核反应堆压力容器的热-机械耦合及断裂分析

摘要

为研究承压热冲击对含表面裂纹的核反应堆压力容器(reactor pressure vessel,RPV)的承载能力的影响,利用ABAQUS软件对裂纹周围的环带区建立三维有限元模型,得到了瞬态温度场和应力场.使用扩展有限元法对热-机械耦合场中裂纹的扩展情况进行模拟.对不同的无延性转变温度下容器的极限承载力进行了弹塑性断裂分析,并与弹性分析的结果进行对比,总结出材料的断裂特性.通过网格的细化发现,由不同单元尺寸得到的裂纹扩展路径及损伤程度是相当的,从而避免了病态网格的依赖性.%To study the influence of pressurized thermal shock on the bearing capacity of the nuclear reactor pressure vessel (RPV) with a surface crack,the 3D finite element model was established for the beltline region around the crack by ABAQUS software.The transient temperature field and stress field were obtained.The XFEM was used to simulate the crack propagation in the thermo-mechanical coupling field.The ultimate bearing capacity of the vessel at different nil-ductility transition temperatures was tested employing elastic-plastic fracture analysis,and the results were compared with those obtained from elastic analysis to sum up the fracture characteristics of the material.Through mesh refinement,it was found that the crack propagation paths and the damage degrees for different element sizes are equivalent,which avoids pathological mesh dependence.