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  Subjects -> ENGINEERING (Total: 2285 journals)
    - CHEMICAL ENGINEERING (192 journals)
    - CIVIL ENGINEERING (185 journals)
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    - ENGINEERING (1206 journals)
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CIVIL ENGINEERING (185 journals)                     

Showing 1 - 185 of 185 Journals sorted alphabetically
ACI Structural Journal     Full-text available via subscription   (Followers: 17)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 2)
Acta Structilia : Journal for the Physical and Development Sciences     Open Access   (Followers: 2)
Advances in Civil Engineering     Open Access   (Followers: 35)
Advances in Structural Engineering     Full-text available via subscription   (Followers: 28)
Ambiente Construído     Open Access   (Followers: 1)
American Journal of Civil Engineering and Architecture     Open Access   (Followers: 31)
Architectural Engineering     Open Access   (Followers: 4)
Archives of Civil and Mechanical Engineering     Full-text available via subscription   (Followers: 1)
Archives of Civil Engineering     Open Access   (Followers: 10)
Archives of Hydro-Engineering and Environmental Mechanics     Open Access   (Followers: 2)
ATBU Journal of Environmental Technology     Open Access   (Followers: 4)
Australian Journal of Structural Engineering     Full-text available via subscription   (Followers: 6)
Baltic Journal of Road and Bridge Engineering     Full-text available via subscription   (Followers: 1)
BER : Building and Construction : Full Survey     Full-text available via subscription   (Followers: 10)
BER : Building Contractors' Survey     Full-text available via subscription   (Followers: 4)
BER : Building Sub-Contractors' Survey     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Building and Construction : An Executive Summary     Full-text available via subscription   (Followers: 4)
Bioinspired Materials     Open Access   (Followers: 5)
Bridge Structures : Assessment, Design and Construction     Hybrid Journal   (Followers: 16)
Building and Environment     Hybrid Journal   (Followers: 15)
Building Women     Full-text available via subscription  
Built Environment Project and Asset Management     Hybrid Journal   (Followers: 15)
Bulletin of Pridniprovsk State Academy of Civil Engineering and Architecture     Open Access   (Followers: 6)
Canadian Journal of Civil Engineering     Hybrid Journal   (Followers: 12)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 8)
Case Studies in Nondestructive Testing and Evaluation     Open Access   (Followers: 11)
Case Studies in Structural Engineering     Open Access   (Followers: 9)
Cement and Concrete Composites     Hybrid Journal   (Followers: 17)
Challenge Journal of Concrete Research Letters     Open Access   (Followers: 2)
Challenge Journal of Structural Mechanics     Open Access   (Followers: 5)
Change Over Time     Full-text available via subscription   (Followers: 2)
Civil and Environmental Engineering     Open Access   (Followers: 7)
Civil And Environmental Engineering Reports     Open Access   (Followers: 5)
Civil and Environmental Research     Open Access   (Followers: 19)
Civil Engineering = Siviele Ingenieurswese     Full-text available via subscription   (Followers: 4)
Civil Engineering and Architecture     Open Access   (Followers: 17)
Civil Engineering and Environmental Systems     Hybrid Journal   (Followers: 3)
Civil Engineering and Technology     Open Access   (Followers: 10)
Civil Engineering Dimension     Open Access   (Followers: 8)
Cohesion and Structure     Full-text available via subscription   (Followers: 2)
Composite Structures     Hybrid Journal   (Followers: 267)
Computer-aided Civil and Infrastructure Engineering     Hybrid Journal   (Followers: 11)
Computers & Structures     Hybrid Journal   (Followers: 36)
Concrete Research Letters     Open Access   (Followers: 6)
Construction Economics and Building     Open Access   (Followers: 2)
Construction Engineering     Open Access   (Followers: 9)
Construction Management and Economics     Hybrid Journal   (Followers: 22)
Construction Science     Open Access   (Followers: 4)
Constructive Approximation     Hybrid Journal  
Curved and Layered Structures     Open Access   (Followers: 2)
DFI Journal : The Journal of the Deep Foundations Institute     Hybrid Journal   (Followers: 1)
Earthquake Engineering and Structural Dynamics     Hybrid Journal   (Followers: 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     Hybrid Journal   (Followers: 2)
Engineering, Construction and Architectural Management     Hybrid Journal   (Followers: 14)
Environmental Geotechnics     Hybrid Journal   (Followers: 5)
European Journal of Environmental and Civil Engineering     Hybrid Journal   (Followers: 9)
Fatigue & Fracture of Engineering Materials and Structures     Hybrid Journal   (Followers: 16)
Frattura ed Integrità Strutturale : Fracture and Structural Integrity     Open Access  
Frontiers in Built Environment     Open Access  
Frontiers of Structural and Civil Engineering     Hybrid Journal   (Followers: 6)
Geomaterials     Open Access   (Followers: 4)
Geosystem Engineering     Hybrid Journal   (Followers: 1)
Geotechnik     Hybrid Journal   (Followers: 3)
Géotechnique Letters     Hybrid Journal   (Followers: 6)
HBRC Journal     Open Access   (Followers: 2)
Hormigón y Acero     Full-text available via subscription  
HVAC&R Research     Hybrid Journal  
Indoor and Built Environment     Hybrid Journal   (Followers: 2)
Infrastructure Asset Management     Hybrid Journal   (Followers: 2)
Infrastructures     Open Access  
Ingenio Magno     Open Access   (Followers: 1)
Insight - Non-Destructive Testing and Condition Monitoring     Full-text available via subscription   (Followers: 22)
International Journal for Service Learning in Engineering     Open Access  
International Journal of 3-D Information Modeling     Full-text available via subscription   (Followers: 3)
International Journal of Advanced Structural Engineering     Open Access   (Followers: 16)
International Journal of Civil, Mechanical and Energy Science     Open Access   (Followers: 1)
International Journal of Concrete Structures and Materials     Open Access   (Followers: 14)
International Journal of Condition Monitoring     Full-text available via subscription   (Followers: 2)
International Journal of Construction Engineering and Management     Open Access   (Followers: 9)
International Journal of Geo-Engineering     Open Access   (Followers: 3)
International Journal of Geosynthetics and Ground Engineering     Full-text available via subscription   (Followers: 4)
International Journal of Masonry Research and Innovation     Hybrid Journal   (Followers: 1)
International Journal of Pavement Research and Technology     Open Access   (Followers: 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: 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: 7)
International Journal Sustainable Construction & Design     Open Access  
Journal of Bridge Engineering     Full-text available via subscription   (Followers: 15)
Journal of Building Engineering     Hybrid Journal   (Followers: 1)
Journal of Building Materials and Structures     Open Access   (Followers: 2)
Journal of Building Performance Simulation     Hybrid Journal   (Followers: 6)
Journal of Civil Engineering and Construction Technology     Open Access   (Followers: 12)
Journal of Civil Engineering and Management     Hybrid Journal   (Followers: 7)
Journal of Civil Engineering and Science     Open Access   (Followers: 7)
Journal of Civil Engineering Research     Open Access   (Followers: 6)
Journal of Civil Engineering, Science and Technology     Open Access  
Journal of Civil Society     Hybrid Journal   (Followers: 4)
Journal of Civil Structural Health Monitoring     Hybrid Journal   (Followers: 4)
Journal of Composites for Construction     Full-text available via subscription   (Followers: 13)
Journal of Computing in Civil Engineering     Full-text available via subscription   (Followers: 24)
Journal of Construction Engineering     Open Access   (Followers: 7)
Journal of Construction Engineering and Management     Full-text available via subscription   (Followers: 19)
Journal of Constructional Steel Research     Hybrid Journal   (Followers: 8)
Journal of Earth Sciences and Geotechnical Engineering     Open Access   (Followers: 4)
Journal of Fluids and Structures     Hybrid Journal   (Followers: 6)
Journal of Frontiers in Construction Engineering     Open Access   (Followers: 2)
Journal of Green Building     Full-text available via subscription   (Followers: 11)
Journal of Highway and Transportation Research and Development (English Edition)     Full-text available via subscription   (Followers: 14)
Journal of Infrastructure Systems     Full-text available via subscription   (Followers: 21)
Journal of Legal Affairs and Dispute Resolution in Engineering and Construction     Full-text available via subscription   (Followers: 5)
Journal of Marine Science and Engineering     Open Access   (Followers: 1)
Journal of Materials and Engineering Structures     Open Access   (Followers: 5)
Journal of Materials in Civil Engineering     Full-text available via subscription   (Followers: 10)
Journal of Nondestructive Evaluation     Hybrid Journal   (Followers: 11)
Journal of Performance of Constructed Facilities     Full-text available via subscription   (Followers: 4)
Journal of Pipeline Systems Engineering and Practice     Full-text available via subscription   (Followers: 7)
Journal of Rehabilitation in Civil Engineering     Open Access   (Followers: 3)
Journal of Solid Waste Technology and Management     Full-text available via subscription   (Followers: 1)
Journal of Structural Engineering     Full-text available via subscription   (Followers: 40)
Journal of Structural Fire Engineering     Full-text available via subscription   (Followers: 6)
Journal of Sustainable Architecture and Civil Engineering     Open Access   (Followers: 3)
Journal of Sustainable Design and Applied Research in Innovative Engineering of the Built Environment     Open Access   (Followers: 1)
Journal of the Civil Engineering Forum     Open Access  
Journal of the South African Institution of Civil Engineering     Open Access   (Followers: 4)
Jurnal Spektran     Open Access   (Followers: 1)
Jurnal Teknik Sipil dan Perencanaan     Open Access   (Followers: 1)
Konstruksia     Open Access  
KSCE Journal of Civil Engineering     Hybrid Journal   (Followers: 2)
Latin American Journal of Solids and Structures     Open Access   (Followers: 4)
Materiales de Construcción     Open Access  
Mathematical Modelling in Civil Engineering     Open Access   (Followers: 3)
Nondestructive Testing And Evaluation     Hybrid Journal   (Followers: 17)
npj Materials Degradation     Open Access  
Obras y Proyectos     Open Access   (Followers: 1)
Open Journal of Civil Engineering     Open Access   (Followers: 7)
Photonics and Nanostructures - Fundamentals and Applications     Hybrid Journal   (Followers: 2)
Practice Periodical on Structural Design and Construction     Full-text available via subscription   (Followers: 4)
Proceedings of the Institution of Civil Engineers - Bridge Engineering     Hybrid Journal   (Followers: 8)
Proceedings of the Institution of Civil Engineers - Civil Engineering     Hybrid Journal   (Followers: 11)
Proceedings of the Institution of Civil Engineers - Management, Procurement and Law     Hybrid Journal   (Followers: 8)
Proceedings of the Institution of Civil Engineers - Municipal Engineer     Hybrid Journal   (Followers: 3)
Proceedings of the Institution of Civil Engineers - Structures and Buildings     Hybrid Journal   (Followers: 4)
Random Structures and Algorithms     Hybrid Journal   (Followers: 5)
Research in Nondestructive Evaluation     Hybrid Journal   (Followers: 7)
Revista IBRACON de Estruturas e Materiais     Open Access   (Followers: 1)
Road Materials and Pavement Design     Hybrid Journal   (Followers: 11)
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: 5)
Steel Construction - Design and Research     Hybrid Journal   (Followers: 3)
Structural and Multidisciplinary Optimization     Hybrid Journal   (Followers: 9)
Structural Concrete     Hybrid Journal   (Followers: 11)
Structural Control and Health Monitoring     Hybrid Journal   (Followers: 9)
Structural Engineering International     Full-text available via subscription   (Followers: 11)
Structural Safety     Hybrid Journal   (Followers: 7)
Structural Survey     Hybrid Journal  
Structure     Full-text available via subscription   (Followers: 23)
Structure and Infrastructure Engineering: Maintenance, Management, Life-Cycle Design and Performance     Hybrid Journal   (Followers: 13)
Structures     Hybrid Journal   (Followers: 1)
Study of Civil Engineering and Architecture     Open Access   (Followers: 9)
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  [3089 journals]
  • Computationally efficient fragility assessment using equivalent elastic
           limit state and Bayesian updating
    • Abstract: Publication date: 15 February 2018
      Source:Computers & Structures, Volume 197
      Author(s): Shinyoung Kwag, Abhinav Gupta
      Conventionally, the seismic response of primary structures such as buildings and secondary systems such as piping is evaluated through uncoupled analyses. Many studies have illustrated that the two systems interact in many different ways (mass interaction, non-classical damping, phasing, etc.). An analysis of the coupled system is not only rational but also eliminates the excessive conservatism that exists in an uncoupled analysis. Consequently, fragility assessments based on uncoupled analysis are also incorrect and a coupled analysis must be conducted in such evaluations. However, nonlinear analyses of such complex systems particularly in the context of fragility assessment, which requires a large number of nonlinear analyses, becomes computationally prohibitive. Tadinada and Gupta (2017) presented an equivalent elastic limit state concept with an intent to reduce the computational effort needed in these assessments and yet evaluate the seismic fragility with sufficient accuracy. This paper outlines some of the limitations that have been experienced in the use of originally proposed equivalent limit-state formulation and presents valuable enhancements. The novel contribution of this study is focused on accounting for the effect of uncertainty in nonlinear characteristics and the effect of non-classical damping. Unlike the originally proposed formulation, the proposed formulation also considers the asymmetric variation of the equivalent limit state with respect to tuning ratio. Furthermore, a Bayesian approach is incorporated into the proposed methodology for increasing the accuracy of seismic fragilities in the case of tuned or nearly tuned primary-secondary systems. Numerical examples are used to illustrate that the modified form improves the accuracy for both the tuned and the detuned systems. In summary, the proposed approach provides an efficient framework of seismic fragility assessment and risk evaluation for coupled systems.

      PubDate: 2017-12-13T09:07:10Z
  • Vibratory behavior prediction of mistuned stator vane clusters: An
           industrial application
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): J. Philippe, F. Thouverez, L. Blanc, M. Gruin
      Geometric and material dispersions of bladed disks imply some mistuning effects, which result in both the loss of cyclic symmetry properties and a vibratory response amplification in areas of high modal density. These conditions complicate the prediction of vibratory behavior, causing high modal density and extreme sensitivity to mistuning. A non-intrusive spectral stochastic method has been developed to predict the vibratory behavior of a mistuned stator vane. To apply this method to an industrial model, a Karhunen-Loève expansion and a double modal synthesis method have been combined with the stochastic method. The complete method was first tested on a simple academic model and then on an industrial stator vane sector.

      PubDate: 2017-12-13T09:07:10Z
  • A framework of finite element procedures for the analysis of proteins
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): Reza Sharifi Sedeh, Giseok Yun, Jae Young Lee, Klaus-Jürgen Bathe, Do-Nyun Kim
      Large-scale, functional collective motions of proteins and their supra-molecular assemblies occur in a physiological solvent environment at finite temperatures. The solution of these motions with standard molecular dynamics algorithms is computationally hardly possible when considering macromolecules. Much research has focused on alternative approaches that use coarse-graining to model proteins, but mostly in vacuum. In this paper, we incorporate realistically the physical effects of solvent damping into the finite element model of proteins. The proposed framework is based on Brownian dynamics and shown to be effective. An important advantage of the approach is that the computational cost is not dependent on the molecular size, which makes the long-time simulation of macromolecules possible. Using the proposed procedure, we demonstrate the analysis of a macromolecule in solvent—an analysis that has not been achieved before and could not be performed with a molecular dynamics algorithm.

      PubDate: 2017-12-13T09:07:10Z
  • Structural response predictions compared to material property estimates
           for structural integrity assessment under operational uncertainty
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): Kyunghoon Lee
      To examine structural integrity in consideration of operational uncertainties, we utilized structural response predictions obtained by transmitting estimates of structural system parameters into a simulation representing the actual system. For this purpose, we resolved inverse parameter estimation by Bayesian inference and constructed a forward model using certified reduced basis methods. For demonstration, we applied the proposed assessment strategy to two isotropic structural systems under static, linear elastic deformation: a beam and a plate subject to bending and shearing dominant loadings, respectively. Numerical investigation with emulated damage cases showed that structural response predictions were superior to material property estimates for inspecting structural integrity, particularly when operational uncertainties were not ignorable.

      PubDate: 2017-12-13T09:07:10Z
  • Rheological-dynamical analogy for analysis of vibrations and low cycle
           fatigue in internally damped inelastic frame structures
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): Dragan D. Milašinović, Aleksandar Landović
      This is a study of viscoelastoplastic (VEP) vibrations and their use for the analysis of low cycle fatigue in internally damped inelastic frame structures (IDIFSs). The background of this inelastic theory is presented in the framework of a mathematical-physical analogy between the rheological model and a dynamical model with viscous damping. The rheological-dynamical analogy (RDA) is a type of inelastic analysis, which transforms one category of material non-linear problems to simpler linear dynamical problems using modal analysis. The aim of this paper is to define internal damping based on both the dynamic modulus and modal damping ratios. The idea underlying these approaches is that fatigue damage appears if internal damping is unevenly distributed over the elements of a structure. The residual force method, which requires the use of the finite element method (FEM), is used for the location of damage and derivation of the fatigue damage vector. Finally, the effective force vector is derived from damage mechanics. An analysis of damaged IDIFSs made of reinforced concrete is carried out. It is shown that the RDA, which correlates with the main mechanical properties of the material measured, can improve the prediction of fatigue damage caused by low cycle fatigue.

      PubDate: 2017-12-13T09:07:10Z
  • Effect of steering limit constraints on the performance of variable
           stiffness laminates
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): Daniël M.J. Peeters, Gustavo Gonzalez Lozano, Mostafa M. Abdalla
      A method to optimise the fibre angle distribution of variable stiffness laminates is proposed. The proposed method integrates a fibre angle retrieval step with a fibre angle optimisation procedure. A multi-level approximation approach is used in combination with the method of successive approximations. First, fibre angle retrieval is done by approximating the structural responses based on the optimal stiffness distribution found using lamination parameters. The full fibre angle optimisation is done by updating the approximations based on the current stacking sequence. Next, the actual fibre paths are optimised taking into account the actual size of a tow, and the maximum size of any gap or overlap appearing. The paths are smoothed out using CATIA, and finally spline curves are found that can be sent to a fibre placement machine for manufacturing. It is shown for a bucking optimisation with a stiffness constraint that the number of finite element analyses reduces significantly by starting the optimisation from the optimal stiffness distribution rather than from a user-specified stacking sequence. Next, it is shown that updating the approximations also leads to considerable improvements over fibre angle retrieval. Similar promising results are obtained for a stress optimisation problem.

      PubDate: 2017-12-13T09:07:10Z
  • Numerical simulation of 2-D weak and strong discontinuities by a novel
           approach based on XFEM with local mesh refinement
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): Tiantang Yu, Tinh Quoc Bui
      The present paper is concerned with numerical simulation of two-dimensional (2-D) cracks and material interfaces by an effective computational approach. A local mesh refinement in terms of extended finite element method is thus described. The new approach combines a posteriori error estimation algorithm, a local non-conformal mesh connection strategy, and local enrichment. An error estimator based on recovery strain for adaptivity is used; allowing the mesh where it is needed is subsequently refined. Unlike preceding local refined methods, variable-node elements are integrated into the present formulation instead, which aims to treat mismatching problem induced by different scale-meshes in an effective way. The discontinuity and singularity of cracks or material interfaces are captured by local enrichments in terms of partition of unity. Due to existence of different types of elements in the model, a special technique is thus proposed for appropriately and accurately treating numerical integration. We address the developed methodology, assessing its numerical properties and performance through several numerical examples. In particular, discontinuity problems with material interfaces, multiple inclusions, single and multiple cracks are analyzed. The obtained results indicate a high accuracy, low cost and good performance of the proposed method in simulation of 2-D cracks and material interfaces.

      PubDate: 2017-12-13T09:07:10Z
  • An element subscale refinement for representation of the progressive
           fracture based on the phantom node approach
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): S. Mostofizadeh, F.P. van der Meer, M. Fagerström, L.J. Sluys, R. Larsson
      A new approach for the analysis of the ductile fracture of thin-walled large scale structures is developed. The method proposes a subscale refinement of the elements containing the crack. It allows for smooth progression of the crack without furnishing required level of the mesh refinement, and a more detailed representation of the crack tip and crack kink within the cracked elements. This approach is based on the phantom node method and is intended to be applicable for different types of elements including both low and high order elements. Numerical examples for dynamic crack propagation are presented and compared to conventional solutions to prove the accuracy and effectiveness of the proposed approach.

      PubDate: 2017-12-13T09:07:10Z
  • Damage identification using inverse analysis for 3D coupled
           thermo-hydro-mechanical problems
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): Long Nguyen-Tuan, Carsten Könke, Tom Lahmer
      In this paper, location and degree of damages in massive masonry structures are identified by a multi-field based inverse analysis which relies on a series of measurements such as transient displacements, temperatures and water pressures. As it is typical for the multi-field problems, the existence of damage leads to local changes in parameters of the different physical fields. The degree of the damage is defined by one primary variable, from which other quantities are derived. For fluid-flow problems in deformable porous media under non-isothermal boundary conditions such a quantity is the porosity of the material. The inverse analysis bases on a global search method, in which a dual-level parallel-computation is applied to improve computational cost. The effects of uncertainties in measurements and the size of the damage on the accuracy of the solutions are also discussed in the paper.

      PubDate: 2017-12-13T09:07:10Z
  • A novel node-based smoothed radial point interpolation method for 2D and
           3D solid mechanics problems
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): Y. Li, G.R. Liu, J.H. Yue
      This paper presents a novel node-based radial point interpolation method (NS-RPIM), which has two different versions termed as NS-RPIM−Tr4−Cd (for 2D problems) and NS-RPIM−Tr5−Cd (for 3D problems). These NS-RPIMs are created using edge-based Tr4-scheme and face-based Tr5-scheme, respectively. In the formulation, we use the generalized smoothed Galerkin (GS-Galerkin) weak-form which requires only value of shape functions. Because W2 formulation allows the use of discontinuous functions, RPIM can now be used to create proven stable and accurate models. The computational efficiency of the NS-RPIM−Tr4−Cd is rigorously examined against other NS-RPIMs and FEM. It is found that our NS-RPIM produce highly accurate solutions at low computational cost, due to the use of the condensed RPIM shape functions. Numerical results for 2D and 3D problems demonstrate that the NS-RPIMs possess the following important properties: (1) upper bound solution in the strain energy; (2) volumetric locking free; (3) superconvergence in strain energy solution; (4) insensitive to node distribution.

      PubDate: 2017-12-13T09:07:10Z
  • A discrete element model of concrete for cyclic loading
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): Sina Sinaie, Tuan Duc Ngo, Vinh Phu Nguyen
      This paper takes advantage of the discrete element method to develop a model of concrete for cyclic simulations. For this purpose, a micro-mechanical damage model that also allows stress-reversals is formulated for inter-particle bonds. Moreover, a multi-phase implementation of the discrete element method is developed and used for two distinct reasons. First, to characterize aggregate and mortar particles separately. Second, to allow the effect of the interfacial transition zone to be taken into account. A strict validation approach is taken in this work, whereby the developed model is only calibrated against monotonic stress-strain curves and then evaluated for its performance under cyclic loading. Simulation results are constantly compared against experimental values. These comparisons illustrate the capability of the model to predict cyclic properties of concrete. Progression of damage is discussed in terms of numerical variables and also through the visualization of force chains and crack propagation.

      PubDate: 2017-12-13T09:07:10Z
  • Complete monotonic expression of the fourth-moment normal transformation
           for structural reliability
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): Yan-Gang Zhao, Xuan-Yi Zhang, Zhao-Hui Lu
      Probability distributions of basic random variables are essential for the accurate evaluation of structural reliability. In engineering practice, the probability distributions of some random variables are often unknown and the only available information about these may be their statistical moments. To conduct structural reliability analysis without the exclusion of random variables with unknown probability distributions, the fourth-moment normal transformation (FMNT) has been proposed. However, the applicability of expression of the FMNT has not been sufficiently investigated. Furthermore, the monotonic regions of the FMNT are not defined without which the application of the transformation is inconvenient, or even unreliable in reliability analysis. In the present paper, a complete expression of the FMNT including six cases with different combinations of skewness and kurtosis is derived, and the monotonicity of each case of the FMNT expression is confirmed. Literature suggests that the complete monotonic expression of the fourth-moment normal transformation is the first time to be successfully accomplished up to date. Through the numerical examples, the FMNT is found to be quite efficient for normal transformation and to be sufficiently accurate to include random variables with unknown probability distributions in structural reliability analysis.

      PubDate: 2017-12-13T09:07:10Z
  • A generalized micromorphic approach accounting for variation and
           dispersion of preferred material directions
    • Abstract: Publication date: Available online 11 December 2017
      Source:Computers & Structures
      Author(s): Markus von Hoegen, Sebastian Skatulla, Jörg Schröder
      Materials exhibiting a heterogeneous and non-uniform composition in terms of elastic and anisotropic properties such as biological tissues require special efforts to accurately describe their constitutive behavior. In contrast to classical models, micromorphic formulations can predict the macroscopically observable material response as originated from distinct scale-dependent micro-structural deformation mechanisms. This is facilitated by additional independent degrees of freedom and associated additional strain and stress quantities. Here, a generalized continuum is mathematically constructed from a macro-continuum and a micro-continuum which are both adequately coupled on kinematics and constitutive levels as well as by micro-boundary conditions. In view of biomechanical modeling, the potential of the formulation is studied for a number of academic examples characterized by an anisotropic material composition to elucidate the micromorphic material response as compared with the one obtained using a classical continuum mechanics approach. The results demonstrate the ability of the generalized continuum approach to address non-affine elastic reorientation of the preferred material direction in the macro-space and its dispersion in the micro-space as affecting deformation, strain and stress on the macroscopic level. In particular, if the anisotropy in the micromorphic formulation is solely linked to the extra degrees of freedom and associated strain and stress measures, the deformation for small and large strains is shown to be distinctly different to the classical response. Together with the ability to implicitly account for scale-dependent higher-order deformation effects in the constitutive law the proposed generalized micromorphic formulation provides an advanced description, especially for fibrous biological materials.

      PubDate: 2017-12-13T09:07:10Z
  • Simulation of failure in timber with structural inhomogeneities using an
           automated FE analysis
    • Abstract: Publication date: Available online 9 December 2017
      Source:Computers & Structures
      Author(s): C. Jenkel, M. Kaliske
      In this contribution, approaches to analyse timber characterized by structural inhomogeneities are introduced using the Finite Element Method (FEM). In an automatable procedure, the structural behaviour of timber containing knots is simulated on the basis of a few geometrical data obtained by surface scans. To generate FE models automatically, two meshing procedures are introduced. The fibre course is determined numerically using a flow-grain analogy. Elastic, plastic and fracture mechanically based macroscopic material models are used to represent the mechanical properties of homogeneous wood, free of inhomogeneities. The procedure is used to compute global material parameters, as the global longitudinal elasticity modulus and tensile strength similar to EN 338 and therefore can be used for numerical timber grading. For comparison, experiments are considered where the global elasticity modulus and the ultimate load have been determined in tensile tests. The tests are simulated for selected boards. Possible failure zones are identified by the application of plasticity models. To determine the ultimate load at tensile loading numerically, cohesive elements are applied.

      PubDate: 2017-12-13T09:07:10Z
  • Strength predictions of clear wood at multiple scales using numerical
           limit analysis approaches
    • Abstract: Publication date: Available online 7 December 2017
      Source:Computers & Structures
      Author(s): Mingjing Li, Josef Füssl, Markus Lukacevic, Josef Eberhardsteiner, Christopher M. Martin
      This work aims at a new approach for understanding failure mechanisms and predicting wood strengths, which are strongly influenced by the complex hierarchical material system of wood. Thus, a mechanical concept, where different microstructural characteristics are incorporated, appears to be necessary, based on the division of wood into meaningful scales of observation. At each scale, effective strength properties are to be determined and a multiscale approach needs to be applied, for which conventional numerical methods appear to be inefficient. In this work, numerical limit analysis approaches are further developed and applied for the first time to wood, complementing conventional methods successfully at certain scales of observation in a multiscale ‘damage’ approach. Limit analysis belongs to the group of direct plastic analysis methods, focusing exclusively on the time instant of structural collapse, and delivering the ultimate strength. Compared with conventional numerical approaches that have previously been applied to wood, limit analysis approaches are much more stable and efficient. In this work, orthotropic failure criteria and periodic boundary conditions are implemented into both lower bound and upper bound numerical limit analysis formulations. As numerical results, effective failure surfaces are obtained at both annual ring scale and clear wood scale. A validation at clear wood scale indicates that this new approach is very promising.

      PubDate: 2017-12-13T09:07:10Z
  • Adaptive isogeometric analysis in structural frames using a layer-based
           discretization to model spread of plasticity
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): Ning Liu, Ann E. Jeffers
      A distributed plasticity isogeometric frame model utilizing a layer-based discretization is formulated to capture the plasticity growth in large-deformation frames. In our formulation, B-spline basis functions are employed to define the deformation along the length, while a layer-based through-the-thickness discretization is adopted to capture the gradual plastification of the section. This separation of the thickness integration from the length direction enables the full 2D yielding development to be captured while maintaining a 1D data structure. The member-level geometrically nonlinear effects are also included. By introducing a continuity constraint in between two patches, rigid connection between two members is achieved in a multi-patch analysis setting. The formulation includes an adaptive analysis in which knots are inserted based on yield locations. In comparison to conventional layer-based finite elements, fewer degrees of freedom are needed to achieve the same level of accuracy due to the high-order smoothness of B-splines. Compared to existing isogeometric beam elements, the appealing feature is its capability of adaptively capturing the 2D spread of plasticity while maintaining a 1D data structure. The performance of the proposed model is assessed through several numerical examples involving gradual yielding of beams and frames under small and large deformations.

      PubDate: 2017-11-16T03:26:34Z
  • IFC: Editorial board, Aims and Scope
    • Abstract: Publication date: 15 January 2018
      Source:Computers & Structures, Volume 195

      PubDate: 2017-11-02T13:05:36Z
  • Analysis of thin-walled beam-shell structures for concept modeling based
           on higher-order beam theory
    • Abstract: Publication date: 15 January 2018
      Source:Computers & Structures, Volume 195
      Author(s): Ngoc-Linh Nguyen, Gang-Won Jang, Soomin Choi, Jaeyong Kim, Yoon Young Kim
      Many engineering structures consist of thin-walled beams and shells. Especially for fast design in an early design stage, a simplified analysis using beams for load-carrying members and shells for panels is very useful, but there appears no accurate beam-shell combined finite element model. The main reason is that the Timoshenko or Euler beam elements are incapable of representing significant sectional deformations near beam joints or near beam-panel interfaces. Although some progress has been made in developing higher-order beam elements that can accurately capture the sectional deformations, there is no investigation to develop higher-order beam and shell combined models useful to analyze various engineering structures. The main contribution of this work is to present the first attempt to model structures made of thin-walled closed beams and shells in terms of higher-order beam elements and shell elements and to establish the matching conditions between the dissimilar field variables of higher-order beam and shell elements along their interfaces. For the finite element analysis of a whole structure, the interface matching conditions are imposed through Lagrange multipliers. High accuracy of the proposed higher-order beam-shell method is demonstrated through static and modal analyses of various structures including a simplified model of a vehicle body-in-white (BIW).

      PubDate: 2017-11-02T13:05:36Z
  • A three-dimensional plasticity-damage constitutive model for timber under
           cyclic loads
    • Abstract: Publication date: 15 January 2018
      Source:Computers & Structures, Volume 195
      Author(s): Luis F. Sirumbal-Zapata, Christian Málaga-Chuquitaype, Ahmed Y. Elghazouli
      The performance of timber structures is governed by the nonlinear response at their connections, where high deformation levels and stress concentrations are developed, particularly when subjected to load reversals. To date, no constitutive model for wood under cyclic load exists which is able to incorporate its most important failure modes while considering plastic deformations and cyclic stiffness and strength degradation simultaneously. This paper presents the formulation and implementation of a plasticity-damage model with these characteristics within a continuum mechanics approach. The theoretical framework of both plasticity and damage models is described, and a detailed derivation of the constitutive equations required for their computational implementation and coupling as well as the return mapping and iterative algorithms for their integration are presented. The damage evolution process is handled by two independent scalar variables for tension and compression. A general orthotropic plasticity yield surface with isotropic hardening is employed to incorporate timber plastic flow in compression. A closed-form expression for the plasticity-damage consistent tangent operator is derived. It is demonstrated that the proposed constitutive model captures all the key characteristics required for an accurate modelling of timber under large deformation levels until failure.

      PubDate: 2017-11-02T13:05:36Z
  • An adaptive hybrid evolutionary firefly algorithm for shape and size
           optimization of truss structures with frequency constraints
    • Abstract: Publication date: 15 January 2018
      Source:Computers & Structures, Volume 195
      Author(s): Qui X. Lieu, Dieu T.T. Do, Jaehong Lee
      This paper presents a novel adaptive hybrid evolutionary firefly algorithm (AHEFA) for shape and size optimization of truss structures under multiple frequency constraints. This algorithm is a hybridization of the differential evolution (DE) algorithm and the firefly algorithm (FA). An automatically adapted parameter is utilized to select an appropriate mutation scheme for an effective trade-off between the global and local search abilities. An elitist technique is applied to the selection phase to choose the best individuals. Accordingly, the convergence rate is significantly improved with the high solution accuracy. Six numerical examples are examined for the validity of the present algorithm.

      PubDate: 2017-10-25T12:30:10Z
  • Domain-boundary element method for elastodynamics of functionally graded
           Timoshenko beams
    • Abstract: Publication date: 15 January 2018
      Source:Computers & Structures, Volume 195
      Author(s): Iman Eshraghi, Serkan Dag
      A new domain-boundary element method is developed for elastodynamic analysis of functionally graded Timoshenko beams. Three governing partial differential equations of motion are derived by considering through-the-thickness variations of the physical properties. Weighted-residual forms are imposed utilizing the static fundamental solutions. These forms are then reduced to three integral equations containing domain integrals with time derivatives of unknown functions. Through domain discretization and shape function approximation, integral equations are converted to a system of ordinary differential equations in time. Forced dynamic response is revealed by solving the system of equations via Houbolt method. Comparison of dynamic responses generated for homogeneous beams to those calculated through an analytical solution and finite difference method verify the developed procedures. Further parametric analyses are performed for functionally graded Timoshenko beams under step, harmonic, and impulsive loadings. The numerical results presented illustrate the influence of material inhomogeneity on time histories of deflection and stress. Domain-boundary element method is demonstrated to be an effective technique for elastodynamic analysis of functionally graded structures.

      PubDate: 2017-10-25T12:30:10Z
  • A computationally efficient multiscale finite element formulation for
           dynamic and postbuckling analyses of carbon nanotubes
    • Abstract: Publication date: 15 January 2018
      Source:Computers & Structures, Volume 195
      Author(s): Sandeep Singh, B.P. Patel
      The efficient multiscale membrane locking free shell elements are developed to study the dynamic and postbuckling characteristics of carbon nanotubes incorporating material and geometric nonlinearities. The constitutive relation at continuum level is derived through the Cauchy–Born rule incorporating the effect of curvature tensor on bond lengths and using the Tersoff–Brenner atomic interaction potential per unit area of a unit cell. The membrane locking is eliminated by using the smoothed shape functions derived through the least square strain smoothing technique for the interpolation of the transverse displacement in the circumferential strain. The performance of the four/eight noded inconsistent/consistent Kirchhoff rectangular and improved discrete Kirchhoff quadrilateral (IDKQ) shell elements is investigated. It is found that the four noded elements with smoothed interpolation of transverse displacement in the circumferential strain yield accurate results and are computationally efficient. The multiscale modelling results are found to be in close agreement with the molecular mechanics simulations. The significant effect of material nonlinearity on the nonlinear dynamic and postbuckling responses is predicted.

      PubDate: 2017-10-25T12:30:10Z
  • IFC: Editorial board, Aims and Scope
    • Abstract: Publication date: 1 January 2018
      Source:Computers & Structures, Volume 194

      PubDate: 2017-10-25T12:30:10Z
  • Simultaneous topology optimization of supporting structure and loci of
           isolators in an active vibration isolation system
    • Abstract: Publication date: 1 January 2018
      Source:Computers & Structures, Volume 194
      Author(s): Pingzhang Zhou, Jianbin Du, Zhenhua Lü
      We developed a new multi-objective and multi-level optimization method to design an active vibration isolation system. Both the layout of the continuum (i.e. the supporting structure) and the loci of the isolators are designed using topology optimization technique in a unified formulation for the first time. The static, dynamic and vibration-isolation characteristics are taken into account simultaneously in the present model. Due to their different roles in the system it may be appropriate and advantageous to treat the design of the continuum layout and isolator loci as different sub-problems with different objectives in separate stages. The multi-level optimization technique, where the optimization of the supporting structure and the isolator loci are incorporated into a closed-loop, is proposed and implemented so that the interactions between these two sub-problems can be fully taken into account. Numerical results demonstrate the validity of the proposed design cycle. Comparisons show that the overall static, dynamic and vibration-isolation performance of the optimized system outperforms the ones designed by traditional methods.

      PubDate: 2017-10-25T12:30:10Z
  • Adaptive sparse polynomial chaos expansions for global sensitivity
           analysis based on support vector regression
    • Abstract: Publication date: 1 January 2018
      Source:Computers & Structures, Volume 194
      Author(s): Kai Cheng, Zhenzhou Lu
      In the context of uncertainty analysis, Polynomial chaos expansion (PCE) has been proven to be a powerful tool for developing meta-models in a wide range of applications, especially for sensitivity analysis. But the computational cost of classic PCE grows exponentially with the size of the input variables. An efficient approach to address this problem is to build a sparse PCE. In this paper, a full PCE meta-model is first developed based on support vector regression (SVR) technique using an orthogonal polynomials kernel function. Then an adaptive algorithm is proposed to select the significant basis functions from the kernel function. The selection criterion is based on the variance contribution of each term to the model output. In the adaptive algorithm, an elimination procedure is used to delete the non-significant bases, and a selection procedure is used to select the important bases. Due to the structural risk minimization principle employing by SVR model, the proposed method provides better generalization ability compared to the common least square regression algorithm. The proposed method is examined by several examples and the global sensitivity analysis is performed. The results show that the proposed method establishes accurate meta-model for global sensitivity analysis of complex models.

      PubDate: 2017-10-25T12:30:10Z
  • Form-finding algorithm for masonry arches subjected to in-plane earthquake
    • Abstract: Publication date: 15 January 2018
      Source:Computers & Structures, Volume 195
      Author(s): Tim Michiels, Sigrid Adriaenssens
      This paper presents the first form finding method for masonry arches subjected to self-weight and in-plane horizontal loading due to earthquakes. New material-efficient arch shapes are obtained by considering both horizontal and gravitational acceleration in the form finding process. By interpreting the obtained forms, insights into the influence of form on the earthquake resistance of the arches are presented. The form finding algorithm relies on two simplified, first-order equilibrium methods: thrust line analysis and kinematic limit state analysis, which present respectively a lower- and upper-bound approach to the analytic problem of arch stability under gravity and horizontal loading. Through a methodological application of a series of geometric manipulations of the thrust line, shapes are obtained that can resist the design acceleration by guaranteeing a compression-only load path. Forms are obtained for horizontal accelerations of 0.15, 0.3 and 0.45g, as well as for arches of different rise-to-span ratios (1/2, 1/4 and 1/8). The obtained shapes require up to 65% less material than circular arches with constant thickness that are designed to withstand the same horizontal acceleration and self-weight, regardless of acceleration magnitude. The findings of this research will thus allow more material-efficient design of masonry arches in seismic areas.

      PubDate: 2017-10-14T11:03:56Z
  • 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
  • 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
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