An anomalous compression-induced softening behavior of AA6014-T4P during cyclic loading

This paper investigated the cyclic plasticity of AA6014-T4P with the tension-compression (T-C) and compression -tension (C-T) cyclic loading tests. A new compression-induced softening behavior is found and modeled. Spe-cifically, the material was softened permanently during the tensile load when a compressive pre-strain was applied, whereas such an abnormal phenomenon was not observed when the loading sequence is reversed. Moreover, the magnitude of the permanent softening scale linearly with the compressive pre strain. Therefore, we term this phenomenon as compression-induced softening in this paper. Based on this compression-induced softening phenomena, a modified Y-U model is formulated by introducing a correction factor that modifies the hardening rate of the boundary surface to describe the permanent softening effect, which can predict the compression-induced softening well. Our work reveals a new phenomenon for the cyclic loading of metal sheets and stimulates further efforts on the path-dependence of metal plasticity.

Automated summary

This paper investigates a new phenomenon in the cyclic plasticity of AA6014-T4P, namely compression-induced softening, and presents a modified Y-U model to predict this effect. The permanent softening magnitude is found to have a linear relationship with the compressive pre-strain.