断裂破坏是钢桥灾难性破坏的一种主要形式,据1847年至1975年全世界143座桥梁的破坏统计分析,约占15％断裂破坏不同于一般的过载破坏(即材料由于过量的塑性变形而破坏)。断裂不经历宏观的塑性变形,断裂应力(指名义应力)不仅低于屈服极限,而且也小于许可应力。断裂前亦无征兆,一旦断裂发生则瞬时完成,且是粉碎性的。所以这种破坏的危险性很大,引起世界各国的重视。断裂力学的发展为我们分析这类破坏提供 Fracture damage is a major form of catastrophic failure of steel bridges. According to the statistical analysis of the damage of 143 bridges in the world from 1847 to 1975, about 15% fracture failure is different from common overload damage (ie, the material is deformed due to excessive plastic deformation And destroy). Fractures do not undergo macroscopic plastic deformation, fracture stress (nominal stress) not only below the yield point, but also less than the allowable stress. There was also no evidence of fracture before breaking, but instantaneous rupture occurred and was comminuted. Therefore, the danger of such destruction is great and has drawn the attention of all countries in the world. The development of fracture mechanics provides us with the analysis of such damage