Evaluation method for microscopic and macroscopic properties of damaged materials containing distributed elliptical microcracks
Nishioka Toshihisa; Kato Tetsuji
Abstract:The materials containing damages and defects cause the reduction of stiffness of mechanical components. In this paper, a damaged material is regarded as the assembly of periodically distributed unit cells containing one or more elliptical microcracks. An alternating method based on the VNA (Vijayakumar - Nishioka - Atluri) solution is used to solve the problems of periodically distributed elliptical microcracks. The information on the deformation of the central cell (called representative cell) is used to evaluate the effective elastic moduli. Interaction effects of periodically distributed elliptical microcracks are completely included in the present solutions. The effective elastic moduli for various types of damaged materials are estimated. To clarify the mechanism of interaction behavior of microcracks, the stress distributions in the damaged materials are visualized. The presently developed analysis method made it possible to simultaneously estimate microscopic as well as macroscopic material properties such as the stress intensity factor distribution of each microcrack and the effective elastic moduli. Key Words:damaged material, elliptical crack, microcracks, VNA solution, Alternating method, effective elastic moduli, unit cell, periodic distribution, representative cell