Analysis of mechanical properties of carbon nanotube reinforced polymer composites using multi-scale finite element modeling approach

In this paper, a multiscale finite element (FE) modeling approach is proposed for studying the pinhole defects in CNT reinforced polymer composites. Two configurations of CNT i.e. armchair (5, 5) and zigzag (9, 0) are selected for analyses wherein C-C bonds at atomic scale are modeled as Euler beam. The three dimensional solid elements are used for matrix material and square representative volume element (RVE) is constructed for the nanocomposite. These composite materials consist of aligned carbon nanotubes that are uniformly distributed within the matrix. The presence of chemical covalent bonding between functionalized CNT and matrix are modeled as elastic cross links. The influence of the pinhole defects on the nanocomposite are studied under axial load condition. It has been observed that with the increase in the number of atomic vacancies, the elastic modulus of the composite are reduced significantly. The effects of nanotubes chirality and composite stiffness ratio on the elastic properties are also analyzed in presence of atomic vacancies. It has been found from simulation results that zigzag nanotubes provides better reinforcement to composite compared to armchair nanotubes.