A533B-1钢韧脆转变区断裂韧度预测的约束评估法

FRACTURE TOUGHNESS PREDICTION OF A533B-1 STEEL OVER THE DUCTILE-BRITTLE TRANSITION RANGE BASED ON CONSTRAINT EVALUATION

分析A533B-1压力容器钢韧脆转变温度区的断裂韧度、温度以及裂纹尖端约束效应之间的关系。根据实验数据,给出从浅裂纹到深裂纹,不同裂纹长度时单边裂纹弯曲试件(single edge notched bend specimens)的主曲线(master curve)。用有限元分析相应试件裂纹尖端区域的应力场,采用J—A2双参数方法对裂纹尖端的三轴约束水平进行评估,并给出约束参数A2与主曲线参考温度T0之间的关系。由此,建立A533B-1钢断裂韧度KJC与温度T和约束参数A2之间的关系。为利用实验室数据对工程中不同裂纹构件的断裂评估提供一种经济、可行的方法。

The relationship among the fracture toughness, temperature and constraint effect on crack-tip was analyzed over the ductile-brittle transition range of A533B-1 pressure vessel steel. According to the experiment data, the reference temperature To of master curves （MC） were given out on different specimens from deep to shallow cracks. The crack-tip stress fields of relevant SENB（single edge notched bend） specimen were analyzed by using FEM（finite element method）. The constraint level of crack-tip was evaluated by adopting J--A2 two parameters approach, and then the relationship between constraint parameter A2 and reference temperature To was obtained. Therefore, a mathematical expression representing a family of the master curves was constructed as a function of the constraint parameter A2 for steel A533B-1. It produces an convenient method to apply the experiment data into the fracture assessment of various cracked structures in engineering.