Wall Wrinkling Analysis of TWBs during the Deep Drawing Process

Wrinkling is one of the most troublesome modes of failure in sheet forming mainly because of the trend towards thinner, high-strength sheet metals. In this regard, prediction of wrinkling during forming processes is mandatory. In the current research, wall wrinkling of tailor welded blanks (TWBs) with thickness ratio greater than l was considered. TWB consisted of interstitial free (IF) steels with different thicknesses (0.8 and 1.2 mm) was analyzed analytically, numerically and experimentally. Due to more formability of thin segment with respect to weld and thick segment which results in deflection of the thin segment, the principal stress directions were assumed to bedeviated from the principal curvature axes. ‘ ‘Autogrid’ ’ software was applied to measure the geometrical data and strains during the experiments. The predicted results about punch stroke value and critical strain at wrinkling onset were in good agreement with experimental results. The results also showed that wrinkle waves just formed in thin segment of TWB.