Homogeneização de compósitos reforçados por fibras considerando efeitos de interfases

Abstract

Considering the important applications of fiber-reinforced composite materials in engineering, the characterization of these materials is a highly relevant topic. Within this field of study, homogenization techniques present a great applicability potential. Due to the difficulties of knowing precisely the details of the microstructure of such materials, the strategy of replacing the real medium with another equivalent homogenized stands out as a practical solution. Among these techniques, micromechanical modeling stands out. Thus, the micromechanical models find wide application in the characterization of fibers reinforced composites. In this context, this work aims to present homogenization techniques applied in composites reinforced by short and long fibers for determination of effective thermoelastic properties. The influence of the interphases on the effective properties of composites reinforced by unidirectional long fibers is studied, as well as the influence of fiber orientation and aspect ratio on composites reinforced by randomly distributed short fibers. For materials with randomly distributed fibers, analytical models are used while for materials with periodic distribution, the finite element method is used in addition to the analytical models. Results are verified through several examples using experimental data available in the literature or by comparison of methods. The comparison of the results allows to evaluate the influence of the aspect ratio, radius size and fiber orientation on composites reinforced by randomly distributed short fibers; besides to verify the influence of the interphases, the thickness of the interphase and the size of the radius in composites reinforced by unidirectional long fibers.