Finite element evaluation of residual stresses in thick plates

This paper makes use of the Finite Elements Method (FEM) to study and analyze residual stresses in the cold bending and welding of thick plates. The welding model consists of two steps: first, performing of the thermal transient analysis model; and second, the carrying out of the mechanical transient analysis based on the temperature pattern at each node on each particular time. Used in these models is the inelastic temperature-dependent material. The output of the model includes residual stresses and permanent distortion; these were then compared with verified experimental results. The validated model and the results exhibit satisfactory agreement up to a 15-percent difference. As for the cold bending of thick plates, it is modeled using another finite element model and the residual stresses and permanent curvature of the thick plates are computed numerically. Again, the FEM model was validated against some official experimental results and satisfactory agreement between them was observed. Finally, the effects of these two different sources of residual stresses were combined, the combined effects established, and the results then discussed.