基于超单元理论的焊接疲劳分析

Welding Fatigue Analysis Based on Super Element Theory

为解决汽车尾门疲劳工况中激光焊开裂问题,更准确地反映尾门疲劳工况中激光焊开裂情况,文章基于超单元理论,建立用于激光焊的精细化模型,通过对激光焊临近裂纹尖端区域的细化模型,得到修正的多维度刚度矩阵。同时引入密封条的非线性材料属性标定,准确模拟汽车尾门密封条在高应变率下非线性的动态性能,有效提高了车辆尾门激光焊计算效率和疲劳开裂的风险预测精度。最后通过相关试验验证该精细化疲劳模型的合理性和准确性,高效助力尾门结构改进,减少实验周期及成本。

The purpose of this paper is to solve the problem of laser welding cracking in the fatigue condition of automobile tailgate.In order to reflect accurately the laser welding cracking in the tailgate fatigue condition,the super element theory was introduced to establish a refined model for laser welding fatigue analysis.Through the detailed model of laser welding near the crack area,a corrected multi-dimensional stiffness matrix was obtained,and the nonlinear material property calibration of the sealing strip was introduced,which simulated accurately the nonlinear dynamic performance of the automotive tailgate seal under the high strain rate,and effectively improved the calculation efficiency of laser welding of the vehicle tailgate and the risk prediction accuracy of fatigue cracking.Finally,the rationality and accuracy of the refined fatigue model were verified by relevant tests,which effectively improved the tailgate structure and reduced the experimental cycle and cost.