界面現象を考慮した繊維強化複合材料のマイクロメカニックスによる解析 : 第4報,一方向繊維強化複合材料の力学特性の評価

抄録

In the 3rd report of the sequential papers which dealt with analysis of the composite showing interfacial phenomena, micromechanical analysis was performed on a unidirectional fiber-reinforced composite producing interfacial debonding between a fiber and a matrix, and analytical expressions for energy release rates of a matrix crack and a debonding one were derived. In the present paper, evaluation of mechanical properties of a composite with such an interfacial debonding like a resin-based composite, is carried out based on the theoretical analysis of the 3rd paper. As a result, fracture toughness of such a composite can be evaluated in terms of the critical size of the crack at which the unstable propagation of the matrix crack will be arrested and then the debonding between a matrix and a fiber will occur. The effect of material parameters such as the volume fraction of a fiber, and the length of the debonding, etc., on the toughness can be explained by the interfacial phenomenon. The results obtained are consistent with the common experimantal facts. It should be particularly emphasized that there exists an optimal value of the surface energy of the interface for obtaining a tougher composite.