Prediction of the effective damage properties and failure properties of nonlinear anisotropic discontinuous reinforced composites

We studied the tensile behavior and damage of two different composites. An Al2080 reinforced with different volume fractions of silicon carbide particles and an SMC-R (polyester matrix with randomly oriented glass fibres). The main damage mechanism is particle failure (for the Metal Matrix Composites (MMC)) or fibre-matrix interface debonding (for the sheet moulding compound (SMC)). Moreover, for the AlSiCp composite, regions of the matrix adjacent to broken particles are sites with high hydrostatic tension and hence the nucleation of cavities is expected. Using the J integral and HRR modified solution it is possible to calculate the growth of these voids. Macroscopic failure is governed by a critical volume fraction of voids. In this paper, we propose a micro-mechanical approach to model the elastoplastic damageable composite behaviour of the composites. Moreover, in the case of the MMC, the proposed model is able to predict the failure strain of the composite as a function of the micro-structure. For the SMC, the elastic damageable behaviour law is introduced in a finite element code in order to predict the damage of a structure. In all cases, the simulated results are compared to experimental ones and show a fairly good agreement. (C) 2000 Elsevier Science S.A. All rights reserved.