Theoretical crack growth prediction model for thick plate butt welding joints based on stress/strain transitions

A short time scale fatigue crack growth model for butt welding joints that considers the influence of welding residual stress is presented here. The reliability of the proposed model is verified by means of fatigue experiments of mode I crack growth under the influence of residual stress. The results demonstrate that changes in the residual stress distribution in the thickness direction are small on the symmetric plane of the weld line, and the residual stress distribution in the same direction of external load is non-negligible. The crack growth behavior in the weld line fluctuates with respect to time, and the theoretical prediction curve is in good agreement with the experimental data during the early and middle stages of crack growth. This study provides a theoretical basis for predicting the fatigue life of welded parts involving relatively thick plate.