Integrated micro/macro-mechanical model of woven fabric composites under large deformation

Thermoforming of woven composite panels generally involves significant in-plane shear deformation, and induces additional anisotropy into the composites. In our previous paper, a new constitutive model for macro-mechanically characterizing the non-orthogonal material behavior under large deformation was proposed. In the present work, we develop an integrated micro- and macro-constitutive model to predict the mechanical properties of woven composites during large deformation based on the microstructure of composites, i.e., the dimensions of fibers, yarns and unit cell, the material properties of composite constituents, as well as the orientation of yarns. The modeling strategy starts with a geometrical description of the yarn and the unit cell during a trellising shear deformation. Following this, a mechanistic analysis on a unit cell has been conducted to determine the equivalent shear properties of woven composites used in our non-orthogonal model. Meanwhile, a simple and conventional analytical technique is applied to predict the tensile properties of woven composites. The proposed integrated micro/macro-model shows excellent agreement with the experimental data and the 3D finite element results. Finally, a parametric study is performed using the presented models to investigate the effects of major geometrical parameters and material properties of the constituents on the shear properties of plain weave composites.