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| Influence of Welding Residual Stresses on Crack Growth of Fillet Joints |
| Received:January 14, 2023 Revised:April 15, 2023 |
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| DOI：10.7643/issn.1672-9242.2023.07.019 |
| KeyWord:welded joint residual stresses stress intensity factor fatigue crack growth finite element analysis |
| Author | Institution |
| JIAN Hao-chen |
School of Mechanical Engineering, Southwest Jiaotong University, Chengdu , China |
| LU Yao-hui |
School of Mechanical Engineering, Southwest Jiaotong University, Chengdu , China |
| AI Jin-peng |
School of Mechanical Engineering, Southwest Jiaotong University, Chengdu , China |
| ZHANG Ya-dong |
School of Mechanical Engineering, Southwest Jiaotong University, Chengdu , China |
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| Abstract: |
| The work aims to analyze the influence of welding residual stresses on the crack growth of fillet joints. A finite element model of fillet joints was established based on the thermal elastic plastic mechanics, the welding temperature field was calculated, and the welding residual stresses were obtained through thermal mechanical coupling. The fracture mechanics method was used to analyze the stress intensity factor and crack growth rate at the weld toe. The influence of residual stresses on crack growth was compared. The calculated residual stresses of the weld reached the material yield limit and were in a tensile stress state, with Von Mises stress of 345 MPa. Under the stress range of 200 MPa, taking residual stresses into account, data obtained from literature tests and data from IIW standards were used as crack growth parameters, the crack growth life was 2.61×106 and 6.84×105 cycles respectively when stress ratio R=–1; when stress ratio R=0, the crack growth life was 1.16×105 and 2.90×104 cycles respectively. Residual stresses will accelerate crack growth. The control various methods can be used to set the stress range to a constant value. The range of stress intensity factor is enlarged by the residual stresses in the case of the stress ratio R<0. The maximum stress intensity factor is increased after combining the residual stresses under the stress ratio R>0, which is closer to the fracture toughness of the material. Moreover, the average value of stress intensity factor or stress ratio R is changed by the tensile residual stresses. So the crack growth rate is accelerated in this condition. With the increase of crack length, the influence of residual stresses on crack growth rate will increase. Both load and residual stresses have an influence on crack growth, the influence mechanism of stress ratio R and residual stresses on crack growth is the same. Two influencing factors need to be comprehensively considered in the life assessment of welded structures. |
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