Anisotropy of the elastic modulus for hybrid composites reinforced by short fibers and particles with respect to material porosity

Hybrid composites reinforced by short fibers and particles (HCRSFPs) have been widely used in many fields, and more and more scholars are paying attention to hybrid composites. In this study, the elastic moduli of HCRSFPs in arbitrarily chosen directions were investigated with respect to their porosities. A material model was built with the assumption of a compound of particles and polymer matrix containing voids as an effective matrix, and the HCRSFPs were treated as the compound of short fibers and the effective matrix. With consideration of the three-dimensional spatial orientation distribution and the length distribution of the short fibers, the laminate analog approach and the Halpin-Tsai model were used to predict the elastic moduli of the HCRSFPs. Numerical examples and analyses showed that the fiber orientation distribution, reinforcement volume fraction, and porosity had great effects on the elastic moduli of the HCRSFPs. (C) 2016 Wiley Periodicals, Inc.