Modeling and simulation of the forming of aluminum sheet alloys

With advances in computer hardware and software, it is possible to model material processing, product manufacturing, product performance in service, and failure. Although the fine-tuning of product manufacturing and performance is empirical, modeling can be an efficient tool to guide and optimize design, to evaluate material attributes, and to predict lifetime and failure. Moreover, modeling can be used as a research tool for a more fundamental understanding of physical phenomena that can result in the development of improved or new products. This article is concerned with the numerical simulation of the forming of aluminum alloy sheet metals. In order to design a process for a specific material, it is necessary to account for the attributes of the material in the simulations. Although the numerical methods are generic and can be applied to any material, constitutive models, that is, the mathematical descriptions of material behavior, are material-specific. Therefore, macroscopic and microscopic aspects of the plastic behavior of aluminum alloys are reviewed first. The following are then discussed to cover theoretical and implementation aspects of sheet metal forming simulation: Constitutive equations suitable for the description of aluminum alloy sheets; Testing procedures and analysis methods used to measure the relevant data needed to identify the material coefficients; Tensile and compressive instabilities in sheet forming. For tensile instability, both strain- and stress-based forming-limit curves are discussed; Springback analysis; Finite Element (FE) formulation; Stress-integration procedures for both continuum and crystal-plasticity mechanics; and Finite element design. Finally, various examples of the simulation of aluminum sheet forming are presented. These examples include earing in cup drawing, wrinkling, automotive stamping, hemming, hydroforming, and clam-shell-resistant design via FE analysis and the Taguchi optimization method