船体構造用多結晶金属材料の繰返し塑性変形挙動の数値シュミレーションに関する研究 (その1) : 面心立方二次元モデルの計算

抄録

In order to improve a prediction method of the crack initiation or failure life, it is needed to develop a simulation method which estimate macroscopic deformation behavior from microstructural models. In this report, we analyze ununiform deformation of f.c.c. pollycrystalline using 2-Dimentioal FEM model, and evaluate propriety of models for movement and interaction of dislocations. Results of the analyses are summarized as follows: 1) It is possible to represent cyclic plastic behavior of real materials if dislocation structures generated during plastic deformation raise c.r.s.s. only by long-range stress or these structures disappear during unloading. 2) There is concentration of plastic strain on grain boundary of a crystal which faces free surface and is next to crystals with small plastic deformation. It is supposed that PSB (persistent slip band), which cause fatigue failure, appear in such regions.