Prediction of mechanical and thermal properties of polymer nanocomposites reinforced by coiled carbon nanotubes for possible application as impact absorbent

This paper presents three-dimensional finite element modeling of nanocomposite materials made from polyethylene polymer reinforced by coiled carbon nanotubes. A method of Python scripting was used to generate representative volume elements in order to determine the mechanical behavior in elastic and plastic zones as well as effective thermal conductivity using the finite element software. The properties of the nanocomposites are investigated by considering the interphase zone between carbon nanofillers and matrix. The effects of different volume fractions, geometrical parameters, and orientations of the nanofillers on the elastic and thermal characteristics of the nanocomposites are studied considering both cohesive interaction and perfect bonding between the fillers and matrix. Moreover, the effects of applying strain on the effective thermal conductivity of the representative volume elements are analyzed. The results reveal that both stress-strain curves and thermal conductivity coefficients of the nanocomposites are following similar trends vs. the changes of the volume fractions as well as the geometries and orientations of the coiled carbon nanotubes. Analysis of the tensile toughness of all samples reveals that it is affected by both stress and the number of fillers in the representative volume element. In addition, thermal-displacement analysis shows that thermal conductivity coefficient decreases by increasing the applied strain on the representative volume element, while the intensity of decrease of the nanocomposite thermal conductivity depends on the volume fraction and interaction of the nanofillers and interphase zone. Finally, crashworthiness analysis of the nanocomposite material proves that they are appropriate candidates for absorbing energy under impact loadings in comparison to metals.