き裂先端近傍の弾塑性挙動に基づく非線形き裂力学の有効性(機械工学科)

Abstract

The fracture of machines and structures is brought by the growth of a crack in most cases. Moreover the fracture occurs in some cases after producing large plastic deformation near the crack tip. Therefore the measure of mechanical severity of a cracked body in such a case is necessary to assure the occurrence of same phenomena in a cracked specimen and a real cracked object under large scale yielding. Recently, the non-linear crack mechanics was proposed by one of the authors. In this concept, the plastic strain at a crack tip obtained by the finite element method (FEM) is used as the measure of mechanical severity of a cracked body. In this paper, the effectiveness of the non-linear crack mechanics is discussed through the elastic-plastic behavior near a crack tip obtained by the FEM analysis under small scale yielding and large scale yielding.