Effect of straight and wavy carbon nanotube on the reinforcement modulus in nonlinear elastic matrix nanocomposites

Elastomers, particularly rubbers, are viscoelastic polymers with low Young’s modulus. In this research, carbon nanotubes were used in the rubber and a rubber–carbon nanotube composite was modeled by ABAQUS? software. Due to hyperelastic behavior of the rubber, strain function energy was used for the modeling. A sample of rubber was tested and uniaxial, biaxial, as well as planar test data obtained in these tests were used to get an energy function. Polynomial and reduced polynomial form are two common methods to achieve strain energy function. In this paper, elasticity modulus and Poisson ratio were measured for a representative volume element (RVE) of composite. Rubber was also considered as an elastic material and its composite properties in this state compared by hyperelastic rubber matrix assumption. ABAQUS was used to create a three dimensional finite element model of a single long wavy nanotube with diameter of D which perfectly bonded to matrix material. Nanotube waviness was modeled by sinusoidal carbon nanotube shape. Results showed that mechanical properties of the rubber will extremely change by adding carbon nanotube. Furthermore, several volume fractions of carbon nanotube in rubber were modeled and it was shown that stiffness of nanocomposite increases by more volume fraction of carbon nanotubes.