Transactions of Materials and Heat Treatment

Title：Prediction of weld joints fatigue life based on average equivalent stress intensity factor

Authors： Song Kai Cheng Guangming

Unit： Hunan University SAC-GM-Wuling Automobile Co.

KeyWords： weld fatigue life crack nodal forces moments average equivalent stress intensity factor

ClassificationCode：TH114

year,vol(issue):pagenumber：2016,41(10):132-137

Abstract：

At present, the fatigue simulation analysis method of the weld joints are mainly the nominal stress method and the normal structure stress method. For the limitations in application and low prediction accuracy caused by not considering shear structure stress, a new fatigue life prediction method was proposed. Based on the theory of fracture mechanics, the nodal forces and moments around the weld joints were obtained by finite element software, and an average stress intensity factor ΔKeq in the weld crack propagation path was calculated. Furthermore, it was regarded as the evaluation parameters of fatigue life prediction method. Through conducting shear fatigue test for two high-strength steel-DP800GI and HSLA350GI resistance welding joints, and conducting double logarithmic regression analysis for ΔKeq and the fatigue life data of weld joints, a master ΔKeq -N curve as the fatigue life prediction curve for weld joints was obtained. Furthermore, prediction accuracy with the nominal stress method and the normal structure stress method was compared and analyzed. The results show that the prediction accuracy of fatigue life forecasting method of weld joints in this paper is higher than the current nominal stress method and structural stress method.

Funds：

广西科技重大专项(1348005-5)；湖南省科技开发计划项目(2013TT1006)；中国博士后科学基金资助项目（2014M552312）

作者简介：宋凯（1981-），男，博士，副教授 E-mail：song_kai@163.com；通讯作者：程广鸣（1991-），男，硕士 E-mai:chengguang_ming@sina.com

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