Utilization of thermo-elasto-plastic analysis of welding eigenstrain for improvement of the bead flush method

Measurement of welding residual stresses is one of important tasks to assess the structural integrity of welded structures. By now, authors have proposed a new nondestructive evaluation method of welding residual stresses called the bead flush method, and confirmed its utility for simple welded plates by numerical simulations and experiments. In this method, eigenstrains are determined by the inverse analysis using released strains measured during removing reinforcement of weld. And then residual stresses are calculated by simple FEM analyses using eigenstrains determined above. For wider applicability and higher accuracy of this method, eigenstrain field should be determined accurately beforehand in the inverse analysis. Therefore, in this paper, a concept how solution sets of eigenstrains are determined in the inverse analysis is proposed. Based on this concept, influencing factors of welding eigenstrains are investigated and relations between welding eigenstrains and residual stresses are made clear by the thermo-elasto-plastic analysis.