准静态和动态加载对裂纹扩展阻力曲线的影响及其关系的研究

摘要

对典型压力容器用钢 Q345R 预制裂纹夏比冲击试样进行示波冲击试验，得到了Q345R 钢的载荷-位移曲线，并根据试验数据，利用 J 积分增量方程和 Schindler 方法分别计算得到 Q345R 钢在冲击加载下的动态裂纹扩展阻力曲线（J-R 曲线）。然后将动态 J-R 曲线和准静态加载条件下试验得到的 J-R 曲线进行对比发现，动态加载条件下的 J-R 曲线高于准静态加载时得到的结果。最后，建立了动态和准静态加载下 J-R 曲线之间的关系式，对工程应用具有重要的参考意义。%Instrumented impact tests are carried out using precrack Charpy specimens of typical pressure vessel steel Q345R,the load-displacement curves are obtained.Based on the test data,the J-integral in-cremental equation procedure and Schindler method are used to estimate dynamic crack resistance curve of Q345R steel under impact loading respectively.The results of them are compared and verified each other.After comparing the dynamic J-R curve with the qusi-static curve,it is found that the J-R curve under dynamic loading is always higher than that obtained under quasi-static loading.Further analyses of test data lead to an equation which quantitatively describes the relationship between Q345R quasi-static and dynamic crack growth resistance curve.The equation may have important significance in engineering application.