A DESCRIPTION OF MACROSCOPIC DAMAGE THROUGH MICROSTRUCTURAL RELAXATION

In this paper a flexible model for the description of damage in hetero geneous structural materials is presented. The approach involves solvi ng the equations of equilibrium, with unilateral constraints on the ma ximum attainable values of selected internal variables. Due to the uni lateral constraints, the problem is non-linear. Accordingly, a simple iterative algorithm is developed to solve this problem by (1) computin g the internal fields with the initial undamaged microstructure and (2 ) reducing the material stiffness at locations where the constraints a re violated. This process is repeated until a solution, with a corresp onding microstructure, that satisfies the equations of equilibrium and the constraints, is found. The corresponding microstructure is the fi nal 'damaged' material. As an application, the method is used in an in cremental fashion to generate response curves describing the progressi ve macroscopic damage for a sample of commonly used fibre-reinforced A luminum/Boron composite. The results are compared to laboratory experi ments published by Kyono et al.(1) and computational results using sta ndard numerical methods, published by Brockenbrough et al.(2) (C) 1998 John Wiley & Sons, Ltd.