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An evolutionary state variable model is used to predict failure in sheet forming. The development of damage in aluminum sheet is characterized using Bammann's plasticity model. Simulations are carried out with the commercial code LS-Dyna3D. Using the limiting dome height test as an example, the prediction of failure in straining states of draw, plane strain, and stretch is made for AA 6111-T4 sheet. The location of failure and associated major/minor strains are contrasted with experimental forming limit curves. As a further example, the drawing of a square cup from a 5000 series alloy blank is simulated and compared with experimental data. The simulations accurately predict the location of failure and show limit strains which compare favorably with experiment. The damage variable provides a method for predicting the location and time of failure in a framework that accommodates general straining paths.

The aluminum alloy 2036 is presently being used in the production of automotive body panels. In the study presented, specimens of 2036-T4 with varying crystallographic textures were subjected to tensile testing and limiting dome height (LDH) evaluations in an effort to gauge the effect of texture on formability and stamping performance. To describe the texture, relative magnitudes of ideal texture components were derived from the orientation distribution function. Finite element analysis was used to study the effect of anisotropic properties due to texture on thinning in the LDH test. The impact of textural character on formability is discussed.