On modeling of the weld line in finite element analyses of tailor-welded blank forming operations

Finite element analyses of standard tailor-welded blank (TWB) forming tests were performed to determine the effects of weld modeling techniques on simulation results. Finite element models of TWBs were created that either included a simple representation of the weld properties and geometry or excluded both weld geometry or material properties. In all models, shell elements were used to represent parent materials of the TWB. The models excluding weld properties and geometry used nodal rigid bodies to join the thin and thick parent materials. The models including weld properties and geometry used solid elements for the weld materials, and a novel method for joining shells to solids. Simulations of three standard metal forming tests were performed: ASTM tensile test, in-plane plane strain test, and limiting dome height tests representing various biaxial strain states including: uniaxial tension, plane strain and biaxial tension. Results indicate that there are a number of relatively subtle effects associated with the manner in which the weld line is modeled. Most of these effects relate to the constraining effect of the weld line with respect to strain along the axis of the weld line.