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  Subjects -> ENGINEERING (Total: 2291 journals)
    - CHEMICAL ENGINEERING (192 journals)
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    - ENGINEERING (1209 journals)
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CIVIL ENGINEERING (187 journals)                     

Showing 1 - 187 of 187 Journals sorted alphabetically
ACI Structural Journal     Full-text available via subscription   (Followers: 17)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 2)
Acta Structilia : Journal for the Physical and Development Sciences     Open Access   (Followers: 2)
Advances in Civil Engineering     Open Access   (Followers: 34)
Advances in Structural Engineering     Full-text available via subscription   (Followers: 27)
Ambiente Construído     Open Access   (Followers: 1)
American Journal of Civil Engineering and Architecture     Open Access   (Followers: 30)
Architectural Engineering     Open Access   (Followers: 4)
Archives of Civil and Mechanical Engineering     Full-text available via subscription   (Followers: 1)
Archives of Civil Engineering     Open Access   (Followers: 10)
Archives of Hydro-Engineering and Environmental Mechanics     Open Access   (Followers: 2)
ATBU Journal of Environmental Technology     Open Access   (Followers: 4)
Australian Journal of Structural Engineering     Full-text available via subscription   (Followers: 6)
Baltic Journal of Road and Bridge Engineering     Full-text available via subscription   (Followers: 1)
BER : Building and Construction : Full Survey     Full-text available via subscription   (Followers: 9)
BER : Building Contractors' Survey     Full-text available via subscription   (Followers: 4)
BER : Building Sub-Contractors' Survey     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Building and Construction : An Executive Summary     Full-text available via subscription   (Followers: 4)
Berkeley Planning Journal     Open Access   (Followers: 7)
Bioinspired Materials     Open Access   (Followers: 5)
Bridge Structures : Assessment, Design and Construction     Hybrid Journal   (Followers: 15)
Building and Environment     Hybrid Journal   (Followers: 15)
Building Women     Full-text available via subscription  
Built Environment Project and Asset Management     Hybrid Journal   (Followers: 15)
Bulletin of Pridniprovsk State Academy of Civil Engineering and Architecture     Open Access   (Followers: 6)
Canadian Journal of Civil Engineering     Hybrid Journal   (Followers: 11)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 8)
Case Studies in Nondestructive Testing and Evaluation     Open Access   (Followers: 11)
Case Studies in Structural Engineering     Open Access   (Followers: 9)
Cement and Concrete Composites     Hybrid Journal   (Followers: 17)
Challenge Journal of Concrete Research Letters     Open Access   (Followers: 2)
Challenge Journal of Structural Mechanics     Open Access   (Followers: 5)
Change Over Time     Full-text available via subscription   (Followers: 2)
Civil and Environmental Engineering     Open Access   (Followers: 7)
Civil And Environmental Engineering Reports     Open Access   (Followers: 5)
Civil and Environmental Research     Open Access   (Followers: 19)
Civil Engineering = Siviele Ingenieurswese     Full-text available via subscription   (Followers: 4)
Civil Engineering and Architecture     Open Access   (Followers: 17)
Civil Engineering and Environmental Systems     Hybrid Journal   (Followers: 3)
Civil Engineering and Technology     Open Access   (Followers: 9)
Civil Engineering Dimension     Open Access   (Followers: 8)
Cohesion and Structure     Full-text available via subscription   (Followers: 2)
Composite Structures     Hybrid Journal   (Followers: 260)
Computer-aided Civil and Infrastructure Engineering     Hybrid Journal   (Followers: 10)
Computers & Structures     Hybrid Journal   (Followers: 36)
Concrete Research Letters     Open Access   (Followers: 6)
Construction Economics and Building     Open Access   (Followers: 2)
Construction Engineering     Open Access   (Followers: 8)
Construction Management and Economics     Hybrid Journal   (Followers: 22)
Construction Science     Open Access   (Followers: 4)
Constructive Approximation     Hybrid Journal  
Curved and Layered Structures     Open Access   (Followers: 2)
DFI Journal : The Journal of the Deep Foundations Institute     Hybrid Journal   (Followers: 1)
Earthquake Engineering and Structural Dynamics     Hybrid Journal   (Followers: 16)
Enfoque UTE     Open Access   (Followers: 4)
Engineering Project Organization Journal     Hybrid Journal   (Followers: 7)
Engineering Structures     Hybrid Journal   (Followers: 13)
Engineering Structures and Technologies     Hybrid Journal   (Followers: 2)
Engineering, Construction and Architectural Management     Hybrid Journal   (Followers: 14)
Environmental Geotechnics     Hybrid Journal   (Followers: 5)
European Journal of Environmental and Civil Engineering     Hybrid Journal   (Followers: 8)
Fatigue & Fracture of Engineering Materials and Structures     Hybrid Journal   (Followers: 16)
Frattura ed Integrità Strutturale : Fracture and Structural Integrity     Open Access  
Frontiers in Built Environment     Open Access  
Frontiers of Structural and Civil Engineering     Hybrid Journal   (Followers: 6)
Geomaterials     Open Access   (Followers: 4)
Geosystem Engineering     Hybrid Journal   (Followers: 1)
Geotechnik     Hybrid Journal   (Followers: 3)
Géotechnique Letters     Hybrid Journal   (Followers: 6)
HBRC Journal     Open Access   (Followers: 2)
Hormigón y Acero     Full-text available via subscription  
HVAC&R Research     Hybrid Journal  
Indoor and Built Environment     Hybrid Journal   (Followers: 2)
Infrastructure Asset Management     Hybrid Journal   (Followers: 2)
Infrastructures     Open Access  
Ingenio Magno     Open Access   (Followers: 1)
Insight - Non-Destructive Testing and Condition Monitoring     Full-text available via subscription   (Followers: 22)
International Journal for Service Learning in Engineering     Open Access  
International Journal of 3-D Information Modeling     Full-text available via subscription   (Followers: 3)
International Journal of Advanced Structural Engineering     Open Access   (Followers: 16)
International Journal of Civil, Mechanical and Energy Science     Open Access   (Followers: 1)
International Journal of Concrete Structures and Materials     Open Access   (Followers: 13)
International Journal of Condition Monitoring     Full-text available via subscription   (Followers: 2)
International Journal of Construction Engineering and Management     Open Access   (Followers: 8)
International Journal of Geo-Engineering     Open Access   (Followers: 3)
International Journal of Geosynthetics and Ground Engineering     Full-text available via subscription   (Followers: 4)
International Journal of Masonry Research and Innovation     Hybrid Journal   (Followers: 1)
International Journal of Pavement Research and Technology     Open Access   (Followers: 5)
International Journal of Protective Structures     Hybrid Journal   (Followers: 6)
International Journal of Steel Structures     Hybrid Journal   (Followers: 2)
International Journal of Structural Engineering     Hybrid Journal   (Followers: 10)
International Journal of Structural Integrity     Hybrid Journal   (Followers: 2)
International Journal of Structural Stability and Dynamics     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Built Environment     Open Access   (Followers: 4)
International Journal of Sustainable Construction Engineering and Technology     Open Access   (Followers: 8)
International Journal on Pavement Engineering & Asphalt Technology     Open Access   (Followers: 6)
International Journal Sustainable Construction & Design     Open Access  
Journal of Bridge Engineering     Full-text available via subscription   (Followers: 15)
Journal of Building Engineering     Hybrid Journal   (Followers: 1)
Journal of Building Materials and Structures     Open Access   (Followers: 2)
Journal of Building Performance Simulation     Hybrid Journal   (Followers: 6)
Journal of Civil Engineering and Construction Technology     Open Access   (Followers: 11)
Journal of Civil Engineering and Management     Hybrid Journal   (Followers: 7)
Journal of Civil Engineering and Science     Open Access   (Followers: 7)
Journal of Civil Engineering Research     Open Access   (Followers: 6)
Journal of Civil Society     Hybrid Journal   (Followers: 4)
Journal of Civil Structural Health Monitoring     Hybrid Journal   (Followers: 4)
Journal of Composites for Construction     Full-text available via subscription   (Followers: 13)
Journal of Computing in Civil Engineering     Full-text available via subscription   (Followers: 24)
Journal of Construction Engineering     Open Access   (Followers: 7)
Journal of Construction Engineering and Management     Full-text available via subscription   (Followers: 19)
Journal of Construction Engineering, Technology & Management     Full-text available via subscription   (Followers: 4)
Journal of Constructional Steel Research     Hybrid Journal   (Followers: 8)
Journal of Earth Sciences and Geotechnical Engineering     Open Access   (Followers: 4)
Journal of Fluids and Structures     Hybrid Journal   (Followers: 6)
Journal of Frontiers in Construction Engineering     Open Access   (Followers: 2)
Journal of Green Building     Full-text available via subscription   (Followers: 11)
Journal of Highway and Transportation Research and Development (English Edition)     Full-text available via subscription   (Followers: 13)
Journal of Infrastructure Systems     Full-text available via subscription   (Followers: 21)
Journal of Legal Affairs and Dispute Resolution in Engineering and Construction     Full-text available via subscription   (Followers: 5)
Journal of Marine Science and Engineering     Open Access   (Followers: 1)
Journal of Materials and Engineering Structures     Open Access   (Followers: 4)
Journal of Materials in Civil Engineering     Full-text available via subscription   (Followers: 10)
Journal of Nondestructive Evaluation     Hybrid Journal   (Followers: 11)
Journal of Offshore Structure and Technology     Full-text available via subscription  
Journal of Performance of Constructed Facilities     Full-text available via subscription   (Followers: 4)
Journal of Pipeline Systems Engineering and Practice     Full-text available via subscription   (Followers: 7)
Journal of Rehabilitation in Civil Engineering     Open Access   (Followers: 3)
Journal of Solid Waste Technology and Management     Full-text available via subscription   (Followers: 1)
Journal of Structural Engineering     Full-text available via subscription   (Followers: 39)
Journal of Structural Fire Engineering     Full-text available via subscription   (Followers: 6)
Journal of Sustainable Architecture and Civil Engineering     Open Access   (Followers: 3)
Journal of Sustainable Design and Applied Research in Innovative Engineering of the Built Environment     Open Access   (Followers: 1)
Journal of the Civil Engineering Forum     Open Access  
Journal of the South African Institution of Civil Engineering     Open Access   (Followers: 4)
Jurnal Spektran     Open Access   (Followers: 1)
Jurnal Teknik Sipil dan Perencanaan     Open Access   (Followers: 1)
Konstruksia     Open Access  
KSCE Journal of Civil Engineering     Hybrid Journal   (Followers: 2)
Latin American Journal of Solids and Structures     Open Access   (Followers: 4)
Materiales de Construcción     Open Access  
Mathematical Modelling in Civil Engineering     Open Access   (Followers: 3)
Nondestructive Testing And Evaluation     Hybrid Journal   (Followers: 17)
Obras y Proyectos     Open Access   (Followers: 1)
Open Journal of Civil Engineering     Open Access   (Followers: 6)
Photonics and Nanostructures - Fundamentals and Applications     Hybrid Journal   (Followers: 2)
Practice Periodical on Structural Design and Construction     Full-text available via subscription   (Followers: 4)
Proceedings of the Institution of Civil Engineers - Bridge Engineering     Hybrid Journal   (Followers: 7)
Proceedings of the Institution of Civil Engineers - Civil Engineering     Hybrid Journal   (Followers: 11)
Proceedings of the Institution of Civil Engineers - Management, Procurement and Law     Hybrid Journal   (Followers: 8)
Proceedings of the Institution of Civil Engineers - Municipal Engineer     Hybrid Journal   (Followers: 3)
Proceedings of the Institution of Civil Engineers - Structures and Buildings     Hybrid Journal   (Followers: 4)
Random Structures and Algorithms     Hybrid Journal   (Followers: 5)
Recent Trends In Civil Engineering & Technology     Full-text available via subscription   (Followers: 4)
Research in Nondestructive Evaluation     Hybrid Journal   (Followers: 7)
Revista IBRACON de Estruturas e Materiais     Open Access   (Followers: 1)
Road Materials and Pavement Design     Hybrid Journal   (Followers: 10)
Russian Journal of Nondestructive Testing     Hybrid Journal   (Followers: 6)
Science and Engineering of Composite Materials     Hybrid Journal   (Followers: 61)
Selected Scientific Papers - Journal of Civil Engineering     Open Access   (Followers: 3)
Slovak Journal of Civil Engineering     Open Access   (Followers: 2)
Soils and foundations     Full-text available via subscription   (Followers: 4)
Steel Construction - Design and Research     Hybrid Journal   (Followers: 3)
Structural and Multidisciplinary Optimization     Hybrid Journal   (Followers: 9)
Structural Concrete     Hybrid Journal   (Followers: 11)
Structural Control and Health Monitoring     Hybrid Journal   (Followers: 9)
Structural Engineering International     Full-text available via subscription   (Followers: 11)
Structural Safety     Hybrid Journal   (Followers: 7)
Structural Survey     Hybrid Journal  
Structure     Full-text available via subscription   (Followers: 23)
Structure and Infrastructure Engineering: Maintenance, Management, Life-Cycle Design and Performance     Hybrid Journal   (Followers: 12)
Structures     Hybrid Journal   (Followers: 1)
Study of Civil Engineering and Architecture     Open Access   (Followers: 8)
Superlattices and Microstructures     Hybrid Journal   (Followers: 2)
Surface Innovations     Hybrid Journal  
Technical Report Civil and Architectural Engineering     Open Access  
Teknik     Open Access  
The IES Journal Part A: Civil & Structural Engineering     Hybrid Journal   (Followers: 6)
The Structural Design of Tall and Special Buildings     Hybrid Journal   (Followers: 6)
Thin Films and Nanostructures     Full-text available via subscription   (Followers: 2)
Thin-Walled Structures     Hybrid Journal   (Followers: 4)
Transactions of the VŠB - Technical University of Ostrava. Construction Series     Open Access   (Followers: 1)
Transportation Geotechnics     Full-text available via subscription   (Followers: 1)
Transportation Infrastructure Geotechnology     Hybrid Journal   (Followers: 8)
Underground Space     Open Access  
Water Science & Technology     Partially Free   (Followers: 25)
Water Science and Technology : Water Supply     Partially Free   (Followers: 22)


Journal Cover Computers & Structures
  [SJR: 1.71]   [H-I: 90]   [36 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0045-7949
   Published by Elsevier Homepage  [3043 journals]
  • Delamination onset and growth in composite shells
    • Abstract: Publication date: 15 January 2018
      Source:Computers & Structures, Volume 195
      Author(s): Saleh Yazdani, Wilhelm J.H. Rust, Peter Wriggers
      In this paper an efficient numerical tool is proposed to investigate delamination type failure in multi-layered composite shells. In the current contribution the extended finite element method (XFEM), the mixed-mode cohesive zone model, the contact formulation, and the damage criterion are incorporated into a new algorithm to study the interfacial delamination initiation and growth with less computational effort. A flat-shell formulation is developed in the geometrically non-linear regime to study the response of shells in small strains and moderate rotations. In addition, the equivalent single layer theory (ESLT) is applied to simulate the multi-layered laminates. This formulation is enhanced through the XFEM topology to be able to model discontinuous domains and a mixed-mode bilinear cohesive formulation to track the delamination growth. In the current study, the simulation can be initiated in an intact laminate. Thus, unlike formulations in existing finite element models, incorporating cohesive zone model at all available interfaces is not necessary. The interlaminar stresses are calculated during post-processing and they are being used in the delamination onset criterion. As soon as the criterion is satisfied at a specific layer and location, the formulation of that corresponding element is locally changed to XFEM and the cohesive behaviour. Consequently, the possibility to track delamination growth is locally provided; and hence, the computational cost is reduced.

      PubDate: 2017-10-11T07:20:58Z
  • Numerical computation of nonlinear normal modes in a modal derivative
    • Abstract: Publication date: 15 January 2018
      Source:Computers & Structures, Volume 195
      Author(s): C.S.M. Sombroek, P. Tiso, L. Renson, G. Kerschen
      Nonlinear normal modes offer a solid theoretical framework for interpreting a wide class of nonlinear dynamic phenomena. However, their computation for large-scale models can be time consuming, particularly when nonlinearities are distributed across the degrees of freedom. In this paper, the nonlinear normal modes of systems featuring distributed geometric nonlinearities are computed from reduced-order models comprising linear normal modes and modal derivatives. Modal derivatives stem from the differentiation of the eigenvalue problem associated with the underlying linearised vibrations and can therefore account for some of the distortions introduced by nonlinearity. The cases of the Roorda’s frame model, a doubly-clamped beam, and a shallow arch discretised with planar beam finite elements are investigated. A comparison between the nonlinear normal modes computed from the full and reduced-order models highlights the capability of the reduction method to capture the essential nonlinear phenomena, including low-order modal interactions.

      PubDate: 2017-10-11T07:20:58Z
  • A FETI-DP based parallel hybrid stochastic finite element method for large
           stochastic systems
    • Abstract: Publication date: 15 January 2018
      Source:Computers & Structures, Volume 195
      Author(s): Srikara Pranesh, Debraj Ghosh
      The computational cost of uncertainty propagation in a mechanics problem can become prohibitively large as the degrees of freedom (DOF) and the number of basic random variables – also referred to as stochastic dimensionality – increase. While a number of methods have been reported in the literature to address either large DOF or high stochastic dimensionality, there is no work addressing both. This work is aimed at filling this gap. Naturally, parallel computing becomes the only feasible option for these large problems. Accordingly, a parallel domain decomposition-based hybrid method combining stochastic Galerkin and Monte Carlo simulation is developed here. To achieve scalability, which is necessary for solving very large scale problems, first the dual-primal variant of the finite element tearing and interconnecting (FETI-DP) is chosen as the domain decomposition method. Then, three distinct approaches of parallel implementation are followed. Through a set of detailed numerical experiments, scalability and relative costs of computation and communication in these three approaches are studied. Finally, based on the observations in these experiments, the best approach is selected and used to solve a large three dimensional elasticity problem with high dimensional parametric uncertainty.

      PubDate: 2017-10-11T07:20:58Z
  • A composite collocation method with low-period elongation for structural
           dynamics problems
    • Abstract: Publication date: 15 January 2018
      Source:Computers & Structures, Volume 195
      Author(s): Ce Huang, Minghui Fu
      This paper presents a novel time integration algorithm for solving linear structural dynamic problems in the framework of the high-order collocation method. When two Gauss points in the integration interval are selected as collocation points, both an A-stable algorithm with third order accuracy and a non-dissipative algorithm with fourth order accuracy can be derived from a second order collocation polynomial. The only difference is that the former obtains a numerical solution at the middle point of the time interval, while the latter has a solution at the end of the interval. A new composite method is established through applying these two algorithms alternately, which combines the advantages of the numerical dissipation property of the third order algorithm and the high-order accuracy of the fourth order algorithm. The usage frequency of the two algorithms during the whole step-by-step integration procedure is an important parameter affecting the numerical dissipation, which is investigated in this study. As the algebraic equations systems solved by the two algorithms are exactly same, no extra computation effort is introduced.

      PubDate: 2017-10-11T07:20:58Z
  • A data-driven approach to nonlinear elasticity
    • Abstract: Publication date: 1 January 2018
      Source:Computers & Structures, Volume 194
      Author(s): Lu Trong Khiem Nguyen, Marc-André Keip
      The so-called distance-minimizing data-driven computing method is extended to deal with boundary-value problems of continuum mechanics within the finite strain theory. In the merit of a data-driven model the solution process is carried out by using directly the experimental data instead of the conventional constitutive laws. Thus it bypasses the uncertainties in fabricating the stress-strain functional relationships from material data. Consequently, the mathematical formulation involves an optimization problem with equality constraints consisting of the equilibrium equations in continuum mechanics and the compatibility conditions on the displacement field. In the framework of finite element formulation the element tangent stiffness, the generalized internal force and the generalized external force can be computed, which renders it amenable to the implementation of finite element procedures. The proposed scheme is validated through the applications to continuum elements and convergence studies of the data-driven solution in regard to the interpolation order, the mesh size as well as the data size. The variational structure allows to recognize the overall pattern of the system of equations to be solved. This includes the structural tangent stiffness and the generalized force vectors.

      PubDate: 2017-10-04T09:33:35Z
  • 3D crack propagation by the numerical manifold method
    • Abstract: Publication date: 1 January 2018
      Source:Computers & Structures, Volume 194
      Author(s): Shikou Yang, Maosen Cao, Xuhua Ren, Guowei Ma, Jixun Zhang, Haijun Wang
      A method for three-dimensional crack propagation by the numerical manifold method (NMM) is analyzed. With the help of mathematical cover and physical cover, no Heaviside function is required to describe a crack in the NMM, and so the three-dimensional crack propagation with NMM can be analyzed being similar to that of two-dimensional cases. Mohr-Coulomb criterion with a tensile cut-off is used to analyze failure state of each crack tip line. A simplified method for determining the final propagating direction is described. According to the final propagating direction, a non-local crack tracking method is used to determine the updated crack tip line. Quadrilateral or triangle tracking method is selected according to the situation during propagation. For boundary faces, in order to make the deformed surface remain plane, new generated faces are needed to be triangulated. Three numerical examples are analyzed to validate the proposed 3D crack propagation method. The numerical results are all in good agreement with those results in the existing studies. Furthermore, a concrete gravity dam under water pressure with an overload factor is simulated and the progressive failure process of the concrete gravity dam is obtained, which demonstrates the applicability of the proposed method in practical engineering.

      PubDate: 2017-10-04T09:33:35Z
  • Roles of load temporal correlation and deterioration-load dependency in
           structural time-dependent reliability
    • Abstract: Publication date: 1 January 2018
      Source:Computers & Structures, Volume 194
      Author(s): Cao Wang, Hao Zhang
      Aging of structural performance and significant external loads may impair structural safety and serviceability and cause potential economic losses. In the presence of uncertainties associated with both resistance deterioration and external loads, structural safety shall be estimated quantitatively under a probability-based framework. A stochastic load process is often auto-correlated on the temporal scale, with correlations arising from both the occurrence times and intensities. Moreover, a deterioration process is physically dependent on the load magnitudes. This paper investigates the impacts of load temporal correlation and deterioration-load dependency on time-variant structural reliability. The load occurrence process is modeled as a Poisson point process with correlated separation time between two load events. The correlation between the intensities of load events is described by the multi-variate Gaussian copula function. The resistance aging process is considered to be a combination of both gradual and shock deteriorations. Four candidate copula functions, namely Gaussian, Clayton, Gumbel and Frank, are considered to model the dependency of shock deterioration on load intensity. Two types of failure mechanisms are considered: the first is due to the load effect exceeding the resistance, and the second occurs when the cumulative damage within the considered service period reaches the permissible level. A simulation-based method is developed to estimate structural reliability considering the two failure modes. Illustrative examples are presented to demonstrate the applicability of the proposed method. Parametric studies are conducted to investigate the impacts of temporal correlation in loads and deterioration-load dependency on structural failure probability.

      PubDate: 2017-09-26T09:06:01Z
  • A modal projection-based reduction method for transient dynamic responses
           of viscoelastic systems with multiple damping models
    • Abstract: Publication date: 1 January 2018
      Source:Computers & Structures, Volume 194
      Author(s): Zhe Ding, Li Li, Jianyi Kong, Li Qin
      Large and complex engineering systems are usually assembled by subcomponents with different energy dissipation levels. Therefore, these systems often contain multiple damping models, which may lead to great difficulties in analyzing efficiently. In this paper, an efficient modal projection-based reduction method, which accounts for transient dynamic responses of structural system with multiple damping models, is proposed in the framework of a modified precise integration method. Two robust modal reduction bases, namely multi-model method (MM) and modal strain energy by first-order correction method (MSEC), are introduced to reduce the order of the original system. Based on the reduced system and a general damping model (GDM), a reduced state-space formalism for the structural system with multiple damping models is developed. Finally, the transient dynamic responses are derived using a modified precise integration method on the reduced stage. The numerical stability, accuracy and complexity are discussed. Two numerical examples are illustrated to assess the performances of the computational accuracy and efficiency. The results indicate that the proposed method is more efficient than other methods and most suitable for large-scale problems with rather good accuracy.

      PubDate: 2017-09-26T09:06:01Z
  • Stochastic meshfree method for elastic buckling analysis of columns
    • Abstract: Publication date: 1 January 2018
      Source:Computers & Structures, Volume 194
      Author(s): Aman Gupta, C.O. Arun
      This paper proposes a probabilistic approach for the solution of elastic buckling of columns, involving uncertainties, using stochastic element free Galerkin method. In the present work, modulus of elasticity is modeled as a homogeneous random field. Karhunen-Loeve expansion and shape function method are used to represent random field and their effectiveness is compared in modeling the same in a computationally viable manner. Both Gaussian and non-Gaussian field are considered for the present study. The stochastic eigenvalue problem is solved for first and second moment characteristics of buckling load, using perturbation analysis. Numerical examples of columns with different boundary conditions are solved. Monte Carlo simulation is used as a validation tool. The obtained results are found in good agreement with those obtained by Monte Carlo simulation.

      PubDate: 2017-09-14T07:26:55Z
  • IFC: Editorial board, Aims and Scope
    • Abstract: Publication date: December 2017
      Source:Computers & Structures, Volume 193

      PubDate: 2017-09-14T07:26:55Z
  • Computer-based model for the transient dynamics of a tall building during
           digitally simulated Andrews AFB thunderstorm
    • Abstract: Publication date: December 2017
      Source:Computers & Structures, Volume 193
      Author(s): Thai-Hoa Le, Luca Caracoglia
      Thunderstorm downbursts are near ground-level meteorological hazards, exhibiting transient, non-synoptic, short-duration and high intensity wind velocities. Winds can induce nonstationary loads and large-amplitude dynamic response in a slender vertical structure. The thunderstorm-induced response against non-synoptic wind loads is extremely complex and cannot be investigated by conventional wind analysis approaches. This study examines the thunderstorm-induced dynamic response of tall buildings. The wind load is based on the observation of the Andrews Air Force Base (AFB) thunderstorm. The main objectives are to: (i) reconstruct the Andrews thunderstorm wind speed record and replicate structure, lifecycle and the fundamental wind parameters, (ii) digitally synthesize the non-turbulent and turbulent velocities to derive aerodynamic loads on a reference tall building, (iii) formulate the thunderstorm-induced dynamics of the tall building subjected to the Andrews thunderstorm-induced downburst loads, and (iv) investigate the response of a tall building by considering two different plausible scenarios. Some unanswered scientific questions are investigated: uncertainty in vertical wind velocity profiles, abrupt change of wind direction angles and influence of crosswind velocities. Three amplitude modulation functions are employed to simulate the transient turbulent field observed during the Andrews thunderstorm. Numerical simulations analyze the dynamic response of the 183-m CAARC tall building.

      PubDate: 2017-09-14T07:26:55Z
  • Coupled normal-shear stress models for SMA response
    • Abstract: Publication date: December 2017
      Source:Computers & Structures, Volume 193
      Author(s): Sara Malagisi, Sonia Marfia, Elio Sacco
      In the present paper two constitutive models, able to reproduce the mechanical behavior of shape memory alloy (SMA), are proposed. The constitutive laws allow considering the simultaneous presence of normal and shear stresses, accounting for its coupling without developing a full three-dimensional (3D) model. In such a way, two different models suitable for deriving the response of SMA devices, both characterized by the presence of only normal and shear stresses, are presented. In particular, the proposed SMA models reproduce the pseudoelastic behavior, the shape memory effect, the reorientation process and account for the different elastic properties of austenite and martensite. The phase transformations are governed by an equivalent stress defined as function of the normal and shear stresses. A robust numerical algorithm, based on a backward Euler time integration within a predictor–corrector technique, is developed for each model. Numerical simulations of experimental evidences, available in literature, are performed to validate the proposed models and computational strategies. In particular, comparisons of the results obtained by the proposed models with experimental data, are performed. A comparison with a 3D model is also carried out. The ability of the proposed models in satisfactorily reproducing the SMA response with reduced computational cost is verified even for complex loading–unloading histories.

      PubDate: 2017-09-14T07:26:55Z
  • Multi-pass hot-rolling simulation using a meshless method
    • Abstract: Publication date: 1 January 2018
      Source:Computers & Structures, Volume 194
      Author(s): U. Hanoglu, B. Šarler
      This paper describes the development of a computational model for the hot rolling of steel in a continuous rolling mill. The solution procedure consists of slices aligned in the rolling direction. The deformation and heat flow are assumed to be only in the direction perpendicular to the rolling and the assumed behavior of the material is ideal plastic. The strongly coupled thermal and mechanical models are solved by a novel meshless, local radial basis function collocation method, based on subdomains with 5 nodes for the thermal, and 7 nodes for the mechanical model. Multiquadrics radial basis functions with first-order monomials are used for the shape functions. The rearrangement of the collocation nodes in this large deformation problem is based on elliptical node generation. The non-linear relations are coped with a direct iteration, where the material properties are linearized during each of the iterations. Verification is based on comparison with an analytical solution and results from the finite-element method. A complete rolling simulation with 5 rolling stands is presented. The results encompass the roll speed, the separating force and the torque. The displacement and temperature fields of the rolling from the square to the round profile are displayed.

      PubDate: 2017-09-08T00:35:08Z
  • Development of a direct time integration method based on Bezier curve and
           5th-order Bernstein basis function
    • Abstract: Publication date: 1 January 2018
      Source:Computers & Structures, Volume 194
      Author(s): Mohammad Mahdi Malakiyeh, Saeed Shojaee, Saleh Hamzehei Javaran
      In this study, a robust unconditionally stable method for linear analysis of structures based on Bezier curves and Bernstein polynomials is proposed. The Bezier curve is used as interpolation function and Bernstein basis functions are applied for interpolation. The spectral radius, period elongation and amplitude decay are investigated for stability analysis, numerical dispersion and dissipation of proposed method, and results are compared with other methods that are the best in these properties. It is also shown that the behavior of the proposed method in analysis of finite element system is effective and reliable. To show the robustness and features of proposed method, a challenging problem with a very stiff and flexible response, a Howe truss under impact load, a frame under harmonic loading and a rectangular domain in plane strain condition are considered, and derived results are compared with references solutions and other results reported in the literature.

      PubDate: 2017-09-08T00:35:08Z
  • An effective computational approach based on XFEM and a novel three-step
           detection algorithm for multiple complex flaw clusters
    • Abstract: Publication date: December 2017
      Source:Computers & Structures, Volume 193
      Author(s): Chunping Ma, Tiantang Yu, Le Van Lich, Tinh Quoc Bui
      This paper presents an effective computational approach comprised of forward and inverse analyses for detection of multiple complex flaw clusters in elastic solids. A three-step detection strategy is introduced for inverse analysis, whereas extended finite element method (XFEM) is adopted for forward analysis. The use of XFEM is to avoid re-meshing during the change of flaw geometries. The three-step detection strategy involves: firstly, an optimization method that couples an improved discrete artificial bee colony algorithm and hierarchical clustering analysis (IDABC-HCA) is used to capture subdomains containing flaws with limited measure points in the global domain; secondly, additional measure points are introduced locally within each captured subdomain, where the number of flaws and the rough geometry of each flaw are quickly determined with the IDABC-HCA; finally, true geometries of flaws are obtained on the basis of the rough geometries by the Broyden-Fletcher-Goldfarb-Shanno (BFGS) method. To save computational time, “Queue and Kill” method is proposed to actively identify and eliminate the improper candidate flaws and/or flaw clusters. Three numerical examples of multiple flaw detection that include simple and complex flaw geometries are analyzed. The results demonstrate that the proposed approach can effectively detect multiple complex flaw clusters without prior information of the flaw number.

      PubDate: 2017-09-08T00:35:08Z
  • On the advantages of using the first-order generalised-alpha scheme for
           structural dynamic problems
    • Abstract: Publication date: December 2017
      Source:Computers & Structures, Volume 193
      Author(s): C. Kadapa, W.G. Dettmer, D. Perić
      The advantages of using the generalised-alpha scheme for first-order systems for computing the numerical solutions of second-order equations encountered in structural dynamics are presented. The governing equations are rewritten so that the second-order equations can be solved directly without having to convert them into state-space. The stability, accuracy, dissipation and dispersion characteristics of the scheme are discussed. It is proved through spectral analysis that the proposed scheme has improved dissipation properties when compared with the standard generalised-alpha scheme for second-order equations. It is also proved that the proposed scheme does not suffer from overshoot. Towards demonstrating the application to practical problems, proposed scheme is applied to the benchmark example of three degrees of freedom stiff-flexible spring-mass system, two-dimensional Howe truss model, and elastic pendulum problem discretised with non-linear truss finite elements.

      PubDate: 2017-09-08T00:35:08Z
  • The optimal initial self-stress design for tensegrity grid structures
    • Abstract: Publication date: December 2017
      Source:Computers & Structures, Volume 193
      Author(s): Xiaodong Feng
      To achieve the optimal feasible force density vector of a given geometry configuration tensegrity grid structure, an efficient procedure is presented for optimal initial self-stress design of tensegrity grid structures by consecutively solving two linear homogeneous systems in conjunction with a minimization problem. An optimization approach is utilized to seek the global minimum of the problem, leading to a set of force densities which guarantee the non-degeneracy condition for the force density matrix. The evaluation of the eigenvalues of tangent stiffness matrix is also introduced to check the stability of the tensegrity grid structures. Finally, two numerical examples have been investigated comprehensively in this paper to prove the capability of the proposed method in initial self-stress design of tensegrities satisfying either stability or super stability. Furthermore, division of number of member group has been discussed in detail for the purpose of demonstrating the efficiency of the proposed method in seeking initial force densities of tensegrity grid structures according to the need of an actual project.

      PubDate: 2017-09-02T06:22:37Z
  • Finite element analysis of finite strain micromorphic Drucker-Prager
    • Abstract: Publication date: December 2017
      Source:Computers & Structures, Volume 193
      Author(s): Volkan Isbuga, Richard A. Regueiro
      Earlier, Isbuga and Regueiro (2011) and Regueiro and Isbuga (2011) presented three dimensional finite element analysis of finite strain micromorphic isotropic elasticity based on the approach of Eringen and Suhubi (1964). We present the extension of this work to plasticity, following the formulation of Regueiro (2009, 2010) and Isbuga (2012). We assume the existence of an intermediate configuration and apply the separate multiplicative decomposition of the deformation gradient tensor and the micro-deformation tensor. In this paper, we investigate the effect of elastic length scale together with the boundary layer effect on micro-displacement tensor field for uniaxial strain and plane strain conditions, involving elastoplasticity with a Drucker-Prager yield function. We emphasize the importance of the additional degrees of freedom introduced by the micromorphic continuum formulation.

      PubDate: 2017-09-02T06:22:37Z
  • Robust h-adaptive meshing strategy considering exact arbitrary CAD
           geometries in a Cartesian grid framework
    • Abstract: Publication date: December 2017
      Source:Computers & Structures, Volume 193
      Author(s): Onofre Marco, Juan José Ródenas, José Manuel Navarro-Jiménez, Manuel Tur
      Geometry plays a key role in contact and shape optimization problems in which the accurate representation of the exact geometry and the use of adaptive analysis techniques are crucial to obtaining accurate computationally-efficient Finite Element (FE) simulations. We propose a novel algorithm to generate 3D h-adaptive meshes for an Immersed Boundary Method (IBM) based on Cartesian grids and the so-called NEFEM (NURBS-Enhanced FE Method) integration techniques. To increase the accuracy of the results at the minimum computational cost we seek to keep the efficient Cartesian structure of the mesh during the whole analysis process while considering the exact boundary representation of domains given by NURBS or T-Splines. Within the framework of Cartesian grids, the two significant contributions of this paper are: (a) the methodology used for the mesh-geometry intersection, which represents a considerable challenge due to their independence; and (b) the robust procedure used to generate the integration subdomains that exactly represent the CAD model. The numerical examples given show the proper convergence of the method, its capacity to mesh complex 3D geometries and that Cartesian grid-based IBM can be considered a robust and reliable tool in terms of accuracy and computational cost.

      PubDate: 2017-09-02T06:22:37Z
  • Geometrically nonlinear isogeometric analysis of functionally graded
           microplates with the modified couple stress theory
    • Abstract: Publication date: December 2017
      Source:Computers & Structures, Volume 193
      Author(s): Hoang X. Nguyen, Elena Atroshchenko, H. Nguyen-Xuan, Thuc P. Vo
      In this study, a new and efficient computational approach based on isogeometric analysis (IGA) and refined plate theory (RPT) is proposed for the geometrically nonlinear analysis of functionally graded (FG) microplates. While the microplates’ size-dependent effects are efficiently captured by a simple modified couple stress theory (MCST) with only one length scale parameter, the four-unknown RPT is employed to establish the displacement fields which are eventually used to derive the nonlinear von Kámán strains. The NURBS-based isogeometric analysis is used to construct high-continuity elements, which is essentially required in the modified couple stress and refined plate theories, before the iterative Newton-Raphson algorithm is employed to solve the nonlinear problems. The successful convergence and comparison studies as well as benchmark results of the nonlinear analysis of FG microplates ascertain the validity and reliability of the proposed approach. In addition, a number of studies have been carried out to investigate the effects of material length scale, material and geometrical parameters on the nonlinear bending behaviours of microplates.

      PubDate: 2017-09-02T06:22:37Z
  • Contemporary time integration model of atomic systems using a dynamic
           framework of finite element Lagrangian mechanics
    • Abstract: Publication date: December 2017
      Source:Computers & Structures, Volume 193
      Author(s): Ali Radhi, Kamran Behdinan
      Molecular dynamics simulations are essential tools to understand the equilibrium and non-equilibrium behaviour of atomistic structures under the context of classical mechanics. A major disadvantage of such results is that it conventionally encompasses small simulation times ensuing from a high demand in computational power. Certain transport properties can be obtained from such computational simulations only when allowing large enough runtime to observe the kinetic behaviour while considering multiple mechanical conditions such as low strain rates and low cycle fatigues. In this study, we developed a dynamic framework for atomic modeling using finite element Lagrangian mechanics. The method is proposed to obtain thermo-dynamical properties under microcanonical ensembles. We compare the current work with two conventional time integration approaches. It was found that the method has been able to achieve more than 5 times the time step possible for the two chosen methods in strain-loading analyses. The method had much higher numerical stability than conventional approaches, with a larger step size convergence than previously reported for future implementation in an explicit/implicit numerical integration.

      PubDate: 2017-09-02T06:22:37Z
  • Computation modeling of laminated crack glass windshields subjected to
           headform impact
    • Abstract: Publication date: December 2017
      Source:Computers & Structures, Volume 193
      Author(s): Guizhen Yu, Yanting Zhen, Bill Feng, Binghe Liu, Kangpei Meng, Xianfeng Yang, Hongshun Chen, Jun Xu
      Polyvinyl butyral-laminated glass has been extensively applied to automotive windshields to reduce the severity of head injuries resulting from pedestrian–vehicle crashes. Thus, designing an optimized pedestrian protection design for laminated windshields (LWs) has become a priority. In this study, finite element models that describe LWs, headform, and sub-frontend vehicles are established to numerically investigate the dynamic mechanical behavior of LWs subjected to headform impact. First, headform impact tests are conducted on five different locations on an LW. Second, a single-layered model for LW is proposed using a formatted material constitutive description. A reasonable consistency is observed between the numerical simulation and test results for the acceleration–time behavior of LWs. Third, a triple-layered LW model is devised to provide a highly realistic cracking morphology with an enhanced impact response for LWs. Fourth, the characterized material constitutive properties are applied to LWs with different thicknesses on another vehicle. The simulation and test results show a satisfactory correlation, thereby providing a solid foundation for formulating pedestrian protection design guidelines for LWs to reduce the severity of head injuries resulting from pedestrian–vehicle crashes.

      PubDate: 2017-09-02T06:22:37Z
  • An enhanced numerical procedure for the shakedown analysis in
           multidimensional loading domains
    • Abstract: Publication date: December 2017
      Source:Computers & Structures, Volume 193
      Author(s): K.V. Spiliopoulos, K.D. Panagiotou
      The Residual Stress Decomposition Method for Shakedown (RSDM-S) is a new iterative direct method to estimate the shakedown load in a 2-dimensional (2D) loading domain. It may be implemented to any existing finite element code, without the need to use a mathematical programming algorithm. An improved and enhanced RSDM-S is proposed herein. A new convergence criterion is presented that makes the procedure almost double as fast. At the same time, the procedure is formulated in a 3-dimensional (3D) polyhedral loading domain, consisting of independently varying mechanical and thermal loads. Using a cyclic loading program that follows the outline of this domain, it is shown that there is hardly any increase in the computational time when passing from a 2D to a 3D domain. Finally, keeping the efficiency, using an alternative cyclic loading program, an automation of the approach to any n-dimensional loading domain is presented. Examples of application are included.

      PubDate: 2017-09-02T06:22:37Z
  • Application of the meshless generalised RKPM to the transient
           advection-diffusion-reaction equation
    • Abstract: Publication date: December 2017
      Source:Computers & Structures, Volume 193
      Author(s): M. Gharib, M. Khezri, S.J. Foster, A. Castel
      A variety of physical problems may be expressed using the advection–diffusion-reaction (ADR) equation that encompasses transport processes into a porous or nonporous material. Finding a theoretical solution to the ADR equation is difficult with time-dependent nonlinear coefficients, complicated geometries, general initial value and/or boundary conditions. In this paper a meshless model is developed by adapting the generalised reproducing kernel particle method to the strong and weak integral forms of ADR equation. Moreover, mixed–type boundary conditions are directly enforced via generalising the corrected collocation method. The model is validated using existing analytical solutions and shown to be both accurate and efficient.

      PubDate: 2017-09-02T06:22:37Z
  • Performance of the MITC3+ and MITC4+ shell elements in widely-used
           benchmark problems
    • Abstract: Publication date: December 2017
      Source:Computers & Structures, Volume 193
      Author(s): Yeongbin Ko, Youngyu Lee, Phill-Seung Lee, Klaus-Jürgen Bathe
      Recently, new 3-node and 4-node MITC shell elements, the MITC3+ and MITC4+ elements, have been proposed. The two shell elements were tested through theoretically well-established convergence studies. In this paper we continue to investigate the performance of the MITC3+ and MITC4+ shell elements in relatively simple but widely adopted benchmark problems. To perform these tests as usually done, the predictive capability of the elements is assessed through point-wise convergence of displacements at specific locations of shell structures. The results obtained using the MITC3+ and MITC4+ shell elements are compared with those found for some other shell elements.

      PubDate: 2017-09-02T06:22:37Z
  • IFC: Editorial board, Aims and Scope
    • Abstract: Publication date: November 2017
      Source:Computers & Structures, Volume 192

      PubDate: 2017-09-02T06:22:37Z
  • Stochastic finite element response analysis using random eigenfunction
    • Abstract: Publication date: November 2017
      Source:Computers & Structures, Volume 192
      Author(s): S.E. Pryse, S. Adhikari
      A mathematical form for the response of the stochastic finite element analysis of elliptical partial differential equations has been established through summing products of random scalars and random vectors. The method is based upon the eigendecomposition of a system’s stiffness matrix. The computational reduction is achieved by only summing the dominant terms and by approximating the random eigenvalues and the random eigenvectors. An error analysis has been conducted to investigate the effect of the truncation and the approximations. Consequently, a novel error minimisation technique has been applied through the Galerkin error minimisation approach. This has been implemented by utilising the orthogonal nature of the random eigenvectors. The proposed method is used to solve three numerical examples: the bending of a stochastic beam, the flow through a porous media with stochastic permeability and the bending of a stochastic plate. The results obtained through the proposed random eigenfunction expansion approach are compared with those obtained by using direct Monte Carlo Simulations and by using polynomial chaos.

      PubDate: 2017-09-02T06:22:37Z
  • Quasicontinuum method extended to irregular lattices
    • Abstract: Publication date: November 2017
      Source:Computers & Structures, Volume 192
      Author(s): Karel Mikeš, Milan Jirásek
      The quasicontinuum (QC) method, originally proposed by Tadmor, Ortiz and Phillips in 1996, is a computational technique that can efficiently handle regular atomistic lattices by combining continuum and atomistic approaches. In the present work, the QC method is extended to irregular systems of particles that represent a heterogeneous material. The paper introduces five QC-inspired approaches that approximate a discrete model consisting of particles connected by elastic links with axial interactions. Accuracy is first checked on simple examples in two and three spatial dimensions. Computational efficiency is then assessed by performing three-dimensional simulations of an L-shaped specimen with elastic-brittle links. It is shown that the QC-inspired approaches substantially reduce the computational cost and lead to macroscopic crack trajectories and global load-displacement curves that are very similar to those obtained by a fully resolved particle model.

      PubDate: 2017-09-02T06:22:37Z
  • 3D mesoscale finite element modelling of concrete
    • Abstract: Publication date: November 2017
      Source:Computers & Structures, Volume 192
      Author(s): Rongxin Zhou, Zhenhuan Song, Yong Lu
      Concrete is non-homogeneous and is composed of three main constituent phases from a mesoscopic viewpoint, namely aggregates, mortar matrix, and interface transition zone (ITZ). A mesoscale model with explicit representation of the three distinctive phases is needed for investigation into the damage processes underlying the macroscopic behaviour of the composite material. This paper presents a full 3-D mesoscale finite element model for concrete. On top of the conventional take-and-place method, an additional process of creating supplementary aggregates is developed to overcome the low packing density problem associated with the take-and-place procedure. An advanced FE meshing solver is employed to mesh the highly unstructured domains. 3D mesoscale numerical simulation is then conducted for concrete specimen under different loading conditions, including dynamic loading with high strain rate. The results demonstrate that detailed mesoscopic damage processes can be realistically captured by the 3D mesoscale model while the macroscopic behaviour compares well with experimental observations under various stress conditions. The well-known inertial confinement effect under dynamic compression can be fully represented with the 3D mesoscale model and the trend of dynamic strength increase with strain rate from the 3D mesoscale analysis agrees well with the experimental data.

      PubDate: 2017-09-02T06:22:37Z
  • One-dimensional finite element formulation with node-dependent kinematics
    • Abstract: Publication date: November 2017
      Source:Computers & Structures, Volume 192
      Author(s): E. Carrera, E. Zappino
      The present paper presents a refined one-dimensional finite element model with node-dependent kinematics. When this model is adopted, the beam theory can be different at each node of the same element. For instance, in the case of a 2-node beam element the Euler-Bernoulli theory could be used for node 1 and the Timoshenko beam theory could be used for node 2. Classical and higher-order refined models have been established with the Carrera Unified Formulation. Such a capability would allow the kinematic assumptions to be continuously varied along the beam axis, that is, no ad hoc mixing techniques such as the Arlequin method would be required. Different combinations of structural models have been proposed to account for different kinematic approximations of beams, and, beam models based on the Taylor and the Lagrange expansions have in particular been used. The numerical model has been assessed, and a number of applications to thin-walled structures have been proposed. The results have been compared with those obtained from uniform kinematic models and convergence analyses have been performed. The results show the efficiency of the proposed model. The high accuracy of refined one-dimensional models has been preserved while the computational costs have been reduced by using refined models only in those zones of the beam that require them.

      PubDate: 2017-09-02T06:22:37Z
  • A meshless-based local reanalysis method for structural analysis
    • Abstract: Publication date: November 2017
      Source:Computers & Structures, Volume 192
      Author(s): Zhenxing Cheng, Hu Wang
      This study presents a meshless-based local reanalysis (MLR) method. The purpose of this study is to extend reanalysis methods to the Kriging interpolation meshless method due to its high efficiency. In this study, two reanalysis methods: combined approximations CA) and indirect factorization updating (IFU) methods are utilized. Considering the computational cost of meshless methods, the reanalysis method improves the efficiency of the full meshless method significantly. Compared with finite element method (FEM) based reanalysis methods, the main superiority of meshless-based reanalysis method is to break the limitation of mesh connection. The meshless-based reanalysis is much easier to obtain the stiffness matrix K m even for solving the mesh distortion problems. However, compared with the FEM−based reanalysis method, the critical challenge is to use much more nodes in the influence domain due to high order interpolation. Therefore, a local reanalysis method which only needs to calculate the local stiffness matrix in the influence domain is suggested to improve the efficiency further. Several typical numerical examples are tested and the performance of the suggested method is verified.

      PubDate: 2017-09-02T06:22:37Z
  • Computational model for power optimization of piezoelectric vibration
           energy harvesters with material homogenization
    • Abstract: Publication date: November 2017
      Source:Computers & Structures, Volume 192
      Author(s): A.M. Matos, J.M. Guedes, K.P. Jayachandran, H.C. Rodrigues
      Piezoelectric vibration power harvesters are being studied in the literature since they have high energy conversion from mechanical vibrations. A computational model that optimizes piezoelectric vibration energy harvester output power using homogenization of piezoelectric material is presented in this work. This computational model allows piezoelectric material tailoring to create piezoelectric vibrational energy harvesters capable of producing higher electrical power. The materials considered in the study are single crystal and polycrystals of BaTiO3 and PZN-4.5%PT, and piezopolymer PVDF-TrFE and the piezocomposites of these materials. The computational model is used to optimize the harvester power output of the unimorph vibration harvester configuration. The harvesters are modelled using the finite element method which is validated comparing analytical results for four traditional harvester configurations, viz., unimorph, bimorph, longitudinal generator and transverse generator. Single crystals, polycrystals and piezocomposites made by piezoceramic and piezopolymer materials are considered in the optimization procedure. Polycrystalline and piezocomposite properties are computed through a computational model based in the homogenization theory, which is implemented using the finite element method. Electrical resistance is used as the surrogate for the electrical machine connected to the harvesters. The design variables considered are the crystal orientation for single crystal materials, microstructural orientation distribution of the grains for polycrystalline materials, the piezoceramic material volume fraction and piezopolymer orientation for piezocomposites and/or the circuit resistance. A simulated annealing algorithm based in Metropolis algorithm is used as the optimizer. Several examples are presented and discussed considering excitations near as well as far away from resonance frequency. Harvesters with material composites having optimal material configurations that deliver enhanced electrical power have been identified.

      PubDate: 2017-09-02T06:22:37Z
  • Modeling of composite plates with an arbitrary hole location using the
           variable separation method
    • Abstract: Publication date: November 2017
      Source:Computers & Structures, Volume 192
      Author(s): P. Vidal, L. Gallimard, O. Polit
      In this paper, a method to compute explicit solutions for laminated plate with arbitrary hole position is presented using a variable separation method. The displacement field is approximated as a sum of separated functions of the in-plane coordinates x , y , the transverse coordinate z and the coordinates X T , Y T of the hole position. As the parameterized problem involves the geometry, a mapping transformation is introduced to refer to a fixed reference configuration. This choice yields to an iterative process that consists of solving a 2D and three 1D problems successively at each iteration. In the thickness direction, a fourth-order expansion in each layer is considered. For the in-plane description, classical Finite Element Method is used. The functions of X T and Y T are discretized with linear interpolations. Mechanical tests with different numbers of layers are performed to show the accuracy of the method and its capacity to capture local effects and 3D state of the stress near the curved free-edge.

      PubDate: 2017-09-02T06:22:37Z
  • Form-finding of tensegrity structures based on the
           Levenberg–Marquardt method
    • Abstract: Publication date: November 2017
      Source:Computers & Structures, Volume 192
      Author(s): Xing-Fei Yuan, Shuo Ma, Shu-Hui Jiang
      This paper presents a novel and versatile form-finding method for tensegrity structures that is based on solving nonlinear equilibrium equations. Linear equilibrium equations in terms of force densities are transformed into nonlinear equilibrium equations in which the nodal coordinates vector is variable. The input parameters for the form-finding method are the topology, initial configuration of the structure, rest lengths, and axial stiffness of elements. The form-finding process is performed by solving nonlinear least-squares problems converted from nonlinear equilibrium equations, and the Levenberg–Marquardt method is used to deal with the singularity of the stiffness matrix. Several numerical examples are given to demonstrate the accuracy and efficacy of the proposed method.

      PubDate: 2017-09-02T06:22:37Z
  • Dynamic analysis of a multi-span beam subjected to a moving force using
           the frequency domain spectral element method
    • Abstract: Publication date: November 2017
      Source:Computers & Structures, Volume 192
      Author(s): Taehyun Kim, Usik Lee
      This study extends a frequency domain modified spectral element method (SEM) from single-span beams to multi-span beams subjected to moving point forces. Each span is represented by the Timoshenko beam model. The time history of the moving point force is transformed to the frequency domain as a series of quasi-static or stationary point forces acting on the beam simultaneously. The dynamic responses are obtained by superposing the individual dynamic responses excited by each quasi-static point force. The SEM based on the original one-element method provides the exact individual dynamic responses of all spans except for the span on which the quasi-static point force is located. Thus, the exact dynamic responses for this span are obtained based on the modified one-element method by adding some correction terms that are given in closed analytical forms. The method is highly accurate and computationally efficient, as verified by comparison with other techniques such as exact theory, modal analysis method, and finite element method.

      PubDate: 2017-09-02T06:22:37Z
  • Generalization of quadratic manifolds for reduced order modeling of
           nonlinear structural dynamics
    • Abstract: Publication date: November 2017
      Source:Computers & Structures, Volume 192
      Author(s): J.B. Rutzmoser, D.J. Rixen, P. Tiso, S. Jain
      In this paper, a generalization of the quadratic manifold approach for the reduction of geometrically nonlinear structural dynamics problems is presented. This generalization is obtained by a linearization of the static force with respect to the generalized coordinates, resulting in a shift of the quadratic behavior from the force to the manifold. In this framework, static derivatives emerge as natural extensions to the modal derivatives for displacement fields other than the vibration modes, such as the Krylov subspace vectors. In the nonlinear projection framework employed here, the dynamic problem is projected onto the tangent space of the quadratic manifold, allowing for a much lower number of generalized coordinates compared to linear basis methods. The potential of the quadratic manifold approach is investigated in a numerical study, where several variations of the approach are compared on different examples, giving a clear indication of where the proposed approach is applicable.

      PubDate: 2017-09-02T06:22:37Z
  • Computational framework for model updating of large scale linear and
    • Abstract: Publication date: November 2017
      Source:Computers & Structures, Volume 192
      Author(s): Dimitrios Giagopoulos, Alexandros Arailopoulos
      In this work, a computational framework applying-finite element model updating techniques is presented for identifying the linear and nonlinear parts of large scale dynamic systems using vibration measurements of their components. The measurements are taken to be, response time histories and frequency response functions of nonlinear and linear components of the system. Covariance Matrix Adaptation – Evolution Strategy (CMA-ES) a state of the art optimization algorithm was coupled with robust and accurate finite element analysis software in order to effectively produce optimal computational results. The developed framework is applied to a geometrically complex and lightweight experimental bicycle frame with nonlinear suspension fork components. The identification of modal characteristics of the frame (linear part) is based on an experimental investigation of its dynamic response. The modal characteristics are then used to update the finite element model. The nonlinear suspension components are identified using the experimentally obtained response spectra for each of the components tested separately. Single objective structural identification methods without the need of substructuring methods, are used for estimating the parameters (material properties, shell thickness properties and nonlinear properties) of the finite element models, based on minimizing the deviations between the experimental and analytical dynamic characteristics. Finally, the numerical results of the complete system assembly were compared to the experimental results of the equivalent physical structure of the bike.

      PubDate: 2017-09-02T06:22:37Z
  • Truss optimization with buckling considerations using geometrically
           nonlinear beam modeling
    • Abstract: Publication date: November 2017
      Source:Computers & Structures, Volume 192
      Author(s): Hazem Madah, Oded Amir
      A unified approach that accounts for various buckling phenomena in truss design optimization is presented. Euler buckling of slender members, global buckling and stability of sequences of bars are all considered by optimizing the geometric nonlinear response instead of by imposing a large number of constraints. In the proposed approach, each truss member is modeled as a sequence of co-rotational beam elements with appropriate end-releases. By applying various imperfections, buckling of single truss members, unstable configurations and global buckling can be taken into account implicitly. A detailed discussion on key aspects of the proposed approach is presented, showing how the choice of imperfections highlights certain buckling types and leads to respectively stable designs. A comparison to other approaches and to results from the literature shows that the proposed approach can ensure local and global stability without actually imposing any buckling constraints. Finally, truss optimization for various levels of global deflections is presented, exposing the potential of the formulation for optimizing highly nonlinear responses.

      PubDate: 2017-09-02T06:22:37Z
  • A non-oscillatory time integration method for numerical simulation of
           stress wave propagations
    • Abstract: Publication date: November 2017
      Source:Computers & Structures, Volume 192
      Author(s): Sun-Beom Kwon, Jae-Myung Lee
      When the compressive loads are dominant in a composite structure, a tensile stress may be induced owing to the propagation of a stress wave and the interaction between an incident wave and a reflection wave, thus leading to the occurrence of cracks. Therefore, stress wave have a significant effect on the life of composite structures. In this study, a four sub-step explicit time integration scheme is proposed for solving stress wave propagation problems. This method builds on the fourth-order central difference method and a high-order derivative term to minimize the numerical oscillation. The proposed scheme possesses a first-order accuracy in the case of undamped and damped systems. Stability, accuracy, and dispersion of the proposed explicit direct time integration scheme are analyzed. Furthermore, the performance of this scheme is illustrated by the solution of a stress wave propagation and wave reflection in a one-dimensional impact problem and two-dimensional scalar wave propagation.

      PubDate: 2017-09-02T06:22:37Z
  • Discussion of the different contributions of two uncertain analysis
           methods (PCCI in Ref. [1] and PCRSM in Ref. [2])
    • Abstract: Publication date: November 2017
      Source:Computers & Structures, Volume 192
      Author(s): Mingjie Wang, Qibai Huang

      PubDate: 2017-09-02T06:22:37Z
  • Identification and quantification of spatial interval uncertainty in
           numerical models
    • Abstract: Publication date: November 2017
      Source:Computers & Structures, Volume 192
      Author(s): M. Faes, D. Moens
      This paper presents a novel methodology for the identification and quantification of spatial uncertainty, modelled as an interval field. In order to make a realistic assessment of the spatial uncertainty on the model parameters, the dimensionality of the interval field as well as its constituting base functions and interval scalars have to be identified. For this purpose, this work introduces an identification method based on objective measurement data. The specific challenge in this context lies in the fact that a continuous spatial input parameter has to be identified on a high-resolution discretised model of the structure under consideration, based on possibly high-dimensional measurement data set, obtained in the result domain of the analysed model. In the presented method, the field dimensionality is quantified based on the concept of effective dimension of the measurement data. The base functions of the interval field are identified by minimising the difference between the gradients of the halfspaces respectively bounding the measurement data and the realisations of the interval field. The method is illustrated using two case studies: an dynamic model of a cantilever beam and a quasi-static model of a cast pressure vessel. It is shown that the presented methods are capable of accurately identifying the interval field uncertainty that is present on the model parameters, and that this identification is robust against the size of the measurement data set.

      PubDate: 2017-08-02T20:22:16Z
  • A new 4-node MITC element for analysis of two-dimensional solids and its
           formulation in a shell element
    • Abstract: Publication date: November 2017
      Source:Computers & Structures, Volume 192
      Author(s): Yeongbin Ko, Phill-Seung Lee, Klaus-Jürgen Bathe
      We present in this paper a new reliable and efficient 4-node quadrilateral element, which we call the 2D-MITC4 element, for two-dimensional plane stress and plane strain solutions of solids using the MITC method. We also present an extension of the element assuming a constant element pressure, which we call the 2D-MITC4/1 element. The elements show a much better predictive capability than the displacement-based element and perform in linear analyses almost as well as the 4-node element with incompatible modes, an enhanced assumed strain (EAS) element. However, unlike when using EAS elements, we do not observe spurious instabilities in geometrically nonlinear solutions. Embedding the new MITC formulation into the previously presented MITC4+ shell element, we improve the membrane behavior of the shell element. The new 2D solid elements and the improved MITC4+ shell element pass all basic tests (the isotropy, zero energy mode and patch tests). We present the finite element solutions of various benchmark problems to illustrate the solution accuracy of the new elements.

      PubDate: 2017-08-02T20:22:16Z
  • Multiphase topology optimization of lattice injection molds
    • Abstract: Publication date: November 2017
      Source:Computers & Structures, Volume 192
      Author(s): Tong Wu, Kai Liu, Andres Tovar
      This work presents a topology optimization approach for lattice structures subjected to thermal and mechanical loads. The focus of this work is the design of injection molds. The proposed approach seeks to minimize the injection mold mass while satisfying constraints on mechanical and thermal performance. The optimal injection molds are characterized by a quasi-periodic distribution of lattice unit cells of variable relative density. The resulting lattice structures are suitable for additive manufacturing. The proposed structural optimization approach uses thermal and mechanical finite element analyses at two length scales: mesoscale and macroscale. At the mesoscale, lattice unit cells are utilized to obtain homogenized thermal and mechanical properties as a function of the lattice relative density. At the macroscale, the lattice unit cells are optimally distributed using the homogenized properties. The proposed design approach is demonstrated through 2D and 3D examples including the optimal design of an injection mold. The optimized injection mold is prototyped using additive manufacturing. The numerical model of the optimized mold shows that, with respect to a traditional solid mold design, a mass reduction of over 30% can be achieved with a small increase in nodal displacement (under 5 microns) and no difference in nodal temperature.

      PubDate: 2017-08-02T20:22:16Z
  • Prismatic semi-analytical elements for the simulation of linear elastic
           problems in structures with piecewise uniform cross section
    • Abstract: Publication date: November 2017
      Source:Computers & Structures, Volume 192
      Author(s): Fabian Krome, Hauke Gravenkamp, Carolin Birk
      This work addresses the computation of stiffness matrices for general prismatic structures with an arbitrary cross section. The presented approach is based on the scaled boundary finite element method (SBFEM), a semi-analytical method, which can be used to model structures by only discretizing the boundary of a domain. For prismatic structures, the process is further simplified, as only the cross section of the structure has to be discretized. Thus, a particular semi-analytical finite element is constructed for bounded and unbounded domains. The proposed approach leads to a frequency-dependent stiffness matrix. This stiffness matrix can easily be coupled to other prismatic SBFEM domains or general SBFEM domains. Necessary modifications to include forces along the scaling direction, such as body loads, are addressed. The results of the proposed approach are compared to those of traditional FEM models obtained using commercially available software.

      PubDate: 2017-08-02T20:22:16Z
  • IFC: Editorial board, Aims and Scope
    • Abstract: Publication date: 15 October 2017
      Source:Computers & Structures, Volume 191

      PubDate: 2017-08-02T20:22:16Z
  • Theoretical prediction of the progressive buckling and energy absorption
           of the sinusoidal corrugated tube subjected to axial crushing
    • Abstract: Publication date: 15 October 2017
      Source:Computers & Structures, Volume 191
      Author(s): Wenqian Hao, Jiamiao Xie, Fenghui Wang
      A theoretical study is conducted to predict the progressive buckling and energy absorption of the sinusoidal corrugated tube subjected to axial crushing. Based on the super folding element theory, the stationary plastic hinge mechanism is proposed. The theoretical prediction of the progressive buckling and energy absorption is proposed by taking the eccentricity factor and amplitude factor into account. In the theoretical analysis, the idealized elastic-plastic material model is adopted and strain hardening effect is employed. Also, the new lower bound and upper bound of the solutions for the mean crushing force are obtained. The theoretical result can predict the crushing behavior of the circular tube which produces the axisymmetric ring mode under axial crushing. The mean crushing force is related to the eccentricity factor and the amplitude factor, but the total energy is independent of the eccentricity factor. The theoretical results are compared well with the numerical and experimental results of previous studies. The theoretical predicts of corrugated tube produce excellent characteristics in term of force-consistent and low crushing force and provide a reference to the research of the progressive buckling and energy absorption of corrugated tube subjected to axial crushing.

      PubDate: 2017-06-28T07:13:45Z
  • Improving the accuracy of the dual Craig-Bampton method
    • Abstract: Publication date: 15 October 2017
      Source:Computers & Structures, Volume 191
      Author(s): Jeong-Ho Kim, Jaemin Kim, Phill-Seung Lee
      The objective of the work reported in this paper is to improve the well-known dual Craig-Bampton (DCB) method. The original transformation matrix of the DCB method is enhanced by considering the higher-order effect of residual substructural modes through residual flexibility. Using the new transformation matrix, original finite element models can be more accurately approximated in the reduced models. Herein, additional generalized coordinates are newly defined for considering the 2nd order residual flexibility. Additional coordinates related to the interface boundary can be eliminated by applying the concept of SEREP (the system equivalent reduction expansion process). The formulation of the improved DCB method is presented in detail, and its accuracy is investigated through numerical examples.

      PubDate: 2017-06-28T07:13:45Z
  • Generalized warping and distortional analysis of curved beams with
           isogeometric methods
    • Abstract: Publication date: 15 October 2017
      Source:Computers & Structures, Volume 191
      Author(s): Ioannis N. Tsiptsis, Evangelos J. Sapountzakis
      Towards improving conventional beam elements in order to include distortional effects in their analysis, independent parameters have been taken into account in this study. Curved beam’s behavior becomes more complex, even for dead loading, due to the coupling between axial force, bending moments and torque that curvature produces. Thus, the importance of simulating geometry exactly arises in order to approximate accurately the response of the curved beam. For this purpose, the isogeometric tools (b-splines and NURBS), either integrated in the Finite Element Method (FEM) or in a Boundary Element based Method (BEM) called Analog Equation Method (AEM), are employed in this contribution for the static analysis of horizontally curved beams of open or closed (box-shaped) cross sections. Responses of the stress resultants, stresses and displacements to static loading have been studied for various cross sections.

      PubDate: 2017-06-28T07:13:45Z
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