A discrete element modelling approach for fatigue damage growth in cemented materials

Abstract

This study proposes a modelling approach capable of capturing both the fatigue response and localisation of failure in cemented materials. This modelling approach takes advantage of Discrete Element Method (DEM) to reproduce the heterogeneous microstructure and crack development in cemented materials. In conjunction with this, a new constitutive model is developed to characterise the fatigue behaviour of the materials at the grain scale. The model formulation is based on coupling damage mechanics and plasticity theory and combining with a fatigue damage evolution law to describe the degrading response of cemented materials subjected to cyclic loading. The proposed model is employed to govern the explicit behaviours of DEM bonding contacts representing cement bridges between aggregates in the physical materials. The macro-behaviour is then obtained in DEM simulations as the collective response of all contacts and particles in the material domain. Through numerical experiments, the proposed modelling approach is shown to capture well the fatigue behaviour and cracking process in cemented materials subjected to cyclic loading. The microstructural effects on the fatigue response of the materials are naturally reproduced in simulations thanks to the discrete nature of DEM. These results demonstrate the capability of the proposed modelling approach as well as its potential to be a faithfully numerical technique for modelling and investigating fatigue damage in cemented materials.