Showing papers by "Federico París published in 2008"
TL;DR: In this article, the authors investigated the mechanism of failure of a fibrous composite under tension transverse to the fibres and showed that the initial direction of failure predicted agrees with that observed in experiments, following a scheme of analysis of the damage mechanism analogous to that employed for the tension case.
53 citations
TL;DR: In this paper, a numerical study is performed using the boundary element method aimed at explaining the origin and evolution of the damage at micromechanical level, considered as fibre-matrix interface cracks, assuming that the damage starts as small debonds originated by shear stresses at the position where their maximum values are reached.
52 citations
TL;DR: In this paper, the authors investigated the causes that had originated the failure of wind turbine blades and proposed modifications to repair the cracks and in addition contribute to relaxing the stress state in the affected zone.
41 citations
TL;DR: The applicability of the general laminate theory (GLT) to obtain the stiffness properties of non-crimp fabric (NCF) laminates is elucidated in this article.
31 citations
TL;DR: In this article, the authors characterize the stress state at the tip of both, the transverse crack in the 90° ply reaching the interface with the 0° ply, and the delamination crack for different lengths of debonding.
31 citations
TL;DR: In this paper, the numerical implementation of the Green's function for an isotropic exponentially graded three dimensional elastic solid is reported, and the evaluation of the fundamental solution is tested by employing indirect boundary integral formulation using a Galerkin approximation to solve several problems having analytic solutions.
Abstract: The numerical implementation of the Green's function for an isotropic exponentially graded three dimensional elastic solid is reported. The formulas for the nonsingular {\lq}grading term{\rq} in this Green's function, originally deduced by Martin et al., \emph{Proc. R. Soc. Lond. A, 458, 1931-1947, 2000}, are quite complicated, and a small error in one of the formulas is corrected. The evaluation of the fundamental solution is tested by employing indirect boundary integral formulation using a Galerkin approximation to solve several problems having analytic solutions. The numerical results indicate that the Green's function formulas, and their evaluation, are correct.
24 citations
TL;DR: In this paper, a robust boundary element method (BEM) formulation for the numerical solution of three-dimensional linear elastic problems in transversely isotropic solids is developed based on the closed-form real-variable expressions of the fundamental solution in displacements Uik and in tractions Tik.
Abstract: A general, efficient and robust boundary element method (BEM) formulation for the numerical solution of three-dimensional linear elastic problems in transversely isotropic solids is developed in the present work. The BEM formulation is based on the closed-form real-variable expressions of the fundamental solution in displacements Uik and in tractions Tik, originated by a unit point force, valid for any combination of material properties and for any orientation of the radius vector between the source and field points. A compact expression of this kind for Uik was introduced by Ting and Lee (Q. J. Mech. Appl. Math. 1997; 50:407–426) in terms of the Stroh eigenvalues on the oblique plane normal to the radius vector. Working from this expression of Uik, and after a revision of their final formula, a new approach (based on the application of the rotational symmetry of the material) for deducing the derivative kernel Uik, j and the corresponding stress kernel Σijk and traction kernel Tik has been developed in the present work. These expressions of Uik, Uik, j, Σijk and Tik do not suffer from the difficulties of some previous expressions, obtained by other authors in different ways, with complex-valued functions appearing for some combinations of material parameters and/or with division by zero for the radius vector at the rotational-symmetry axis. The expressions of Uik, Uik, j, Σijk and Tik have been presented in a form suitable for an efficient computational implementation. The correctness of these expressions and of their implementation in a three-dimensional collocational BEM code has been tested numerically by solving problems with known analytical solutions for different classes of transversely isotropic materials. Copyright © 2007 John Wiley & Sons, Ltd.
22 citations
TL;DR: In this article, a procedure for the singularity characterization of anisotropic multimaterial corners which typically appear in adhesively bonded lap joints between metals and composites is presented and implemented.
13 citations
TL;DR: In this article, a parallel domain decomposition boundary integral algorithm for three-dimensional exponentially graded elasticity has been developed, which scales well with the number of processors, also helping to alleviate the high computational cost of evaluating the Green's functions.
Abstract: A parallel domain decomposition boundary integral algorithm for three-dimensional exponentially graded elasticity has been developed. As this subdomain algorithm allows the grading direction to vary in the structure, geometries arising from practical functionally graded material applications can be handled. Moreover, the boundary integral algorithm scales well with the number of processors, also helping to alleviate the high computational cost of evaluating the Green's functions. For axisymmetric plane strain states in a radially graded material, the numerical results for cylindrical geometries are in excellent agreement with the analytical solution deduced herein.
5 citations
TL;DR: Two original approaches for the solution of elastic boundary value problems with domain decomposition (DDBVP) using the symmetric Galerkin boundary element method (SGBEM) are presented.
Abstract: Two original approaches for the solution of elastic boundary value problems with domain decomposition (DDBVP) using the symmetric Galerkin boundary element method (SGBEM) are presented. Each approach is based on a variational principle, a difference between them consisting in the treatment of the coupling conditions which connect the solutions through an interface. The computer codes developed are able to deal with curved interfaces in a domain decomposition problem discretized by nonmatching meshes of linear elements along the interfaces. The effectiveness of the methods is documented by a numerically solved example.
1 citations