References of "Computers & Structures"
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See detailSimple and extensible plate and shell finite element models through automatic code generation tools
Hale, Jack UL; Brunetti, Matteo; Bordas, Stéphane UL et al

in Computers & Structures (2018), 209

A large number of advanced finite element shell formulations have been developed, but their adoption is hindered by complexities of transforming mathematical formulations into computer code. Furthermore ... [more ▼]

A large number of advanced finite element shell formulations have been developed, but their adoption is hindered by complexities of transforming mathematical formulations into computer code. Furthermore, it is often not straightforward to adapt existing implementations to emerging frontier problems in thin structural mechanics including nonlinear material behaviour, complex microstructures, multi-physical couplings, or active materials. We show that by using a high-level mathematical modelling strategy and automatic code generation tools, a wide range of advanced plate and shell finite element models can be generated easily and efficiently, including: the linear and non-linear geometrically exact Naghdi shell models, the Marguerre-von K ́arm ́an shallow shell model, and the Reissner-Mindlin plate model. To solve shear and membrane-locking issues, we use: a novel re-interpretation of the Mixed Interpolation of Tensorial Component (MITC) procedure as a mixed-hybridisable finite element method, and a high polynomial order Partial Selective Reduced Integration (PSRI) method. The effectiveness of these approaches and the ease of writing solvers is illustrated through a large set of verification tests and demo codes, collected in an open-source library, FEniCS-Shells, that extends the FEniCS Project finite element problem solving environment. [less ▲]

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See detailOn the effect of grains interface parameters on the macroscopic properties of polycrystalline materials
Akbari, Ahmad; Kerfriden, Pierre; Bordas, Stéphane UL

in Computers & Structures (2018), 196

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 ... [more ▼]

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. [less ▲]

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See detailStrain smoothed for compressible and nearly-incompressible finite elasticity
Lee, Chang-Kye; Mihai, L. Angela; Hale, Jack UL et al

in Computers & Structures (2017), 182

We present a robust and efficient form of the smoothed finite element method (S-FEM) to simulate hyperelastic bodies with compressible and nearly-incompressible neo-Hookean behaviour. The resulting method ... [more ▼]

We present a robust and efficient form of the smoothed finite element method (S-FEM) to simulate hyperelastic bodies with compressible and nearly-incompressible neo-Hookean behaviour. The resulting method is stable, free from volumetric locking and robust on highly distorted meshes. To ensure inf-sup stability of our method we add a cubic bubble function to each element. The weak form for the smoothed hyperelastic problem is derived analogously to that of smoothed linear elastic problem. Smoothed strains and smoothed deformation gradients are evaluated on sub-domains selected by either edge information (edge-based S-FEM, ES-FEM) or nodal information (node-based S-FEM, NS-FEM). Numerical examples are shown that demonstrate the efficiency and reliability of the proposed approach in the nearly-incompressible limit and on highly distorted meshes. We conclude that, strain smoothing is at least as accurate and stable, as the MINI element, for an equivalent problem size. [less ▲]

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See detailLocally equilibrated stress recovery for goal oriented error estimation in the extended finite element method
Bordas, Stéphane UL; gonzález-estrada, octavio andrés; ródenas, Juan josé et al

in Computers & Structures (2015)

Goal oriented error estimation and adaptive procedures are essential for the accurate and efficient evaluation of finite element numerical simulations that involve complex domains. By locally improving ... [more ▼]

Goal oriented error estimation and adaptive procedures are essential for the accurate and efficient evaluation of finite element numerical simulations that involve complex domains. By locally improving the approximation qual- ity, for example, by using the extended finite element method (XFEM), we can solve expensive problems which could result intractable otherwise. Here, we present an error estimation technique for enriched finite element approxi- mations that is based on an equilibrated recovery technique, which considers the stress intensity factor as the quantity of interest. The locally equilibrated superconvergent patch recovery is used to obtain enhanced stress fields for the primal and dual problems defined to evaluate the error estimate. [less ▲]

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See detailAnalysis of composite plates through cell-based smoothed finite element and 4-noded mixed interpolation of tensorial components techniques
Rodrigues, J. D.; Natarajan, S.; Ferreira, Ana UL et al

in Computers & Structures (2014), 135

The static bending and the free vibration analysis of composite plates are performed with Carrera's Unified Formulation (CUF). We combine the cell-based smoothed finite element method (CSFEM) and the 4 ... [more ▼]

The static bending and the free vibration analysis of composite plates are performed with Carrera's Unified Formulation (CUF). We combine the cell-based smoothed finite element method (CSFEM) and the 4-noded mixed interpolation of tensorial components approach (MITC4). The smoothing method is used for the approximation of the bending strains, whilst the mixed interpolation allows the calculation of the shear transverse stress in a different manner. With a few numerical examples, the accuracy and the efficiency of the approach is demonstrated. The insensitiveness to shear locking is also demonstrated. © 2014 Elsevier Ltd. All rights reserved. [less ▲]

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See detailAn isogeometric boundary element method for elastostatic analysis: 2D implementation aspects
Simpson, Robert; Bordas, Stéphane UL; Lian, Haojie et al

in Computers & Structures (2013), 118

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See detailAn isogeometric boundary element method for elastostatic analysis: 2D implementation aspects
Simpson, R. N.; Bordas, Stéphane UL; Lian, H. et al

in Computers & Structures (2013), 118

The concept of isogeometric analysis, whereby the parametric functions that are used to describe CAD geometry are also used to approximate the unknown fields in a numerical discretisation, has progressed ... [more ▼]

The concept of isogeometric analysis, whereby the parametric functions that are used to describe CAD geometry are also used to approximate the unknown fields in a numerical discretisation, has progressed rapidly in recent years. This paper advances the field further by outlining an isogeometric boundary element Method (IGABEM) that only requires a representation of the geometry of the domain for analysis, fitting neatly with the boundary representation provided completely by CAD. The method circumvents the requirement to generate a boundary mesh representing a significant step in reducing the gap between engineering design and analysis. The current paper focuses on implementation details of 2D IGABEM for elastostatic analysis with particular attention paid towards the differences over conventional boundary element implementations. Examples of Matlab® code are given whenever possible to aid understanding of the techniques used. [less ▲]

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See detailLinear free flexural vibration of cracked functionally graded plates in thermal environment
Natarajan, S.; Baiz, P. M.; Ganapathi, M. et al

in Computers & Structures (2011), 89(15-16), 1535-1546

In this paper, the linear free flexural vibrations of functionally graded material plates with a through center crack is studied using an 8-noded shear flexible element. The material properties are ... [more ▼]

In this paper, the linear free flexural vibrations of functionally graded material plates with a through center crack is studied using an 8-noded shear flexible element. The material properties are assumed to be temperature dependent and graded in the thickness direction. The effective material properties are estimated using the Mori-Tanaka homogenization scheme. The formulation is developed based on first-order shear deformation theory. The shear correction factors are evaluated employing the energy equivalence principle. The variation of the plates natural frequency is studied considering various parameters such as the crack length, plate aspect ratio, skew angle, temperature, thickness and boundary conditions. The results obtained here reveal that the natural frequency of the plate decreases with increase in temperature gradient, crack length and gradient index. © 2011 Elsevier Ltd. All rights reserved. [less ▲]

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See detailHybridized enriched space-time finite element method for analysis of thin-walled structures immersed in generalized Newtonian fluids
Zilian, Andreas UL; Netuzhylov, H.

in Computers & Structures (2010), 88(21-22), 1265-1277

The paper addresses the numerical treatment of a specific class of fluid-structure interaction problems: flow-immersed thin structures undergoing considerable motion and deformation. The simultaneous ... [more ▼]

The paper addresses the numerical treatment of a specific class of fluid-structure interaction problems: flow-immersed thin structures undergoing considerable motion and deformation. The simultaneous solution procedure uses a mixed-hybrid velocity-based formulation of both fluid and structure discretized by a stabilized time-discontinuous space-time finite element method. The continuity at the interface is ensured by a localized mixed-hybrid interface method avoiding Lagrange multipliers and penalty approaches. The XFEM is utilized for enrichment of the approximation space of the fluid variables in order to represent non-smooth (discontinuous) solution features resulting from immersing a thin structure in a fluid. © 2010 Elsevier Ltd. All rights reserved. [less ▲]

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See detailOn three-dimensional modelling of crack growth using partition of unity methods
Rabczuk, Timon; Bordas, Stéphane UL; Zi, Goangseup

in Computers & Structures (2010), 88(23-24), 1391-1411

This paper reviews different crack tracking techniques in three-dimensions applicable in the context of partition of unity methods, especially meshfree methods. Issues such as describing and tracking the ... [more ▼]

This paper reviews different crack tracking techniques in three-dimensions applicable in the context of partition of unity methods, especially meshfree methods. Issues such as describing and tracking the crack surface are addressed. A crack tracking procedure is proposed in detail and implemented in the context of the extended element-free Galerkin method (XEFG). Several three-dimensional cracking examples are compared to other results from the literature or the experimental data and show good agreement. [less ▲]

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See detailStrain smoothing in FEM and XFEM
Bordas, Stéphane UL; Rabczuk, T.; Hung, N.-X. et al

in Computers & Structures (2010), 88(23-24), 1419-1443

We present in this paper recent achievements realised on the application of strain smoothing in finite elements and propose suitable extensions to problems with discontinuities and singularities. The ... [more ▼]

We present in this paper recent achievements realised on the application of strain smoothing in finite elements and propose suitable extensions to problems with discontinuities and singularities. The numerical results indicate that for 2D and 3D continuum, locking can be avoided. New plate and shell formulations that avoid both shear and membrane locking are also briefly reviewed. The principle is then extended to partition of unity enrichment to simplify numerical integration of discontinuous approximations in the extended finite element method. Examples are presented to test the new elements for problems involving cracks in linear elastic continua and cracked plates. In the latter case, the proposed formulation suppresses locking and yields elements which behave very well, even in the thin plate limit. Two important features of the set of elements presented are their insensitivity to mesh distortion and a lower computational cost than standard finite elements for the same accuracy. These elements are easily implemented in existing codes since they only require the modification of the discretized gradient operator, B. © 2008 Elsevier Ltd. All rights reserved. [less ▲]

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