Simulation of fatigue crack growth behavior in welded plates considering different material properties of weld and base metals

Simulation method of fatigue crack growth considering material discontinuity was developed based on Abaqus, Zencrack and relevant user subroutines to accurately describe the fatigue crack growth behavior in welded structures. For initial embedded cracks located in weld region of a welded plate, faitigue crack growth simulations with different matching strengths between weld and base metal were carried out, and the influence of different matching strengths on fatigue crack growth life and characteristic for the welded structure were invesgated. It is found that distinct differences of SIF calculation results are obtained once the crack propagate from weld to base metals. Also, the difference gradually increases with increasing the crack size. As the values of crack growth parameters in weld are increasing, the relative crack growth rate of the crack located in the base metal decreases gradually and the crack shape transits from round to flat. In contrast, the relative crack growth rate in the base metal increases gradually, and the crack shape transits from round to ellipse. The present simulation method can provide an effictive way to accurately predict crack evolution in multi-materials of welded structures.