Multi-scale Modeling of Non-Orthogonal Twill Weave Composites

Abstract

Advantages such as ultra-lightweighting, parts consolidation, and using newly available fast-curing resin formulations are driving the need to develop improved understanding of carbon fiber composites. Towards this end, the present segment of research is focused on developing a multi-scale model to predict the performance of non-orthogonal woven fabric composites. Woven fabrics (where the fiber tows are orthogonal) are used extensively to manufacture components with complex geometries due to their excellent drapability. However, during draping, the fiber tows in the composite preform reorient themselves to conform to the part geometry (the fiber tows are sheared to become non-orthogonal), and the fiber directions may change drastically compared to the original preform, resulting in significant changes in strength and stiffness of the final composite. The ability to include these processing induced effects in predicting the structural performance of these non-orthogonal fabric composites allows us to improve the accuracy of the prediction and optimize the designs. In this paper, a multi-scale modeling approach was developed to predict the performance of composites made using non-orthogonal woven fabrics. Sample coupons molded with and without a pre-determined amount of shearing were evaluated in tensile and three-point bend experiments, and the numerical predictions were compared with the experimental results. A good correlation was observed, validating the developed model.