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This paper examines a history of numerical methods for evaluating drawbeads in sheet metal forming, from early work with Dr. Sing Tang at the Ford Scientific Research Laboratory on special purpose drawbead simulation software, to modern general purpose software simulations incorporating analytic drawbeads in full 3D sheet forming analyses. Future directions in the field are explored through an example utilizing nonlinear optimization for drawbead design.

This work compares the relative importance of material anisotropy in sheet forming as compared to other material and process variables. The comparison is made quantitative by the use of normalized dependencies of depth to failure (forming limit is reached) on various measures of anisotropy, as well as strain and rate sensitivity, friction, and tooling. Comparisons are made for a variety of forming processes examined previously in the literature as well as two examples of complex stampings in this work. The examples cover a range from nearly pure draw to nearly pure stretch situations, and show that for materials following a quadratic yield criterion, anisotropy is among the most sensitive parameters influencing formability. For materials following higher-exponent yield criteria, the dependency is milder but is still of the order of most other process parameters.