裂纹尖端应力强度因子的有限元计算方法分析

Analysis of Finite Element Calculation Methods for Crack-tip Stress Intensity Factor

通过在裂纹前缘附近采用退化的奇异单元,远离裂纹部分则采用常规单元的方式,建立了带穿透性裂纹板的有限元模型。分析了1/4节点位移法、位移外推法、虚拟裂纹闭合法3种方法计算裂纹尖端应力强度因子的特点。根据有限元后处理结果,分别采用以上3种方法计算了裂纹尖端的应力强度因子,结果显示3种方法计算结果一致性较好。研究了载荷、裂纹长度、构件几何参数对裂纹尖端应力强度因子的影响。3种方法的比较分析,对裂纹尖端应力强度因子的计算方法选择具有指导意义。

In this paper,a finite element model of plate with throughwall crack is established,with using degraded singular element near crack front,and applying conventional element away from crack area.The characteristics of 1/4-node displacement method,displacement extrapolation method and virtual crack closure method are analyzed.Crack-tip stress intensity factor is calculated by the methods above,based on the results of finite element post-processing,the results got by the three method show high consistency.The influences of load,crack length and geometry of component on crack-tip stress intensity factor are also studied.The comparative analysis of three methods is conductive for choosing an appropriate approach to calculate crack-tip stress intensity factor.