20 - Multiscale modelling of open-hole composite laminates and three-dimensional woven composites

Abstract

An analytical micromechanics-based multiscale model is presented, for predicting the progressive damage and failure analysis of laminated and three-dimensional woven textile composites (3DWTCs). The framework of the proposed two-scale computational method is very general and applied to two types of composites of interest and validated by experiments. The material system is IM-7/977-3 for notched, prepreg-based continuous fibre laminates and 3DWTCs are hybridized configuration of dry fibres (carbon, glass, and kevlar tows), infused with SC-15 polymer matrix. The prepeak nonlinearity, caused by matrix microdamage, is modelled at the subscale using a two-concentric cylinder model and upscaled (homogenized) to the ply level in the case of laminated composites, and the fibre tow level in the case of textile composites. At the ply level the 3D orthotropic smeared crack approach is used for modelling postpeak strain-softening behavior, caused by both fibre and matrix failure modes. Readily available 3D finite elements are used for modelling, and the input constituent properties are obtained from standard coupon level tests, by inverse analysis. The predictive capability of the proposed method is established by demonstrating the prediction of failure mechanisms, and laminate strengths, in comparison to experimental results.