Mechanical constraint effect on residual stress and distortion in T-fillet welds by three-dimensional finite element analysis

Severe local heating and the mechanical constraints caused by the initial tack welding or clamping of parts to be arc-welded create undesirable residual stress or distortion in the parts. A three-dimensional model using a finite element method has been developed for the analysis of T-fillet welds with initially different tack-welded types. The temperature-dependent material properties, linear strain hardening, and Von-Mises yield criterion were applied in an uncoupled thermal and mechanical analyses, and the heat source of the weld has been modeled by a combination of volumetric and surface heat flux. The reliability of the modeling procedure has been verified with temperature, displacement, and residual stress measurements found in the literature and from experiments. The results show that the residual stresses and the extent of distortion are influenced by the type of constraint. The residual stress could be reduced but at the expense of enhanced distortion.