Estimation of Manifestations of Material Properties and Mechanical Effects on a Macrocrack, Induced by a Cluster of Elliptical Microracks.

Abstract

A macrocrack in a brittle material containing a cluster of microcracks experiences the stress shielding effect when the macrocrack front locates in the domain of stress relaxation induced by the microcacks. This is called the microcrack toughening effect for the macrocrack in a brittle material such as ceramic. Therefore the existence of microcracks improves the fracture toughness of the macrocracked solid. This paper presents the numerical analyses for the macrocrack in an anisotropically damaged materials. The homogenization method based on the superposition method is used to evaluate the material properties of the damaged materials and the mechanical behavior of the macrocrack in the damaged materials. In order to evaluate the mixed-mode stress intensity factors of a macrocrack in the anisotropically damaged materials, we derive the component separation method based on three dimensional path independent J integral. This paper provides the numerical results for the effective elastic moduli of the damaged materials and for the J integrals and the stress intensity factors of the macrocrack.