Modeling Microstructural Evolution in Particulate Composites under Compression: A Mean-Field Homogenization Approach

From the early strain stages, particulate composites can exhibit a nonlinear effective response even when their constituents exhibit linear behavior, due to microstructural rearrangements such as porosity reduction, reorientation, and particle shape evolution. This work proposes a constitutive multi-scale model aiming at obtaining the macroscopic response of multiphase composites (pores and inclusions) while taking into account, in an approximate manner, the evolution of their microstructure and its impact on the effective anisotropic response of said composites. For this purpose, an incremental model is developed in which the microstructural state is characterized by the volume fractions, aspect ratios, and orientation of the inclusions, whose evolution is governed by equations derived from kinematic relations and estimates of the average strain and rotation rates of each phase [1, 2]. The latter are obtained through a homogenization process using mean-field approaches such as Mori-Tanaka, Lielens, and the differential scheme ([3, 4, 5]), allowing for a computationally efficient integration of essential microstructural features. The effective response is eventually obtained via a tangential operator. The model thus developed is then applied to describe the compressive behavior of concretes with a porous matrix enriched with vegetal particles.

References

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