Fatigue life prediction under variable amplitude loading using a microplasticity-based constitutive model

Abstract

We predict the fatigue life of a P355NL1 steel alloy under variable amplitude loading conditions using a newly-developed small-strain-based implicit plasticity model. The core idea behind the fatigue model is its capability to capture the inelastic work dissipation due to microplasticity whose critical value determines the fatigue life. Fatigue tests under different variable amplitude load spectra are simulated numerically and the results are compared with experimental data as well as other models for fatigue. It is shown that the model is able to describe the experimental data better than current empirical approaches, using only a few measured, physically motivated parameters.