Effective Moduli of Woven Composites

Abstract

The objectives of this paper are: (1) to identify the dominant characteristics of a weave that govern the engineering properties; (2) to explain why certain behaviors of weave are observed; and (3) to evaluate a very simple building block strategy for estimating the effects of waviness on engineering properties. Based on the hypothesis that complexities in the mechanical response are encapsulated in the wavy regions, factors such as undulated tow length and material rotation angles are investigated to see how they affect the effective properties as a function of waviness. Simple formulas that ignore the “bridging effects” are proposed for Exx, Ezz,. xz and Gxz. Results from the simple formulas are compared with three-dimensional finite element results for three satin weaves and a twill weave and for two material systems.