Application of Thickness Gradient Based Necking Criterion to Investigate the Influence of Weld Configuration on the Forming Limit of Tailor Welded Blanks

摘要

The application of thickness gradient based necking criterion to understand the effect of weld conditions on the forming limit of TWB is explored in this paper. The weld conditions considered for the analysis are weld-base material property combination, weld orientation and weld location. Limiting Dome Height (LDH) test is simulated using PAM STAMP 2G, an elastic-plastic finite element code and limit strains of un-welded, welded blanks are predicted using thickness gradient based necking criterion. Transverse weld has insignificant effect on the limit strains when it is placed at the centre of the sheet. In the case of transverse weld placed at critical locations of the sheet, decrease in limit strains is observed. In other cases, weld properties show negligible influence on the forming limit strains of transverse welded blanks. Longitudinal weld has significant effect on the limit strains of TWB depending on the weld properties and strain path. However, the overall FLC of longitudinal welded blank is by and large similar to that of un-welded blank. Some of the simulation results are found to be consistent with the available experimental observations qualitatively.