Homogeneização térmica e elástica de compósitos periódicos com interfases

Abstract

This work presents three-dimensional expansions of the parametric Finite Volume Theory (FVT) for thermal and thermoelastic homogenization of multiphasic composites with periodic microstructure of generalized architecture. The proposed and implemented micromechanical formulations look for, especially, the evaluation of thermal conductivity, elastic properties and thermal expansion coefficients of the mentioned periodic heterogeneous materials. To verify and validate the formulations, some cases involving composites reinforced by long fibers, short fibers and cubic particles are analyzed and discussed. In particular, the work emphasizes the presence of interphases located between the matrix and inclusions, because such interphases can strongly influence the macroscopic behavior of actual composites. The analyses involve investigations with respect to the influences of several factors on the thermal conductive and thermoelastic properties of composite materials. Among these factors, it can be cited: volume fraction of inclusions, fiber aspect ratio, inclusion size, physical properties and thickness of the interphases. The results of these evaluations are compared with others obtained by analytical formulations based on Fourier series, homogenization models that utilize Finite Element Method and, when available, experimental tests. These comparisons demonstrate a good performance of the developed formulations and strengthen the conclusion that, as already established in previous works, the Parametric Finite Volume Theory consists in an excellent numerical tool for the description of the behavior of heterogeneous materials, as well as, is a simple and versatile alternative to the traditional Finite Element Method. Also, it is worthwhile mentioning that the results of the analyses of the different cases of composites, here carried out, contribute to a best understanding about the relations between the macroscopic behaviors and the corresponding microstructural characteristics.