Abstract: Stress intensity factors (SIFs) for weld root crack of T-butt joints are researched. Semi-ellipse crack models for weld root of T-butt joints are built with finite model. Geometric parameters and boundary conditions are established according to finite model. Singular element method is used to simulate stress singularity of crack tip with finite element calculation. Element size of crack tip is obtained by convergence experiment. Calculation results show that, SIFs of crack tip have regularity for different initial crack size under same load, and the importance of different geometric parameters affect SIF is different. Therefore, some geometric parameters must be focused on fatigue research for weld root of T-butt joint. The simulation results are fitted by multiple linear regression method. These results could provide a valuable reference for further research of crack propagation and fatigue life prediction.

Key words: Stress intensity factor, T-butt joints, Weld root