Dynamic Analysis of a Clamped Wavy Single Walled Carbon Nanotube Based Nanomechanical Sensors

This paper deals with the dynamic analysis of carbon nanotube with surface deviation along its axis. The type of carbon nanotube used in this analysis is a single-walled carbon nanotube that is doubly clamped at a source and a drain and this type of nanotube is used to represent a single mode resonator. In previous studies, experimentally measured resonance frequencies of carbon nanotubes have been used along with classical beam theory for straight beams. However, it is found that these carbon nanotubes are not straight, and that they have some significant surface deviation associated with them. The resonant frequency of the doubly clamped single walled carbon nanotube (SWCNT) with deviation (waviness) has been investigated. The results showed the sensitivity of the single-walled carbon nanotubes having different waviness to different masses (attached at the center of a doubly clamped SWCNT) and different lengths. The sensitivity of resonant frequency shifts to tube length and waviness has been demonstrated. The vibration signature exhibits superharmonic and subharmonic responses with different levels of mass. The vibration spectra of CNT with varying attached mass from $10−5fg$ to $10−3fg$ show dense signature near peak of excitation. It is found that with the increase in mass attached to CNT with 60 nm length, the peak excitation appears in the vibration signature in chaotic nature with reduced vibration amplitude.