Numerical studies of electrical contacts of carbon nanotubes-embedded epoxy under tensile loading

Numerical studies were performed to determine electrical contacts in carbon nanotubes (CNTs)-embedded epoxy under quasi-static tensile loading conditions. A realistic CNT network in epoxy was generated by random orientation and waviness by employing the Monte Carlo method. Two kinds of contacts between CNTs, namely Type-I (overlap) and Type-II (in-plane), were considered in generating a conductive network. A commercial finite element package, COMSOL, was used to determine the distance between these contacts and variation of these contacts during elastic deformation under tensile loading. Numerical predictions were later compared with the analytical results derived from experimental findings. The effect of initial f-ratio and the amount of waviness of CNTs on the variation of f-ratio (which is determined as a ratio of Type-II contacts to total contacts) was investigated as a function of axial strain. The initial f-ratio as well as the extent of waviness showed a significant effect on the change in the type of contacts with increasing axial strain values.