Finite element analysis on tensile behaviour of 3D random fibrous materials: Model description and meso-level approach

Three-dimensional (3D) random fibrous materials exhibit extraordinary mechanical properties due to their complex morphological characteristic of bonded fibre networks on the meso-level. Based upon experimental characterisation, a simplified numerical model is presented that reveals the disordered features of bonded fibre networks and allows investigation of the tensile behaviour of 3D random fibrous (3DRF) materials. The calculated results' dependence on the quantity of numerical samples, mesh density and model size is analysed using finite element analysis (FEA); consequently, an optimised FEA model is obtained. The 3DRF materials' tensile behaviour is then predicted using the optimised FEA model. The calculated results agree well with the experimental data. Moreover, the predicted failure mechanism is consistent with SEM observations. The experimental data thus validate the FEA model. On this basis, we conduct a comprehensive investigation to understand the influences of the fibres' deformation mode, the bonding properties and the proportion of the constituent fibres on the macro-mechanical properties of 3DRF materials. These analyses provide insight into the mechanical behaviour of such materials.