A Fatigue Life Simulation Analysis Method for Spot Weld Joints Considering Fatigue Crack Propagation

Abstract:

A new fatigue life simulation analysis method for spot weld joints is proposed which considers the fatigue crack propagation from the point of fracture mechanics. The traditional fatigue simulation analysis methods for spot weld joints are mainly LBF method based on force and LMS method based on stress, while there exist some issues such as the prediction accuracy is not high, modeling and computational efficiency is low. A modular spot weld model is adopted in this paper, the node forces and moments around the spot weld are extracted through the finite element analysis, then a average stress intensity factor through the crack propagation path is calculated as the evaluation parameter of fatigue life. Shear fatigue test is designed for spot weld joints with two high strength steel materials (HSLA340GI and DP600GI) and four different thicknesses, then double logarithmic regression analysis is implemented between the average stress intensity factor and the fatigue life data of spot weld joints, then a matching curve is obtained as the fatigue life prediction curve for spot welds. Comparative analysis of prediction accuracy is implemented for these three methods, the results show that the prediction accuracy of fatigue simulation method for spot weld joints in this paper is higher than traditional LBF and LMS methods.

• Periodical: Applied Mechanics and Materials (Volumes 799-800)
• Pages: 819-825
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.799-800.819
• Online since: October 2015
• Authors: Jun Cheng Lv, Tao Qian*, Kai Song, Bing Heng Qin, Xiao Ming Ding
• Keywords: Average Stress Intensity Factor, Fatigue Crack Propagation, Fatigue Life, Modular Spot Weld Model, Spot Welds

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