双材料界面裂纹应力强度因子的无网格分析

Numerical computation of SIFs for bimaterial-interfacial crack by meshless method

应用改进的无网格方法对双材料界面裂纹进行了分析,积分区域采用基于节点的Voronoi图,通过在裂纹尖端加密节点提高位移场的计算精度,采用位移外插法确定出应力强度因子,避免了应力场的奇异性和振荡性。本文对由环氧树脂和铝 环氧树脂组成的双材料进行分析,对比了均匀离散、均匀细化和局部细化三种不同模型,通过与光弹性实验结果比较可知,采用裂纹尖端局部细化的模型计算量低并且计算效果好,其计算结果与实验结果基本吻合。

A modified meshless method was presented for numerical investigation of stress intensity factors (SIFs) for bimaterial interfacial cracks. The domain was diecretized into integral subdomains based on the nodal Voronoi diagram, which assured this method was a true meshless method. By adopting nodal refinement at the vicinity of the crack tip, the computational accuracy of displacement field was improved. Displacement extrapolation method was used to determine the SIFs, this could bypass the singularity of the stresses. Bimaterial structures, bonded by Araldite and Al-filled Araldite, were analyzed at the end of this paper. Three computational models: coarse model, uniform refinement model, and local refinement model were used and compared. The numerical results calculated with local refinement model agree well with the results from photoelastic experiment, which validates the efficiency of this method.