Numerical Study on Weld Line Displacement in Rubber Pad Forming of Tailor Welded Blanks

Tailor welded blanks (TWBs) are increasingly used in the automotive and aerospace industries with the aim of reducing weight. Studying the forming processes of these sheets, examining their formability, as well as controlling factors such as the displacement of the weld line during forming can help to develop their application. The rubber pad forming process is a flexible forming process in which the sheet is deformed due to the pressure of a rigid punch with the help of a rubber cushion. In this paper, the rubber pad forming of tailor welded blank consisting of two welded sections with the same material but different thicknesses were simulated based on the finite element method and using ABAQUS software. The effects of various factors such as friction, thicknesses of the sheets that compose the TWB and the force applied to each section on the maximum displacement of the weld line were investigated through the use of a design of an experimental method. The results illustrated that increasing the thicknesses of the sheets that compose TWB, increasing the blank holding forces applied to each section, and reducing the friction between the TWB and the punch reduce the maximum amount of weld line displacement. In addition, increasing the thickness ratio of tailor welded blank led to an increase in the maximum weld line displacement. The simultaneous increase in the thickness of each section and the blank holding force applied to that section or the opposite section reduced the maximum amount of weld line displacement.