The average response and isotropy of 3D representative volume elements for random distributed short fibers reinforced elastomer

The average response and isotropy of the 3D representative volume elements (RVEs) for random short fiber reinforced elastomer composites (SFECs) have been explored by finite element method with different fiber volume fractions (V-f) and RVE sizes. The RVEs were loaded spatially by directly applying stretches in nine loading directions and the homogenized response in each direction was obtained. The coefficient of variation of the responses of an RVE over different loading directions was used to represent the anisotropy of the RVE. The orientation tensor error was used to represent the anisotropy of all the fibers and was compared with the anisotropy of the RVEs. The simulation results for the SFEC were compared with the elastic modulus obtained by traditional empirical equations based on Halpin-Tsai estimations. The results show that the anisotropy of the RVEs decreases with the increase of the RVE size and is higher for RVEs with higher V-f. The anisotropy of the fibers decreases with the increase of the V-f. A method of averaging responses of each RVE over all loading directions greatly reduces the variation in response over different RVEs, which can be used to improve the prediction accuracy more efficient than increasing the RVE size.