Evaluation of longitudinal residual stress variations along the thickness of welded joint of 5086 aluminum alloy

Welding residual stresses, especially longitudinal ones, have a significant role in the fatigue and fracture of the structures. The common residual stress measurement methods have an important restriction that they are incapable in measuring the residual stresses versus depth. In this study, the combination of FEM simulation and X-ray diffraction experimental method has been used for residual stress measurement along specimen depth. Residual stresses were induced by the TIG welding of two 5086 aluminum plates with a thickness of 8 mm. The welding process was simulated in Abaqus and then the simulation results were validated with X-ray diffraction ones. It was observed that in weld centerline, by increasing depth, maximum longitudinal residual stresses decreased by 37 MPa while this reduction in heat affected zone and in the distance of 10 to 25 mm from the weld centerline was 70 MPa. At farther points from the weld centerline, the longitudinal residual stresses decreased and the compressive residual stresses were formed in the specimen depths. With respect to significant variation of residual stress along the depths of the specimen, residual stress measurement along specimen depths seems to be necessary for performing accurate analysis.