Highly nonlinear contact interaction and dynamic energy dissipation by forest of carbon nanotubes

Mechanical response and energy dissipation of an array of carbon nanotubes under high-strain rate deformation was studied using a simple drop-ball test with the measurement of the dynamic force between the ball and forest of nanotubes. This convenient process allows extracting force-displacement curves and evaluating dissipated energy by the nanotubes. The contact force exhibits a strongly nonlinear dependence on displacement being fundamentally different than the Hertz law. The forest of vertically aligned nanotubes may be used as a strongly nonlinear spring in discrete systems for monitoring signal propagation speed, and as a microstructure for localized energy absorption. (C) 2004 American Institute of Physics.