Characterising Fatigue Behaviour of Nodular Cast Iron Using Micromechanical Simulations

Abstract

Elastic-plastic porous materials experience an increase in the mean void volume fraction when they are subjected to cyclic loading. This behavior is known both from the experiments and simulations in the literature. The authors have first time used this mechanism for the evaluation of the fatigue life in nodular cast iron. In this contribution, the stress-life approach is presented for the characterization of fatigue failure. For this purpose, micromechanical finite-element simulations are carried out using the axisymmetric cell model. The cell model having isotropic/non-linear kinematic hardening behavior is subjected to fully reversed cyclic stress controlled loading. The finite element simulations are carried out cycle by cycle until the final failure of the cell model. The numbers of cycles to failure are extracted from the simulations. The stress-life curves are shown for spherical and elliptical graphite particle cell models. The results of the micromechanical simulations are in qualitative agreement with the typical experimental stress-life curves.