PREDICTION OF COMPOSITE PROPERTIES, FROM A REPRESENTATIVE VOLUME ELEMENT

A vigorous mechanics foundation is established for using a representat ive volume element (RVE) to predict the mechanical properties of unidi rectional fiber composites. The effective elastic moduli of the compos ite are determined by finite element analysis of the RVE. It is paramo unt in such analyses that the correct boundary conditions be imposed s uch that they simulate the actual deformation within the composite; th is has not always been done previously. In the present analysis, the a ppropriate boundary conditions on the RVE for various loading conditio ns are determined by judicious use of symmetry and periodicity conditi ons. The non-homogeneous stress and strain fields within the RVE are r elated to the average stresses and strains by using Gauss theorem and strain energy equivalence principles. The elastic constants predicted by the finite element analysis agree well with existing theoretical pr edictions and available experimental data.