裂纹在异种材料扩展中的能量变化

Energy Variation of Ductile Crack Propagating in Two Steels

在对裂尖张开角度和临界裂尖张开角度测试方法研究的基础上 ,考察了延性裂纹在异种材料中扩展时的能量变化规律 ,建立了扩展能增量、材料屈服强度、临界裂尖张开角度以及管段长度之间的关系公式 ,并讨论了公式产生误差的原因和大小。结果发现 ,不论对何种类型试样或管段 ,误差系数均在 0～ 0 .0 79之间 ,而对大型管道 ,该误差可以忽略 ,从而为管道止裂设计提供了新的方法和理论计算依据。

We investigated the basic theories of CTOA and two-specimen method to get the material's critical CTOA. Then the energy variation in ductile crack propagating from one steel class to another was studied. Based on the analysis results, formula connecting propagation energy increment, steel yield strength, critical CTOA and the ratio of these two pipe lengths was deduced. Also, the elements causing discrepancy were discussed.The results indicate that for any kind of specimen or any pipe length, the discrepancy coefficient will always fall in 0～0.079, and can be neglected for long pipe analysis. On the help of these equations, crack arrest design can be done more precisely.