Active damping in polymer-based nanocomposites

Abstract

In this research, we present the preliminary results related to our investigations on the potential of electrical signals through the network of nanoscale reinforcements and the consequent Joule heating in polymer-based nanocomposites as a means to augment damping in the material. The intended damping mechanism in this case is the creep and relaxation in the matrix phase, which is to be intensified via locally increased temperatures. The reinforcement of choice will be carbon nanotubes. The effectiveness of this method partly depends on rate and special uniformity at which the temperature of the matrix is increased, and as such it scales with the surface to volume ratio of the reinforcements. To demonstrate active damping augmentation experimentally, composites were then fabricated with the carbon nanotubes (CNTs) randomly distributed within an epoxy matrix. The active control of the damping behavior was pursued by joule heating the CNT reinforcements during the dynamic tensile testing on a Dynamic Mechanical Analyzer (DMA). Damping was quantified by the ratio of loss to storage modulus, equivalent to the ratio of dissipated mechanical energy to the elastic energy stored in the material during dynamic loading.