Predicting Deformation Response and Failure of 3D Textile Composites Using Realistic Micromechanical Models

Abstract

3D woven composites are increasingly being utilized to construct structural components due to their ability to obtain high fiber volume fractions, potential for improved interlaminar properties, and ability to reduce manufacturing time via automated formation of component-shaped preforms. Properties of the 3D woven composite are determined by weaving architecture and the constituent material system. A detailed representation of its woven unit cell architecture is thus sought to closely capture local variations and imperfections arising during the weaving process, in order to predict mechanical properties with greater accuracy. Accurate mechanical property prediction can reduce the material selection cost and cycle time by minimizing coupon fabrication and testing. In this paper, a complex 3D woven angle interlock (3DWAI) unit cell is first modeled using DEA Fabric and Composite Analyzer (DFCA). Cross-section slices from the numerical model are compared to micrographs from the corresponding test sample to highlight the important meso-scale features that are captured by the model in a detailed fashion. Then a progressive damage model based on a gradual stiffness reduction technique is implemented to predict the tensile, compressive and shear stress-strain responses as well as failure strengths of the 3DWAI unit cell. The numerical predictions are compared to the test results and a discussion on the failure mechanisms is presented. The results demonstrate that the proposed modeling methodology not only captures the actual microstructures, but also predicts properties of 3D woven composites with a high degree of accuracy.