Modelling low-cycle fatigue tests using a gradient-enhanced continuum damage model

Abstract

This study is concerned with the modelling of uniaxial low-cycle fatigue tests using a gradient-enhanced continuum damage model. The aim of the paper is to show that a simple but adequate description can be performed using such kind of phenomenological approach. The model accounts for the coupling between plasticity and damage, including a mathematically consistent description of the softening behaviour and size dependency. It successfully predicts low-cycle fatigue and can deal with regular cycles. A consistent procedure to identify experimentally the constitutive parameters that appear in the theory is proposed. Lifetime predictions for different loading amplitudes are compared with experimental data for two aluminium alloys showing a good agreement. The one-dimensional model can be interpreted as a particular version of a more general gradient-enhanced damage model, which is summarized at the end of the paper.