Multiscale modeling of hybrid nanocomposites using molecular dynamics, micromechanics, and finite element methods

In this paper, multiscale modeling of Epoxy-based hybrid nanocomposites was performed. Single-walled carbon nanotube and carbon nanoparticle (diamond) were used as reinforcements and the elastic behavior of hybrid nanocomposite was investigated. In the multiscale modeling, at the nanoscale and pico-second time range, molecular dynamics method was used to make an accurate model of the interaction between the nano-scale reinforcements and the polymer matrix to predict the interface behavior more realistically. At the micro and macro scales, micromechanical models were used to predict the elastic properties of the nanocomposites, incorporating the effects of interface behavior. Finite element method was also used to check the accuracy of the results obtained at the macro scale. First, pure thermoset polymer with 75% crosslinking ratio was simulated using molecular dynamics method. Then two nanocomposites, one consisting of a single-walled carbon nanotube and another one containing a carbon nanoparticle (diamond) were simulated to obtain equivalent fiber mechanical properties. Next, a micromechanical model was developed for hybrid nanocomposite using the equivalent fiber and pure thermoset polymer mechanical properties. In addition, the results obtained from the molecular dynamics simulations, along with a correction coefficient were employed in the micromechanical models and finite element simulations. Finally, micromechanical multiscale modeling results were compared with finite element multiscale modeling results and a good agreement was observed. Results suggest that the use of two types of nano-reinforcement together, hybrid nanocomposite, improves nanocomposite mechanical properties.