Micromechanical modeling of particle breakage of granular materials in the framework of thermomechanics

The particle breakage of granular materials under compression is a phenomenon of great importance. In this paper, a micromechanically based model for the compression of crushable granular materials is developed in the framework of thermomechanics. Both the internal and dissipative energies in the model are derived using the micro-macro volume averaging approach to ensure that all parameters involved have concrete physical meanings. The particle breakage is quantified by the change of the maximum particle size, the size polydispersity and the fractal dimension of the gradation. Compared to other breakage models, there is a major difference that highlights the novelty of the proposed model: neither the ultimate particle size distribution, nor the evolution path of the gradation is predefined in the model. The initiation, evolution and the attenuation of the breakage can be determined by the maximum dissipation principle using thermomechanics and micromechanics. Finally, it is demonstrated that the proposed model can predict the stress dependence of the elastic bulk modulus, the size dependence of the yielding stress and the elastic-plastic-pseudoelastic phase transition of granular materials.