一、前言随着工业的发展,近几十年来大量采用高强度材料,工程中焊接结构、大型锻件等产品也日益增多。低应力脆性破坏事故不断发生。对这些脆性破坏事故的进一步分析和大量的实验结果指出:在远低于材料屈服极限的应力下发生的脆性断裂,总是由宏观尺寸的裂缝(或者缺陷)的扩展而引起的。断裂力学是研究有裂纹构件的强度及裂纹扩展规律的一门学科。 I. INTRODUCTION With the development of industry, a large number of high-strength materials have been used in recent decades, and welding structures, large forgings and other products have also been increasing. Low-stress brittle failures continue to occur. Further analysis of these brittle failures and a large number of experimental results indicate that brittle fractures occurring at stresses well below the material yield limit are always caused by the expansion of macroscopic cracks (or defects). Fracture mechanics is a discipline that studies the strength and crack propagation of cracked components.