Determination of residual stresses in tailored welded blanks with thickness transition for crack assessment

Residual stresses play a major role in the characterization of welded structures. The Cut-Compliance-method uses fracture mechanics principles and delivers stress intensity factors caused by the residual stresses, which is convenient for the evaluation of components that contain a crack. As sheets with different gauge were friction stir welded (FSW) a geometry with thickness transition evolved. Hence, the required influence function for the Cut-Compliance-method was derived for specimens with thickness transition by means of finite element simulations with fracture mechanical analysis. In order to compute residual stress profiles for the geometry with thickness transition, a weight function solution has been determined as well. Consequently, experimental data in terms of residual stress profiles and corresponding stress intensity factor distribution are obtained and presented in the paper for a FSW butt joint of an AlMgSc alloy (AA5028-H116) with identical and different sheet thicknesses.