用于压力容器破前漏(LBB)断裂分析的各种评估理论及计算精度研究

对压力容器LBB断裂分析的各种评估理论作了简要评述,并以环向贯穿裂纹的断裂评定为实例对各种评定方法的精度加以对比.指出:JR曲线稳定性评定图法是根据推动力曲线与阻力曲线的相切条件确定失效点的,理论清晰,可以作为各种评估方法的理论依据.R6的失效评定图法属近似的图解评定方法,评定结果最为保守;JR曲线映象法(RCI)是变更裂纹尺寸的失效评定图法,它能给出与JR曲线稳定性分析相同的预测,属精细的图解评定方法;最大相容应力法是通过求解综合的稳定平衡方程而确定失稳应力的,它能精细地给出裂纹撕裂扩展的全过程,比JR曲线稳定性分析方法更为简洁精确.

STUDIES ON THE VARIOUS ASSESSMENT THEORIES ANDTHEIR COMPUTATIONAL PRECISIONS USED TO LBB FRACTURE ANALYSIS OF PRESSURE VESSELS

The various assessment theories used to LBB fracture analysis of pressure vessels have been remarked and their assessment precisions have also been contrasted by using actual stability computation for the circumferential throughwall crack.It is point to that J_R curve stability assessment diagram method is based on the tendency condition between driven and resistance curves to determine the instability point,so may be considered to be theoretical basis of all assessment methods.R6 failure assessment diagram method belongs to the approximate graphical method,its assessment result is much conservative.J_R curve image method(RCI) is alternative failure assessment diagram method for changing crack size,it can give the same prediction with J_R curve stability analysis and belongs to accurate graphical assessment method.The maximum admissible stress method by solving the comprehensive stability equilibrium equation determines the instability stress,it can give all process of crack ductile tearing and is more explicit and more accurate than J_R curve stability analysis.