1727 マイクロ繊維分散複合材料の局所塑性損傷における評価

Abstract

Short fiber dispersed composite are widely used in many fields. The existing constitutive models describing the global mechanical property of composite were built on the relation between the phase-average stress and strain, as treated in monolithic materials. In the present work, however, it was found that the averaged characteristic of the phase material, in which the plastic damage occurs, is quite different from that of the monolithic material. And the morphology of the non-uniform local rigidity remarkably gives effects on the global property of the composite. It was observed that the development of the damage region outside void cracks is recognized to be a fetal factor for material failure. Therefore, it is very important to estimate, with certain accuracy, the damage region in composite for the usage and design of the composite. In this paper, a statistical distribution function was introduced to describe the local stress and the damage region induced by the void crack. The mixture law is developed to estimate the percentage of the damage region by applying Localized Rigidity Method (LRM) which was proposed by the authors before, combined with Self Consistent Compliance (SCC) method to the plasticity constitutive law. The results of the numerical calculation with present mixture law are presented. A numerical calculation by the present model was performed for investigating the global nonlinear phenomena of the short fiber dispersed composite due to the plastic damage, and the high performance of the present model are verified.