Record Details

Study Of Squeeze Film Effects In Modelling Dynamic MEMS Devices

Electronic Theses of Indian Institute of Science

View Archive Info
 
 
Field Value
 
Title Study Of Squeeze Film Effects In Modelling Dynamic MEMS Devices
 
Creator Mohite, Suhas
 
Subject Microelectromechanical Devices
Squeeze Film Effects
Microelectromechanical Devices - Modelling
Squeeze Film Model
Equivalent Circuits
Simulink Models
MEMS Device
Squeeze Films
Electromechanical Engineering
 
Description We present studies on squeeze film effects in dynamic MEMS devices with a special emphasis on the development of compact analytical models.
First, the efficacy of lumped parameter modelling of dynamic MEMS devices is illustrated in MATLAB/SIMULINK software environment using a MEMS gyroscope and a MEMS microphone as examples. This is followed by a comparative study of equivalent electrical circuit models for a MEMS microphone wherein the importance of accurate extraction of lumped mass, stiffness and damping is brought into focus. In this context, a need for an in depth study of squeeze film behaviour in MEMS structures is highlighted and a strong motivation is drawn for the development of compact squeeze film models.
A 2D analytical model for estimating squeeze film damping and spring force in perforated MEMS structures is presented. The governing equations based on isothermal compressible Reynolds equation are derived by considering an approximate circular pressure cell around a hole which is representative of the spatially invariant pressure pattern over the interior of the flow domain. The advantages and limitations of the solution are discussed with relevance to MEMS structures.
Next, a comprehensive analytical model for 3D MEMS structures that includes effects of compressibility, inertia, and rarefaction in the flow between two parallel plates forming the squeeze region as well as the flow through perforations is developed. A modified Reynolds equation that includes the unsteady inertial term is derived from the Navier-Stokes equation to model the flow in the circular cell and the losses through the holes are modelled using Poiseuille flow. Rarefaction effects in the flow through the air-gap as well as the holes are accounted for by considering the slip boundary conditions. The analytical results are compared with extensive numerical simulations carried out using full 3-D Navier-Stokes equation solver in a commercial simulation package (ANSYS-CFX). We show that the analytical solution performs very well in tracking the net force
up to the first resonant frequency of the entrapped air.
 
Contributor Pratap, Rudra
 
Date 2011-02-21T06:59:56Z
2011-02-21T06:59:56Z
2011-02-21
2007-09
 
Type Thesis
 
Identifier http://hdl.handle.net/2005/1072
 
Language en_US
 
Relation G21676