scholarly journals A numerical study of squeeze-film damping in MEMS-based structures including rarefaction effects

2012 ◽  
Vol 7 (23) ◽  
pp. 103-113 ◽  
Author(s):  
Maria F. Pantano ◽  
Leonardo Pagnotta ◽  
Salvatore Nigro
Keyword(s):  
Numerical Study ◽  
Squeeze Film ◽  
Squeeze Film Damping ◽  
Rarefaction Effects

Coupled effects of surface interaction and damping on electromechanical stability of functionally graded nanotubes reinforced torsional micromirror actuator

2021 ◽  
pp. 030932472110368
Author(s):  
Weidong Yang ◽  
Menglong Liu ◽  
Linwei Ying ◽  
Xi Wang
Keyword(s):  
Casimir Force ◽  
Volume Fraction ◽  
Nonlocal Parameter ◽  
Saddle Points ◽  
Functionally Graded ◽  
Heteroclinic Orbits ◽  
Phase Portraits ◽  
Squeeze Film ◽  
Squeeze Film Damping ◽  
Tilting Angle

This paper demonstrated the coupled surface effects of thermal Casimir force and squeeze film damping (SFD) on size-dependent electromechanical stability and bifurcation of torsion micromirror actuator. The governing equations of micromirror system are derived, and the pull-in voltage and critical tilting angle are obtained. Also, the twisting deformation of torsion nanobeam can be tuned by functionally graded carbon nanotubes reinforced composites (FG-CNTRC). A finite element analysis (FEA) model is established on the COMSOL Multiphysics platform, and the simulation of the effect of thermal Casimir force on pull-in instability is utilized to verify the present analytical model. The results indicate that the numerical results well agree with the theoretical results in this work and experimental data in the literature. Further, the influences of volume fraction and geometrical distribution of CNTs, thermal Casimir force, nonlocal parameter, and squeeze film damping on electrically actuated instability and free-standing behavior are detailedly discussed. Besides, the evolution of equilibrium states of micromirror system is investigated, and bifurcation diagrams and phase portraits including the periodic, homoclinic, and heteroclinic orbits are described as well. The results demonstrated that the amplitude of the tilting angle for FGX-CNTRC type micromirror attenuates slower than for FGO-CNTRC type, and the increment of CNTs volume ratio slows down the attenuation due to the stiffening effect. When considering squeeze film damping, the stable center point evolves into one focus point with homoclinic orbits, and the dynamic system maintains two unstable saddle points with the heteroclinic orbits due to the effect of thermal Casimir force.

Deep Hole Honing Based on Squeeze Film Damping Technology

2009 ◽  
Vol 76-78 ◽  
pp. 252-257
Author(s):  
Tian Biao Yu ◽  
Ya Dong Gong ◽  
Wan Shan Wang
Keyword(s):  
Differential Equation ◽  
Experimental Result ◽  
Squeeze Film ◽  
Design Parameters ◽  
Improve Quality ◽  
Deep Hole ◽  
Squeeze Film Damper ◽  
Squeeze Film Damping ◽  
Hole Machining

In order to improve quality of deep hole machining, a new method of deep hole honing based on squeeze film damping technology is put forward. For analysis effect on damper parameters on honing quality, motion differential equation of honing spindle with a squeeze film damper (SFD) is established according to D' Alembert principle and according simulations are studied. Spindle of deep hole honing with a SFD is designed based on the result of simulations and experiments are carried on. Experimental result shows that SFD with reasonable design parameters has excellent damping function to honing spindle, and it can make the vibration of honing spindle reduced 20%～30% and the quality of deep hole machining improved 10%～20%.

Damping Analysis of Asymmetrical Comb Accelerometer

2007 ◽  
Vol 353-358 ◽  
pp. 2597-2600 ◽  
Author(s):  
Wei Ping Chen ◽  
Zhen Gang Zhao ◽  
Xiao Wei Liu ◽  
Yu Min Lin
Keyword(s):  
Damping Ratio ◽  
Resonance Phenomenon ◽  
Damping Coefficient ◽  
Anodic Bonding ◽  
Squeeze Film ◽  
Frequency Bandwidth ◽  
Vibration Method ◽  
Capacitive Accelerometer ◽  
Squeeze Film Damping

The resonance phenomenon is suppressed by adjusting the damping of the comb accelerometer structure to widen the frequency bandwidth of the capacitive accelerometer. The capacitive accelerometer with asymmetrical combs, fabricated with DRIE and anodic bonding, is presented. The damping category of the accelerometer is introduced, in which the squeeze-film damping coefficient and the damping ratio factor are detailed. The damping ratio factor of the accelerometer, measured by a vibration method, is 0.17. The damping ratio factor of the optimized structure is calculated of 0.15 to 0.18 with the change of experiential modulus C from 25 to 30, theoretically.

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