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前言在评定有缺陷构件的安全性中,广泛应用线弹性断裂力学,《ASME 锅炉与压力容器标准》第Ⅲ、Ⅺ卷也是用线弹性断裂力学进行评定的。但人们普遍认为,对于高温设备上部平台使用的高韧性材料,用线弹性断裂力学进行评定过于保守。要确切评定这种高温区的破坏情况,用弹塑性断裂力学更有效。近年来,这一领域里的研究工作正在取得进展。把 J 积分和裂纹张口位移(COD)等作为弹塑性断裂力学的参数,对于实际构件上存在的缺陷,用这些参数是难于求得的,有必要用有限元法进行数值解析。对于构件设计和维修中存在的缺陷进行安全性评定,用数值解析法求取 J 积分等断
Preface The linear elastic fracture mechanics is widely used in assessing the safety of defective components. The ASME Boiler and Pressure Vessel Standards, Volumes III and XI, are also evaluated using linear elastic fracture mechanics. However, it is generally accepted that the evaluation of linear elastic fracture mechanics is too conservative for high-toughness materials used in the upper platform of high-temperature equipment. To accurately assess the destruction of this high temperature region, the more effective with elastoplastic fracture mechanics. In recent years, research work in this field is making progress. Using J integral and crack mouth displacement (COD) as the parameters of elasto-plastic fracture mechanics, these parameters are difficult to obtain for the defects existing in the actual components. It is necessary to use finite element method for numerical analysis. For component design and maintenance of defects in the safety assessment, using numerical analysis of J integral and so on