应用改进的虚拟裂纹闭合方法求解三维裂纹应力强度因子

基于有限元计算结果计算结构的能量释放率,利用能量释放率来计算结构的应力强度因子。本文对现有的虚拟裂纹闭合方法作了改进,即应用本文改进的虚拟裂纹闭合方法求解三维裂纹体应力强度因子时,裂纹前缘的裂纹面可以是任意形状,且裂纹前缘的有限元单元宽度可以不等。文中以三维表面裂纹为例,应用改进的虚拟裂纹闭合方法计算了该结构的应力强度因子,同时讨论了裂纹前缘有限单元宽度对应力强度因子的影响。

Modified Virtual Crack Closure Technique and its Application to Calculating the Stress Intensity Factors of Three Dimensional Cracks

In virtual crack closure technique(VCCT),the energy release rate is computed based on the results of finite element calculation,and the stress intensity factor(SIF) is computed from the energy release rate.In this paper,on the basis of the conventional three dimensional VCCT,a modified virtual crack closure technique(MVCCT) for three dimensional linear fracture mechanics analysis is presented,which is required to open one element face area whose shape is arbitrary and finite element widths are unequal across the crack front.By application of the MVCCT,we calculate and analyze the stress intensity factors of the three-dimensional surface crack.At the same time,the effect of unequal element widths is studied.Comparison of the numerical estimations with the reference solutions shows good agreement.