Dynamic Response of a Piezoelectric Flextensional Microactuator

2005 ◽  
Author(s):  
Jongpil Cheong ◽  
Srinivas Tadigadapa ◽  
Christopher D. Rahn
Keyword(s):  
Dynamic Response ◽  
Frequency Response ◽  
Natural Frequencies ◽  
Rf Mems ◽  
Squeeze Film ◽  
Beam Shape ◽  
Initial Beam ◽  
Carbon Tape ◽  
Squeeze Film Damping ◽  
Soft Carbon

Microactuators capable of providing high resolution displacement and controlled force have many applications in RF MEMS, microfluidics, and motion control. This paper theoretically and experimentally investigates the dynamic response of a piezoelectric flextensional microactuator consisting of a clamped beam that buckles in response to contraction of a bonded PZT support. The DRIE and solder bonding fabrication process produces beams with initial curvature that affects their dynamic response. Unlike previous research where sinusoidal initial beam shapes are analyzed, polynomial initial beam shape enables more accurate prediction of beam natural frequencies and frequency response when compared with experimental results. The inclusion of squeeze film damping between the beam and PZT support enables the model to predict frequency response. Experiments show that mounting the PZT with soft carbon tape limits PZT vibration.

Reduction of squeeze-film damping in a wafer-level encapsulated RF MEMS DC shunt switch

2011 ◽  
Vol 171 (2) ◽  
pp. 118-125
Author(s):  
Feixiang Ke ◽  
Jianmin Miao ◽  
Chee Wee Tan
Keyword(s):  
Rf Mems ◽  
Squeeze Film ◽  
Wafer Level ◽  
Squeeze Film Damping

Squeeze film damping effect on the dynamic response of a MEMS torsion mirror

1998 ◽  
Vol 8 (3) ◽  
pp. 200-208 ◽  
Author(s):  
Feixia Pan ◽  
Joel Kubby ◽  
Eric Peeters ◽  
Alex T Tran ◽  
Subrata Mukherjee
Keyword(s):  
Dynamic Response ◽  
Squeeze Film ◽  
Damping Effect ◽  
Squeeze Film Damping

A Fully Coupled FEM Model of Electromechanically Actuated MEMS With Squeeze Film Damping

2009 ◽  
Author(s):  
Stephan D. A. Hannot ◽  
Daniel J. Rixen
Keyword(s):  
Rf Mems ◽  
Squeeze Film ◽  
Fem Model ◽  
Mems Switch ◽  
Squeeze Film Damping ◽  
Air Damping ◽  
Mems Resonators ◽  
Fluid Damping ◽  
Frequency Behavior ◽  
Damping Model

A specific type of Microsystems or MEMS is the so called RF-MEMS switch. In contrast to MEMS resonators switches generally do not operate in a vacuum. Therefore at the small scales of MEMS fluid (or air) damping is the most dominant damping form. This means that if one is interested in transient or frequency behavior a proper damping model is required. This paper presents a way of using the non-linear Reynolds equation to model the squeeze film damping that is often the type of fluid damping present in these switches. The formulation is provided ready for FEM implementation. Also the tangent matrices required for linearized eigen frequencies are derived. The equations are tested on a model of simple micro switch. The results show that with this model it is possible to predict the damped motion as well as the frequency behavior. The frequency results also show that damping shifts the zero frequency point away from the pull-in point. With a simple mechanical contact model it is also possible to model the closing and opening transient of a microsystem.

Squeeze-Film Damping of Flexible Microcantilevers at Low Ambient Pressures

2008 ◽  
Author(s):  
Jin Woo Lee ◽  
Arvind Raman ◽  
Hartono Sumali
Keyword(s):  
Natural Frequencies ◽  
Ambient Pressure ◽  
Slip Boundary Condition ◽  
Squeeze Film ◽  
Continuum Models ◽  
Inertia Effect ◽  
Quality Factors ◽  
Slip Boundary ◽  
Squeeze Film Damping ◽  
Oscillating Plate

An improved theoretical approach is presented to calculate and predict the quality factors of flexible microcantilevers affected by squeeze-film damping at low ambient pressures, and moderate to high Knudsen numbers. Veijola’s model [1], originally derived for a rigid oscillating plate near a wall, is extended to a flexible cantilever beam and both the gas inertia effect and slip boundary condition are considered in deriving resulting damping pressure. The model is used to predict the natural frequencies and quality factors of silicon microcantilevers with small gaps and their dependence on ambient pressure. In contrast to non-slip, continuum models, we find that quality factor depends strongly on ambient pressure, and that the damping of higher modes is more sensitive to ambient pressure than the fundamental.

A Study of Non-Uniform SPST RF-MEMS Switch under the Effect of Squeeze Film Damping

2013 ◽  
Vol 339 ◽  
pp. 157-162
Author(s):  
Omar A. Awad ◽  
Ameen El-Sinawi ◽  
Maher Bakri-Kassem ◽  
Taha Landolsi
Keyword(s):  
Rf Mems ◽  
Mode Shapes ◽  
Squeeze Film ◽  
Rf Mems Switch ◽  
Mems Switch ◽  
Squeeze Film Damping ◽  
Squeeze Film Effect ◽  
Proposed Model ◽  
Modal Model ◽  
Hankel Norm

This work presents a practical technique that can be used to construct the dynamic model of any RF MEMS switch regardless of its shape. The presented technique also allows for inclusion of squeeze film effect in the model without resorting to complex mathematical development of the latter. The technique utilizes Finite element methods to determine mode shapes and natural frequencies of the switch. A modal-model is then constructed from the FEA results. The model can be reduced using by retaining modes with highest Hankel norm modes to reduce calculations effort associated with large models. Simulation results have shown that the proposed model has merit and agrees with published experimental data.

Simulation of the Squeeze Film Damping in a RF MEMS Switch

2013 ◽  
Vol 427-429 ◽  
pp. 116-119
Author(s):  
Xiang Guang Li ◽  
Qin Wen Huang ◽  
Yun Hui Wang
Keyword(s):  
Surface Pressure ◽  
Reynolds Equation ◽  
Dynamic Models ◽  
Mechanical Response ◽  
Rf Mems ◽  
Squeeze Film ◽  
Damping Force ◽  
Rf Mems Switch ◽  
Mems Switch ◽  
Squeeze Film Damping

Two different dynamic models have been presented to investigate the transient mechanical response of a RF MEMS switch under the effects of squeeze-film damping based on a modified Reynolds equation. Both the perforated and non-perforated structures are built for comparison. The models include realistic dimensions. The surface pressure, the damping force, and the tip displacement are simulated in three different ambient pressures, such as 500Pa, 5kPa, and 0.05MPa. The result shows that the increased damping leads to a substantial decrease in oscillation with increasing pressure for the non-perforated structure. Compared with the perforated pad, there is a much larger damping force acts on the non-perforated surface, and an obvious decrease in damping force with increasing pressure.

DYNAMIC PULL-IN INSTABILITY AND VIBRATION ANALYSIS OF A NONLINEAR MICROCANTILEVER GYROSCOPE UNDER STEP VOLTAGE CONSIDERING SQUEEZE FILM DAMPING

2013 ◽  
Vol 05 (03) ◽  
pp. 1350032 ◽  
Author(s):  
M. MOJAHEDI ◽  
M. T. AHMADIAN ◽  
K. FIROOZBAKHSH
Keyword(s):  
Differential Equations ◽  
Natural Frequencies ◽  
Proof Mass ◽  
Dynamic Instability ◽  
Squeeze Film ◽  
Electrostatically Actuated ◽  
Damping Coefficients ◽  
Step Voltage ◽  
Runge Kutta Method ◽  
Squeeze Film Damping

In this paper, a nonlinear model is used to analyze the dynamic pull-in instability and vibrational behavior of a microcantilever gyroscope. The gyroscope has a proof mass at its end and is subjected to nonlinear squeeze film damping, step DC voltages as well as base rotation excitation. The electrostatically actuated and detected microgyroscopes are subjected to coupled flexural-flexural vibrations that are related by base rotation. In order to detune the stiffness and natural frequencies of the system, DC voltages are applied to the proof mass electrodes in drive and sense directions. Nonlinear integro differential equations of the system are derived using extended Hamilton principle considering nonlinearities in curvature, inertia, damping and electrostatic forces. Afterward, the Gelerkin decomposition method is implemented to reduce partial differential equations of microgyroscope deflection to a system of nonlinear ordinary equations. By using the 4th order Runge–Kutta method, the nonlinear ordinary equations are solved for various values of damping coefficients, air pressures, base rotation and various initial gaps between the proof mass electrodes and the substrates. Results show that the geometric nonlinearity increases the dynamic pull-in voltage and also consideration of the base rotation gives an improved evaluation of the dynamic instability. It is shown that the squeeze film damping has a considerable influence on the dynamic deflection of the microgyroscopes.

Dynamic Analysis of Micro Devices with Squeeze-Film Damping Effect Using Hybrid Numerical Scheme

2013 ◽  
Vol 811 ◽  
pp. 474-477
Author(s):  
Chin Chia Liu
Keyword(s):  
Dynamic Response ◽  
Numerical Scheme ◽  
Coupling Effect ◽  
Electrostatic Force ◽  
Transformation Method ◽  
Squeeze Film ◽  
Damping Effect ◽  
Squeeze Film Damping ◽  
Fringing Field Effect ◽  
Electrostatic Coupling

Using traditional methods such as perturbation theory or Galerkin approach method to analyze the dynamic response of electrostatic devices is not easy due to the complexity of the interactions between the electrostatic coupling effect, the fringing field effect, the residual stress, the nonlinear electrostatic force and squeeze-film damping effect. Accordingly, the present study proposes a new approach for analyzing the dynamic response of such devices using a hybrid numerical scheme comprising the differential transformation method and the finite difference method by pure DC or combined DC / AC loading. The validity of the proposed scheme is confirmed by comparing the results obtained for the pull-in voltage of the micro-beam with those presented in the literature derived using a variety of schemes. Overall, the results show that the hybrid numerical scheme provides a suitable means of analyzing the nonlinear dynamic behavior of a wide variety of common electrostatically-actuated microstructures.

Sign in / Sign up

Export Citation Format

Share Document