Stiffening of cambered sheet metal designs: numeric bead optimization by a coupled algorithm considering nonlinear forming limits

点击翻译按钮获取中文摘要

Beads are used in deep drawn sheet metal parts for increasing the part stiffness. Thus reductions of sheet metal thickness and consequently weight reduction can be reached. Style guides for types and positions of beads exist, which are often applied. However, higher stiffness effects can be realized using numeric optimization. Existing algorithms for the optimization of beads have disadvantages concerning the relationship between computing times and stiffening effect. Manufacturing processes as well as the geometry of the sheet metal part are also not taken into account sufficiently by these algorithms.Within this research project, an optimization method will be developed which combines the advantages of two different optimization strategies and furthermore considers the manufacturing process of cupping with an additional deep drawing of beads. The bead paths will be determined with a cost-efficient optimality criteria-based (OC) method, the bead profile parameters will be detected by a sensitivity-based optimization method. This combination of two different optimization strategies also allows the consideration of the maximum formability under justifiable computational costs.The optimization algorithm to be developed considers the two-stepped manufacturing process consisting of deep drawing and beading. The formability in both manufacturing steps represents a limiting factor. Considering nonlinear strain paths, acceptable geometry and process parameters will be determined in numerical and experimental tests. These will be integrated in the optimization algorithm. Furthermore the algorithm considers the effect of beads on the stiffness according to the camber of the deep drawn geometry. This will also be verified using simulation and experiment.