Crack propagation behavior of different zones in weldment under creep-fatigue loadings

In this paper, crack propagation behaviors in a weldment are simulated under cyclic loadings using crystal plasticity finite element coupled with the XFEM. The result shows that the cracks in heat affected zone grow faster than that in the welded zone. Short crack propagation dominated by dislocation activity takes approximately 4 to 5 grains, followed by long crack propagation which is unrelated to dislocation activity and the growth direction kept an angle to the loading direction (45°-51°). Experimentally observed deflections within grains and at grain boundaries, retardation at grain boundaries are captured by the simulation.