Three-dimensional modeling of woven-fabric composites for effective thermo-mechanical and thermal properties

This paper presents effective thermo-mechanical and thermal properties of plain-weave fabric-reinforced composite laminates obtained from micromechanical analyses and a two-scale asymptotic homogenization theory. A unit cell, enclosing the characteristic periodic repeat pattern in the fabric weave, is isolated and modeled. The orthotropic tensors for effective mechanical stiffness, coefficient of thermal expansion and thermal conductivity are obtained by numerically solving appropriate microscale boundary value problems (BVPs) in the unit cell by the use of three-dimensional finite element analyses. Further, analytical models consisting of series-parallel thermal resistance networks are developed in order, to obtain orthotropic thermal conductivity. The numerical and analytical models are explicitly based on the properties of the constituent materials and three-dimensional features of the weave style. Results obtained from the models are compared with experimental values and with models available in the literature. Non-linear mechanical constitutive behavior due to resin stress/strain non-linearity and to transverse yarn damage under in-plane uni-axial loads are also investigated. Parametric studies are conducted to examine the effect of varying fiber volume fractions on the effective thermal properties.