Viscous damping of nanobeam resonators: Humidity, thermal noise, and a paddling effect
C Chen and M Ma and JZ Liu and QS Zheng and ZP Xu, JOURNAL OF APPLIED PHYSICS, 110, 034320 (2011).
A nanobeam resonator is a key mechanical component of a nano- electromechanical system. Because of its small dimensions, the system can reach very high frequencies, but it is also very sensitive to its environment, as a large surface area of the material is exposed. Molecular dynamics (MD) simulations and theoretical analysis are used here to quantitatively predict the damping behavior of a nanobeam, including its critical damping conditions and lifetime, directly mapping fluid-structure properties and interaction into dynamics. We show here how the humidity defines the critical damping condition through viscous forces, marking the transition from the under-damping to the over- damping regime at elevated humidity. Phenomena such as thermal fluctuations and the paddling effect are also discussed with an explanation using a simple one-dimensional model. (C) 2011 American Institute of Physics. doi:10.1063/1.3619854
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