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Thermoviscous Acoustic Effects in MEMS.

Naderyan, Vahid.

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Thermoviscous Acoustic Effects in MEMS.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Thermoviscous Acoustic Effects in MEMS./
Author:	Naderyan, Vahid.
Published:	Ann Arbor : ProQuest Dissertations & Theses, : 2020,
Description:	86 p.
Notes:	Source: Dissertations Abstracts International, Volume: 82-08, Section: B.
Contained By:	Dissertations Abstracts International82-08B.
Subject:	Physics. -
Online resource:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10230698
ISBN:	9798569980932

Thermoviscous Acoustic Effects in MEMS.
Naderyan, Vahid.

Thermoviscous Acoustic Effects in MEMS. - Ann Arbor : ProQuest Dissertations & Theses, 2020 - 86 p.

Source: Dissertations Abstracts International, Volume: 82-08, Section: B.

Thesis (Ph.D.)--The University of Mississippi, 2020.

This item must not be sold to any third party vendors.

In this study, the thermal and viscous effects in perforated micro-electro-mechanical systems (MEMS) are investigated. The low-reduced frequency (LRF) method is employed to develop solutions for the damping and spring force coefficients that include all the relevant physical aspects of the problem. The presented model is based on a full-plate approach that accurately takes into account the geometry and the boundary conditions of the system. First, the thermoviscous acoustic LRF formulation is used to develop solutions for non-perforated parallel-plate MEMS with a small gap compared to the lateral dimensions. Then the model is extended to the perforated MEMS by taking into account the finite impedance of the perforated back-plate. Particularly, the end effects of the perforations are studied extensively and formulae are developed for the reactive and resistive end corrections. The model assumes a rigid diaphragm with a piston-like motion, due to its simplicity. However, in reality, the diaphragms are flexible and have a flexible motion depending on their geometry and boundary conditions. Next, the models are extended to include the effect of the flexibility of the moving diaphragm. Solutions are derived for circular structures with both open-edge and closed-edge boundaries which are most common among the MEMS microphones. For all cases, frequency domain thermoviscous acoustic finite-element analysis (FEA) has been conducted. The derived analytical solutions are compared with the FEA results and other models in the literature. All of the analytical solutions derived from the LRF method provide good agreements with the FEA results for a wide range of parameters for both damping and spring force coefficients. Finally, an experimental procedure is introduced to measure the damping coefficient of two types of perforated circular MEMS. The measured results for all cases have a very good agreement with the analytical results (within 6%) for all samples, which validates the accuracy of the proposed LRF model. Although specific cases are studied in this dissertation, the presented LRF framework can be used to derive solutions for various geometries and boundary conditions. The presented model provides a simple analytical tool for better understanding and calculation of the thermoviscous effects in perforated MEMS that can be used as a predictive model for design improvement of the performance of the MEMS devices.

ISBN: 9798569980932Subjects--Topical Terms:

516296
Physics.
Subjects--Index Terms:

Acoustics

Thermoviscous Acoustic Effects in MEMS.
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100 1 $a Naderyan, Vahid. $3 3192827
245 1 0 $a Thermoviscous Acoustic Effects in MEMS.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2020
300 $a 86 p.
500 $a Source: Dissertations Abstracts International, Volume: 82-08, Section: B.
500 $a Advisor: Raspet, Richard;Hickey, Craig.
502 $a Thesis (Ph.D.)--The University of Mississippi, 2020.
506 $a This item must not be sold to any third party vendors.
520 $a In this study, the thermal and viscous effects in perforated micro-electro-mechanical systems (MEMS) are investigated. The low-reduced frequency (LRF) method is employed to develop solutions for the damping and spring force coefficients that include all the relevant physical aspects of the problem. The presented model is based on a full-plate approach that accurately takes into account the geometry and the boundary conditions of the system. First, the thermoviscous acoustic LRF formulation is used to develop solutions for non-perforated parallel-plate MEMS with a small gap compared to the lateral dimensions. Then the model is extended to the perforated MEMS by taking into account the finite impedance of the perforated back-plate. Particularly, the end effects of the perforations are studied extensively and formulae are developed for the reactive and resistive end corrections. The model assumes a rigid diaphragm with a piston-like motion, due to its simplicity. However, in reality, the diaphragms are flexible and have a flexible motion depending on their geometry and boundary conditions. Next, the models are extended to include the effect of the flexibility of the moving diaphragm. Solutions are derived for circular structures with both open-edge and closed-edge boundaries which are most common among the MEMS microphones. For all cases, frequency domain thermoviscous acoustic finite-element analysis (FEA) has been conducted. The derived analytical solutions are compared with the FEA results and other models in the literature. All of the analytical solutions derived from the LRF method provide good agreements with the FEA results for a wide range of parameters for both damping and spring force coefficients. Finally, an experimental procedure is introduced to measure the damping coefficient of two types of perforated circular MEMS. The measured results for all cases have a very good agreement with the analytical results (within 6%) for all samples, which validates the accuracy of the proposed LRF model. Although specific cases are studied in this dissertation, the presented LRF framework can be used to derive solutions for various geometries and boundary conditions. The presented model provides a simple analytical tool for better understanding and calculation of the thermoviscous effects in perforated MEMS that can be used as a predictive model for design improvement of the performance of the MEMS devices.
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653 $a MEMS
653 $a Microphone
653 $a Squeeze-film damping
653 $a Thermoviscous acoustic
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690 $a 0986
710 2 $a The University of Mississippi. $b Physics. $3 3192828
773 0 $t Dissertations Abstracts International $g 82-08B.
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791 $a Ph.D.
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793 $a English
856 4 0 $u https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10230698