A B S T R A C TA new entangled cross-linked material was recently developed in order to present a new core material that can resolve the drawbacks of the honeycomb. The optimization of entangled carbon fibres requires a deep understanding of the influence of the parameters of a fibre network on its macroscopic behaviour. This paper presents a 3D finite element model to investigate the compressive behaviour of this fibrous material. The current work focuses on a representative volume element (RVE) with appropriate boundary conditions and initial fibre distribution close to that of the experimental test. The morphology of the RVE is examined before loading. The simulation results show a good correlation with the experimental data in terms of stress-strain curves. The descriptors of the morphology such as the distance between contacts and fibre orientation are studied under compression loading.

To cite this version:Fadhel Chatti, Christophe Bouvet, Guilhem Michon, Dominique Poquillon. Numerical analysis of shear stiffness of an entangled cross-linked fibrous material. a b s t r a c tThe objective of this paper is to understand and study the effect of morphological parameters on the shear stiffness of an entangled cross-linked fibrous material made with carbon fibres where some of the contacts are bonded by the epoxy resin. This current work presents a 3D finite element model using ABAQUS/Standard in order to characterize the mechanical behaviour of different carbon fibre networks rigidified by epoxy cross-links. Numerical simulations are achieved on a representative volume element (RVE) with the orientation distribution of the fibres based on a tested sample. Since not all the strands are perfectly separated, an equivalent diameter of fibre is determined to obtain the rigidity experimentally measured in shear. Then, an investigation of the influence of morphological descriptors, such as the distance between cross-links, distribution fibre orientations and junction properties, is carried out. For the entangled cross-linked fibrous material with a small fibre volume fraction, the relationship between the shear stiffness and the fibre volume fraction is a linear function whereas the relation between the shear stiffness and the distance between junctions is a power law with exponent of −3/2. The shear stiffness depends slightly on the twisting joint stiffness, and its relationship with the tension joint stiffness is a logarithmic function. The effect of fibre stiffness is also investigated by taking Young's modulus values corresponding to those of glass fibres, inox fibres or aramid fibres. A linear function is obtained between the shear stiffness and the Young's modulus. These results are consistent with the analytical models in the literature for a cross-linked fibrous material.