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在损伤容限的设计概念中,当未达到引起破坏的状态时,认为这种缺陷是允许的。根据这个原则,日本制定了一个实用的验收标准,它提供了根据 COD 判据评定焊缝缺陷的方法。但是,因为这个标准尤其是没有仔细考虑有关断裂现象的概率特性,故存在若干待改进的问题。很多因素如外力、材料的韧性、疲劳裂纹扩展及无损检验方法等都促成了破坏的概率特点。在本报告中,对这些参数中的一个,即对材料的韧性做了研究。本研究的目的是搞清楚包含在评定断裂韧性δ的现行程序中的不确定性,并提出了一种基于可靠性分析的修正程序。
In the design concept of damage tolerance, this defect is considered to be acceptable when failure-causing conditions are not met. Based on this principle, Japan has developed a practical acceptance criteria that provides a method of assessing weld defects based on COD criteria. However, since this standard does not carefully consider the probabilistic characteristics of the fracture phenomena in particular, there are several problems to be solved. Many factors such as external forces, material toughness, fatigue crack propagation and non-destructive testing methods have contributed to the probability of destruction of the characteristics. In this report, one of these parameters is studied, namely the toughness of the material. The purpose of this study is to understand the uncertainty involved in the current procedure for assessing fracture toughness δ and to propose a correction procedure based on reliability analysis.