A finite element model for the Portevin-Le Chatelier effect based on polycrystal plasticity

摘要

A polycrystal plasticity model, embedded in a finite element framework, is used to describe the Portevin-Le Chatelier effect in a velocity controlled tension test. The transition from continuous to discontinuous band propagation is captured as the applied strain rate is decreased. Statistical analysis of the stress drops also indicate power law distributions for continuous propagation shifting to peaked distributions at lower strain rates, consistent with experimental observations. The model requires no 'artificial' initial inhomogeneity since spatial gradients exist naturally due to grain incompatibilities. [References: 29]