• CN：11-2187/TH
• ISSN：0577-6686

• 材料科学与工程 •

### 一种基于平均应力强度因子的焊点疲劳寿命预测方法

1. 1.湖南大学汽车车身先进设计制造国家重点实验室 长沙 410082
2.上汽通用五菱汽车股份有限公司 柳州 545000
• 出版日期:2015-08-20 发布日期:2015-08-20
• 基金资助:
湖南大学“青年教师成长计划”、湖南省自然科学基金(14JJ3055)、湖南省科技开发计划(2013TT1006)、广西科技计划重大专项(桂科重1348003-5)和中国博士后科学基金(2014M552132)资助项目

### A Fatigue Life Prediction Method for Resistance Spot Welds Based on Average Stress Intensity Factor

SONG Kai1,2, QIAN Tao1, CHEN Tao1, LI Guangyao1, YUAN Zhijun2

1. 1.State Key Laboratory of Advanced Designing and Manufacture for Vehicle Body, Hunan University, Changsha 410082
2.SAIC-GM-Wuling Automobile Co., Ltd., Liuzhou 545000
• Online:2015-08-20 Published:2015-08-20

Abstract: The traditional fatigue simulation analysis methods of spot weld joints are mainly LBF method based on force and LMS method based on stress. As the prediction accuracy is not high, modeling and computational efficiency is low and other issues for these two methods, a new fatigue life prediction method for spot welds is proposed, which considers the fatigue failure of spot welds from the point of fracture mechanics. A modular spot weld model is adopted, the node force and moment around the spot weld is extracted through the finite element analysis, then the average stress intensity factor through the crack propagation path is calculated as the evaluation parameters of fatigue life. Shear fatigue test is conducted for two high-strength steel—HSLA340GI and DP600GI, four different thickness resistance spot welding joints, then double logarithmic regression analysis is conducted for the average stress intensity factor and the fatigue life data of spot weld joints, then a curve between the average stress intensity factor and the fatigue life is obtained as the fatigue life prediction curve for spot welds, then comparative analysis of prediction accuracy is conducted among these three method, the results show that the prediction accuracy of fatigue life forecasting method of spot welds in this paper is higher than traditional LBF and LMS methods.