Correction Factors for the Analytical Transverse Stiffness of Unidirectional Fiber Composites

Abstract

An analytical expression for the transverse elastic stiffness of unidirectional fiber composites is developed in this paper. Based on a basic solution adopting 1D analysis of square fiber cross-section, analytical results from (i) simplified 3D analysis using square fiber cross-section, and (ii) 1D analysis using circular fiber cross-section lead to Poisson’s ratio and geometrical correction, respectively. The Poisson’s ratio correction factor is shown to be a factor to the Young’s Modulus of matrix material while the geometrical correction factor is shown to be a factor to the fiber volume fraction. A geometrical correction function, which describes the fiber-matrix boundary with respect to the representative volume element, is identified. This function transforms results based on square fiber to those of circular fiber cross-section. Comparison of the Poisson’s ratio and geometrically corrected transverse moduli to experimental results reveal good agreement.