3-DIMENSIONAL MODELING OF WOVEN-FABRIC COMPOSITES FOR EFFECTIVE THERMOMECHANICAL AND THERMAL-PROPERTIES

This paper presents effective thermo-mechanical and thermal properties of plain-weave fabric-reinforced composite laminates obtained from mi cromechanical analyses and a two-scale asymptotic homogenization theor y. A unit cell, enclosing the characteristic periodic repeat pattern i n the fabric weave, is isolated and modeled. The orthotropic tensors f or effective mechanical stiffness, coefficient of thermal expansion an d 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 mod els consisting of series-parallel thermal resistance networks are deve loped in order, to obtain orthotropic thermal conductivity. The numeri cal and analytical models are explicitly based on the properties of th e constituent material and three-dimensional features of the weave sty le. Results obtained from the model are compared with experimental val ues 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 invest igated. Parametric studies are conducted to examine the effect of vary ing fiber volume fractions on the effective thermal properties.