破壊力学 弾塑性境界要素法による異種接合材界面端の解析

Abstract

Elastoplastic boundary element analysis is carried out to investigate the effect of linear hardening coefficient on the stress singularity and stress field near an interface edge in bonded dissimilar materials. The results show that the elastoplastic stress distribution near an interface edge can be divided into 3 regions, i.e., elastoplastic singular stress dominated zone, transition zone and elastic zone, sizes and properties of which depend on the size of yielding zone and the hardening coefficient. If the linear hardening coefficient is relatively large, the elastoplastic stress distribution agrees with the quasi-elastic theoretical result. It is also found that the transition zone increases and the elastoplastic singular stress dominated zone decreases with decreasing the hardening coefficient. If the linear hardening coefficient is small enough, the transition zone may become the main part of the yield zone, and the theoretical results may be correct only in a very small region near the edge, hence it would lose physical meanings for the evaluation of elastoplastic fracture. On the other hand, for small scale yield problems, the numerical results show that the behavior of stress distribution in the elastic zone is almost similar to the elastic theoretical results (i.e. the stress singularity order is almost the same), but the stress intensity coefficient becomes somewhat larger.