Meshfree micromechanical modelling of the mechanical properties and responses of woven composites

Abstract

Obtaining a clear understanding of the elastic properties and overall responses of woven composites is a significant prerequisite for cost-effective design of these materials. Such an understanding is often achieved via developing unit cell (UC) models using analytical or the FEM-based approaches, which leads to either the problem of a reduced accuracy, resulting from the analytical nature, or the concern of high complexity, associated with using elements. The aim of this work is to simultaneously address the above concerns by developing a meshfree-based UC modelling approach to predict the elastic properties and overall responses of woven composites. Specifically, high-fidelity UC models have been developed to describe the internal architecture of woven composites, which addresses the accuracy problem in analytical approaches. Also, meshfree methods have been employed to implicitly implement the UC models, eliminating the complexity problem in the FEM-based approaches. For predicting the overall responses, constitutive modelling has been performed for the constituents of woven composites, with a viscoplasticity-based model being selected to describe the nonlinear and rate-dependent behaviour of polymer matrix and a Weibull function based formulation being proposed to identify the damage of yarn material. Furthermore, in-house computer programs implementing the UC models, the constitutive models and the meshfree methods have been coded, and numerical examples have been conducted for predicting the elastic properties and overall responses of woven composites. It has demonstrated that the meshfree-based predictions agree well with the experimental results and the data in the literature, validating the proposed approach. The significance of this work is that it eliminates the problems in traditional approaches and meanwhile extends the capability of the UC modelling methodology from homogenising only the elastic properties in the normal directions to predicting the elastic properties and overall responses of woven composites in both the normal and off-axis directions.