Modelling the plastic behaviour of metals under complex loading conditions

Aluminium alloys and low carbon steel exhibit a transient work-hardening rate when the strain path is abruptly modified. The underlying physical mechanisms are latent hardening in the case of cross-loading and massive disappearance of the dislocations pertaining to prestrain when the loading stress is reversed. The modelling approach previously proposed for strain reversal is extended to cross-loading. In the model, the work-hardening rate is controlled by the evolutionary laws of three dislocation densities related to forward, backward and cross-loading. A parameter which measures the amplitude of the strain path change is incorporated in this approach. It is believed that these three densities are sufficient to model many cases consisting of two stage strain paths.X112539sciescopu