一、前言近年来,断裂力学不仅用于解释基础断裂现象,而且开始广泛用于评定材料的强度、韧性和容许缺陷,设定检查基准等各个方面。因为在判定脆性裂纹和疲劳裂纹的扩展速度时,需要依据裂纹尖端的局部应力条件,所以应用应力强度因子这一断裂力学参数的研究越来越盛行。但是这些研究大多是使用小型试件的基础研究,在解释机械零件和结构的断裂方面以及在设计上如何应用断裂力学还有许多实际问题。 I. Introduction In recent years, fracture mechanics is not only used to explain the basic fracture phenomenon, but also began to be widely used to assess the strength of materials, toughness and allowable defects, set the benchmark for inspection and other aspects. Because in judging the propagation speed of brittle crack and fatigue crack, it needs to depend on the local stress condition of the crack tip. Therefore, the research on the fracture mechanics parameter using stress intensity factor is more and more prevalent. However, most of these studies are based on the use of small specimens. There are still many practical problems in explaining the fracture of mechanical parts and structures and how to apply fracture mechanics in their design.