Abstract
The microstructure-based finite element modeling (MB-FEM) of material representative volume element (RVE) is a widely used tool in the characterization and design of various composites. However, the MB-FEM has a number of deficiencies, e.g., time-consuming in the generation of a workable geometric model, challenge in achieving high volume-fractions of inclusions, and poor quality of finite element mesh. In this paper, we first demonstrate that for particulate composites the particle inclusions have homogeneous distribution and random orientation, and if the ratio of particle characteristic length to RVE size is adequately small, elastic properties characterized from the RVE are independent of particle shape and size. Based on this fact, we propose a microstructure-free finite element modeling (MF-FEM) approach to eliminate the deficiencies of the MB-FEM. The MF-FEM first generates a uniform mesh of brick elements for the RVE, and then a number of the elements, with their total volume determined by the desired volume fraction of inclusions, is randomly selected and assigned with the material properties of the inclusions; the rest of the elements are set to have the material properties of the matrix. Numerical comparison showed that the MF-FEM has a similar accuracy as the MB-FEM in the predicted properties. The MF-FEM was validated against experimental data reported in the literature and compared with the widely used micromechanical models. The results show that for a composite with small contrast of phase properties, the MF-FEM has excellent agreement with both the experimental data and the micromechanical models. However, for a composite that has large contrast of phase properties and high volume-fraction of inclusions, there exist significant differences between the MF-FEM and the micromechanical models. The proposed MF-FEM may become a more effective tool than the MB-FEM for material engineers to design novel composites.
Highlights
Particulate composites are widely used in industrial products and engineering structures due to their merits, such as ease-of-manufacturing and great design flexibility
Analytical solutions developed from micromechanics models are convenient and efficient; they have various limitations in application because they are based on special assumptions regarding composite microstructure
The validity of the hypothesis demonstrated in the previous section justifies the idea of microstructure-free finite element modeling (MF-FEM) for particulate composites
Summary
Particulate composites are widely used in industrial products and engineering structures due to their merits, such as ease-of-manufacturing and great design flexibility. To eliminate the limitations of the conventional MB-FEM for the characterization and design of fine-particulate composites, we first demonstrate that if the size ratio of inclusion to RVE is adequately small, elastic properties of RVE computed by finite element modeling are independent of inclusion shape and size. Based on this fact, we propose microstructure-free finite element modeling (MF-FEM). To study the effect of inclusion shape and size on the elastic properties of particulate composites, the following assumptions are made: (1) the materials of the matrix and the inclusions are homogeneous, isotropic, and perfectly bond to each other; (2) the distribution and orientation of inclusions of small aspect ratio are statistically homogeneous;.
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