DEM study on the macro- and micromechanical behaviours of breakable granular materials under cyclic loading

Abstract

The effect of cyclic loading on the macro- and micromechanical behaviours of breakable granular materials was investigated via DEM. Breakable particle models composed of Voronoi cells with realistic shapes were constructed. A series of confined cyclic loading tests were performed at different loading amplitudes. The macroscopic deformation behaviours were investigated in terms of the cumulative plastic strain and dynamic resilience modulus. Then, particle breakage characteristics, including the extent of particle breakage, crack orientation distribution, breakage pattern and correlation between the particle breakage and energy input, were explored. Furthermore, micromechanical results, including the coordination number, sliding contact and contact orientation anisotropy, were examined. It is found that both particle breakage and cumulative plastic strain increase rapidly in the early stage of loading. In the stable state, both showed an S-shaped increase with increasing loading amplitude. This study highlights that particle breakage is one of the main sources of permanent deformation.