Analysis of size-dependent mechanical properties of CNTs mass sensor using energy equivalent model

In this study a theoretical modified continuum mechanics model is applied to investigate the vibration characteristics of a pretension carbon nanotubes (CNTs) carrying a concentrated mass as a mass sensor. The energy-equivalent model (EEM) that derived from basis of molecular mechanics is exploited to describe the size-dependence of Young's modulus, shear modulus, and Poisson's ratio for both zigzag and armchair CNTs. Carbon nanotube is modeled as Timoshenko nanobeam including rotary inertia and shear deformation effects. The proposed model is solved analytically and then verified with both theoretical and molecular dynamics simulation. The results show that the CNTs resonator can measure a very tiny mass with weight 10−1 zg. The effects of CNTs orientation, CNTs length, and mass position on the fundamental frequencies are investigated. These findings are helpful in mechanical design consideration of high-precision measurement devices manufactured from CNTs.