Analysis of fatigue crack propagation behavior in fillet welded T-joint

Abstract

In the fatigue analysis, the crack growth behavior in a two-dimensional welded T-joint was studied both numerically and experimentally. The geometric parameters were weld size, initial crack orientation and unsupported flange length. Crack growth direction was predicted using the minimum strain energy density factor theory. The results show that even though the fillet size and initial crack orientation affected the crack growth in the early stage, the cracks tended to converge when they entered the far-field stress region. This observation shows the initial period of crack growth could be distinguished from the rest of the propagation due to its crack growth behavior. There was reasonable agreement between the predicted and the experimentally observed crack growth paths. A correlation between the crack growth rate and the driving force parameter range was obtained for a T-joint constructed from hot-rolled AISI 1035 steel. A separate study showed that grain size had an insignificant effect on fatigue strength of the edge-cracked plate model.