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  Subjects -> ENGINEERING (Total: 2336 journals)
    - CHEMICAL ENGINEERING (200 journals)
    - CIVIL ENGINEERING (192 journals)
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    - ENGINEERING (1225 journals)
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CIVIL ENGINEERING (192 journals)                     

Showing 1 - 192 of 192 Journals sorted alphabetically
ACI Structural Journal     Full-text available via subscription   (Followers: 19)
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: 39)
Advances in Structural Engineering     Full-text available via subscription   (Followers: 31)
Agregat     Open Access   (Followers: 1)
Ambiente Construído     Open Access   (Followers: 1)
American Journal of Civil Engineering and Architecture     Open Access   (Followers: 33)
Architectural Engineering     Open Access   (Followers: 4)
Archives of Civil and Mechanical Engineering     Full-text available via subscription   (Followers: 2)
Archives of Civil Engineering     Open Access   (Followers: 13)
Archives of Hydro-Engineering and Environmental Mechanics     Open Access   (Followers: 2)
ATBU Journal of Environmental Technology     Open Access   (Followers: 4)
Australian Journal of Structural Engineering     Full-text available via subscription   (Followers: 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: 11)
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 & Management     Open Access   (Followers: 1)
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: 13)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 7)
Case Studies in Nondestructive Testing and Evaluation     Open Access   (Followers: 12)
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: 6)
Change Over Time     Full-text available via subscription   (Followers: 2)
Civil and Environmental Engineering     Open Access   (Followers: 8)
Civil And Environmental Engineering Reports     Open Access   (Followers: 7)
Civil and Environmental Research     Open Access   (Followers: 20)
Civil Engineering = Siviele Ingenieurswese     Full-text available via subscription   (Followers: 4)
Civil Engineering and Architecture     Open Access   (Followers: 21)
Civil Engineering and Environmental Systems     Hybrid Journal   (Followers: 3)
Civil Engineering and Technology     Open Access   (Followers: 11)
Civil Engineering Dimension     Open Access   (Followers: 10)
Civil Engineering Infrastructures Journal     Open Access   (Followers: 1)
Cohesion and Structure     Full-text available via subscription   (Followers: 2)
Composite Structures     Hybrid Journal   (Followers: 279)
Computer-aided Civil and Infrastructure Engineering     Hybrid Journal   (Followers: 11)
Computers & Structures     Hybrid Journal   (Followers: 37)
Concrete Research Letters     Open Access   (Followers: 6)
Construction Economics and Building     Open Access   (Followers: 4)
Construction Engineering     Open Access   (Followers: 11)
Construction Management and Economics     Hybrid Journal   (Followers: 23)
Construction Science     Open Access   (Followers: 5)
Constructive Approximation     Hybrid Journal  
Curved and Layered Structures     Open Access   (Followers: 3)
DFI Journal : The Journal of the Deep Foundations Institute     Hybrid Journal   (Followers: 1)
Earthquake Engineering and Structural Dynamics     Hybrid Journal   (Followers: 17)
Enfoque UTE     Open Access   (Followers: 4)
Engineering Project Organization Journal     Hybrid Journal   (Followers: 7)
Engineering Structures     Hybrid Journal   (Followers: 13)
Engineering Structures and Technologies     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: 17)
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: 7)
GISAP : Technical Sciences, Construction and Architecture     Open Access  
HBRC Journal     Open Access   (Followers: 2)
Hormigón y Acero     Full-text available via subscription  
HVAC&R Research     Hybrid Journal  
Indonesian Journal of Urban and Environmental Technology     Open Access  
Indoor and Built Environment     Hybrid Journal   (Followers: 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: 29)
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: 18)
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: 10)
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: 9)
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: 14)
Journal of Civil Engineering and Management     Hybrid Journal   (Followers: 7)
Journal of Civil Engineering and Science     Open Access   (Followers: 9)
Journal of Civil Engineering Research     Open Access   (Followers: 7)
Journal of Civil Engineering, Science and Technology     Open Access   (Followers: 1)
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: 25)
Journal of Construction Engineering     Open Access   (Followers: 8)
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)
Journal of Water and Environmental Nanotechnology     Open Access  
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   (Followers: 1)
Mathematical Modelling in Civil Engineering     Open Access   (Followers: 4)
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: 9)
Photonics and Nanostructures - Fundamentals and Applications     Hybrid Journal   (Followers: 3)
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: 13)
Proceedings of the Institution of Civil Engineers - Management, Procurement and Law     Hybrid Journal   (Followers: 9)
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: 10)
Structural Concrete     Hybrid Journal   (Followers: 11)
Structural Control and Health Monitoring     Hybrid Journal   (Followers: 9)
Structural Engineering International     Full-text available via subscription   (Followers: 12)
Structural Mechanics of Engineering Constructions and Buildings     Open Access   (Followers: 1)
Structural Safety     Hybrid Journal   (Followers: 7)
Structural Survey     Hybrid Journal  
Structure     Full-text available via subscription   (Followers: 24)
Structure and Infrastructure Engineering: Maintenance, Management, Life-Cycle Design and Performance     Hybrid Journal   (Followers: 14)
Structures     Hybrid Journal   (Followers: 1)
Study of Civil Engineering and Architecture     Open Access   (Followers: 10)
Superlattices and Microstructures     Hybrid Journal   (Followers: 2)
Surface Innovations     Hybrid Journal  
Technical Report Civil and Architectural Engineering     Open Access   (Followers: 1)
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]   [37 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0045-7949
   Published by Elsevier Homepage  [3177 journals]
  • A mesoscale approach for modeling capillary water absorption and transport
           phenomena in cementitious materials
    • Abstract: Publication date: 15 April 2018
      Source:Computers & Structures, Volume 200
      Author(s): Antonio Caggiano, Diego Said Schicchi, Christoph Mankel, Neven Ukrainczyk, Eduardus A.B. Koenders
      This paper proposes a mesoscale approach for simulating moisture transport by capillary action in partly-saturated porous cementitious composites. The modeling approach explicitly accounts for moisture transport through a mesostructure composed of coarse aggregates, surrounding cementitious mortar and interfaces. These latter, namely interface transition zones (ITZs), allow to describe the interaction between aggregates and mortar, and may cause an alternative path for the internal moisture movements. Basic morphology effects of the ITZs are simulated using a ribbon approach. Random spatial distribution of cement particles are stacked in the meso-geometry. Aggregate particles are introduced as randomly perturbed polygons and the moisture transport is modeled as a diffusion problem and solved by means of the finite element method. The proposed constitutive models are based on a proper description of the permeability and pore size distribution which strongly affect the local moisture content. Numerical results at both macro- and mesoscale levels demonstrate the soundness and capability of the proposed approach. The integrated modeling results actually demonstrate the potential of the mesoscale approach and shows the role of the ITZs as an internal interconnected network.

      PubDate: 2018-02-25T22:35:52Z
  • Dynamic analysis of three-dimensional polycrystalline materials using the
           boundary element method
    • Abstract: Publication date: 15 April 2018
      Source:Computers & Structures, Volume 200
      Author(s): Andres F. Galvis, Rene Q. Rodríguez, Paulo Sollero
      A new computational framework to analyse the microscale dynamic behaviour of three-dimensional polycrystalline materials with different lattice structures is presented. The absence of analytical solutions for these stochastic materials has been a challenge in validating the numerical results. In macroscale analysis, when the number of crystal aggregates in the microscale is large, polycrystalline aggregates exhibit an effective isotropic nature. To model the elastodynamic effects, random crystalline orientations and morphology configurations are used for each polycrystalline aggregate. The recently proposed fundamental solution based on double Fourier series for general anisotropy coupled to the dual-reciprocity boundary element method is used. A drastic reduction in the degrees of freedom is achieved owing to the nature of the boundary mesh. The stochastic time-dependent displacement wave under various boundary conditions is evaluated, and the validation is carried out using homogenisation over the grain surfaces. An assessment of the effective macroscopic properties of the available analytical isotropic models is proposed, wherein the convergence is evaluated using statistical samples. Numerical results are presented using a large number of simulations to obtain a good confidence interval.

      PubDate: 2018-02-25T22:35:52Z
  • Shear deformable plate elements based on exact elasticity solution
    • Abstract: Publication date: 15 April 2018
      Source:Computers & Structures, Volume 200
      Author(s): Anssi T. Karttunen, Raimo von Hertzen, J.N. Reddy, Jani Romanoff
      The 2-D approximation functions based on a general exact 3-D plate solution are used to derive locking-free, rectangular, 4-node Mindlin (i.e., first-order plate theory), Levinson (i.e., a third-order plate theory), and Full Interior plate finite elements. The general plate solution is defined by a biharmonic mid-surface function, which is chosen for the thick plate elements to be the same polynomial as used in the formulation of the well-known nonconforming thin Kirchhoff plate element. The displacement approximation that stems from the biharmonic polynomial satisfies the static equilibrium equations of the 2-D plate theories at hand, the 3-D Navier equations of elasticity, and the Kirchhoff constraints. Weak form Galerkin method is used for the development of the finite element model, and the matrices for linear bending, buckling and dynamic analyses are obtained through analytical integration. In linear buckling problems, the 2-D Full Interior and Levinson plates perform particularly well when compared to 3-D elasticity solutions. Natural frequencies obtained suggest that the optimal value of the shear correction factor of the Mindlin plate theory depends primarily on the boundary conditions imposed on the transverse deflection of the 3-D plate used to calibrate the shear correction factor.

      PubDate: 2018-02-25T22:35:52Z
  • The new paradigm of finite element solutions with overlapping elements in
           CAD – Computational efficiency of the procedure
    • Abstract: Publication date: 1 April 2018
      Source:Computers & Structures, Volume 199
      Author(s): Lingbo Zhang, Ki-Tae Kim, Klaus-Jürgen Bathe
      We consider the new paradigm of finite element analysis, present an effective overlapping finite element, and study the computational efficiency of the discretization scheme. The important new ingredient in the formulation of the overlapping element is that, unlike in meshless methods, we only use local polynomial functions in the displacement interpolations. We achieve this property by replacing the Shepard functions by local polynomials. As a consequence, the bandwidth of the resulting stiffness matrix for the overlapping finite element is much reduced when compared with earlier developments. We study the distortion insensitivity of the new overlapping finite element, the convergence properties and the required computational effort when compared with the use of the traditional 4-node finite element and that element with covers. The results show the overlapping element to be very promising, in particular in the new paradigm of analysis using finite elements in CAD.

      PubDate: 2018-02-25T22:35:52Z
  • Transient implicit wave propagation dynamics with overlapping finite
    • Abstract: Publication date: 1 April 2018
      Source:Computers & Structures, Volume 199
      Author(s): Ki-Tae Kim, Lingbo Zhang, Klaus-Jürgen Bathe
      We present novel overlapping finite elements used with the Bathe time integration method to solve transient wave propagation problems. The solution scheme shows two important properties that have been difficult to achieve in the numerical solution of general wave propagations: monotonic convergence of calculated solutions with decreasing time step size and a solution accuracy almost independent of the direction of wave propagation through the mesh. The proposed scheme can be efficiently used with irregular meshes. These properties make the scheme (the combined spatial and temporal discretizations) promising to solve general wave propagation problems in complex geometries involving multiple waves. A dispersion analysis is given and various example problems are solved to illustrate the performance of the solution scheme.

      PubDate: 2018-02-25T22:35:52Z
  • A reduced model to simulate the damage in composite laminates under low
           velocity impact
    • Abstract: Publication date: 1 April 2018
      Source:Computers & Structures, Volume 199
      Author(s): S. Metoui, E. Pruliere, A. Ammar, F. Dau
      This article presents an efficient numerical strategy to simulate the damage in composite laminates under low velocity impact. The proposed method is based on a separated representation of the solution in the context of the Proper Generalized Decomposition (PGD). This representation leads to an important reduction of the number of degrees of freedom. In addition to the PGD, the main ingredients of the model are the following: (a) cohesive zone models (CZM) to represent the delamination and the matrix cracking, (b) a modified nonlinear Hertzian contact law to calculate the impact force, (c) the implicit Newmark integration scheme to compute the evolution of the solution during the impact. The method is applied to simulate an impact on a laminated plate. The results are similar to the solution obtained with a classical finite element simulation. The shape of the delaminated area is found to be coherent with some experimental results from the literature.

      PubDate: 2018-02-25T22:35:52Z
  • Electromechanical wave finite element method for interconnected
           piezoelectric waveguides
    • Abstract: Publication date: 1 April 2018
      Source:Computers & Structures, Volume 199
      Author(s): B. Lossouarn, M. Aucejo, J.-F. Deü
      A novel finite element (FE) formulation involving external electrical degrees of freedom is proposed for cases dealing with the coupling of mechanical and electrical waveguides through an array of piezoelectric patches. Interconnections between successive periodic unit cells enable the use of the transfer matrix (TM) formalism. It is thus shown that the wave finite element (WFE) method can be applied to electromechanical waveguides. As both mechanical and electrical variables are enclosed in the state vectors, the resulting attenuation and phase constants define waves that propagate in the two domains. For the computation of frequency response functions, it is proposed to employ the Riccati transfer matrix (RTM) method in order to avoid numerical instability. The whole computational method is validated through two examples involving a rod and a beam coupled to passive electrical transmission lines interconnecting a piezoelectric array.

      PubDate: 2018-02-25T22:35:52Z
  • Modeling of mechanical behavior of amorphous solids undergoing fatigue
           loadings, with application to polymers
    • Abstract: Publication date: 1 April 2018
      Source:Computers & Structures, Volume 199
      Author(s): Sami Holopainen, Thierry Barriere
      An approach suitable for modeling viscoelastic-viscoplastic response with isothermal fatigue damage in amorphous solids is proposed. The theory explicitly accounts for frame-indifference and dependence of the free energy on both the viscoelastic-viscoplastic deformation and fatigue damage in a thermodynamically consistent manner. The damage evolution per se is formulated by utilizing an endurance surface that shifts in an effective stress space independent on damage. The idea is suitable for solids in which the fatigue behavior is ductile, i.e. localized damage during the creation of micro-cracks governs majority (up to 95%) of the total fatigue life. Based on implicit numerical integration, the solution procedure is presented, and its capability for technologically important polycarbonate (PC) polymer is addressed. To simulate the fatigue in real specimens, the approach is implemented in a finite-element program. A microscopic, rectangular region representing a RVE of a test specimen is investigated. Simulations, in accordance with experimental observations, indicate that damage develops in small zones around involved inhomogeneities while majority of the material remains undamaged for most of the fatigue life. The results also show that fatigue life can be predicted using a single point at which fatigue most intensively initiates.

      PubDate: 2018-02-25T22:35:52Z
  • Analysis of nonlinear soil-structure interaction effects: 3D frame
           structure and 1-Directional propagation of a 3-Component seismic wave
    • Abstract: Publication date: Available online 24 February 2018
      Source:Computers & Structures
      Author(s): M.P. Santisi d'Avila, F. Lopez-Caballero
      In this paper, a finite element modeling technique, taking into account the effects of soil-structure interaction (SSI) is proposed for structural analysis and design. The one-dimensional model of a nonlinear multilayered soil profile is assembled with a multi-story multi-span frame model and the dynamic equilibrium problem is solved directly. The one-directional propagation of three-component seismic waves (1D-3C) is modeled taking into account the SSI, in the case of rigid shallow foundation and negligible rocking effects. The 1D-3C wave propagation model provides the three components of motion at the base of the frame structure, allowing the reduction of mesh size and computation time, compared with a fully three-dimensional model, and avoiding modeling difficulties to realize a reliable three-dimensional soil domain, related among others to boundary conditions. The proposed model allows the analysis of those structural dynamic features, seismic wave and local soil stratigraphy, that produce changes in the ground motion at the surface. The model reproduces well expected phenomena, in the case of layered soil with increasing nonlinearity and for different inertia distribution in the frame structure. SSI combined with seismic site effects is analyzed in a Japanese soil profile, using as seismic loading a 3C record of 2011 Tohoku earthquake.

      PubDate: 2018-02-25T22:35:52Z
  • On the provenance of hinged-hinged frequencies in Timoshenko beam theory
    • Abstract: Publication date: 15 February 2018
      Source:Computers & Structures, Volume 197
      Author(s): W.P. Howson, A. Watson
      An exact differential equation governing the motion of an axially loaded Timoshenko beam supported on a two parameter, distributed foundation is presented. Attention is initially focused on establishing the provenance of those Timoshenko frequencies generated from the hinged-hinged case, both with and without the foundation being present. The latter option then enables an exact, neo-classical assessment of the ‘so called’ two frequency spectra, together with their corresponding modal vectors, to be undertaken when zero, tensile or compressive static axial loads are present in the member. An alternative, ‘precise’ approach, that models Timoshenko theory efficiently, but eliminates the possibility of a second spectrum, is then described and used to confirm the original eigenvalues. This leads to a definitive conclusion regarding the structure of the Timoshenko spectrum. The ‘precise’ technique is subsequently extended to allow, either the full foundation to be incorporated, or either of its component parts individually. An illustrative example from the literature is solved to confirm the accuracy of the approach, the nature of the Timoshenko spectrum and a wider indication of the effects that a distributed foundation can have.

      PubDate: 2018-02-25T22:35:52Z
  • A subinterval decomposition analysis method for uncertain structures with
           large uncertainty parameters
    • Abstract: Publication date: 15 February 2018
      Source:Computers & Structures, Volume 197
      Author(s): C.M. Fu, L.X. Cao, J.C. Tang, X.Y. Long
      A simple and efficient subinterval decomposition analysis method is proposed to evaluate the lower and upper bounds of structural responses with large uncertain parameters. The proposed method decomposes the original structural system with multi-dimensional interval parameters into multiple one-dimensional subsystems. Every subsystem has only one interval parameter and the other interval parameters are substituted by their midpoint values. By dividing the interval parameter of each subsystem into several subintervals with small uncertainty, the lower and upper bounds of the system are approximately calculated by only a few subinterval combinational analyses instead of all possible combinations of subintervals. Finally, the accuracy and efficiency of the proposed method compared with the first-order Taylor method, Chebyshev interval method and traditional subinterval method are verified by several numerical examples and applications.

      PubDate: 2018-02-05T07:27:55Z
  • Shell structures in civil and mechanical engineering by Professor Alphose
           Zingoni, University of Cape Town, South Africa
    • Abstract: Publication date: 15 February 2018
      Source:Computers & Structures, Volume 197
      Author(s): David P. Thambiratnam

      PubDate: 2018-02-05T07:27:55Z
  • Towards real-time modelling of passive and active behaviour of the human
           heart using PODI-based model reduction
    • Abstract: Publication date: Available online 3 February 2018
      Source:Computers & Structures
      Author(s): R.R. Rama, S. Skatulla
      In this research, a reduced order method (ROM) called the Proper Orthogonal Decomposition with Interpolation (PODI) is used to drastically reduce computation time of highly complex and nonlinear problems as encountered in simulating the heart. The idea behind the method is to first construct a database of pre-computed full-scale solutions using the Element Free Galerkin method (EFG) or the Finite Element Method (FEM), project the set of solutions to a low-dimensional space, use the Moving Least Square method to carry out the interpolation for the problem at hand and project it back to the original high-dimensional solution space. Calculations are carried out on a left and a bi-ventricle model taking into account the passive elastic and the active contraction behaviour of the heart. In order to address varying time increments of datasets used for interpolation, a time standardisation method is developed to facilitate full-cycle heart modelling. The performance and accuracy of the approach is investigated while considering variations of the hemodynamics in terms of pre- and afterload.

      PubDate: 2018-02-05T07:27:55Z
  • Transient multi-Fickian hygro-mechanical analysis of wood
    • Abstract: Publication date: 15 February 2018
      Source:Computers & Structures, Volume 197
      Author(s): Daniel Konopka, Michael Kaliske
      A new hygro-mechanically coupled material model to simulate the structural behaviour of wooden objects below the fibre saturation area is introduced. A multi-Fickian moisture transport model is coupled to a moisture-dependent, orthotropic, elasto-plastic, mechanical material model. It is applied to wooden specimens at simulated climate changes of the ambient air and analysed by the finite element method with respect to internal stresses due to swelling and shrinkage. A simulation of the ductile failure of a swelling pressure experiment is presented. The results are compared to different, widely used moisture transport models. The importance of capturing water vapour diffusion inside the object and its emissivity at the objects’ surface are discussed.

      PubDate: 2017-12-27T11:53:22Z
  • Effective iterative algorithm for the Limit Analysis of truss-frame
           structures by a kinematic approach
    • Abstract: Publication date: 15 February 2018
      Source:Computers & Structures, Volume 197
      Author(s): Rosalba Ferrari, Giuseppe Cocchetti, Egidio Rizzi
      A former algorithm of Limit Analysis (LA) at the continuum mechanics scale by a kinematic, upper-bound approach is here re-interpreted in the realm of LA of large-scale 3D truss-frame structures and effectively implemented toward fast and convenient collapse load multiplier and mechanism evaluation. First, the algorithm is described in its iterative design, and convergence is demonstrated. Some initial applications to truss-frame test structures under bending and torsion are also discussed. Then, the algorithm is successfully applied to two benchmark multi-story frames. It is shown that very consistent and quick evaluations of the collapse characteristics are obtained by this direct method, in comparison to those provided by alternative classical mathematical programming approaches and much expensive evolutive step-by-step solutions of the whole structural elastoplastic response. The algorithm shows a superior performance, with the kinematic multiplier truly precipitating from above on the collapse one, in very few iterations, with a consistent associated estimation of the plastic collapse mechanism.

      PubDate: 2017-12-27T11:53:22Z
  • Model reduction schemes for the wave and finite element method using the
           free modes of a unit cell
    • Abstract: Publication date: 15 February 2018
      Source:Computers & Structures, Volume 197
      Author(s): Y. Fan, C.W. Zhou, J.P. Laine, M. Ichchou, L. Li
      The wave and finite element method (WFEM) is an efficient numerical tool for analysing wave propagation characteristics and forced response at intermediate and high frequencies. In this work, we introduce free-interface component modal synthesis (CMS) methods into WFEM to accelerate the calculation while maintaining the accuracy. Several free-interface CMS methods with different approximations of the residual effects are implemented and compared. A new eigenvalue scheme based on the dynamic compliance matrix is proposed. A periodic open thin-wall structure is considered as an application for which both free-wave characteristics and forced responses are computed. Aspects such as accuracy, efficiency, and convergence of the proposed method are discussed and compared with those of the Craig-Bampton fixed-interface CMS method. The methods and main findings are further verified by using another more complex periodic structure. Among the implemented models, the minimum model size is achieved by the exact CMS method. The exact CMS method only requires the modes below the maximum analysing frequency, thereby reducing the model size of the open thin-wall structure from 4416 to 16. The most numerically efficient model for WFEM is MacNeal’s CMS method, where the CPU time of free-wave analysis can be reduced by 97% for the open thin-wall structure.

      PubDate: 2017-12-27T11:53:22Z
  • An efficient multi-time-step method for train-track-bridge interaction
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): Zhihui Zhu, Wei Gong, Lidong Wang, Qi Li, Yu Bai, Zhiwu Yu, Issam E. Harik
      In this paper, the multi-time-step method (MTS) of time integration is proposed to reduce the computational cost of solving the dynamic interaction of a train-track-bridge coupled system (TTBS). Considering the different domain frequency characteristics of the dynamic responses of the train, track, and bridge, the MTS method decomposes the TTBS into two smaller subdomains: the train-track coupled subsystem with a high domain frequency, and the bridge subsystem with a low domain frequency. A fine time-step and a coarse time-step are respectively adopted for the train-track subsystem and the bridge subsystem to improve the computational efficiency. The two subsystems are coupled by the interaction forces between the track and bridge. Two partition types of the TTBS are introduced and the effect of different decomposition types on the accuracy and efficiency of the MTS method are discussed. The proposed method is validated by comparing the numerical results with field measurement data of a simply supported bridge. A numerical simulation of a train traversing a long-span cable-stayed bridge is used to demonstrate the computational efficiency and accuracy of the proposed method. It is shown that the proposed method is accurate and computationally more efficient than using a uniform time-step for the entire TTBS.

      PubDate: 2017-12-27T11:53:22Z
  • Towards improving the enhanced Craig-Bampton method
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): Seung-Hwan Boo, Jeong-Ho Kim, Phill-Seung Lee
      In this study, we improve the performance of the enhanced Craig-Bampton (ECB) method. The improved ECB method is derived by employing the algebraic substructuring and interface boundary reduction. Unlike for the original method, the residual substructural modes are compensated only for the reduced mass matrix, and this is the most attractive feature of the proposed method to reduce the computation time significantly. In addition, for effective implementation and computer memory management, we give a computer-aided formulation of the reduced mass, stiffness, and transformation matrices. Several large structural FE models are used to illustrate the significantly improved solution accuracy and computational efficiency of the improved method.

      PubDate: 2017-12-27T11:53:22Z
  • Bi-material V-notched SIFs analysis by XFEM and conservative integral
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): Gao Yi, Tiantang Yu, Tinh Quoc Bui, Satoyuki Tanaka
      In this paper, a new effective approach based on conservative integral approach associated with extended finite element method (XFEM) is developed for evaluating stress intensity factors (SIFs) of bi-material V-notched structures. The XFEM model for bi-material V-notches is established, which owns various features: (a) jump enrichment functions are taken for describing the intersection of notch-faces; (b) eight (real eigenvalue) or sixteen (complex eigenvalue) branch functions are employed for capturing nodes surrounding the notch-tip; and (c) interface enrichment function is used to model the material interface. These enrichments allow the representation of notch-faces and material interface independent of the finite element mesh. The conservative integral approach derived from the Betti reciprocal principle is used for the evaluation of SIFs. The conservative integral approach avoids the complicated stress fields around the notch-tip, so good accuracy of SIFs can be obtained. Also, the proposed XFEM model can easily be used to solve homogenous V-notched structures by setting the same material parameters of two materials. Numerical results of the SIFs calculated by the present method indicate the independence of integral paths. Several bi-material V-notched numerical examples for single and mixed modes fractures are analyzed to demonstrate the accuracy and effectiveness of the developed method.

      PubDate: 2017-12-27T11:53:22Z
  • Multiphysics model for spalling prediction of brick due to in-pore salt
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): Marcin Koniorczyk, Dariusz Gawin, Bernhard A. Schrefler

      PubDate: 2017-12-27T11:53:22Z
  • New opensees models for simulating nonlinear flexural and coupled
           shear-flexural behavior of RC walls and columns
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): Kristijan Kolozvari, Kutay Orakcal, John W. Wallace
      This paper describes new model elements and material constitutive relationships implemented by the authors into the widely-used open-source computational platform OpenSees (Open System for Earthquake Engineering Simulation), aimed to enhance current nonlinear analysis and response assessment capabilities for reinforced concrete (RC) walls and columns. Classes added to the existing OpenSees library include: (1) the Multiple-Vertical-Line-Element-Model (MVLEM) element with uncoupled axial/flexural and shear responses, (2) the Shear-Flexure-Interaction-Multiple-Vertical-Line-Element-Model (SFI-MVLEM) element with coupled axial/flexural and shear responses, (3) the Fixed-Strut-Angle-Model (FSAM), which is a two-dimensional constitutive model for RC panel elements, (4) an improved uniaxial constitutive model for concrete, and (5) an improved uniaxial constitutive model for reinforcing steel. Representative validation studies are also presented, where the analytical model predictions are compared with results of quasi-static lateral load tests on selected RC column and wall specimens. Response comparisons reveal that the implemented models capture, with reasonable accuracy, the experimentally-observed behavior of the test specimens investigated. Based on the comparisons presented, model capabilities are assessed and potential model improvements are identified.

      PubDate: 2017-12-27T11:53:22Z
  • A Rayleigh-Ritz approach for postbuckling analysis of variable angle tow
           composite stiffened panels
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): V. Oliveri, A. Milazzo
      A Rayleigh-Ritz solution approach for generally restrained multilayered variable angle tow stiffened plates in postbuckling regime is presented. The plate model is based on the first order shear deformation theory and accounts for geometrical nonlinearity through the von Kármán’s assumptions. Stiffened plates are modelled as assembly of plate-like elements and penalty techniques are used to join the elements in the assembled structure and to apply the kinematical boundary conditions. General symmetric and unsymmetric stacking sequences are considered and Legendre orthogonal polynomials are employed to build the trial functions. A computer code was developed to implement the proposed approach and to establish its applicability and its features for investigating variable angle tow structures. The proposed solution is validated by comparison with literature and finite elements results. Original results are presented for postbuckling of variable angle tow stiffened plates showing the potentialities of the method.

      PubDate: 2017-12-27T11:53:22Z
  • On a discrete element method to simulate thermal-induced damage in 2D
           composite materials
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): W. Leclerc, H. Haddad, M. Guessasma
      The present contribution deals with a discrete element method to simulate thermal-induced damage in 2D composite materials. We consider a hybrid particulate-lattice model based on the equivalence between a granular system and a network of cohesive beam elements. This choice is mainly motivated by previous papers exhibiting its ability to model heterogeneous materials in which complex fracture phenomena occur. Our objectives are twofold. First, we aim to introduce a thermo-elastic coupling using a recently developed model of thermal expansion based on the dilatation of the beam element. Second, we are interested in studying the suitability of the discrete element method to model the thermal-induced damage due to thermal expansion mismatch. For that purpose, several preliminary studies are performed to verify the validity of the thermal expansion model in the context of continuous media. Then, damage effects and interfacial debonding are taken into account and the model is applied to the case of 2D metallic fiber composites with a brittle alumina matrix. Results exhibit the ability of the present approach to simulate the suitable damage mode as a function of thermal conditions. Besides, realistic failure patterns with radial propagations are obtained in the context of cracks opening.

      PubDate: 2017-12-27T11:53:22Z
  • A practical grid generation procedure for the design of free-form
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): Boqing Gao, Tierui Li, Teng Ma, Jun Ye, Jurgen Becque, Iman Hajirasouliha
      Computer aided design software enables the rapid conceptual creation of a curved surface geometry, whereas it is neither a convenient nor an obvious task for engineers to create a discrete grid structure on a complex surface that meets architectural and aesthetic requirements. This emphasizes the importance of grid generating tools and methods in the initial design stage. This paper presents an efficient design tool for the synthesis of free-form grid structures based on the “guide line” method, employing a fast and straightforward approach which achieves grids with rods of balanced length and fluent lines. The process starts with defining a limited number of curves (named the “guide lines”) on the surface, which are then used to determine the directions of the ‘rods’ of the grid. Two variations of this concept are introduced in this paper: the ‘Guide Line Scaling Method’ (GSM) and the ‘Two Guide Lines with Two End Vertices Method’ (2G2VM). Case studies are provided which illustrate the successful execution of these procedures. The results show that the free-form grid structures generated with the proposed methods feature a regular shape and fluent lines, thereby satisfying aesthetic requirements. These two methods have been programmed into the software ZD-Mesher, enabling rapid grid generation for structural design purposes.

      PubDate: 2017-12-27T11:53:22Z
  • A 2D fully coupled hydro-mechanical finite-discrete element model with
           real pore seepage for simulating the deformation and fracture of porous
           medium driven by fluid
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): Chengzeng Yan, Yu-Yong Jiao
      Based on the finite-discrete element method (FDEM), a 2D fully coupled model with real pore seepage is proposed. This model can solve the problem of the deformation and fracture of porous medium driven by fluid. In this model, the fluid flow in the fracture is expressed by the cubic law, while the fluid flow in the rock matrix is characterized by Darcy's law and solved by the finite volume method. The interaction between pore seepage and fracture seepage is realized at the fracture. Three analytical solutions are presented to verify the correctness of the proposed model. The results show that the numerical solutions agree well with the analytical solutions. In addition, a hydraulic fracturing problem with a complex fracture network is studied using this model. The simulation results show that the model can capture the fracture initiation, propagation, and intersection, the interaction of natural fractures and newly generated fractures, and the evolution of fluid pressure during hydraulic fracturing. The model can be used not only to simulate hydraulic fracturing in shale gas and geothermal mining but also to solve a series of geomechanical problems related to the effect of fluid. Thus, this model has broad application prospects.

      PubDate: 2017-12-27T11:53:22Z
  • Axisymmetric semi-analytical finite elements for modelling waves in
           buried/submerged fluid-filled waveguides
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): Michał K. Kalkowski, Jennifer M. Muggleton, Emiliano Rustighi
      Efficient and accurate predictions of wave propagation are a vital component of wave-based non-destructive interrogation techniques. Although a variety of models are available in the literature, most of them are suited to a particular wave type or a specific frequency regime. In this paper we present a multi-wave model for wave propagation in axisymmetric fluid-filled waveguides, either buried or submerged in a fluid, based on the semi-analytical finite elements. The cross-section is discretised with high-order spectral elements to achieve high efficiency, and the singularities resulting from adopting a Lobatto scheme at the axis of symmetry are handled appropriately. The surrounding medium is modelled with a perfectly matched layer, and a practical rule of choice of its parameters, based only on the material properties and the geometry of the waveguide, is derived. To represent the fluid and the solid-fluid coupling, an acoustic SAFE element and appropriate coupling relationships are formulated. The model is validated against both numerical results from the literature and experiments, and the comparisons show very good agreement. Finally, an implementation of the method in Python is made available with this publication.

      PubDate: 2017-12-27T11:53:22Z
  • On the effect of grains interface parameters on the macroscopic properties
           of polycrystalline materials
    • Abstract: Publication date: February 2018
      Source:Computers & Structures, Volume 196
      Author(s): Ahmad Akbari, Pierre Kerfriden, Stéphane Bordas
      In this paper, the influence of microscopic parameters on the macroscopic behaviour of polycrystalline materials under different loading configuration is investigated. Linear elastic grains with zero-thickness cohesive interfaces are considered at the microscale with in depth introduction of effective parameters. A multiscale method based on homogenisation technique is employed to bridge the scales. In order to minimize the homogenisation error, a representative volume element (RVE) of the microscopic structure is statistically determined to be used in the numerical analysis. For each loading condition of the RVE, several numerical examinations are conducted to illustrate the relationship between the microscopic parameters. Finally, the effects of microscopic critical fracture energies, maximum tensile and shear strengths of grain interfaces on the mechanical properties, i.e. stress-strain curve and yield surface at the macroscale are discussed in details. It is shown that macroscopic yield surface and stress-strain curves can be used to characterise the microscopic properties.

      PubDate: 2017-12-27T11:53:22Z
  • 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
  • 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
  • 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
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