Use of Carbon Nanotubes for Strain Sensing of Epoxy Based Composites

Abstract

The interest in structural health monitoring of carbon fiber reinforced polymers using electrical methods to detect damage in structures is growing because of its simplicity and feasibility. In order to get conductivity, polymer matrix must be turned conductive and the use of nanoreinforcement seems to be the most feasible method. In this work the behavior of nanoreinforced polymer with carbon nanotubes (CNTs) and composites with glass and carbon fibers with nanoreinforced matrices has been studied. These composites have been evaluated in tensile test by simultaneously measuring stress, strain and resistivity. During elastic deformation, a linear increase in resistance was observed and during fracture of the composite fibers stronger and discontinuous changes in the resistivity were observed. The percentage of nanotubes incorporated in the matrix has turned out to be an important factor in the sensitivity of the method.