GB/T 30064-2013 in English

《GB/T 30064-2013金属材料 钢构件断裂评估中裂纹尖端张开位移（CTOD）断裂韧度的拘束损失修正方法》由TC183（全国钢标准化技术委员会）归口，TC183SC4（全国钢标准化技术委员会力学及工艺性能试验方法分会）执行，主管部门为中国钢铁工业协会。
在含裂纹钢结构的断裂评估中,一般假设断裂韧度试样的抗断能力与构件抗断能力是相等的,但这种假设往往导致过于保守的断裂评估结果。这是由于构件在主要受拉伸荷载作用时,裂纹尖端附近区域出现塑性拘束损失所致,相比之下断裂韧度试样由于承受弯曲荷载作用条件而在裂纹尖端附近区域产生很高的多轴拘束应力状态。最近几年来广泛应用于工程结构中的高强度钢因其屈强比较高(屈服强度/抗拉强度)而表现出构件裂纹尖端的拘束损失十分显著,断裂评估中迫切地需要进行修正。
本标准规定了一种方法,通过考虑拘束损失,将通过试验试样得到的CTOD(裂纹尖端张开位移)
断裂韧度转化为构件等效CTOD。这种方法适用于使用应力强度因子和J 积分概念所进行的断裂韧
度评估(见第8章)。
本标准适用于由裂纹类缺陷或铁素体结构钢疲劳裂纹所引发的失稳断裂,失稳断裂前出现明显的
延性裂纹扩展情况不包括在本标准的适用范围之内。
结构钢CTOD断裂韧度按照ISO12135:2002,BS7448-1:1991或ASTM E1290―1999中任何一
个规范中所规定的相应程序进行测试。含裂纹构件的断裂评估通常使用一种相关机构认可的方法进
行,如FAD(失效评定图),相关细节本标准没有提及。
本标准可用于消除过度保守观念,这种保守观念与传统断裂力学方法有着密切联系。既可以通过结构钢断裂韧度精确地评估构件失稳断裂的初始界限,也可用于合理地确定材料断裂韧度临界值(验收值),以满足有关钢构件对材料成型性能方面的设计要求。

Scope

In the fracture evaluation of cracked steel structures, it is generally assumed that the fracture resistance of fracture toughness specimens is equal to the fracture resistance of components, but this assumption often leads to overly conservative fracture evaluation results. This is due to the loss of plastic restraint in the region near the crack tip when the component is mainly subjected to tensile loads. Shaft-confined stress state. In recent years, high-strength steels, which have been widely used in engineering structures, show significant restraint loss at the tip of cracks due to their high yield strength ratio (yield strength/tensile strength), which urgently needs to be corrected in fracture evaluation. This standard specifies a method to convert the CTOD (crack tip opening displacement) fracture toughness obtained by the test specimen into the equivalent CTOD of the component by taking into account the restraint loss. This approach is suitable for assessment of fracture toughness using the stress intensity factor and J-integral concepts (see Chapter 8). This standard applies to unstable fractures caused by crack defects or fatigue cracks in ferritic structural steels, and the obvious ductile crack growth before unstable fractures is not included in the scope of application of this standard. The CTOD fracture toughness of structural steel is tested in accordance with the corresponding procedures specified in any one of ISO 12135:2002, BS 7448-1:1991 or ASTM E1290-1999. Fracture assessment of cracked components is usually carried out using a method recognized by the relevant agency, such as FAD (Failure Assessment Diagram), the relevant details of which are not mentioned in this standard. This standard can be used to eliminate overly conservative concepts, which are closely related to traditional fracture mechanics methods. The fracture toughness of structural steel can be used to accurately evaluate the initial limit of component instability and fracture, and it can also be used to reasonably determine the critical value (acceptance value) of material fracture toughness to meet the design requirements of steel components on material formability.