Evaluation of elastic modulus of epoxy reinforced with 200 nm thick alumina platelets through finite element analysis

Abstract

Effective elastic modulus of epoxy composites reinforced with randomly distributed and oriented platelets is evaluated for the case of uniaxial tensile loading using the finite element method. The composites considered had 200 nm thick platelets having in plane size in the range of 3–20 μm as reinforcements. Considering the platelets as elliptical discs, an elaborate study was first conducted using the representative volume element (RVE) approach to investigate the effect of size of the platelets, their distribution, orientation and local stacking on the elastic modulus for composites having up to 10% platelet volume fraction. For each case, comparison was also made with the estimates obtained using Mori–Tanaka method. Further RVE with platelets of assorted size was analyzed to identify the effect of size assortment on the elastic modulus. The assortment of size was carried out by discretizing the actual size distribution of the platelets used to prepare the composites. The elastic modulus obtained from the RVE with assorted size platelets, oriented and distributed randomly, agreed well with the experimental data once the local stacking of platelets was accounted for. The results of the study indicated that for highly planar reinforcements like platelets oriented randomly, the local stacking of the platelets has greater influence on the composite modulus whereas the assorted size has only lesser significance.