3D numerical simulation for the elastic properties of random fiber composites with a wide range of fiber aspect ratios

A new automatic searching & coupling (ASC) technique is proposed to generate the 3D representative volume element (RVE) to analyze the random fiber composite (RaFC) with a wide range of fiber aspect ratios (FAR), particularly the RaFC with a high FAR. Compared with the conventional model, the present model is easier to generate and more time-saving as it eliminates the drawback of free meshing. In addition, the ASC technique can remove the additional stiffness introduced by the embedded element technique (EET), and hence can improve precision and convergence. Moreover, our technique facilitates the direct application of the 3D periodic boundary conditions (PBC) to the RVE. Using the finite element (FE) method, the elastic properties of RVE are calculated, and the critical RVE size is determined. Furthermore, the 3D elastic properties of RaFC are predicted, which accord well with experimental data. Besides, the RVE is employed to explore the influences of FAR, fiber volume fraction (FVF) and the fiber incline angle on the elastic properties of RaFC, and a comparison with theoretical results is also presented.