Plastic waves of combined stress based on self-consistent slip models (Q1168805)

A computational procedure for obtaining the macroscopic, rate-independent stress-strain behavior of a polycrystalline metal from the plastic flow characteristics of the slip systems of a large number of randomly oriented single crystals is extended to cases of combined stress loading. The procedure, based on the simplex method of linear programming, is applied to the computation of simple wave solutions for combined longitudinal and torsional plastic wave propagation in thin-walled cylindrical tubes. The solutions obtained are in better agreement with results from experiments on aluminium alloy tubes than solutions obtained by assuming an isotropic work-hardening material. The intermediate constant state region, which is predicted by the latter theory but not observed in the experiments, is not obtained for the theory based on the slip model.