal     Open Access   (Followers: 1)
Cohesion and Structure     Full-text available via subscription   (Followers: 2)
Composite Structures     Hybrid Journal   (Followers: 291)
Computer-aided Civil and Infrastructure Engineering     Hybrid Journal   (Followers: 11)
Computers & Structures     Hybrid Journal   (Followers: 37)
Concrete Research Letters     Open Access   (Followers: 7)
Construction Economics and Building     Open Access   (Followers: 4)
Construction Engineering     Open Access   (Followers: 11)
Construction Management and Economics     Hybrid Journal   (Followers: 21)
Constructive Approximation     Hybrid Journal  
Construindo     Open Access  
Curved and Layered Structures     Open Access   (Followers: 3)
DFI Journal : The Journal of the Deep Foundations Institute     Hybrid Journal   (Followers: 1)
Earthquake Engineering and Structural Dynamics     Hybrid Journal   (Followers: 17)
Enfoque UTE     Open Access   (Followers: 4)
Engineering Project Organization Journal     Hybrid Journal   (Followers: 7)
Engineering Structures     Hybrid Journal   (Followers: 13)
Engineering Structures and Technologies     Open Access   (Followers: 3)
Engineering, Construction and Architectural Management     Hybrid Journal   (Followers: 10)
Environmental Geotechnics     Hybrid Journal   (Followers: 5)
European Journal of Environmental and Civil Engineering     Hybrid Journal   (Followers: 10)
Fatigue & Fracture of Engineering Materials and Structures     Hybrid Journal   (Followers: 19)
Frontiers in Built Environment     Open Access   (Followers: 1)
Frontiers of Structural and Civil Engineering     Hybrid Journal   (Followers: 6)
Gaceta Técnica     Open Access  
Geomaterials     Open Access   (Followers: 3)
Geosystem Engineering     Hybrid Journal   (Followers: 2)
Geotechnik     Hybrid Journal   (Followers: 4)
Géotechnique Letters     Hybrid Journal   (Followers: 8)
GISAP : Technical Sciences, Construction and Architecture     Open Access  
HBRC Journal     Open Access   (Followers: 2)
Hormigón y Acero     Full-text available via subscription  
HVAC&R Research     Hybrid Journal  
Indonesian Journal of Urban and Environmental Technology     Open Access  
Indoor and Built Environment     Hybrid Journal   (Followers: 3)
Infrastructure Asset Management     Hybrid Journal   (Followers: 3)
Infrastructures     Open Access  
Ingenio Magno     Open Access   (Followers: 1)
Insight - Non-Destructive Testing and Condition Monitoring     Full-text available via subscription   (Followers: 36)
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: 17)
International Journal of Civil, Mechanical and Energy Science     Open Access   (Followers: 2)
International Journal of Concrete Structures and Materials     Open Access   (Followers: 15)
International Journal of Condition Monitoring     Full-text available via subscription   (Followers: 2)
International Journal of Construction Engineering and Management     Open Access   (Followers: 10)
International Journal of Engineering and Geosciences     Open Access  
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: 6)
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: 9)
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: 5)
International Journal of Sustainable Construction Engineering and Technology     Open Access   (Followers: 8)
International Journal on Pavement Engineering & Asphalt Technology     Open Access   (Followers: 7)
International Journal Sustainable Construction & Design     Open Access   (Followers: 2)
Journal of Applied Research in Water and Wastewater     Open Access   (Followers: 1)
Journal of Bridge Engineering     Full-text available via subscription   (Followers: 13)
Journal of Building Engineering     Hybrid Journal   (Followers: 2)
Journal of Building Materials and Structures     Open Access   (Followers: 2)
Journal of Building Performance Simulation     Hybrid Journal   (Followers: 6)
Journal of Civil Engineering     Open Access   (Followers: 1)
Journal of Civil Engineering and Construction Technology     Open Access   (Followers: 16)
Journal of Civil Engineering and Management     Open Access   (Followers: 7)
Journal of Civil Engineering and Science     Open Access   (Followers: 10)
Journal of Civil Engineering Research     Open Access   (Followers: 8)
Journal of Civil Engineering, Science and Technology     Open Access   (Followers: 1)
Journal of Civil Society     Hybrid Journal   (Followers: 5)
Journal of Civil Structural Health Monitoring     Hybrid Journal   (Followers: 4)
Journal of Composites     Open Access   (Followers: 79)
Journal of Composites for Construction     Full-text available via subscription   (Followers: 13)
Journal of Computing in Civil Engineering     Full-text available via subscription   (Followers: 23)
Journal of Construction Engineering     Open Access   (Followers: 9)
Journal of Construction Engineering and Management     Full-text available via subscription   (Followers: 18)
Journal of Construction Engineering, Technology & Management     Full-text available via subscription   (Followers: 4)
Journal of Constructional Steel Research     Hybrid Journal   (Followers: 6)
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: 10)
Journal of Highway and Transportation Research and Development (English Edition)     Full-text available via subscription   (Followers: 14)
Journal of Infrastructure Systems     Full-text available via subscription   (Followers: 19)
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: 6)
Journal of Materials in Civil Engineering     Full-text available via subscription   (Followers: 8)
Journal of Nondestructive Evaluation     Hybrid Journal   (Followers: 9)
Journal of Offshore Structure and Technology     Full-text available via subscription  
Journal of Performance of Constructed Facilities     Full-text available via subscription   (Followers: 3)
Journal of Pipeline Systems Engineering and Practice     Full-text available via subscription   (Followers: 6)
Journal of Rehabilitation in Civil Engineering     Open Access   (Followers: 4)
Journal of Road and Traffic Engineering     Open Access  
Journal of Solid Waste Technology and Management     Full-text available via subscription   (Followers: 1)
Journal of Structural Engineering     Full-text available via subscription   (Followers: 36)
Journal of Structural Fire Engineering     Full-text available via subscription   (Followers: 6)
Journal of Structural Mechanics     Open Access   (Followers: 1)
Journal of Structures     Open Access   (Followers: 4)
Journal of Sustainable Architecture and Civil Engineering     Open Access   (Followers: 4)
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   (Followers: 2)
Journal of the South African Institution of Civil Engineering     Open Access   (Followers: 2)
Journal of Water and Environmental Nanotechnology     Open Access  
Journal of Water and Wastewater / Ab va Fazilab     Open Access  
Jurnal Spektran     Open Access   (Followers: 1)
Jurnal Teknik Sipil     Open Access  
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)
Lithosphere     Open Access  
Materiales de Construcción     Open Access   (Followers: 1)
Mathematical Modelling in Civil Engineering     Open Access   (Followers: 5)
Media Komunikasi Teknik Sipil     Open Access  
Media Teknik Sipil     Open Access  
Mokslas – Lietuvos ateitis / Science – Future of Lithuania     Open Access  
Nondestructive Testing And Evaluation     Hybrid Journal   (Followers: 15)
npj Materials Degradation     Open Access  
Obras y Proyectos     Open Access   (Followers: 1)
Open Journal of Civil Engineering     Open Access   (Followers: 9)
Periodica Polytechnica Civil Engineering     Open Access  
Photonics and Nanostructures - Fundamentals and Applications     Hybrid Journal   (Followers: 4)
Practice Periodical on Structural Design and Construction     Full-text available via subscription   (Followers: 3)
Proceedings of the Institution of Civil Engineers - Bridge Engineering     Hybrid Journal   (Followers: 8)
Proceedings of the Institution of Civil Engineers - Civil Engineering     Hybrid Journal   (Followers: 14)
Proceedings of the Institution of Civil Engineers - Management, Procurement and Law     Hybrid Journal   (Followers: 10)
Proceedings of the Institution of Civil Engineers - Municipal Engineer     Hybrid Journal   (Followers: 2)
Proceedings of the Institution of Civil Engineers - Structures and Buildings     Hybrid Journal   (Followers: 4)
Promet : Traffic &Transportation     Open Access  
Random Structures and Algorithms     Hybrid Journal   (Followers: 5)
Recent Trends In Civil Engineering & Technology     Full-text available via subscription   (Followers: 5)
REDER : Revista de Estudios Latinoamericanos sobre Reducción del Riesgo de Desastres     Open Access  
Research in Nondestructive Evaluation     Hybrid Journal   (Followers: 6)
Resilience     Open Access   (Followers: 1)
Revista de Investigación     Open Access  
Revista IBRACON de Estruturas e Materiais     Open Access   (Followers: 1)
Revista Sul-Americana de Engenharia Estrutural     Open Access  
Road Materials and Pavement Design     Hybrid Journal   (Followers: 11)
Russian Journal of Nondestructive Testing     Hybrid Journal   (Followers: 5)
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: 5)
Steel Construction - Design and Research     Hybrid Journal   (Followers: 3)
Structural and Multidisciplinary Optimization     Hybrid Journal   (Followers: 11)
Structural Concrete     Hybrid Journal   (Followers: 11)
Structural Control and Health Monitoring     Hybrid Journal   (Followers: 8)
Structural Engineering International     Full-text available via subscription   (Followers: 11)
Structural Mechanics of Engineering Constructions and Buildings     Open Access   (Followers: 1)
Structural Safety     Hybrid Journal   (Followers: 6)
Structural Survey     Hybrid Journal  
Structure     Full-text available via subscription   (Followers: 24)

        1 2 | Last

Journal Cover
International Journal of Structural Stability and Dynamics
Journal Prestige (SJR): 1.005
Citation Impact (citeScore): 2
Number of Followers: 7  
 
  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]
  • Dynamic Stability of Slender Concrete-Filled Steel Tubular Columns with
           General Supports
    • Authors: Youqin Huang, Jiyang Fu, Di Wu, Airong Liu, Wei Gao, Yonglin Pi
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The static stability of slender concrete-filled steel tubular (CFST) columns has been explored thoroughly while few researches have been carried out on the dynamic stability of CFST columns even if all applied loadings are naturally time-dependent. This paper presents an analytical procedure for evaluating the dynamic stability of CFST columns of various composite cross-sections under general boundary conditions. This paper is featured by the following facts: (1) proportional damping is considered in derivation of the governing equations on the lateral parametric vibration of the CFST columns subject to axial excitation; (2) Bolotin’s method is used to determine the boundaries of the regions of dynamic instability for the CFST columns with general supports; (3) the relationship of static and dynamic stability, and the effects of boundary conditions and cross-sectional forms are uncovered. New findings of this investigation are (1) larger amplitude or constant component of excitation make it easier for the dynamic instabilities of the CFST columns to occur, while increasing the constant component of excitation reduces the critical value of frequency ratio for the dynamic instability to occur; (2) the dynamic stability analysis can determine the critical loads for both the static and dynamic instability of CFST columns, and the critical instability load decreases with increasing disturbance on the static load; (3) under the same consumptions of steel and concrete, the square columns have better performance of dynamic stability than the circular columns, but there is no definite conclusion on the effect of hollow size on the dynamic stability of double-skin columns.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-12-10T02:21:15Z
      DOI: 10.1142/S0219455419500457
       
  • Spectro-Temporal Responses of Curved Railway Tracks with Variable Radii of
           Arc Curves
    • Authors: Sakdirat Kaewunruen, Chayut Ngamkhanong, Xin Liu
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      On curved railway tracks, wheel/rail interface can usually cause a traveling source of sound and vibration, which constitutes high-pitch or tonal noise pollution causing considerable concern to rail asset owners, commuters and people living or working along the railway corridor. The sound and vibration can be in various forms and spectra. The undesirable tonal sound on curves caused by excessive lateral wheel/rail dynamics in resonance with falling friction states are often called ‘squeal noises’. This paper evaluates the transient effect of curve radii on the possible occurrence of lateral track resonances, which is a principal cause of dynamic wheel/rail mode coupling that could trigger ‘curve squeal’. This study is devoted to systems thinking approach and better insight into dynamic phenomena of railway tracks that could resolve the railway curve noise problems. Curved track models in three-dimensional space have been developed using a finite element package, STRAND7. The dynamic responses of curved track have been simulated by applying a moving train load. The transient loading model of a common wheel/rail slip has been adopted. The simulations of railway tracks with different curve radii have been carried out to develop state-of-the-art understanding of lateral track dynamics, including rail dynamics, cant dynamics and overall track responses. Parametric studies have been conducted to evaluate lateral displacements, velocities and accelerations of rail over sleeper and rail at midspan, both in static and dynamic conditions. The study firstly reveals that the lateral resonance of tangent tracks is relatively rare and the mode coupling behavior is unlikely to occur on moderately curved tracks. The lateral vibration responses have been presented in terms of time histories and spectro-temporal responses (also called “Spectogram”). The dynamic lateral responses of the track are found to be sensitive to the change of curved radii. The resonance peak in the lateral direction is related to the agreement of corresponding natural frequencies of rail and the vibration excitation frequencies under an individual rolling velocity. The outcome of this study establishes new insight into the dominant influences of different track parameters to track lateral dynamic behaviors.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-12-10T02:21:10Z
      DOI: 10.1142/S0219455419500445
       
  • Energy Harvesting Optimizing with a Magnetostrictive Cantilever Beam
           System
    • Authors: Marek Borowiec, Arkadiusz Syta, Grzegorz Litak
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Vibration energy is scavenged by a beam system based on magnetostrictive material (MsM). The system consists of interconnected substructural beams (aluminum and magnetostrictive layers) with a neutral stress axis shifted away from the axis of symmetry of the magnetostrictive beam. The coil that generates the electromotive force is wound on the composite beam. The study investigates the effects of a tip mass placed at the end of the beam and the beam thickness influence. Multiple solutions are found for high amplitudes, and the optimal configuration of the operating conditions is proposed. In addition, the sensitivity of the system to the initial conditions is compared for the first three resonance areas, leading to determination of two types of solutions with different levels of power output.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-12-05T06:10:04Z
      DOI: 10.1142/S0219455419410025
       
  • Assessment of Internal Loads in the Joints of the Lower Extremities During
           the Snatch in Young Weightlifters
    • Authors: Adam Czaplicki, Krzysztof Dziewiecki, Zenon Mazur, Wojciech Blajer
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The aim of this paper is to present the results of an assessment of internal loads in the joints of the lower limbs during the snatch performed by young weightlifters. A planar model of a weightlifter composed of 7 rigid segments (the lower trunk, thighs, lower legs and feet) connected by six hinge joints was used in the computations. The dynamic equations of the motion of the model were obtained using a projective technique. Kinematic data were recorded by a Vicon system with a sampling frequency of 200 Hz. The ground reactions were measured independently for the left and right limbs on two force platforms. The inverse dynamics problem was solved to assess the internal loads (the muscle forces and joint reactions) in the lower limbs. Relatively high differences in the reactions in the joints and muscle forces in the left and right lower extremities were identified. The obtained results also reveal that the snatch, a lift which tends to be geometrically symmetrical in the sagittal plane, is not necessarily characterized by symmetry of internal loads. Thus, this study has shown that a kinematics analysis of the lifter’s movement, which is commonly used to assess the technique of the snatch, is insufficient and should be supplemented with a dynamics analysis.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-12-03T02:43:42Z
      DOI: 10.1142/S0219455419410116
       
  • Amplitude-Dependent Damping: Experimental Determination and Functional
           Interpretation for Metal–Plastic Composites
    • Authors: Matthias Klaerner, Mario Wuehrl, Lothar Kroll, Steffen Marburg
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Composite materials offer a high freedom of design with regard to stiffness, strength and damping. In contrast to efficient anisotropic but linear material models, these composites often tend to react nonlinearly. Commonly, such nonlinear material damping models imply frequency and temperature dependency. In addition, some materials show a substantial amplitude sensitivity of the damping. Within this study, metal–plastic composites with highly dissipating shear sensitive cores have been used to experimentally determine the damping values with varying amplitudes. The results show a significance of this parameter already for small deflection within the geometrically linear range. The derived nonlinearity is further described by an exponential approach and parametrized by a regression analysis. Furthermore, the amplitude sensitivity is retraced to the contributions of the layered material by a detailed numerical analysis of the stress states. Therefrom, the mean strain energy density per material is derived as an amplitude criterion for the nonlinear damping model. The resulting model can be further applied to the finite element analysis to improve the determination of vibrations as well as structure borne sound of such acoustically improved materials.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-12-03T02:43:42Z
      DOI: 10.1142/S0219455419410013
       
  • An Influence of Homogeneity of Magnetic Field on Stability of a
           Rectangular Plate
    • Authors: Piotr Kȩdzia, Krzysztof Magnucki, Mikołaj Smyczyński, Iwona Wstawska
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The main objective of presented work is a rectangular plate subjected to dynamic in-plane load generated by magnetic field. The plate is made of polyethylene (PE). There are two pockets on each of the two opposite edges of the plate. These pockets with porous structure are filled in with ferrofluid. The coil system consists of two magnetic field coil subsystems. These systems are built of Helmholtz (MC) and Golay coils (GC) and generate nonhomogeneous magnetic field. If the magnetic field is more homogeneous, the compression load is induced. In other cases, local tensile load occurs (compression load dominates). For presented coil systems, the intensity of load was examined for two variants. For the first of them, the intensity of load was dependent on the radius of Golay coil arcs. The change of the radius of saddle coils also influences on the strength of the gradient of the magnetic field. The second one describes the intensity of load which depends on the change of GC radius without changing the strength of magnetic field (the strength of magnetic field is compensated with changing the current flowing through the coils wires or with changing the number of wires). In this paper, the analytical model of the plate is presented. The model of the plate was formulated with the use of classical Kirchhoff–Love hypothesis. Elastic strain energy, kinetic energy as well as work of load were formulated. The equation of motion was derived based on the Hamilton’s principle. The numerical studies were related to the analysis of the intensity of load distribution.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-12-03T02:43:41Z
      DOI: 10.1142/S0219455419410037
       
  • Analytical and Numerical Study on a Parametric Pendulum with the Step-Wave
           Modulation of Length and Forcing
    • Authors: Paweł Olejnik, Michal Fečkan, Jan Awrejcewicz
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      A parametric pendulum excited by a discrete wave-modulated step function of length is subjected to a mathematical analysis and numerical modeling. We observe an existence of almost periodic solutions of ordinary differential equations with linear boundary value conditions. An exemplary oscillator subject to both an almost periodic step elongation and forcing synchronizes with the forcing, tending to almost periodic motions like stable limit cycles. Conditions for that synchronization as well as trajectories of numerical solutions on time history plots and phase planes are shown to confirm correctness of the analytical derivations and dedicated numerical modeling.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-12-03T02:43:41Z
      DOI: 10.1142/S0219455419410062
       
  • Control Force Recalculation for Balancing Problems
    • Authors: Bálint Bodor, László Bencsik, Tamás Insperger
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Understanding the mechanism of human balancing is a scientifically challenging task. In order to describe the nature of the underlying control mechanism, the control force has to be determined experimentally. A main feature of balancing tasks is that the open-loop system is unstable. Therefore, reconstruction of the trajectories using the measured control force is difficult, since measurement inaccuracies, noise and numerical errors increase exponentially with time. In order to overcome this problem, a new approach is proposed in this paper. In the presented technique, first the solution of the linearized system is used. As a second step, an optimization problem is solved which is based on a variational principle. A main advantage of the method is that there is no need for the numerical differentiation of the measured data for the calculation of the control forces, which is the main source of the numerical errors. The method is demonstrated in case of a human stick balancing.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-12-03T02:43:40Z
      DOI: 10.1142/S0219455419410104
       
  • Enhancing the Stability of the Switched Systems Using the Saltation Matrix
    • Authors: Juan-Guillermo Muñoz, Arnold Pérez, Fabiola Angulo
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Controlling switched systems is a difficult task, even when dealing with piecewise linear systems (CPWLs), which consist of a set of linear differential equations and a set of switching conditions. This difficulty is largely due to the loss of linearity in the entire system, and it is necessary to solve differential and algebraic equations to determine the solution. In this paper, a new method to tune the parameters of the controllers applied to switched systems is derived using information from the saltation matrix, particularly its induced norm. First, the parameters are tuned using classical methods, and then, after analyzing the norm of the saltation matrix, a new set of parameters that guarantees the stability of the period-1 orbit is obtained. The method is validated using analytical solutions for two different systems (boost and boost-flyback power converters) and is also experimentally validated for the boost-flyback power converter.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-12-03T02:43:40Z
      DOI: 10.1142/S0219455419410049
       
  • Selected Properties of the Hybrid Micro-Installation Model Based on
           Electrochemical Battery and PV Module
    • Authors: Adrian Chmielewski, Jakub Możaryn, Krzysztof Bogdziński, Piotr Piórkowski, Tomasz Mydłowski, Robert Gumiński, Jędrzej Mączak
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In this paper, a theoretical model of an electrochemical battery connected with three diode model of a photovoltaic module is presented. To calculate selected parameters of the electrochemical battery model an iteration-approximation method has been employed. Then there are presented chosen curves of LiFePO4 batteries obtained from the experimental research and simulation of the thermal-electrochemical model well known as a combined model. Moreover, by using a combined model, the heat generation of the battery has been calculated. The model was prepared to analyze the influence of selected thermodynamic and electrochemical parameters including the shunt resistance value, series resistance value, solar radiation power density on the photovoltaic module power value for winter and summer season. As a result of the performed simulations with photovoltaic (PV) module and without PV module in the specific daily cycle, the curves of battery state of charge (SOC) have been shown. The presented results inform about the dynamic operation of the simulated LiFePO4 batteries which are integrated with PV module in hybrid micro-installation.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-12-03T02:43:39Z
      DOI: 10.1142/S0219455419410050
       
  • Modeling and Control of an Eight-Legged Walking Robot Driven by Different
           Gait Generators
    • Authors: Dariusz Grzelczyk, Jan Awrejcewicz
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In this paper, we studied both kinematic and dynamic models of a mammal-like octopod robot. To control robot legs, we employed a simple gait generator based on a sine function and we proposed modified generators of gait. The introduced generators allowed us to obtain better kinematic and dynamic properties of motion of the whole robot during walking. By changing the length and the height of a single robot step, it is possible to use one model to control the initial, regular, and final phases of the robot gait without the need of generating additional control signals. The simulation parameters were estimated based on the prototype designed in Inventor software. In turn, for numerical research, we used a simulation model implemented in Mathematica. The obtained results were presented in the form of time histories of basic kinematic and dynamic quantities of the robot gait as well as the configuration of the robot legs at the chosen time moments. The presented method allows us to precisely control the robot position in the vertical direction, which is also presented in this paper. As a result, we obtained better stability of the whole robot during walking and performing tasks, also on slippery terrains, i.e. on terrains with relatively low coefficient of friction between the ground and the robot feet.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-12-03T02:43:38Z
      DOI: 10.1142/S0219455419410098
       
  • Elastically Mounted Double Aerodynamic Pendulum
    • Authors: Yury D. Selyutskiy, Andrei P. Holub, Marat Z. Dosaev
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Elastically mounted double aerodynamic pendulum is an aeroelastic system with two rotational degrees of freedom. A wing is attached to the second link of the pendulum. It is shown that it is possible to select values of parameters in such a way as to make the trivial equilibrium (where both links of the pendulum are stretched along the flow) unstable. Numerical simulation of behavior of the system in such situations is performed, and arising limit cycles are studied. Experimental investigation of such aerodynamic pendulum is performed in the subsonic wind tunnel of the Institute of Mechanics of Lomonosov Moscow State University. Characteristics of periodic motions are registered for different values of parameters of the system. It is shown that experimental data are in qualitative agreement with results of numerical simulation.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-12-03T02:43:35Z
      DOI: 10.1142/S0219455419410074
       
  • Dynamic Characteristics of a Rotating Tapered Cantilevered Timoshenko Beam
           with Preset and Pre-Twist Angles
    • Authors: Xiangying Guo, Xiao-Dong Yang, Shao-Wen Wang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper is concerned with the free vibration of a rotating tapered Timoshenko beam with preset and pre-twist angles. The power series method is used to obtain the frequencies and complex modes of the structure. The rotating velocity related terms are re-classified into three types, namely, static centrifugal terms, dynamic centrifugal terms and the gyroscopic terms. This reclassification provides clearer descriptions of the varying frequencies with respect to the rotating velocity. The gyroscopic coupling among different directions are discussed. The overall contour of the complex modal vibrations is recorded and investigated by time series snapshots of neutral line motions and tip end cross-section motions.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-11-28T09:01:15Z
      DOI: 10.1142/S0219455419500433
       
  • Dynamic Response of Multi-bay Frames Subjected to Successive Moving Forces
    • Authors: Salih Demirtas, Hasan Ozturk, Mustafa Sabuncu
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper investigates the dynamic responses of multi-bay frames with identical bay lengths subjected to a transverse single moving load and successive moving loads with a constant interval at a constant speed. The effects of the bay length and the speed of the moving load on the response of the multi-bay frame subjected to a single point load are investigated numerically by the finite element method. A computer code is developed by using MATLAB to perform the finite element analysis. The Newmark method is employed to solve for the dynamic responses of the multi-bay frame. With this, the dynamic response of the frame subjected to successive moving loads with a constant interval is investigated. Also, the resonance and cancellation speeds are determined by using the 3D relationship of speed parameter-force span length to beam length ratio-dynamic magnification factor and the associated contour lines. The maximum impact factor of a 1-bay frame and multi-bay frames under single moving load are determined at the specific speed parameters. Those values are independent of elastic modulus, area moment of inertia, beam/column lengths of the frame and also the number of bays forming the frame. It is also found that the first resonance response in the vertical direction of the frame is related to the second mode of vibration.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-11-19T04:02:19Z
      DOI: 10.1142/S0219455419500421
       
  • An Innovative Structural Health Monitoring System for Large Transmission
           Towers Based on GPS
    • Authors: X. X. Cheng, Y. J. Ge
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In this paper, we propose an innovative structural health monitoring (SHM) system for large transmission towers that are frequently subjected to strong winds. The system is based on the strategy of using a static force equilibrium equation to calculate the whole structure’s real-time stress distribution according to its real-time behavior, as captured by the global positioning system (GPS). The reason for adopting this approach is that large transmission towers are fundamentally quasi-static structures and they are not prone to resonance under wind excitations. A case study is used to present the SHM system, then its effectiveness is validated by comparing the simulated SHM results with the exact solution obtained by a realistic time-history dynamic analysis. Additionally, we discuss the use of a new reliability analysis method based on the Ditlevsen’s bounds to assess the real-time structural conditions.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-11-12T03:05:41Z
      DOI: 10.1142/S0219455419710020
       
  • Calculation of Evolutionary Power Spectral Density of Bridge Response to
           Earthquakes by Convolution Summation
    • Authors: Xianting Du, Hong Qiao, Chaoyi Xia, He Xia
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper presents a method for calculating the evolutionary power spectral density (EPSD) of the seismic response of bridges using the convolution summation. With zero initial values, a formula for the dynamic component of the response of bridges to spatially varying seismic ground motions is derived as the convolution summation, by assuming the seismic acceleration to vary linearly between two adjacent time stations. The convolution summation is used for calculating the convolution integral of the dynamic component response factor in the EPSD, in which the constant coefficients are independent of the harmonically modulated excitation. The constant coefficients are obtained by the time-history analysis using triangular unit impulse acceleration excitations. The computational cost of the EPSD depends mainly on the amount of degrees-of-freedom (DOFs) numbers of bridge supports in contact. The corresponding computational scheme is proposed, and its validity is indirectly verified with a single DOF system, by comparing the results obtained with those of the existing methods. Finally, a three-span continuous rigid-frame bridge is taken as a case study to illustrate the applicability and effectiveness of the proposed scheme.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-11-12T03:05:36Z
      DOI: 10.1142/S021945541950041X
       
  • An Optimized Approach for Tracing Pre- and Post-Buckling Equilibrium Paths
           of Space Trusses
    • Authors: Alireza Habibi, Shaahin Bidmeshki
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In this paper, a novel optimization-based method is proposed to analyze steel space truss structures undergoing large deformations. The geometric nonlinearity is considered using the total Lagrangian formulation. The nonlinear solution is obtained by introducing and minimizing an objective function subjected to the displacement-type constraints. The proposed approach can fully follow the equilibrium path of the geometrically nonlinear space truss structures not only before the limit point, but also after it, namely, including both the pre- and post-buckling paths. Moreover, a direct estimation of the buckling loads and their corresponding displacements is possible by using the method. Particularly, it has been shown that the equilibrium path of a structure with highly nonlinear behavior, multiple limit points, snap-through, and snap-back phenomena can be traced via the proposed algorithm. To demonstrate the accuracy, validity, and robustness of the proposed procedure, four benchmark truss examples are analyzed and the results compared with those by the modified arc-length method and those reported in the literature.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-11-12T03:05:23Z
      DOI: 10.1142/S0219455419500408
       
  • Cylindrical Bending Vibration of Multiple Graphene Sheet Systems Embedded
           in an Elastic Medium
    • Authors: Chih-Ping Wu, Yen-Jung Chen
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Based on the Eringen nonlocal elasticity theory and multiple time scale method, an asymptotic nonlocal elasticity theory is developed for cylindrical bending vibration analysis of simply-supported, [math]-layered, and uniformly or nonuniformly-spaced, graphene sheet (GS) systems embedded in an elastic medium. Both the interactions between the top and bottom GSs and their surrounding medium and the interactions between each pair of adjacent GSs are modeled as one-parameter Winkler models with different stiffness coefficients. In the formulation, the small length scale effect is introduced to the nonlocal constitutive equations by using a nonlocal parameter. The nondimensionalization, asymptotic expansion, and successive integration mathematical processes are performed for a typical GS. After assembling the motion equations for each individual GS to form those of the multiple GS system, recurrent sets of motion equations can be obtained for various order problems. Nonlocal multiple classical plate theory (CPT) is derived as a first-order approximation of the current nonlocal plane strain problem, and the motion equations for higher-order problems retain the same differential operators as those of nonlocal multiple CPT, although with different nonhomogeneous terms. Some nonlocal plane strain solutions for the natural frequency parameters of the multiple GS system with and without being embedded in the elastic medium and their corresponding mode shapes are presented to demonstrate the performance of the asymptotic nonlocal elasticity theory.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-11-08T09:40:31Z
      DOI: 10.1142/S0219455419500354
       
  • Buckling Analysis of Nanobeams Based on Nonlocal Timoshenko Beam Model by
           the Method of Initial Values
    • Authors: Erol Demirkan, Reha Artan
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Investigated herein is the buckling of nanobeams based on a nonlocal Timoshenko beam model by the method of initial values within the framework of nonlocal elasticity. Since the nonlocal Timoshenko beam theory is of higher order than the nonlocal Euler–Bernoulli beam theory, it is known to be superior in predicting the small-scale effect. The buckling determinants and critical loads for bars with various kinds of supports are presented. The Carry-Over matrix (Transverse Matrix) is presented and the priorities of the method of initial values are depicted. To the best of the researchers’ knowledge, this is the first work that investigates the buckling of nonlocal Timoshenko beam with the method of initial values.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-11-08T09:40:30Z
      DOI: 10.1142/S0219455419500366
       
  • Vibration-Based Damage Identification Using Wavelet Transform and a
           Numerical Model of Shearography
    • Authors: J. V. Araujo dos Santos, A. Katunin, H. Lopes
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper presents a method for the identification of damage in plates based on the post-processing with wavelets of modal rotation fields. These modal rotation fields are obtained by use of a numerical model of shearography, which includes the simulation of noise in the data generated. The discrete wavelet transform was chosen because of its high sensitivity to perturbations in the modal rotations. Distinct damage scenarios, defined by regions where the thickness of a plate is reduced, are considered in this paper. A study on the differences in the natural frequencies and the changes in modal rotation fields due to the damage is carried out. The order of the B-spline wavelets used in the post-processing of the modal rotation fields is discussed. The damage detectability in terms of its intensity, the selected mode, and the type of rotation field and wavelet coefficient is also studied. Finally, a scheme for the damage detectability enhancement, in particular for multiple damage scenarios, is proposed.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-11-07T02:12:34Z
      DOI: 10.1142/S021945541950038X
       
  • An Efficient Strategy for Solving Structural Nonlinear Equations by
           Combining the Orthogonal Residual Method and Normal Flow Technique
    • Authors: Dalilah Pires Maximiano, Ricardo A. M. Silveira, Andréa R. D. Silva, Paulo B. Gonçalves
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper presents a new procedure for solving structural nonlinear problems by combining the orthogonal residual method (ORM) and normal flow technique (NFT). The perpendicularity condition to the Davidenko flow, introduced by the NFT, which must be satisfied during the iterative process, overcome the difficulties, i.e. the poor convergence and inefficiency of the ORM close to the limit points, particularly the displacement limit points (snap-back behavior). Basically, the idea of the proposed strategy is to adjust the load parameter, which is treated as a variable in the nonlinear incremental-iterative solution process, assuming that the unbalanced forces (residual forces) must be orthogonal to the incremental displacements. This constraint is used together with the NFT perpendicularity condition. The proposed procedure is tested, and its efficiency is corroborated through the analyses of slender shallow and nonshallow arches and an L-frame since they exhibit highly nonlinear behaviors under certain loading conditions. It is concluded that the proposed procedure can overcome the numerical instability problems in the neighborhood of critical points when using only the conventional OR process, and the procedure compares favorably with the arc-length method, minimum residual displacement method, and generalized displacement control method.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-11-07T02:12:31Z
      DOI: 10.1142/S0219455419500391
       
  • Stochastic Vibration Analysis of Functionally Graded Plates with Material
           Randomness Using Cell-based Smoothed Discrete Shear Gap Method
    • Authors: Mohitrajhu Lingan Kumaraian, Jayamanideep Rebbagondla, Tittu Varghese Mathew, Sundararajan Natarajan
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      A cell-based smoothed finite element method with discrete shear gap technique is used to study the stochastic free vibration behavior of functionally graded plates with material uncertainty. The plate kinematics is based on the first-order shear deformation theory and the effective material properties are estimated by simple rule of mixtures. The input random field is represented by the Karhunen–Loéve expansion and the polynomial chaos expansion is used to represent the stochastic output response. The accuracy of the proposed approach in terms of the first- and the second-order statistical moments are demonstrated by comparing the results with the Monte Carlo Simulations. A systematic parametric study is carried out to bring out the influence of the material gradient index, the plate aspect ratio and the skewness of the plate on the stochastic global response of functionally graded plates. It is inferred that all the considered parameters significantly influence the statistical moments of the first fundamental mode.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-11-02T07:34:28Z
      DOI: 10.1142/S0219455419500378
       
  • Nonlinear Vibration of Sandwich Beams with Functionally Graded Negative
           Poisson’s Ratio Honeycomb Core
    • Authors: Chong Li, Hui-Shen Shen, Hai Wang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper investigates the nonlinear flexural vibration of sandwich beams with functionally graded (FG) negative Poisson’s ratio (NPR) honeycomb core in thermal environments. The novel constructions of sandwich beams with three FG configurations of re-entrant honeycomb cores through the beam thickness direction are proposed. The temperature-dependent material properties of both face sheets and core of the sandwich beams are considered. 3D full-scale finite element analyses are conducted to investigate the nonlinear vibration, and the variation of effective Poisson’s ratio (EPR) of the sandwich beams in the large deflection region. Numerical simulations are carried out for the sandwich beam with FG-NPR honeycomb core in different thermal environmental conditions, from which results for the same sandwich beam with uniform distributed NPR honeycomb core are obtained as a basis for comparison. The effects of FG configurations, temperature changes, boundary conditions, and facesheet-to-core thickness ratios on the nonlinear vibration ratio curves and EPR–deflection curves of sandwich beams are discussed in detail.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-10-26T07:23:00Z
      DOI: 10.1142/S0219455419500342
       
  • Dynamic Analysis of Sandwich Plates with Isotropic Skins and Viscoelastic
           Core
    • Authors: R. K. Ojha, S. K. Dwivedy
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The free and forced vibration characteristics of three-layered sandwich plates with thin isotropic faces and Leptadenia pyrotechnica rheological elastomer (LPRE) core are studied in this investigation. The LPRE core is fabricated and experimented to determine its shear storage modulus and loss modulus. It is observed that the stiffness and damping characteristics of the LPRE core is significantly higher than those of the room-temperature vulcanized silicone rubber elastomer (RTVE) core. The governing equation of motion for the sandwich plate is derived by the Lagrange principle and given in finite element form. The natural frequencies and loss factors of the three-layered sandwich plate are studied by varying the thicknesses of the core and the constraining isotropic layer, and material of the constraining layer with different boundary conditions. The results are compared with those of similar structures with different core materials and boundary conditions. In addition, a LPRE-based sandwich plate is fabricated and its fundamental frequency is determined experimentally and compared with the finite element result. The forced vibration response of the three-layered sandwich plate is also explored under a harmonic excitation force. This study provides supports for the application of the LPRE-based sandwich plates potentially to the passive vibration suppression of structures.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-10-26T07:22:59Z
      DOI: 10.1142/S0219455419500330
       
  • Calculation of Critical Lateral-Torsional Buckling Loads of Beams
           Subjected to Arbitrarily Transverse Loads
    • Authors: Zhenlei Chen, Jiancheng Li, Longfei Sun
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper presents a novel approach for determining the critical lateral-torsional buckling loads of beams subjected to arbitrarily transverse loads. This new method is developed based on the classical energy method. However, the difference of the present method from the traditional energy methods is the formulation of potential energy of external loads, which is expressed in terms of the internal bending moment and internal shear force in the pre-buckling stage regardless of the type of loading. Compared to the traditional formulations of the potential energy of external loads, not only is the present formula simple in the form, easy and convenient in the calculation, but it also provides a unified form for calculating accurate critical load of lateral-torsional buckling of the beams.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-10-25T05:49:28Z
      DOI: 10.1142/S0219455419500317
       
  • Stochastic Single Footfall Trace Model for Pedestrian Walking Load
    • Authors: Jun Chen, Guo Ding, Stana Živanović
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Developing a model for the dynamic force generated by a pedestrian’s foot on a supporting structure (single footfall trace model) is crucial to advanced numerical analysis and vibration serviceability assessment of the structure. A reliable model needs to reflect the inter-subject and intra-subject randomness of human walking. This paper introduces a stochastic single footfall trace model in the form of a Fourier series in which body weight, walking frequency, and the first eight harmonics are treated as random variables. An experiment used 73 test subjects, walking at a range of pacing frequencies, to record force time histories and the corresponding gait parameters. Two variability descriptors were used to indicate inter-subject and intra-subject randomness. Further statistical analysis identified the relationships between key parameters as well as the probability distribution functions of random variables. In the final step, an application of the proposed single footfall trace model was developed and tested. The proposed model represented the experimental data well in both time and frequency domains.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-10-25T05:49:27Z
      DOI: 10.1142/S0219455419500299
       
  • Determination of Critical and Cancellation Speeds of Euler–Bernoulli
           Beam Subject to a Continuously Moving Load
    • Authors: Salem Bashmal
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Treated herein is an elastic beam that is subjected to a constant load that travels continuously (back and forth) along its span. The dynamic deflection of the beam is investigated analytically so as to predict the critical and cancellation speeds. Closed-form solutions are obtained for the damped system for each load condition and superimposed to determine the total solution of the response. Unlike the classical case of load traveling at constant speed in one direction, multiple resonance peaks are observed for reciprocating load at speeds that are lower than the classical critical speed. It is also observed that resonance may not exist at the classical critical speed for simply supported beams due to the symmetry of the beam. The dynamic deflection is examined for simply supported beams to determine the speeds that cause amplification or cancellation of the free response. The current load condition may have possible application in view of its potential use for vibration suppression, as a moving vibration absorber, or for magnification, in energy harvesting. The results are interpreted in order to understand the variation of dynamic deflection and to estimate the critical speeds for different load conditions.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-10-25T05:49:25Z
      DOI: 10.1142/S0219455419500305
       
  • Exact Solution for Free Vibration and Buckling of Sandwich S-FGM Plates on
           Pasternak Elastic Foundation with Various Boundary Conditions
    • Authors: S. J. Singh, S. P. Harsha
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In the present study, free vibration and buckling characteristics of a sandwich functionally graded material (FGM) plate resting on the Pasternak elastic foundation have been investigated. The formulation is based on non-polynomial higher-order shear deformation theory with inverse hyperbolic shape function. A new modified sigmoid law is presented to compute the effective material properties of sandwich FGM plate. The governing equilibrium equations have been derived using Hamilton’s principle. Non-dimensional frequencies and critical buckling loads are evaluated by considering different boundary conditions based on admissible functions satisfying the desired primary and secondary variables. Comprehensive parametric studies have been performed to analyze the influence of geometric configuration, volume fraction exponent, elastic medium parameter, and non-dimensional load parameter on the non-dimensional frequency and critical buckling load. These parametric studies have been done for various boundary conditions and different configurations of the sandwich plate. The computed results can be used as a benchmark for future comparison of sandwich S-FGM plates.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-10-25T05:49:25Z
      DOI: 10.1142/S0219455419500287
       
  • Deformation Behavior of Fiber-Reinforced Hydrogel Structures
    • Authors: Yu Zhou, Jianying Hu, Zishun Liu
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Proposed herein is a new theory for the anisotropic deformation of fiber-reinforced hydrogels. This new model takes into account the real fabrication of the fiber-reinforced hydrogels, in which the hydrogels are polymerized with fibers and polymer solutions. The new free energy function is established by adding the anisotropic free energy component contributed by fibers into the Flory–Rehner model. The proposed model is implemented through a user-defined material subroutine (UMAT) in the finite element software package ABAQUS. In particular, the consistent tangent modulus is derived in detail. Then, several illustrative examples with analytical and numerical results are demonstrated. In order to study deformation behavior of natural materials, we design some simple bilayer structures to mimic the opening of seedpods and the closure of flowers, in which the buckling behavior of fiber-reinforced hydrogels have been demonstrated. We hope that the proposed approach may help to study more complex deformation phenomena in hydrogel structures.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-10-25T05:49:24Z
      DOI: 10.1142/S0219455419500329
       
  • New Higher-Order Models for Sandwich Plates with a Flexible Core and their
           Accuracy Assessment
    • Authors: Ali Tian, Renchuan Ye, Peng Ren, Pengming Jiang, Zengtao Chen, Xiaochun Yin, Yuanshuai Zhao
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Two higher-order analytical models based on a new higher-order theory for sandwich plates with flexible cores are developed considering the effect of the core material density and skin-to-core-stiffness-ratio (SCSR). The main difference between the two models is the role of the flexible core in the dynamic response of sandwich plates with cores of different stiffnesses. Firstly, the governing equations of a simply supported sandwich plate with a flexible core are derived based on the two models, and the analytical solutions are determined by using Navier’s approach. Then, the free vibration, static, dynamic bending and stress field characteristics of the sandwich plates with different SCSRs are investigated. The results obtained by the proposed method are compared with other published results. In particular, an accuracy assessment of the present dynamic models is conducted for different SCSRs. Finally, conclusions on the applicability of the proposed method and other theories on sandwich plates with different SCSRs are drawn.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-10-22T08:27:02Z
      DOI: 10.1142/S021945541950024X
       
  • Approximate Quantification of Higher-Mode Effects on Seismic Demands of
           Buildings
    • Authors: Jui-Liang Lin
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Quantifying the higher-mode effects on the seismic demands of buildings may benefit not only the awareness of characteristics of the seismic responses of buildings, but also the development of rapid/simplified methods for the seismic assessment of buildings. This study proposes an approach that is applicable for quantifying the aforementioned effects, covering the full range of building heights and deformation types. The vehicle used in this proposed approach is the generalized building model, which has been modified from the conventional cantilever beam model. In addition to building height and deformation type, the strength ratio of each vibration mode and the site class of buildings are the parameters considered in this study. The higher-mode effects on floor displacements, inter-story drift ratios, floor accelerations, and base shears with relation to the aforementioned parameters are investigated. Finally, the proposed approach is verified via the investigation of the higher-mode effects of a 20-story exemplar building.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-10-22T08:27:01Z
      DOI: 10.1142/S0219455419500238
       
  • Three-Dimensional Vibration of Fluid-Conveying Laminated Composite
           Cylindrical Shells with Piezoelectric Layers
    • Authors: Seyed Mohammad Miramini, Abdolreza Ohadi
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Cylindrical shells containing flowing fluid have wide applications in various industries. They can be enhanced as smart structures through inclusion of piezoelectric layers, of which the dynamic behavior, however, has not been fully understood. In this paper, the vibration and dynamic analysis of a laminated composite hollow cylinder with piezoelectric layers, subjected to an internal incompressible fluid flow is investigated. It is assumed that the shell is simply supported and the fluid is inviscid and irrotational. The differential equations of the elastic layers, piezoelectric layers, and flowing fluid are derived by the three-dimensional (3D) theory of elasticity, theory of piezoelectricity, and potential flow theory, respectively. A well-known recursive method is applied and extended for the first time to solve the fluid-conveying pipes using 3D theory. This approach makes it possible for the solutions to converge to the exact ones with reasonable computational cost. After validating the results against those available in the literature, the vibrational behavior of the system is examined for various cases with the effect of each parameter investigated. Also, the influence of fluid on the vibration and stability of the shell has been analyzed. The present method can be used to analyze and design hybrid shells conveying fluid with high accuracy and low computational cost.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-10-22T08:26:59Z
      DOI: 10.1142/S0219455419500263
       
  • Sensitivity Analysis of Cable Parameters on Tension of a Suspended Cable
           under Combination Resonances
    • Authors: Kyu Won Kim, No-Cheol Park, Weon Keun Song, Moon Kyum Kim, Manukid Parnichkun
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper studies the vibration of a suspended cable with small sag excited by a second excitation (normal) mode causing combination resonance in the three modes, i.e. tangent, normal and bi-normal modes. The displacement response spectra in the time domain and phase portraits are provided as evidence of the transition from the unstable steady-state motion to the stable one for nonlinear cable oscillation. A nondimensional equation for the cable tension is established with its variation evaluated for the unstable zone. The half-normalized sensitivity analysis of cable parameters, such as damping coefficient, excitation amplitude, arc length parameter and initial conditions, for their influence on cable tension is conducted in the time domain by a direct integration method. Also, the characteristics of the dynamic sensitivity of cable tension to the parameters are discussed. As a result, a sensitivity ranking chart is prepared based on the sensitivity analyses for the parameters considered. It is clearly revealed that cable tension is very sensitive to tangent and normal initial displacements in spite of their small values, whereas the same is not true for the arc length parameter and bi-normal damping coefficient. To verify the sensitivity analysis algorithm, a forced Rayleigh oscillator is introduced. A feasibility study using the oscillator shows that the numerical results obtained are in good qualitative agreement with the analytical predictions, implying that the associated algorithm works well.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-10-22T08:26:58Z
      DOI: 10.1142/S0219455419500251
       
  • Analytical Buckling Loads of Columns Weakened Simultaneously with
           Transverse Cracks and Partial Delamination
    • Authors: Igor Planinc, Simon Schnabl
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper focuses on development of a new mathematical model and its analytical solution for buckling analysis of elastic columns weakened simultaneously with transverse open cracks and partial longitudinal delamination. Consequently, the analytical solution for buckling loads is derived for the first time. The critical buckling loads are calculated using the proposed analytical model. A parametric study is performed to investigate the effects of transverse crack location and magnitude, length and degree of partial longitudinal delamination, and different boundary conditions on critical buckling loads of weakened columns. It is shown that the critical buckling loads of weakened columns can be greatly affected by all the analyzed parameters. Finally, the presented results can be used as a benchmark solution.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-10-22T08:26:57Z
      DOI: 10.1142/S0219455419500275
       
  • Dynamic Analysis of Nonclassically Damped Systems with Linear Behavior
           Using Load-Dependent Ritz Vectors
    • Authors: Huating Chen, Hong Hao, Kaiming Bi, Ping Tan, Lingyun Peng, Fulin Zhou
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In the present paper, a practical superposition method is proposed for complex load-dependent Ritz (CLDR) vectors for use in the dynamic analysis of nonclassically damped systems. In particular, an algorithm for CLDR vector generation is developed and the CLDR vectors are calculated in the physical space, instead of the state space, to reduce the computational effort and storage space, while improving the stability of the algorithm. Moreover, single CLDR vector (i.e. using only one starting vector) and block CLDR vector (i.e. using multi-starting vectors) generation procedures are introduced for the uni and multidirectional loading patterns respectively, and the latter is applied to the system with repeated natural frequencies. In addition, a criterion, which is based on the spatial load distribution, is proposed to determine a proper number of the CLDR vectors prior to their use in the dynamic analysis. Two numerical examples are provided to illustrate the accuracy and efficiency of the proposed method. Also, the performance of the cut-off criterion is presented and 10% error or less in the participation loading distribution is recommended for practical applications.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-10-08T06:23:15Z
      DOI: 10.1142/S0219455419500226
       
  • A Comparative Study of Cantilever- and Integral-Type Dead Loads on the
           Seismic Responses of High Arch Dams
    • Authors: Shengshan Guo, Hui Liang, Deyu Li, Houqun Chen, Jianxin Liao
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The actual dead load of an arch dam should be applied gradually through staged construction and sequenced grouting. However, the cantilever- and integral-type dead loads commonly used in the analysis of arch dams represent simplified versions of the actual loading. In this paper, these two types of dead loads, i.e. cantilever and integral types, are presented based on the Lagrange multiplier method considering the nonlinear behaviors of contraction joints. Based on the finite element method and an appropriate contact model together with artificial viscoelastic boundary conditions, a dynamic analysis model of a dam–foundation–reservoir system is established in consideration of the interactions between the arch dam and foundation, the opening and closing of contraction joints, and the radiation damping effect of the far-field boundary. Taking a 300 m high arch dam in the strong earthquake area of West China as an example, a fine mesh finite element model with a total of approximately 3.5 million degrees of freedom is established. The separate effects of the cantilever and integral dead loads on the static and dynamic responses of the dam are studied. The results demonstrate that the distribution and magnitude of the contraction joint opening width and maximum tensile stress are different under the two different dead load simplifications.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-09-25T12:11:49Z
      DOI: 10.1142/S0219455419500214
       
  • Semi-Active Fluid Viscous Dampers for Seismic Mitigation of RC Elevated
           Liquid Storage Tanks
    • Authors: Manisha V. Waghmare, Suhasini N. Madhekar, Vasant A. Matsagar
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The effectiveness of the semi-active control strategies using fluid viscous dampers (SAFVDs) for seismic mitigation of reinforced concrete (RC) elevated liquid storage tanks is investigated. Three control algorithms are employed for regulating the damping coefficient of the SAFVDs: (1) Passive-OFF, (2) Passive-ON, and (3) Clipped Optimal Control (COC). The uncontrolled response of the tank is compared with those installed with SAFVD of different control algorithms. Focus is also placed on various positions of the dampers, viz., dampers installed at alternate levels (Configurations I, II, IV, and V) and at all levels (Configurations III and VI) of the staging. A discrete two-mass model for the liquid and multi-degree-of-freedom system for the staging, installed with the dampers, is developed for the RC elevated liquid storage tanks. The response of the broad and slender tanks is studied, for which the ratios of the height of the liquid to the radius of the container are 0.5 and 2.0, respectively. The time-history response of the elevated tank is evaluated for eight different earthquake ground motions, including near- and far-field earthquakes. A MATLAB code was developed to solve the coupled differential equations of motion of the system using the state-space approach. Key parameters, viz., convective displacement, rigid mass displacement, base shear, overturning moment, and damper force, are evaluated. The results show that all the control systems considered herein are beneficial in reducing the seismic responses. The frequency response function for the uncontrolled and semi-actively controlled liquid storage tank in frequency domain exhibits significant response reduction, highlighting the effectiveness of the SAFVDs. The structural response is effectively controlled using the SAFVDs with Passive-OFF (valve closed) and COC algorithms. The COC algorithm employed in this study is a promising candidate for the seismic mitigation of RC elevated liquid storage tanks using the semi-active control.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-09-21T02:19:27Z
      DOI: 10.1142/S0219455419500202
       
  • Nonlinear Stochastic Optimal Control of MDOF Partially Observable Linear
           Systems Excited by Combined Harmonic and Wide-Band Noises
    • Authors: R. C. Hu, X. F. Wang, X. D. Gu, R. H. Huan
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In this paper, nonlinear stochastic optimal control of multi-degree-of-freedom (MDOF) partially observable linear systems subjected to combined harmonic and wide-band random excitations is investigated. Based on the separation principle, the control problem of a partially observable system is converted into a completely observable one. The dynamic programming equation for the completely observable control problem is then set up based on the stochastic averaging method and stochastic dynamic programming principle, from which the nonlinear optimal control law is derived. To illustrate the feasibility and efficiency of the proposed control strategy, the responses of the uncontrolled and optimal controlled systems are respectively obtained by solving the associated Fokker–Planck–Kolmogorov (FPK) equation. Numerical results show the proposed control strategy can dramatically reduce the response of stochastic systems subjected to both harmonic and wide-band random excitations.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-09-17T02:41:02Z
      DOI: 10.1142/S0219455419500196
       
  • Buckling of an Oscillating Rod Under Longitudinal Impact
    • Authors: Marat A. Ilgamov
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The dynamics of a thin rod under the action of compressive force is considered. The compressive force increases abruptly and then remains constant. The compression of the rod is assumed to take place instantly throughout its length. The motion of the rod is studied, depending on the magnitude and time of action of the compressive force defined by the phase of the initial free oscillation of the rod. Only the initial stage of the process is investigated, for which the linear bending theory is valid. The friction forces are not taken into account. An essential relationship is shown to exist between the dynamics of the rod and the initial conditions determined by the phase of the bending oscillations at the instant of impact. Relatively weak impact leads to excitation of the bending oscillations. Rearrangement of harmonics develops with time under specified initial maximum deflection from a straight line and zero velocity. The fastest buckling takes place at some initial deflection with the velocity directed toward the increasing bend.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-09-17T02:41:02Z
      DOI: 10.1142/S0219455419710019
       
  • Vibration of Hemispherical-Cylindrical-Hemispherical Shells and Complete
           Hollow Spherical Shells with Variable Thickness
    • Authors: Soo-Min Ko, Jae-Hoon Kang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The natural frequencies and mode shapes of enclosed shell typed structures with variable thickness (hemispherical-cylindrical-hemispherical shells and complete hollow spherical shells) are determined by the Ritz method using a three-dimensional (3D) analysis. However, in the conventional shell analysis, mathematically two-dimensional (2D) thin shell theories or higher order thick shell theories are often employed, which adopt limiting assumptions about the displacement variation through the shell thickness. While most researchers have adopted the 3D shell coordinates that are normal and tangential to the shell mid-surface, the present analysis is based upon the circular cylindrical coordinates. By the Ritz method, the Legendre polynomials, which are mathematically orthonormal and minimal, are used as the admissible functions, instead of the ordinary algebraic polynomials. The strain and kinetic energies of the combined shell structures are formulated, and upper bound solutions of the frequencies are obtained by minimizing the solution for frequencies. As the degree of the Legendre polynomials is increased, frequencies converge to the exact values. Convergence to four-digit exactitude is demonstrated for the first five frequencies. The frequencies from the present 3D method are compared with those from other 3D approach and 2D thin and thick shell theories existing in the literature. The present 3D analysis is applicable to both very thick shells and very thin shells.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-09-14T09:48:50Z
      DOI: 10.1142/S0219455419500184
       
  • Reference-Free Breathing Crack Identification of Beam-Like Structures
           Using an Enhanced Spatial Fourier Power Spectrum with Exponential
           Weighting Functions
    • Authors: J. Prawin, A. Rama Mohan Rao
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Detection of incipient damage of structures at the earliest possible stage is desirable for successful implementation of any health monitoring system. In this paper, we focus on breathing crack problem and present a new reference-free algorithm for fatigue crack detection, localization, and characterization for beam-like structures. We use the spatial curvature of the Fourier power spectrum as a damage sensitive feature for fatigue crack identification. An exponential weighting function that takes into account nonlinear dynamic signatures, such as sub- and superharmonics, is proposed in the Fourier power spectrum in order to enrich the damage-sensitive features of the structure. Both numerical and experimental studies have been carried out to test and verify the proposed algorithm.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-09-14T09:48:48Z
      DOI: 10.1142/S0219455419500172
       
  • Thermo-Mechanical Buckling of CFRP Cylindrical Shells with FGPM Coating
    • Authors: Kai Xu, Zhenhuan Zhou, Qingzhen Lu, Jiabin Sun, Ziguang Jia
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In this paper, the buckling behaviors of cylindrical shells made of a new kind of carbon fiber reinforced polymer (CFRP) and coated with functionally graded polymeric material (FGPM) are investigated. The fundamental equations of a moderately-thick shell are established within the framework of Reddy’s higher-order shear deformation theory (HSDT). The material model is derived by combining the conventional micro-mechanical CFRP model with the hybrid FGPM model. Micro-crack damage in CFRP core is included via the damage variables. The buckling compressive stresses of the shells exposed to the thermal environment are obtained by the Galerkin’s method. The solutions reveal that the lay-up sequence of the laminas and the thickness ratio of the FGPM coating to CFRP core have significant influence on the computed results. The variation of the buckling loads with respect to the content of carbon fiber and distributed profile of the FGPM components follows some nonlinear laws. The structural instability induced by damages appear to be more remarkable with the increased shell thickness. However, this effect can be reduced by optimizing the ply angles of the stacking laminas. More factors, such as geometric parameters, numbers of fiber layers, lamina stacking sequences, damage, material properties and thermal loads, are also discussed in detail.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-09-12T02:33:43Z
      DOI: 10.1142/S0219455419500160
       
  • Vector Form Intrinsic Finite Element Method for Analysis of Train–Bridge
           Interaction Problems Considering The Coach-Coupler Effect
    • Authors: Y. F. Duan, S. M. Wang, J. D. Yau
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In this paper, the vector form intrinsic finite element (VFIFE) method is presented for analysis the train–bridge systems considering the coach-coupler effect. The bridge is discretized into a group of mass particles linked by massless beam elements and the multi-body coach with suspension systems is simulated as a set of mass particles connected by parallel spring-dashpot units. Then the equation of motion of each mass particle is solved individually and the internal forces induced by pure deformations in the massless beam elements are calculated by a fictitious reverse motion method, in which the structural stiffness matrices need not be updated or factorized. Though the vector-form equations resulting from the VFIFE method cannot be used to compute the structural frequencies by the eigenvalue approach, this study proposes a numerical free vibration test to identify the bridge frequencies for evaluating the bridge damping. Numerical verifications demonstrate that the present VFIFE method performs as accurately as previous numerical ones. The results show that the couplers play an energy-dissipating role in reducing the car bodies’ response due to the bridge-induced resonance, but not in their response due to the train-induced resonance because of the bridge’s intense vibration. Meanwhile, a dual-resonance phenomenon in the train–bridge system occurs when the coach-coupler effect is considered in the vehicle model.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-09-10T03:01:02Z
      DOI: 10.1142/S0219455419500147
       
  • Mitigation of Wind-Induced Vibration of a 600[math]m High Skyscraper
    • Authors: J. W. Zhang, Q. S. Li
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The serviceability of super-tall buildings depends primarily on the wind-induced structural responses, especially accelerations. To mitigate the discomforting structural vibrations, pendulum-type tuned mass damper (TMD) systems are commonly employed in high-rise buildings. However, for a super-tall building with a considerably low fundamental natural frequency, the suspension length of a pendulum-suspended TMD (PTMD) becomes too long to be feasible as it would occupy substantial building space. For the sake of saving valuable space in a super-tall building, a multistage PTMD system is recommended for vibration control. This paper presents a detailed assessment study on the performance of a multistage PTMD system designed for a 600 m high skyscraper located in a typhoon-prone region in China. Wind tunnel tests are first conducted to determine the wind loads on the building for estimation of structural dynamic responses for the scenarios with and without installation of the multistage PTMD system. Optimal design of the multistage PTMD system is then carried out through examining the mitigation efficiency of the PTMD system for a variety of mass and damping ratios. To restrict the strokes of mass dampers in the PTMD system, two-section damping strategy is proposed. The assessment results demonstrate that the multistage PTMD system with two-section damping can function efficiently to suppress the excessive vibrations of the skyscraper, while occupying a minimal space in vertical and horizontal directions. This paper aims to provide an effective and economic design strategy for vibration control of super-tall buildings under wind excitations.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-09-07T04:05:24Z
      DOI: 10.1142/S0219455419500159
       
  • Analytical and Experimental Flutter Analysis of a Typical Wing Section
           Carrying a Flexibly Mounted Unbalanced Engine
    • Authors: A. S. Mirabbashi, A. Mazidi, M. M. Jalili
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In this paper, both experimental and analytical flutter analyses are conducted for a typical 5-degree of freedon (5DOF) wing section carrying a flexibly mounted unbalanced engine. The wing flexibility is simulated by two torsional and longitudinal springs at the wing elastic axis. One flap is attached to the wing section by a torsion spring. Also, the engine is connected to the wing by two elastic joints. Each joint is simulated by a spring and damper unit to bring the model close to reality. Both the torsional and longitudinal motions of the engine are considered in the aeroelastic governing equations derived from the Lagrange equations. Also, Peter’s finite state model is used to simulate the aerodynamic loads on the wing. Effects of various engine parameters such as position, connection stiffness, mass, thrust and unbalanced force on the flutter of the wing are investigated. The results show that the aeroelastic stability region is limited by increasing the engine mass, pylon length, engine thrust and unbalanced force. Furthermore, increasing the damping and stiffness coefficients of the engine connection enlarges the stability domain.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-09-07T04:05:24Z
      DOI: 10.1142/S0219455419500135
       
  • Vibration Frequency Analysis of Beam–Ring Structure for Circular
           Deployable Truss Antenna
    • Authors: R. Q. Wu, W. Zhang, K. Behdinan
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The circular truss antenna of the large aperture is considered to be a flexible structure which may cause vibration in space and may affect its performance. The frequency analysis of the circular truss antenna is an important problem for understanding its vibration mechanism. In this paper, we investigate the frequency characteristics of a beam–ring structure which is proposed for the first time to model the circular truss antenna in the case of the antenna expended and locked. Based on describing the displacements of the beam–ring system in detail, the kinetic energy and potential energy are calculated. The partial differential governing equations of motion and boundary conditions for the beam–ring structure are derived by Hamilton principle. From the linear parts of the governing equations of motion and the corresponding boundary conditions, the linear frequencies of the beam–ring structure are theoretically obtained. The effects of the physical parameters on the frequency characteristics of the beam–ring structure are studied, which are further verified by the numerical results. The finding phenomena of this paper are helpful for designing and controlling the beam–ring structure such as the circular truss antenna.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-08-27T06:13:15Z
      DOI: 10.1142/S0219455419500123
       
  • Generalized Second Moment of Areas of Regular Polygons for Ludwick Type
           Material and its Application to Cantilever Column Buckling
    • Authors: Joon Kyu Lee, Byoung Koo Lee
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This study deals with the generalized second moment of area (GSMA) of regular polygon cross-sections for the Ludwick type material and its application to cantilever column buckling. In the literature, the GSMA for the Ludwick type material has only been considered for rectangular, elliptical and superellipsoidal cross-sections. This study calculates the GSMAs of regular polygon cross-sections other than those mentioned above. The GSMAs calculated by varying the mechanical constant of the Ludwick type material for the equilateral triangle, square, regular pentagon, regular hexagon and circular cross-sections are reported in tables and figures. The GSMAs obtained from this study are applied to cantilever column buckling, with results shown in tables and figures.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-08-21T07:06:30Z
      DOI: 10.1142/S021945541950010X
       
  • A Practical Wheel-Rail Interaction Element for Modeling
           Vehicle-Track-Bridge Systems
    • Authors: Quan Gu, Yongdou Liu, Wei Guo, Weiquan Li, Zhiwu Yu, Lizhong Jiang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      A novel practical element is presented for simulating the vertical wheel-rail interaction (WRI) of vehicle-track-bridge (VTB) coupling systems. The WRI is time- and location-varying, which makes the simulation of the VTB system complicated. The new element simulates the WRI using a location dependent internal resisting force, which enables the finite element (FE) model of the VTB system to remain unchanged in analysis. This element is capable of simulating the nonlinear WRI, the rail irregularity and the ‘additional’ displacement of the rail. The ‘additional’ displacement is the extra displacement caused by the WRI besides that interpolated from the element nodal displacements, which is usually ignored by existing models, but may be non-negligible in some cases. The WRI element is implemented into a general FE software framework, OpenSees, and verified by the dynamic analysis of a simply-supported beam subjected to a moving sprung mass. Furthermore, a realistic VTB system with a moving four-wheel vehicle is investigated to evaluate the cases where the additional displacement and nonlinear WRI should be considered. Finally, using another realistic VTB system subjected to rail irregularities and earthquakes, the effects of rail irregularity and earthquake on the dynamic responses of the WRI system are studied and compared.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-08-21T07:06:28Z
      DOI: 10.1142/S0219455419500111
       
  • Nonlinear Whirling Motion of Monopile Offshore Wind Turbines Subjected to
           Harmonic and Seismic Base Excitations
    • Authors: Zhicheng Cai, Xiang Yuan Zheng
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The triggering mechanism and the vibration patterns of the nonlinear whirling motion of monopile offshore wind turbines subjected to unidirectional base excitations are investigated both theoretically and experimentally via a 64:1 scaled model of the prototype NREL-5MW monopile offshore wind turbine. For motion, two nonlinear coupled integro-differential equations containing cubic nonlinearities due to curvature and inertia are solved by both analytical and numerical methods. Harmonic and random seismic base excitations with different amplitudes and frequencies are considered in the analysis to understand the instability mechanism. Extensive shake table tests show that the experimental results have good qualitative agreements with the theoretical results, and as observed in eight load cases, the nonlinear whirling motions of nacelle do exist and tend to be induced by large harmonic excitations with structural resonant frequency.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-08-21T07:06:27Z
      DOI: 10.1142/S0219455419500093
       
  • Rigid-Mass Vehicle Model for Identification of Bridge Frequencies
           Concerning Pitching Effect
    • Authors: Judy P. Yang, Bo-Lin Chen
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The concept of vehicle-bridge interaction (VBI) was originally developed to investigate the dynamic behavior of bridges subjected to moving loads such as high-speed trains. In recent years, the VBI system was introduced to further explore the possibility of identifying bridge frequencies in order to monitor the health of bridges via the use of passing vehicles. Among the models of test vehicles, the sprung mass vehicle model with a single-degree-of-freedom vehicle body is the most common adopted one due to its simplicity. Nevertheless, for a test vehicle moving over the uneven pavement, the pitching effect arising from the vertical and rotational movements of the vehicle actually influences the identification of bridge frequencies. As such, a rigid-mass vehicle model is proposed in this work to improve the sprung mass vehicle model by including both vertical and rotational deflections. The analytical solutions to the rigid-mass VBI system are derived to verify the proposed model, and the numerical examples are provided to investigate the dynamic behavior of the VBI system subjected to road irregularity.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-08-20T04:14:56Z
      DOI: 10.1142/S0219455419500081
       
  • Seismic Interaction between a Lined Tunnel and a Hill under Plane SV Waves
           by IBEM
    • Authors: Zhongxian Liu, Hai Zhang, Alexander Cheng, Chengqing Wu, Guogang Yang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper investigates the dynamic interaction between a lined tunnel and a hill under plane SV waves using the indirect boundary element method (IBEM), with the displacement and stress characteristics of the system presented in frequency domain. The IBEM has several unique advantages such as reducing calculation dimension, automatically satisfying the infinite radiation condition, etc. The numerical results indicated that the dynamic response of the tunnel–hill system is strongly dependent on incident wave characteristics, geometrical and material properties of the lined tunnel, as well as the topography of the hill. For a dimension ratio between the hill and tunnel of less than 10.0, the lined tunnel has large amplification or deamplification effect on the dynamic response of the hill. Correspondingly, the hill also greatly amplifies the displacement and stress concentration of the tunnel especially in the lower-frequency range, due to the complicated interference effect among the reflected waves and diffracted waves induced by the tunnel and hill. Also demonstrated is that the displacement and stress amplitude spectrums highly depend on the incident frequency and the space location, and there exist multiple peaks and troughs in the spectrum curve with the peaks usually appearing in the low-frequency range. Thus, for the seismic safety assessment of a hill slope or hill tunnel in practice, the dynamic interaction within the tunnel–hill system should be taken into consideration.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-08-13T09:38:10Z
      DOI: 10.1142/S0219455419500044
       
  • Critical Comparison of Bresse–Timoshenko Beam Theories for Parametric
           Instability in the Presence of Pulsating Load
    • Authors: Isaac Elishakoff, Florian Hache, Noël Challamel
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In this paper, we investigate parametric instability of Bresse–Timoshenko columns subjected to periodic pulsating compressive loads. The results are derived from three theories, namely the Bernoulli–Euler model for thin beams and two versions of the Bresse–Timoshenko model valid for thick beams: The truncated Bresse–Timoshenko model and the Bresse–Timoshenko model based on slope inertia. The truncated Bresse–Timoshenko model has been derived from asymptotic analysis, whereas the Bresse–Timoshenko model based on slope inertia is an alternative shear beam model supported by variational arguments. These models both take into account the rotary inertia and the shear effect. Simple supported boundary conditions are considered, so that the time-dependent deflection solution can be decomposed into trigonometric spatial functions. The instability domain in the load–frequency space is analytically characterized from a Meissner-type parametric equation. For small slenderness ratio, these last two Bresse–Timoshenko models coincide but for much higher slenderness ratio, the parametric instability regions in the load–frequency space shift to the left and widen them as compared to the Bernoulli–Euler model. The importance of these effects differs between the models.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-08-13T09:38:07Z
      DOI: 10.1142/S0219455419500068
       
  • Nonlinear Pull-In Instability of Strain Gradient Microplates Made of
           Functionally Graded Materials
    • Authors: R. Gholami, R. Ansari, H. Rouhi
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In this paper, the size-dependent nonlinear pull-in behavior of rectangular microplates made from functionally graded materials (FGMs) subjected to electrostatic actuation is numerically studied using a novel approach. The small scale effects are taken into account according to Mindlin’s first-order strain gradient theory (SGT). The plate model is formulated based on the first-order shear deformation theory (FSDT) using the virtual work principle. The size-dependent relations are derived in general form, which can be reduced to those based on different elasticity theories, including the modified strain gradient, modified couple stress and classical theories (MSGT, MCST and CT). The solution of the problem is arrived at by employing an efficient matrix-based method called the variational differential quadrature (VDQ). First, the quadratic form of the energy functional including the size effects is obtained. Then, it is discretized by the VDQ method using a set of matrix differential and integral operators. Finally, the achieved discretized nonlinear equations are solved by the pseudo arc-length continuation method. In the numerical results, the effects of material length scale parameters, side length-to-thickness ratio and FGM’s material gradient index on the nonlinear pull-in instability of microplates with different boundary conditions are investigated. A comparison is also made between the predictions by the MSGT, MCST and CT.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-08-13T09:38:07Z
      DOI: 10.1142/S021945541950007X
       
  • 3D Vibration Analysis of Combined Shells of Revolution
    • Authors: Jae-Hoon Kang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      A three-dimensional (3D) method of analysis is presented for determining the natural frequencies and the mode shapes of combined hemispherical–cylindrical shells of revolution with and without a top opening by the Ritz method. Instead of mathematically two-dimensional (2D) conventional thin shell theories or higher-order thick shell theories, the present method is based upon the 3D dynamic equations of elasticity. Mathematically, minimal or orthonormal Legendre polynomials are used as admissible functions in place of ordinary simple algebraic polynomials which are usually applied in the Ritz method. The analysis is based upon the circular cylindrical coordinates instead of the shell coordinates which are normal and tangent to the shell mid-surface. Strain and kinetic energies of the combined shell of revolution with and without a top opening are formulated, and the Ritz method is used to solve the eigenvalue problem, thus yielding upper bound values of the frequencies by minimizing the frequencies. As the degree of the Legendre polynomials is increased, frequencies converge to the exact values. Convergence to four-digit exactitude is demonstrated for the first five frequencies. Numerical results are presented for the combined shells of revolution with or without a top opening, which are completely free and fixed at the bottom of the combined shells. The frequencies from the present 3D Ritz method are compared with those from 2D thin shell theories by previous researchers. The present analysis is applicable to very thick shells as well as very thin shells.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-08-13T09:38:05Z
      DOI: 10.1142/S0219455419500056
       
  • Coupled Bi-Flexural–Torsional Vibration of Fluid-Conveying Pipes
           Spinning About an Eccentric Axis
    • Authors: Feng Liang, Xiao-Dong Yang, Wei Zhang, Ying-Jing Qian
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper presents a dynamical model of a fluid-conveying pipe spinning about an eccentric axis. The coupled bi-flexural–torsional free vibration and stability are analyzed for such a doubly gyroscopic system. The partial differential equations of motions are derived by the extended Hamilton principle, and are then truncated by a 4-term Galerkin technique. The frequency and energy evolutions and representative mode shapes in the two transverse directions and torsional direction are investigated to unveil the essential dynamical attributes of the system. It is indicated that the stability of the present system mainly depends on spinning speed, flow velocity and eccentricity, while the torsional frequencies are almost immune to the flow velocity. The pipe reveals ‘traveling-wave’ modal vibrations in both transverse directions, and a general ‘standing-wave’ modal vibration in the torsional direction.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-08-13T09:38:05Z
      DOI: 10.1142/S0219455419500032
       
  • Dynamics and Stability of Non-planar Rigid Rotor Equipped with Two
           Ball-Spring Autobalancers
    • Authors: Mousa Rezaee, Mir Mohammad Ettefagh, Reza Fathi
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Recently, a new type of automatic ball balancer (ABB), called the ball-spring autobalancer (AB), has been proposed, which substantially eliminates the drawbacks of the traditional ABBs. In previous studies, the dynamics of the Jeffcott planar rotor equipped with ball-spring AB has been investigated. In the Jeffcott model, it is assumed that the ABB is located on the plane of the unbalance disk. However, for the non-planar rigid rotor with distributed imbalances, out-of-plane motions may occur, and the Jeffcott model becomes unreliable as the tilting motion cannot be explained. To this end, the aim of this paper is to analyze the capability of the ball-spring AB in balancing non-planar rotors and to reconfirm its pre-claimed advantages over the traditional ABBs for balancing non-planar rotors. To start, the mathematical model of the rigid rotor with two ball-spring ABs is established, based on which the nonlinear equations of motion are derived. Then, the system time responses are computed numerically and the balanced stable regions are acquired by the Lyapunov’s first method. The results of this study show that the ball-spring ABs can balance the non-planar rotors and the tilting motion does not impair the pre-claimed advantages of the ball-spring AB.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-08-06T08:06:07Z
      DOI: 10.1142/S0219455419500019
       
  • Finite Element Formulation for Linear Stability Analysis of Axially
           Functionally Graded Nonprismatic Timoshenko Beam
    • Authors: Masoumeh Soltani, Behrouz Asgarian
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      An improved approach based on the power series expansions is proposed to exactly evaluate the static and buckling stiffness matrices for the linear stability analysis of axially functionally graded (AFG) Timoshenko beams with variable cross-section and fixed–free boundary condition. Based on the Timoshenko beam theory, the equilibrium equations are derived in the context of small displacements, considering the coupling between the transverse deflection and angle of rotation. The system of stability equations is then converted into a single homogeneous differential equation in terms of bending rotation for the cantilever, which is solved numerically with the help of the power series approximation. All the mechanical properties and displacement components are thus expanded in terms of the power series of a known degree. Afterwards, the shape functions are gained by altering the deformation shape of the AFG nonprismatic Timoshenko beam in a power series form. At the end, the elastic and buckling stiffness matrices are exactly determined by the weak form of the governing equation. The precision and competency of the present procedure in stability analysis are assessed through several numerical examples of axially nonhomogeneous and homogeneous Timoshenko beams with clamped-free ends. Comparison is also made with results obtained using ANSYS and other solutions available, which indicates the correctness of the present method.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-08-06T08:06:06Z
      DOI: 10.1142/S0219455419500020
       
  • Experimental Study on High-Performance Buckling-Restrained Braces with
           Perforated Core Plates
    • Authors: Liang-Jiu Jia, Yang Dong, Hanbin Ge, Kana Kondo, Ping Xiang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The compressive deformation is mainly contributed by axial compressive deformation and high-order in-plane and out-of-plane global buckling deformation for conventional buckling-restrained braces (BRBs). A novel type of all-steel BRBs with perforated core plates, termed as perforated BRBs (PBRBs), are proposed in this study, where shear deformation can occur in addition to the aforementioned deformations in a conventional BRB under compression. Experimental study was carried out using five specimens with different configurations of holes under cyclic loading. Stable hysteretic properties, high ductility, and energy dissipation capacity were obtained for the PBRBs. The effects of two parameters, i.e. the slenderness ratio of the chord and hole spacing factor defined as the ratio of the hole length to the hole spacing, on seismic performance of the specimens were investigated. The compressive deformation mechanisms of the PBRBs were further investigated through a numerical study. The compressive deformation was found to be composed of axial compressive deformation, flexural deformation owing to in-plane and out-of-plane global buckling, and in-plane shear deformation of the latticed core plate.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-06-01T06:08:33Z
      DOI: 10.1142/S0219455419400042
       
  • Operational Modal Analysis and Bayesian Model Updating of a Coupled
           Building
    • Authors: Jun Hu, Jia-Hua Yang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper reports the step-by-step procedures of a full-scale ambient vibration test and the corresponding modal identification and Bayesian structural model updating of a coupled building. The building is characterized as a combination of a main part and a complementary part connected together by corridors in between. Compared with the main part, the volume of the complementary part is much smaller. Therefore, the influence on the dynamic properties of the complementary part from its counterpart is expected. To capture the dynamic properties of the coupled building, a 21-setup ambient vibration test was designed to cover all the degrees of freedom (DOFs) of interest. The modal parameters of each setup were identified following the frequency domain decomposition (FDD) method and the partial mode shapes from different setups were assembled following a least-squares method. To determine the stiffness of the linkage between the two parts, the coupled building was simulated with two linked shear buildings and updated utilizing the Markov chain Monte Carlo (MCMC)-based Bayesian model updating method. The identified modal parameters revealed interesting features about the coupled effects between the main part and complementary part and were discussed in detail. The good match between the model-predicted and identified modal parameters verified the validity of proposed shear building model. This study provides valuable experience in the area of structural model updating and structural health monitoring.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-06-01T06:08:33Z
      DOI: 10.1142/S0219455419400121
       
  • Second Harmonic Generation of Guided Wave at Crack-Induced Debonding in
           FRP-Strengthened Metallic Plates
    • Authors: Yi Yang, Ching-Tai Ng, Andrei Kotousov
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The use of fiber-reinforced polymer (FRP) has been widely recognized to be an effective and economical way to strengthen existing structures or repair damaged structures for extending their service life. This study investigates the feasibility of using nonlinear guided wave to monitor crack-induced debonding in FRP-strengthened metallic plates. The study focusses on investigating the nonlinear guided wave interaction with the crack-induced debonding. A three-dimensional (3D) finite element (FE) model is developed to simulate the crack-induced debonding in the FRP-strengthened metallic plates. The performance of using fundamental symmetric ([math] and anti-symmetric ([math] modes of guided wave as incident wave in the second harmonic generation at the crack-induced debonding is investigated in detail. It is found that the amplitude of the second harmonic and its variation with different damage sizes are very different when using [math] and [math] guided wave as the incident wave, respectively. The results suggest that it is possible to detect potential damage and distinguish its type based on the features of the generated second harmonic.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-06-01T06:08:32Z
      DOI: 10.1142/S0219455419400066
       
  • Master [math]-[math] Curve-Based Fatigue Life Assessment of Steel Bridges
           Using Finite Element Model and Field Monitoring Data
    • Authors: X. W. Ye, Y. H. Su, T. Jin, B. Chen, J. P. Han
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The accuracy of fatigue life assessment for the welded joint in a steel bridge is largely dependent on an appropriate [math]-[math] curve. In this paper, a master [math]-[math] curve-based fatigue life assessment approach for the welded joint with an open-rib in orthotropic steel bridge deck is proposed based on the finite element model (FEM) and field monitoring data from structural health monitoring (SHM) system. The case studies on fatigue life assessment by use of finite element analysis (FEA) for constant-amplitude cyclic loading mode and field monitoring data under variable-amplitude cyclic loading mode are addressed. In the case of FEA, the distribution of structural stress at fatigue-prone weld toe is achieved using 4-node shell element model and then transformed into equivalent structural stress by fracture mechanics theory. The fatigue life of the welded joint is estimated with a single master [math]-[math] curve in the form of equivalent structural stress range versus the cycles to failure. In the case of monitoring data-based fatigue life assessment, the daily history of structural stress at diaphragm to U-rib is derived from the raw strain data measured by the instrumented fiber Bragg grating (FBG) sensors and transformed into equivalent structural stress. The fatigue life of the investigated welded joint is calculated by cyclic counting method and Palmgren–Miner linear damage cumulative rule. The master [math]-[math] curve method provides an effective fatigue life assessment process, especially when the nominal stress is hard to be defined. A single master [math]-[math] curve will facilitate to solve the difficulty in choosing a proper [math]-[math] curve which is required in the traditional fatigue life assessment methods.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-06-01T06:08:31Z
      DOI: 10.1142/S0219455419400133
       
  • Effect of Column Base Behavior on Seismic Performance of Multi-Story Steel
           Moment Resisting Frames
    • Authors: Yao Cui, Fengzhi Wang, Satoshi Yamada
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Column base is one of the most important elements of steel structures. Exposed column base is commonly used in low-to-medium-rise steel moment resisting frames because of better constructability and low cost. To study the effect of exposed column base behavior on the seismic behavior of low-to-medium-rise steel moment resisting frames, a four-story, four-bay steel moment frame is studied by the nonlinear time history analysis. In the numerical analysis, two types of column base connections (rigid and semi-rigid) are considered. The width–thickness ratio of column and stiffness ratio of column base to column are chosen as the analysis parameters. The characteristics of structural responses, hysteresis loops, and the distribution of plastic energy dissipation are compared. It indicates that the collapse margin ratio is significantly increased when the exposed column base behavior is considered for the moment resisting frames with large width–thickness ratio. Moreover, if the column base connection is allowed to rotate and transfer a portion of the moment, the demand of plastic deformation capacity of steel columns is reduced, then subsequently strength deterioration caused by the local buckling at the bottom of column could be avoided. Also, the whole structure has a better ductility, the ability of plastic deformation and energy absorbance of the moment resisting frame under earthquake are therefore enhanced. The structure with the semi-rigid column base connection has larger potential to avoid the structural collapse caused by the local buckling of first-story columns.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-06-01T06:08:31Z
      DOI: 10.1142/S0219455419400078
       
  • Neutral Axis-Based Health Monitoring and Condition Assessment Techniques
           for Concrete Box Girder Bridges
    • Authors: Ye Xia, Peng Wang, Limin Sun
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The neutral axis position is considered as a potential parameter of early abnormal and long term performance for flexural members of structures. This paper is to propose the Neutral Axis Indicator (NA) based on strain measurements, to evaluate the behavior of NA, and to investigate challenges associated with the neutral axis for structural health monitoring purpose. A numerical example of a simply supported reinforced concrete (RC) beam was first developed and analyzed followed by an experimental study for further verification. With the aim of application to real bridges, a case study was conducted on Gantao River Bridge, a typical concrete box girder bridge, for detailed analysis using field data. The numerical and experimental examples, as well as field tests, aim to figure out: (1) the sensitivity of NA to structural damages, especially at early age; (2) stability and uncertainty of NA using field data; (3) capability of NA on detecting abrupt and slowly changing structural degradation. The results show that: NA takes on good index accuracy and damage sensitivity on numerical and experimental cases; NA tends to keep constant during linear elastic phase, while responses quickly and sharply to nonlinear behaviors such as concrete cracking and hardening; and NA is a potentially reliable indicator both to capture nonlinear performance and to detect minute damage. Additionally, the uncertainty of multiple disturbing effects can be mostly eliminated through statistical analysis. Thus, it can be employed effectively in condition assessment of concrete box girder bridges for long-term health monitoring.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-06-01T06:08:30Z
      DOI: 10.1142/S0219455419400157
       
  • Dynamic Capacity Reduction of Railway Prestressed Concrete Sleepers Due to
           Surface Abrasions Considering the Effects of Strain Rate and Prestressing
           Losses
    • Authors: Chayut Ngamkhanong, Dan Li, Alex M. Remennikov, Sakdirat Kaewunruen
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In reality, railway prestressed concrete sleepers frequently experience significant aggressive loading conditions and harsh environments. Especially in sharp curves, lateral loading of train wheels in combination with incompressible hydraulic pressure aggravates the lateral oscillation and abrades the surface of sleepers right underneath the rail seats. Many investigators in the past have proposed various material models to improve abrasive resistance characteristics, but those have been mostly applied to the new products using novel materials such as fiber-reinforced concrete. On the other hand, prestressed concrete sleepers have been used for over 50 years and they have become worn over time. This paper highlights the dynamic capacity evaluation of worn sleepers, which will lead to predictive models that could be realistically applied to asset management of railway lines. This paper presents an investigation into the structural capacity reduction in worn railway prestressed concrete sleepers considering the effects of strain rate and loss of prestressing steel. RESPONSE2000 has been used to evaluate the residual dynamic capacity based on the modified compression field theory. Unprecedented parametric studies have been carried out to determine the influences of uniform and gradient prestress losses on prestressed concrete capacity. The study results exhibit the level of wear and tear, which is critical to the dynamic integrity of sleepers required for immediate replacement. The outcome of this study will help improve the practical maintenance and monitoring technology in railway industry.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-06-01T06:08:30Z
      DOI: 10.1142/S0219455419400017
       
  • Incremental Analysis for Seismic Assessment of Bridge with Functional
           Bearing System Subjected to Near-Fault Earthquake
    • Authors: Li-Wei Liu, Kuang-Yen Liu, Deng-Gang Huang
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      A bridge with the functional bearing system, where sticking-sliding mechanism of rubber bearing reduces the force transmission between the substructure and the superstructure, shows viscoelastoplastic behavior. In the present paper, we show a simplified two-degree-of-freedom (2DOF) model for a bridge with the bearing system containing Coulomb’s friction element that displays mechanical behavior including the sticking (viscoelastic) and the sliding (viscoplastic) modes and we arrange its mathematical formulation into a two-phase framework which is a well-implemented form for incremental analysis. Solutions of the two-phase system are explored thoroughly and the exact solution of on-phase under piecewise constant input is obtained. Furthermore, we discuss on–off switching criteria of the bridge bearing system and propose an algorithm, including off-phase (viscoelastic) module, on-phase (viscoplastic) module, pull-back module, admissible condition, and straining condition, to simulate responses of the bridge bearing system. Based on the proposed algorithm, the assessment of the bridge with the functional bearing system which undergoes the near-fault earthquakes was made by investigation of the influence of five kinds of design parameters.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-06-01T06:08:29Z
      DOI: 10.1142/S0219455419400030
       
  • Experimental Verification of the Statistical Time-Series Methods for
           Diagnosing Wind Turbine Blades Damage
    • Authors: Hesheng Tang, Suqi Ling, Chunfeng Wan, Songtao Xue
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper presents an experimental verification of the statistical time-series methods, which utilize adapted frequency response ratio (FRR), autoregressive (AR) model parameter and AR model residual as performance characteristics, for diagnosing the damage of wind turbine blades. Specifically, the statistical decision-making techniques are used to identify the status patterns from turbine vibration data. For experiments, a small-size, laboratory-used operating wind turbine structure is used. The performance of each method in diagnosing damages simulated by saw cut in three critical positions in the blade are assessed and compared. The experimental results show that these methods yielded a promising damage diagnosis capability in the condition monitoring of wind turbine.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-06-01T06:08:29Z
      DOI: 10.1142/S021945541940008X
       
  • Analysis of Anti-Collapse Performance of Beam–Column Substructure with
           Welded Flange-Bolted Web Connection in Minor-Axis Direction Under
           Different Span Ratios
    • Authors: Zhong Weihui, Song Xiaoyan, Ma Baoqian
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      The failure modes, mechanical properties, and resistance mechanisms of beam–column substructures with welded flange-bolted web connection in the minor-axis direction under different span ratios (1:0.6, 1:1.0, 1:1.4) were compared and analyzed under the condition of progressive collapse. The beam–column substructures included three columns and two beams, and monotonic static loading tests were conducted using the alternate load path method. The test results indicated that the specimens began to fracture at the beam tension flange; and then, part of the main internal force was transferred by the bolts on the web, followed by buckling of the compression flange at the beam end. Finally, specimens were deactivated by the shear failure of bolt holes or the fracturing of the web and junction plate. The joint with a welded flange-bolted web connection was found to have high redundancy, with sufficient rotational capacity after the fracture of the tension flange. As a result of the effective pulling force between the beam and column, combined with sufficient rotation of the beam end, the remaining structure could give full play to the catenary effect, which would play a leading role in the later stage of large deformation. The deformation of the beam–column joint increased rapidly, which was conducive to the beam–column substructure to bear the load by collaboration between the beam and column. The simplified model and the numerical simulation are proved to be reliable by test results. The results of numerical simulations and analyses of anti-collapse performances of beam–column substructures under different span ratios showed that the large beam-span ratio was beneficial to the development of ultimate failure displacement of the substructure and increase the ratio of ultimate to initial failure load. The resistance provided by catenary mechanism also increased, and the short beam developed a better catenary effect than the long one.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-06-01T06:08:28Z
      DOI: 10.1142/S0219455419400054
       
  • Uncertainty Quantification of Load Effects under Stochastic Traffic Flows
    • Authors: He-Qing Mu, Qin Hu, Hou-Zuo Guo, Tian-Yu Zhang, Cheng Su
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Load effect characterization under traffic flow has received tremendous attention in bridge engineering, and uncertainty quantification (UQ) of load effect is critical in the inference process. Bayesian probabilistic approach is developed to overcome the unreliable issue caused by negligence of uncertainty of parametric and modeling aspects. Stochastic traffic load simulation is conducted by embedding the random inflow component into the Nagel–Schreckenberg (NS) model, and load effects are calculated by stochastic traffic load samples and influence lines. Two levels of UQ are performed for traffic load effect characterization: at parametric level of UQ, not only the optimal parameter values but also the associated uncertainties are identified; at model level of UQ, rather than using a single prescribed probability model for load effects, a set of probability distribution model candidates is proposed, and model probability of each candidate is evaluated for selecting the most suitable/plausible probability distribution model. Analytic work was done to give closed-form solutions for the expression involved in both parametric and model UQ. In the simulated examples, the efficiency and robustness of the proposed approach are firstly validated, and UQ are performed to different load effect data achieved by varying the structural span length under the changing total traffic volume. It turns out that the uncertainties of load effects are traffic-specific and response-specific, so it is important to conduct UQ of load effects under different traffic scenarios by using the developed approach.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-06-01T06:08:26Z
      DOI: 10.1142/S0219455419400091
       
  • Dynamic Property Evaluation of a Long-Span Cable-Stayed Bridge (Sutong
           Bridge) by a Bayesian Method
    • Authors: Yan-Chun Ni, Qi-Wei Zhang, Jian-Feng Liu
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Modal identification aims at identifying the dynamic properties including natural frequency, damping ratio, and mode shape, which is an important step in further structural damage detection, finite element model updating, and condition assessment. This paper presents the work on the investigation of the dynamic characteristics of a long-span cable-stayed bridge-Sutong Bridge by a Bayesian modal identification method. Sutong Bridge is the second longest cable-stayed bridge in the world, situated on the Yangtze River in Jiangsu Province, China, with a total length of 2 088[math]m. A short-term nondestructive on-site vibration test was conducted to collect the structural response and determine the actual dynamic characteristics of the bridge before it was opened to traffic. Due to the limited number of sensors, multiple setups were designed to complete the whole measurement. Based on the data collected in the field tests, modal parameters were identified by a fast Bayesian FFT method. The first three modes in both vertical and transverse directions were identified and studied. In order to obtain modal parameter variation with temperature and vibration levels, long-term tests have also been performed in different seasons. The variation of natural frequency and damping ratios with temperature and vibration level were investigated. The future distribution of the modal parameters was also predicted using these data.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-06-01T06:08:24Z
      DOI: 10.1142/S0219455419400108
       
  • Discrete Tangent Stiffness Estimation Method for Pseudo Dynamic Test
    • Authors: Liang Huang, Cheng Chen, Tong Guo, Menghui Chen
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      In pseudo dynamic (PSD) test, researchers have long recognized the importance and potential benefits of utilizing the tangent stiffness of experimental specimen to correct the restoring force and analyze the energy error. However, improving accuracy and efficiency of the instantaneous stiffness estimation still presents a challenge. Based on the theory of discrete curve parameter recognition and the geometrical analysis approach, this paper proposes a discrete tangent stiffness estimation (DTSE) method to estimate the instantaneous tangent stiffness of a single degree of freedom (SDOF) experimental specimen. For different magnitudes of measurement noise, the proposed method can adaptively select and retain a series of latest valid data and ignore outdated information, of which the advantage is highly improving the accuracy and promptness of instantaneous stiffness estimation. The numerical study shows that the DTSE method has better accuracy and promptness of tangent stiffness estimation when compared with other existing methods. In a PSD test involving a sliding isolator, the DTSE method is utilized to analyze the cumulative energy error, the result of which shows the cumulative energy error is negative and decreases gradually. The analysis of experimental results demonstrates that the undershooting error of actuator added extra energy into the PSD testing system. Thus, the proposed method provides a desirable solution to instantaneous stiffness estimation.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-06-01T06:08:23Z
      DOI: 10.1142/S0219455419400145
       
  • Damage Identification of Periodically-Supported Structures Following the
           Bayesian Probabilistic Approach
    • Authors: Tao Yin, Hong-ping Zhu, Shao-jun Fu
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      This paper presents a probabilistic damage identification methodology tailor-made for periodically-supported structures with finite-length. The free wave motion of a general periodically-supported structure with a single disorder is analyzed through the characteristic receptance approach, and the corresponding frequency characteristic equation is developed. In addition, a concept of nondimensional frequency is introduced, and the sensitivity matrix of the nondimensional frequencies with respect to changes in stiffness of periodic cells is obtained by solving the frequency characteristic equation and utilizing the sensitivity analysis technique. Following the sensitivity-based identification equation with nondimensional frequency information, the probabilistic methodology for identifying the damage occurring in the periodically-supported structures is developed by implementing the Bayesian approach and the Markov chain Monte Carlo (MCMC) simulation with the Metropolis–Hasting sampling algorithm. The validity of the proposed methodology is demonstrated by both numerical simulations for a periodically-supported flanged pipeline example and experimental case studies conducted for a multi-span aluminum beam model endowed with bolted connections in the laboratory.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-06-01T06:08:21Z
      DOI: 10.1142/S021945541940011X
       
  • Performance of Steel-Reinforced Concrete-Filled Stainless Steel Tubular
           Columns at Elevated Temperature
    • Authors: Qinghua Tan, Leroy Gardner, Linhai Han
      Abstract: International Journal of Structural Stability and Dynamics, Ahead of Print.
      Steel-reinforced concrete-filled stainless steel tubular (SRCFSST) columns combine the advantages of concrete-filled stainless steel tubular (CFSST) columns and steel-reinforced concrete (SRC) columns, resulting in excellent corrosion resistance, good economy, good ductility, and excellent fire resistance. Thus, SRCFSST columns have many potential structural engineering applications, especially in offshore structures. The performance of SRCFSST columns at elevated temperatures is investigated by finite element (FE) analysis in this paper. Firstly, FE models capable of capturing the full load-deformation response of structural members at elevated temperatures are developed and validated against relevant published tests on CFSST and SRC columns under fire conditions. Based on the validated FE models, the behavioral mechanisms of the SRCFSST columns under fire are explained by analysis of the sectional temperature distribution, typical failure modes, axial deformation versus time response, and load redistribution. Finally, the fire resistance of SRCFSST columns is evaluated in comparison to CFSST columns with equivalent sectional load-bearing capacity at ambient temperature or equivalent steel ratios. The results lay the foundation for the development of fire resistance design rules for SRCFSST columns.
      Citation: International Journal of Structural Stability and Dynamics
      PubDate: 2018-06-01T06:08:20Z
      DOI: 10.1142/S0219455419400029
       
 
 
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