Prediction of strain distribution in aluminum tailor welded blanks for different welding techniques

The numerical prediction of strain distribution in multi-gauge, aluminum al loy sheet tailor welded blanks (TWBs) is undertaken using the explicit dyna mic finite element code LS-DYNA. The limiting dome height test (LDH) is mod eled considering three gauge combinations: 2mm to 1mm, 2mm to 1.6mm and 1.6 mm to 1mm and various weld line orientations relative to loading direction. Two welding techniques are considered: non-vacuum electron beam (NVEB) and dual beam Nd:YAG. Formability data is presented in terms of limiting dome height to failure measurements, as well as measured limit strains and indic ates that the Nd:YAG process is superior to the NVEB process considered. In general, the model agrees with measured strain distributions relatively we ll, particularly in cases when weld failure dominates as in the NVEB welds. The model is overly conservative, however, for the higher performance Nd:Y AG-welded blanks which generally fail in the thinner parent metal away from the fusion zone. The shell element-based model fails to capture through-th ickness constraint effects near the weld and consequently localizes in the row of elements immediately adjacent to the weld line.