Numerical modelling of shear hysteresis of entangled cross-linked carbon fibres intended for core material

Abstract

The analysis of an entangled cross-linked fibrous material at low deformation is explored as way of predicting the shear behaviour, especially the shear hysteresis. This paper presents a 3D finite element model to characterize the carbon fibre network rigidified by epoxy cross-links. The morphology of the representative volume element (RVE) is studied to guarantee that it is representative of the actual material that was characterized experimentally. Two steps are simulated, namely the initial compression during the shaping and before the polymerization of the epoxy resin and the cyclic shear testing of the material with its rigidified network of fibres. A numerical simulation of an RVE is used to present a description of the measured hysteresis loop that is decomposed of linear and nonlinear parts. A comparison between the numerical prediction and the experiment data is discussed. Even if the 3D numerical model under-predict the average shear stiffness of the material, it can capture the complex shapes of the measured hysteresis loops at different strain amplitudes.