Thermo-mechanical modelling of welding with experimental verification

Sammanfattning: Residual stresses and deformations after welding were studied numerically and experimentally. The numerical simulations were performed using the finite element method. In the calculations a thermoelastoplastic material model was used. This means that temperature dependence of material properties and volume changes due to phase transformations were considered. Different finite element models of welded structures were investigated. In these models brick elements, shell elements, plane elements and a combination of brick elements and shell elements were used. The results achieved in the finite element simulations were evaluated by experimental measurements. The neutron diffraction technique and the hole-drilling strain gauge method were utilized for the determination of residual stresses. Also transient measurements of strains were performed. The residual diametrical shrinkage after circumferential welding of a pipe was measured and compared to calculated results.