Weld zone representation methods during the stretching of friction stir welded blanks with dissimilar sheet thickness: A study using numerical simulations

摘要

In this work, the validity of weld zone representation as single zone or double zone under varied weld conditions of friction stir welded (FSW) blanks with dissimilar thicknesses sheets is explored. During LDH test simulations, representative base material of 1.5 mm and 1.1 mm thickness is considered. It is observed that modeling FSW blanks with double zone assumption plays a vital role for accurate formability prediction. There are possibilities of obtaining multiple domains of weld conditions for the single zone and double zone assumption validity. The failure locations also affect the weld zone representation along with the critical error percentage difference between reference model (single zone) and double zone model FSW blanks. The number of single zone models has increased in transverse weld orientation and number of double zone models has increased in longitudinal weld orientation in the case of FSW blanks with dissimilar thickness as compared to similar thickness FSW blanks. A comparison is done between the limit strain values for single zone and double zone assumptions with reference model. The pattern that is observed in the load-punch stroke behavior is also seen in limit strain comparison for weld zone representation.