基于Seam型裂纹的复合型裂纹起裂角预测的有限元法

Finite Element Method for Predicting Crack Initiation Angle of Mixed Mode Crack Based on Seam Crack Model

目的对处于多轴应力状态下的复合型裂纹起裂角进行预测。方法考虑材料的弹性性能,利用商业有限元软件ABAQUS中的Seam裂纹模拟穿透型裂纹损伤,建立双轴载荷作用下中心带孔边裂纹板的三维有限元模型,通过位移外推法得到裂纹尖端的应力强度因子(Stress Intensity Factor,SIF),并利用求得的SIF基于最大周向应力断裂准则预测孔边裂纹的起裂角。结果通过与相关文献结果进行对比,发现通过该有限元方法计算得到的应力强度因子与文献结果的最大误差在2%以内,预测的裂纹起裂角与文献结果的最大误差在3%以内。结论该有限元方法计算的裂纹起裂角与文献结果一致,因此文中求解复合型裂纹起裂角所使用的有限元方法是可靠有效的。

Objective To predict the initiation angle of mixed-mode crack under multiaxial stress. Methods The Seam crack in commercial finite element software ABAQUS was used to simulate penetrating crack damage according to elastic property of materials. A 3-D finite element model of center-hole with edge cracking plate under multiaxial stress was established. Displacement and extrapolation method and linear fitting method were used to calculate the SIF of crack tip. Initiation angles of cracks were predicted by maximum circumferential stress criterion, which were compared with those obtained by relative papers. Results The maximum error of SIF between the result obtained by finite element models and that of document was within 2%, while the maximum error of initiation angles was within 3%. Conclusion The results obtained by the finite element method in this paper are in line with document; therefore, the finite element method used for calculating the initiation angle of mixed-mode crack is reliable.