A new and general formulation of three-dimensional finite-volume micromechanics for particulate reinforced composites with viscoplastic phases

This paper presents a fully triply periodic version of finite-volume direct averaging micromechanics (FVDAM), enabling refined analysis of multiphase composites with arbitrary internal microstructures. Explicit three-dimensional FVDAM equations including plastic effects are derived. The surface-averaged continuity of displacements and tractions, and volume-averaged equilibrium equations are imposed based on the local/global stiffness approach. Further, the viscoplastic behavior for the composites can be modeled by incorporating state-variable-based Bodner-Partom constitutive model into the three-dimensional FVDAM framework. The presented model is used to simulate uniaxial tensile and strain cycling response of SiC/Al composites with various strain rates at room and high temperatures, respectively. Simultaneously, the microscopic stress and strain fields at different loading stages are also revealed in the simulations. The theoretical results agree well with the corresponding experimental data, indicating that the proposed model can predict the rate-dependent behavior of particulate reinforced composites reasonably.