An asymptotic homogenization model for evaluating the mechanical properties of random fiber reinforced composites with high volume fraction

In this study, we propose an asymptotic homogenization strategy based on local-global RVEs to predict the elastic properties of random fiber reinforced composites (RFCs) with high fiber volume fraction (HFVF). During the calculation, RFCs were divided into a set of local pseudo units with various material properties determined by its spatial orientation of the short fibers. The macroscopic mechanical properties of the RFCs with HFVF were asymptotically determined by integrating transformation matrices, periodic boundary conditions, and numerical homogenization method. The results show that the proposed models were in good agreement with the experimental tests of short fiber reinforced magnesium matrix (C_fs/Mg) composites. When the length ratio of the RVE to the local pseudo L/L_s was >10, the overall orientation of the fibers tended to be completely random, and the results gradually converged. With an increase in the fiber volume fraction, the effective elastic properties of the C_fs/Mg composites grew linearly. Additionally, the proposed asymptotic homogenization framework can also be extended to evaluate other macroscopic physical properties of RFCs such as thermal and electric conductivities.