Authors: L. Zalamea and R.B. Pipes
Affilation: Purdue University, United States
Pages: 194 - 197
Keywords: carbon nanotubes, hexagonal arrays, shearing traction, natural frequencies, harmonic oscillators, flexural modulus, flexural stiffness
The present study springs from the investigation of Salvetat et al.4 wherein the ratio of flexural deformation to applied load of the carbon nanotube array was used to determine a reduced Young’s modulus and effective shearing modulus of the CNT array. Results were presented that showed Young’s modulus of the CNT array to decrease with increasing array size. In the present study, the authors describe a mechanism that accounts for the dependence of the flexural compliance of the CNT array on the shearing tractions between the individual CNT that are expected to occur due to van der Waals forces. The magnitude of the shearing traction is determined by matching the model prediction of array stiffness to the experimental results.<br>Independently, the harmonic properties of single walled carbon nanotube (10,10) arrays in cantilever geometry have been measured recently and a linear relationship between first natural frequency and the ratio of array diameter and the square of the span length, D/L2 was postulated1. In the present work, using the model described above, the authors show that this relationship is highly non-linear especially for large values of the ratio, D/L2.<br>In addition, the increase in stiffness of an electron beam irradiated array can be described using our model through an increase in the value of shear transfer efficiency.