P.H. Wen¹, M.H. Aliabadi²

CMES-Computer Modeling in Engineering & Sciences, Vol.61, No.2, pp. 133-154, 2010, DOI:10.3970/cmes.2010.061.133

Abstract A meshless local Petrov-Galerkin method, for the micro-mechanical material model of woven fabric composite material is presented in this paper. The material models are based on a repeated unit cell approach and two smooth fibre modes. A unit step function is used as the test functions in the local weak-form which leads to local boundary integral equations. The analysed domain is divided into small sub-domains and the radial basis function interpolation without element mesh is adopted. The woven fabric composite elastic moduli evaluated have been shown to be in good agreement with finite element results. More >

R. Valisetty^1,2, A. Rajendran^1,3, D. Grove²

CMES-Computer Modeling in Engineering & Sciences, Vol.60, No.1, pp. 41-72, 2010, DOI:10.3970/cmes.2010.060.041

Abstract A multi-scale model exhibiting progressive damage is considered for a 3D-woven composite. It is based on the evolution of some fundamental damage modes in a representative volume element (RVE) of a composite's woven architecture. The overall response of a woven composite due to a variety of damage modes is computationally obtained through a transformation field analysis (TFA) that is capable of quantifying the effects of spatial distribution of micro stresses and strains on strength. Since the model is computationally intensive, its numerical requirements are to be understood before it can successfully be used in design studies or in conjunction with… More >

L. Távara¹, V. Manticˇ ¹, E. Graciani¹, J. Cañas¹, F. París¹

CMES-Computer Modeling in Engineering & Sciences, Vol.58, No.3, pp. 247-270, 2010, DOI:10.3970/cmes.2010.058.247

Abstract The problem of a crack in a thin adhesive layer is considered. The adherents may have orthotropic elastic behavior which allows composite laminates to be modeled. In the present work a linear elastic-brittle constitutive law of the thin adhesive layer, called weak interface model, is adopted, allowing an easy modeling of crack propagation along it. In this law, the normal and tangential stresses across the undamaged interface are proportional to the relative normal and tangential displacements, respectively. Interface crack propagation is modeled by successive breaking of the springs used to discretize the weak interface. An important feature of the BEM… More >

G.I. Giannopoulos¹, S.K. Georgantzinos², D.E. Katsareas², N.K. Anifantis²

CMES-Computer Modeling in Engineering & Sciences, Vol.56, No.3, pp. 231-248, 2010, DOI:10.3970/cmes.2010.056.231

Abstract A hybrid finite element formulation, combining nanoscopic and macroscopic considerations is proposed, for the prediction of the elastic mechanical properties of single walled carbon nanotube (SWCNT)-based composites. The nanotubes are modeled according to the molecular mechanics theory via the use of spring elements, while the matrix is modeled as a continuum medium. A new formulation concerning the load transfer between the nanotubes and matrix is proposed. The interactions between the two phases are implemented by utilizing appropriate stiffness variations describing a heterogeneous interfacial region. A periodic distribution and orientation of the SWCNTs is considered. Thereupon, the nanocomposite is modeled using… More >

A.N. Guz, V.A. Dekret¹

CMES-Computer Modeling in Engineering & Sciences, Vol.49, No.1, pp. 69-80, 2009, DOI:10.3970/cmes.2009.049.069

Abstract The two models in the three-dimensional theory of stability of the nanotube reinforced composite materials are discussed. The model of "infinite fibers" and the model of "short fibers" are considered. The primary objective is attended to "short fibers" model. All results are obtained in the framework of the three-dimensional linearized theory of stability of deformable bodies. More >

B.R.Kim¹ and H.K.Lee^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.47, No.3, pp. 253-282, 2009, DOI:10.3970/cmes.2009.047.253

Abstract Damage characteristic of particulated ductile composites is a complex evolutionary phenomenon that includes particle debonding and void evolution with the accumulation of the plastic straining of the ductile matrix. In this paper, a micromechanical elastoplastic damage model for ductile matrix composites considering gradually incremental damage (particle debonding and void evolution) is proposed to predict the overall elastoplastic behavior and damage evolution in the composites. The constitutive damage model proposed in an earlier work by the authors [Kim and Lee (2009)] considering particle debonding is extended to accommodate the gradually incremental damage and elastoplastic behavior of the composites. On the basis… More >

A. Djeukou¹, O. von Estorff²

CMES-Computer Modeling in Engineering & Sciences, Vol.47, No.1, pp. 23-42, 2009, DOI:10.3970/cmes.2009.047.023

Abstract The paper deals with the response of rectangular composite plates to low-velocity impact. A third-order shear deformation theory as well as the Newmark integration are used to determine the contact force history analytically. The interaction between the impactor and the plate is modeled with the help of a two degrees-of-freedom system, consisting of springs and masses. The Choi's linearized Hertzian contact model is used to determine the contact force. The maximum impact force is employed for a static damage analysis of the composite plate by means of the radial point interpolation method, while the Tsai-Wu failure criterion is applied for… 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 >

S.H. Pyo¹, H.K. Lee^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.40, No.3, pp. 271-306, 2009, DOI:10.3970/cmes.2009.040.271

Abstract This paper presents a micromechanical approach for predicting the elastic and multi-level damage response of aligned and randomly oriented whisker-/ short fiber-reinforced composites. Based on a combination of Eshelby's micromechanics and the evolutionary imperfect interface approach, the effective elastic moduli of the composites are derived explicitly. The modified Eshelby's tensor for spheroidal inclusions with slightly weakened interface [Qu (1993b)] is extended in the present study to model whiskers or short fibers having mild or severe imperfect interfaces. Aligned and random orientations of spheroidal reinforcements are considered. A multi-level damage model in accordance with the Weibull's probabilistic function is then incorporated… More >

M. Patrício¹, R. Mattheij², G. de With³

CMES-Computer Modeling in Engineering & Sciences, Vol.38, No.2, pp. 89-118, 2008, DOI:10.3970/cmes.2008.038.089

Abstract The behaviour of composite materials with periodically distributed constituents is considered. Mathematically, this can be described by a boundary value problem with highly oscillatory coefficient functions. An algorithm is proposed to handle the case when the underlying periodicity is locally disturbed. This procedure is constructed using fundamental concepts from homogenisation theory and domain decomposition techniques. Applications to layered materials are considered. More >