1. EFFECT OF WELDING RESIDUAL STRESS ON CRACK PROPAGATION AND FATIGUE PERFORMANCE OF HIGH STRENGTH STEEL SPOT WELDING JOINT
- Author
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LUO JiaYuan, LI Xin, and TAN Chao
- Subjects
Spot welding residual stress ,Kinked crack ,Stress intensity factor ,Fatigue life ,Mechanical engineering and machinery ,TJ1-1570 ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
Due to the high stress concentration of spot welding joints, it is very easy to initiate fatigue cracks at the edge of the nugget, and the residual stress produced by spot welding will affect its propagation. To explore the influence of spot welding residual stress on fatigue crack propagation, a three-dimensional finite element simulation model of DP600 high strength steel spot welding joint was established. Based on the thermal-elastic-plastic theory, the residual stress field of spot welding was solved. On this basis, the local stress intensitv factor (SIF) solution of the kinked crack with and without residual stress was calculated. By analvzing the variation curve of the local stress intensity factor at the deepest point of the crack with the crack depth ratio under the two conditions, the influence of residual stress of spot welding on the propagation of kinked crack was studied. Based on the fracture mechanics theory, the improved two-parameter model is used to predict the fatigue life wit th and without residual stress. The results show that the residual stress of spot welding significantly increases the local stress intensity factor, and the influence of residual stress on it increases with the increase of crack depth ratio. Considering the residual stress, the overall crack propagation trend remains unchanged but the propagation rate increases significantly, and the fatigue life decreases from 35 616 times to 12 564 times.
- Published
- 2024
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