A FFT-based plastic model of heterogeneous rock-like geomaterials considering micro-void evolution

Abstract

This study focuses on the evaluation of the effective elastoplastic properties of heterogeneous rock-like geomaterials with a porous-matrix inclusion system. To investigate its effective elastoplastic properties, the material is divided into two scales. At the microscale, the porous matrix contains randomly distributed spherical micro-voids and the a solid phase, which satisfies the Drucker–Prager criterion, then. its yield behavior is described under an analytical strength-homogenization criterion of porous media. In addition, an extended evolution of micro-porosity is introduced to consider the influence of micro-void nucleation, growth, and coalescence. At the mesoscale, the material consists of a continuous porous matrix and embedded mineral inclusions. Using the two-scale heterogeneous characteristics, we develop a two-step homogenization process to determine the macroscopic mechanical properties of the material by combining with a Fast Fourier Transform-based numerical homogenization at the mesoscale and the analytical strength-homogenization method at the micro-scale. A series of numerical studies is conducted to clarify the influence of the micro-void evolution and meso inclusion on the macroscopic mechanical properties. The numerical results show that the proposed model can capture the main features of the studied geomaterial with a porous-matrix inclusion microstructure.