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 partic les and an SMC-R (polyester matrix with randomly oriented glass fibres). Th e main damage mechanism is particle failure (for the Metal Matrix Composite s (MMC)) or fibre-matrix interface debonding (for the sheet moulding compou nd (SMC)). Moreover, for the AlSiCp composite, regions of the matrix adjace nt to broken particles are sites with high hydrostatic tension and hence th e nucleation of cavities is expected. Using the J integral and HRR modified solution it is possible to calculate the growth of these voids. Macroscopi c failure is governed by a critical volume fraction of voids. In this paper , we propose a micro-mechanical approach to model the elastoplastic damagea ble 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 th e damage of a structure. In all cases, the simulated results are compared t o experimental ones and show a fairly good agreement. (C) 2000 Elsevier Sci ence S.A. All rights reserved.