Determination of Strength and Damping Characteristics of Carbon Nanotube-Epoxy Composites

Abstract

In this paper, the strength and damping properties of carbon nanotube-epoxy composites are examined. Carbon nanotubes (Single-walled and Multi-walled) were grown on stainless steel substrates using thermal chemical vapor deposition process. The nanotube-epoxy composites were then prepared by applying a layer of epoxy on the grown nanotubes and a PZT actuator was attached on this layer. The composite beam consisting of steel, nanotube-epoxy layer and PZT actuator was used as a cantilever beam for vibration experiments in order to determine the enhancement in strength and damping properties of the nanotube-epoxy layer. Several different samples were prepared for this purpose. Impulse and frequency sweep tests were conducted on these beams to obtain the impulse response and frequency response functions. Fast Fourier Transform of the impulse response was used to find the natural frequency of the composite beam. It was observed that there was an increase in the stiffness by using multi-walled nanotubes in the epoxy, while the damping ratio increased by using single-walled nanotubes. The stick-slip mechanism is discussed in order to explain the results obtained.