A multi-scale three-dimensional finite element analysis of polymeric rubber foam reinforced by carbon nanotubes under tensile loads

Abstract

A multi-scale FEM analysis was set up using two different unit cells to estimate the properties of a nanoparticle-reinforced rubber foam from the base material. Rubber foam was made up of EPDM rubber and reinforced by multiwall carbon nanotubes. This analysis was performed in two stages. In the first stage, the mechanical behavior of polymeric nanocomposite was predicted under uniaxial tension using the unit cell type I; in the second stage, the overall foam behavior was predicted by implementing the results of the first stage in unit cell type II as a constitutive material, with both cell types being in different dimensional scales. The polymeric material was assumed as an incompressible media and Ogden hyperelastic model was used as a material model. Both simulation stages incorporated unit cells as representative volume element and periodic boundary conditions. Polymeric material parameters for Ogden hyperelastic model were calculated using tensile testing of vulcanized pure EPDM. To validate the model, numerical analysis results were compared to experimental tensile tests of nanoparticle-reinforced foam, which was prepared with similar density and nanoparticle content as in the simulation. The foam porosity size and content of carbon nanotubes were adjustable in this study using unit cell parameters.