Evaluation of hyperelastic models for unidirectional short fibre reinforced materials using a representative volume element with refined boundary conditions

The simulation of a short fibre reinforced structure by means of the FEM requires the knowledge of the material behaviour at every Gauss point. In order to obtain such information, a representative volume element (RVE) containing unidirectional short fibres is analysed in the presented work. The findings are used to assess the applicability of several hyperelastic models describing transversal isotropic materials under consideration of large deformations. As the RVE's average response represents the homogenised behaviour at a macroscopic material point, the material models' parameters can be identified by fitting them to stress-strain curves obtained from simulations with the RVE. The application of periodic boundary conditions to the RVE in tensorial form enables a simple access to consider tilted fibres and catch the anisotropy induced by the fibres. The comparison of the calibrated material model with the RVE allows the assessment of the material model's applicability and quality. Both the modelling and the calculations are carried out with the commercial FEM software ABAQUS.