ANALYSIS OF FATIGUE CRACK-PROPAGATION BEHAVIOR IN FILLET-WELDED T-JOINTS - EXPERIMENTAL-OBSERVATION OF CRACK-GROWTH UNDER VARIOUS LOADING CONDITIONS HELPS TO DEVELOP PREDICTIVE MODEL

Abstract

Using fatigue analysis, 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 model was compared with an inclined crack in a thin plate of finite width.

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. Using this observation shows the initial period of crack growth could be distinguished from the rest of the propagations.

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 construction from hot-rolled AISI 1035 steel.