Mechanical and electrical behaviors of self-sensing nanocomposite-based MWCNTs material when subjected to twist shear load

Abstract

For the industrial applications of self-sensing multi-walled carbon nanotubes (MWCNTs)/polymers nanocomposites, it is very important to investigate their behavior under complex experimental conditions, such as the torsion twist test. In this study, self-sensing nanocomposites specimens based on different concentrations of MWCNTs were fabricated by a hot-press technique. The dispersion of MWCNTs in the matrix was examined by scanning electronic microscopy and evaluated by Raman spectra. The results show a good distribution of the MWCNTs inside the matrix, which also was in agreement with the increase of the electrical conductivity when increased the content of the MWCNTs. Additionally; it has been shown throughout this investigation that the piezoresistive properties of MWCNTs/phenolic nanocomposites depend principally on the MWCNTs concentration. A high value of change in resistance was observed for the specimens with low content of the MWCNTs. We also addressed the influence of subjected static and cyclic torsion shear loadings to investigate the influences of MWCNTs content, strain rate and strain amplitude on the strain sensitivity [i.e., gauge factor (GF)] performances. The results show that a wide range of GFs ranging from 0.88 for phenolic with 1.5 wt.% MWCNTs at the strain rate of 0.4 min − 1 to 4.11 for phenolic with 0.5 wt.% MWCNTs at the strain rate of 1.2 min − 1. Therefore, the results obtained here provide good understanding guidelines for the behavior of the nanocomposite-based MWCNTs when subjected to a torsional shear loading and its sensing sensitivity for different strain patterns.