M.R. Khoshravan¹, M. Hosseinzadeh¹

CMES-Computer Modeling in Engineering & Sciences, Vol.45, No.2, pp. 179-206, 2009, DOI:10.3970/cmes.2009.045.179

Abstract A sandwich panel's optimum core height and composite face thickness, under defined loading, have been computed in order to reach the structure's lowest weight and highest stiffness. The Tsai-Hill criterion was used in order to control the support of transverse loading by the panel. Regarding the relationships in the sandwich materials, the studied material was modeled with the MATLAB package. The Genetic Algorithm (GA) that is based on statistics was used. Our goal was to obtain the best methods of the GA in order to present an optimization method for the sandwich structure. Hence, a sensibility analysis was performed. In… More >

Dongdong Wang^1,2, Yue Sun², Ling Li²

CMES-Computer Modeling in Engineering & Sciences, Vol.45, No.1, pp. 57-82, 2009, DOI:10.3970/cmes.2009.045.057

Abstract A discontinuous Galerkin meshfree formulation is proposed to solve the potential and elasticity problems of composite material where the material interface has to be appropriately modeled. In the present approach the problem domain is partitioned into patches or sub-domains and each patch holds the same material properties. The discretized meshfree particles within a patch are classified as one particle group. Various patches occupied by different particle groups are then linked using the discontinuous Galerkin formulation where an averaged interface flux or traction is constructed based on the fluxes or tractions computed from the adjacent patches. The gradient jump condition across… More >

A.N.Guz¹, V.A.Dekret¹

CMES-Computer Modeling in Engineering & Sciences, Vol.42, No.3, pp. 177-186, 2009, DOI:10.3970/cmes.2009.042.177

Abstract Stability problem of composite material reinforced by periodical rows of short fibers is solved. The problem is formulated with application of equations of linearized three-dimensional theory of stability. The composite is modeled as piecewise-homogeneous medium. The influence of geometrical and mechanical parameters of the composite to the critical strain is investigated. More >

G. Haasemann¹, M. Kästner², V. Ulbricht³

CMES-Computer Modeling in Engineering & Sciences, Vol.42, No.1, pp. 35-58, 2009, DOI:10.3970/cmes.2009.042.035

Abstract The purpose of this paper is the presentation of a new efficient modelling strategy based on the combination of Binary Model and Extended Finite Element Method (X-FEM). It is applied to represent the internal architecture of textile reinforced composites where the resin-saturated fabric is characterised by a complex geometry. Homogenisation methods are used to compute the effective elastic material properties. Thereby, the discrete formulation of periodic boundary conditions is adapted regarding additional degrees of freedom used by finite elements which are based on the X-FEM. Finally, the results in terms of effective material properties reveal a good agreement with parameters… More >

M. Patrício¹, R. Mattheij¹, G. de With²

CMES-Computer Modeling in Engineering & Sciences, Vol.41, No.1, pp. 69-94, 2009, DOI:10.3970/cmes.2009.041.069

Abstract In this paper the effect of the local structure of a highly heterogeneous composite material on the parameters that characterise crack propagation is analysed. The evaluation of stress intensity factors is discussed. A hybrid approach based on domain decomposition and homogenisation methods is employed to obtain accurate solutions with reduced computational complexity. More >

Thi D. Dang¹, Bhavani V. Sankar²

CMES-Computer Modeling in Engineering & Sciences, Vol.26, No.3, pp. 169-188, 2008, DOI:10.3970/cmes.2008.026.169

Abstract In this paper the meshless local Petrov-Galerkin (MLPG) method is used in the micromechanical analysis of a unidirectional fiber composite. The methods have been extended to include shear loadings, thus permitting a more complete micromechanical analysis of the composite subjected to combined loading states. The MLPG formulation is presented for the analysis of the representative volume element (RVE) of the periodic composite containing material discontinuities. Periodic boundary conditions are imposed between opposite faces of the RVE. The treatment of periodic boundary conditions in the MLPG method is handled by using the multipoint constraint technique. Examples are presented to illustrate the… More >

Shuji Takashima¹, Michihiko Nakagaki², Noriyuki Miyazaki¹

CMES-Computer Modeling in Engineering & Sciences, Vol.20, No.3, pp. 193-202, 2007, DOI:10.3970/cmes.2007.020.193

Abstract Composite materials have complicated microstructures. These microstructures affect the macroscopic deformation of composite materials. In the present study, we focus on the effect of particle size in a particle-dispersed composite material on the mechanical strength of the material. For this purpose, we derived a macroscopic elastic-plastic constitutive equation using a modified version of the Eshelby's equivalent inclusion method combined with the gradient plasticity. We incorporated this macroscopic elastic-plastic constitutive equation into a finite element program and performed a homogenized finite element analysis of a particle-dispersed composite material in which both the macroscopic and microscopic behaviors of the composite material were… More >

D.S. Liu^1,2 , C.Y. Chen² , D.Y. Chiou³

CMES-Computer Modeling in Engineering & Sciences, Vol.9, No.2, pp. 179-192, 2005, DOI:10.3970/cmes.2005.009.179

Abstract A three-dimensional heterogeneous infinite element method (HIEM) for modeling inclusions with interphases in composite materials is presented. This special element is formulated based on the conventional finite element method (FEM) using the similarity stiffness property and matrix condensation operations. An HIE-FE coupling scheme is also developed and implemented using the commercial software ABAQUS to conduct the elastostatic analysis. The proposed approach was validated first to study heterogeneous material containing one spherical inclusion. The displacement and stress variations around the inclusion vicinity are verified against conventional FEM. The proposed approach was next applied to analyze the effective modulus of single-particle and… More >

H. Okada¹, C. T. Liu², T. Ninomiya¹, Y. Fukui¹, N. Kumazawa¹

CMES-Computer Modeling in Engineering & Sciences, Vol.6, No.4, pp. 333-348, 2004, DOI:10.3970/cmes.2004.006.333

Abstract Formulations and applications of an element overlay technique for the mesoscopic analyses of composite structures are presented in this paper. As a zooming technique, the element overlay technique has been applied to various engineering problems. A finite element mesh having finer mesh discretization is superposed at the region to zoom the spatial resolution of analysis. Such a numerical technique is known as the s-version FEM (S-FEM). This paper aims at developing an S-FEM technique that is suited for the mesoscopic analysis of particulate composite materials. Local finite element models that contain the second phase material and its immediate vicinity are… More >

R. Han¹, M.S. Ingber¹, H.L. Schreyer¹

CMC-Computers, Materials & Continua, Vol.4, No.3, pp. 163-176, 2006, DOI:10.3970/cmc.2006.004.163

Abstract Decohesion is an important failure mode associated with fiber-reinforced composite materials. Analysis of failure progression at the fiber-matrix interfaces in fiber-reinforced composite materials is considered using a softening decohesion model consistent with thermodynamic concepts. In this model, the initiation of failure is given directly by a failure criterion. Damage is interpreted by the development of a discontinuity of displacement. The formulation describing the potential development of damage is governed by a discrete decohesive constitutive equation. Numerical simulations are performed using the direct boundary element method. Incremental decohesion simulations illustrate the progressive evolution of debonding zones and the propagation of cracks… More >