NONPROPORTIONAL CYCLIC HARDENING OF POLYCRYSTALLINE MATERIALS

A previously proposed single crystal hardening law is applied to the p rediction of responses of polycrystalline material under non-proportio nal cyclic loading. In this paper, the Kroner, Budiansky and Wu model is adopted and the relevant numerical schemes for both the iteration r elated to the nonproportional loading paths acid the search of active slip systems are established. Two typical engineering materials: oxyge n-free, high-conductivity (OFHC) copper and 316 stainless steel, which differ greatly from each other in microstructure, are used for predic tions and comparisons with experiments. Loading paths include the symm etric tension-compression cycle, the circular cycle and the rectangula r cycle. The behaviour of 316 stainless steel, at both room and elevat ed temperature is modelled. Comparisons show that the predictions are in quantitative agreement with the corresponding experiments for all t he cases mentioned above. In addition, comparisons of different single crystal hardening laws are also presented.