FINITE-ELEMENT SIMULATION AND MEASUREMENT OF WELDING RESIDUAL-STRESSES

Residual strains and stresses in a hollow steel beam that had been wel ded to a D-shaped cross-section have been simulated by plane deformati on finite element models and compared with experimental measurements o btained using the neutron diffraction strain-scanning technique. Neutr on strain scanning, in contrast to other experimental techniques, is c apable of measuring, accurately, non-destructively and in detail, the internal strain state at selected locations and directions within a co mponent. This makes it a preferred method for validating model calcula tions of strain and stress distributions in components. In the finite element simulations a plane deformation model incorporating temperatur e-dependent material properties was adopted. With the assumptions for material properties that were made, the plane deformation model predic ts the overall bending of the beam and the overall residual strains an d stresses reasonably well. Locally, in the weld metal the predicted r esidual strains and stresses depend very much on the values of the the rmal strain, which in one simulation include volume changes due to sol id-state phase transformations. In the other simulation presented here the volume changes due to solid-state phase transformations were not accounted for.