Multiscale modelling of anisotropic damage of discontinuous reinforced metal matrix composites

Abstract
Composite materials are used in many industries. Depending of the limit conditions of application, it is possible to choose the type of reinforcement, its volume fraction, its orientation, its size, the type of matrix and its mechanical properties. It has been experimentally observed that damage often initiates very early during the loading. It is diffused in all the material on the micro-cracks form. It contribute to the strain of the composite under stress. The mechanical properties as stiffness, yield stress, hardening are influenced by damage. So, it is necessary to take into account the damage mechanisms as source of deformation coupled with the classical deformation mechanisms as elasticity, plasticity, viscosity. This paper deals with the way of taking into account damage in the behaviour law based on a micro-macro relationship. We will focus only on discontinuous reinforced composite. A Mori and Tanaka model has been used with damage laws written at the microscale. The macroscopic mechanical properties are obtained by homogenisation. The type of reinforcement could be particulates, short fibres, plates, which are randomly oriented in the matrix. The matrix could be in polymer, in metal.