基于XFEM的主次裂纹间应力强度因子相互作用

Study of interaction between stress intensity factors of main and secondary cracks based on XFEM

采用新型裂尖改进函数构建的Reduced XFEM,研究次裂纹与主裂纹的相互作用,以及次裂纹对主裂纹应力强度因子的影响,并在裂纹尖端采用互作用积分法计算应力强度因子。计算结果表明:次裂纹存在会使主裂纹的应力强度因子减小;次裂纹长度越长,主裂纹应力强度因子减小得越明显;次裂纹距主裂纹的位置与主裂纹的应力强度因子之间有一定的规律,主裂纹的应力强度因子随主、次裂纹间距离的增大呈"勺"形分布,且当该距离达到一定数值后主裂纹的应力强度因子变化较小,接近单裂纹状态。

In this study, the interaction between the main crack and secondary crack was investigated using the Reduced XFEM, which is constructed with a new type of crack tip enrichment function. The effect of the secondary crack on the stress intensity factor （ SIF） of the main crack was studied, and the SIF was calculated with the interaction energy integral method at crack tips. The calculation results show that the existence of the secondary crack decreases the SIF of the main crack. The SIF of the main crack decreases significantly with the increasing length of the secondary crack. The changes of the distance from the main crack to the secondary crack and the SIF of the main crack follow certain rules： the SIF of the main crack shows a scoop-shaped distribution as the distance increases, and it changes insignificantly, being close to a single crack state, as the distance reaches a certain value.