Method of using isotropic plasticity to model the forming of anisotropic sheet

摘要

A method of fabricating an article from a blank (12) of material (e.g., aluminum alloy sheet) having anisotropic deformation properties, with tooling (14) which has been designed by predicting flow and deformation of the blank (12) using an analysis which decouples the anisotropic deformation properties of the blank (12). The method calculates the response of a small amount of the blank (12) using crystal plasticity theory. The blank (12) can be represented as a mesh having a plurality of elements. A strain path is predicted for each element using finite element analysis (FEA), and a stress-strain curve is defined for each element by performing a material point simulator (MPS) calculation for each element using its respective strain path. A second FEA is then carried out on the elements using the respective stress-strain curve for each element. The stress-strain curve for each element may be defined by assigning to each element a curve which lies between an upper bound curve and a lower bound curve, using various methods. The computational model requires much less CPU time compared to prior art methods.