Experimentally verified dual-scale modelling framework for predicting the strain rate-dependent nonlinear anisotropic deformation response of unidirectional non-crimp fabric composites

Abstract

A new hierarchical dual-scale modelling framework is developed for predicting the strain rate-dependent nonlinear deformation response of a unidirectional non-crimp fabric (NCF) carbon fiber/snap-cure epoxy composite. A linear Drucker-Prager model that considers tension–compression asymmetry of the yield surface was used to capture the elastic–plastic response of the epoxy within the microscale finite element (FE) model, while randomly dispersed carbon fibers were treated as linear elastic. For the mesoscale FE model, the effective elastic–plastic response of the impregnated tow was modelled using Hill’s anisotropic yield function. The post-yield strain rate dependency of the epoxy and impregnated tow was captured with the Johnson-Cook model, with the former being calibrated using available experimental data. The predicted post-yield response of the impregnated tow was found to be dependent on the applied strain rate. An excellent agreement was observed between the predicted and experimentally measured stress–strain response for the NCF composite at quasi-static strain rates. The predicted in-plane and out-of-plane shear stress–strain responses revealed a strong dependence on the applied strain rate. The newly developed dual-scale modelling framework can be utilized as a tool to effectively predict the strain rate-dependent non-linear response for other fabric-reinforced composite material systems.