G Rezazadeh
Mechanical Engineering Department, Urmia University
[ 1 ] - Thermo-elastic Damping in a Capacitive Micro-beam Resonator Considering Hyperbolic Heat Conduction Model and Modified Couple Stress Theory
In this paper, the quality factor of thermo-elastic damping in an electro-statically deflected micro-beam resonator has been investigated. The thermo-elastic coupled equations for the deflected micro-beam have been derived using variational and Hamilton principles based on modified couple stress theory and hyperbolic heat conduction model. The thermo-elastic damping has been obtained discretizi...
[ 2 ] - Effect of Electric Potential Distribution on Electromechanical Behavior of a Piezoelectrically Sandwiched Micro-Beam
The paper deals with the mechanical behavior of a micro-beam bonded with two piezoelectric layers. The micro-beam is suspended over a fixed substrate and undergoes the both piezoelectric and electrostatic actuation. The piezoelectric layers are poled through the thickness and equipped with surface electrodes. The equation governing the micro-beam deflection under electrostatic pressure is deriv...
[ 3 ] - Study Of Thermoelastic Damping in an Electrostatically Deflected Circular Micro-Plate Using Hyperbolic Heat Conduction Model
Thermoelastic damping (TED) in a circular micro-plate resonator subjected to an electrostatic pressure is studied. The coupled thermo-elastic equations of a capacitive circular micro plate are derived considering hyperbolic heat conduction model and solved by applying Galerkin discretization method. Applying complex-frequency approach to the coupled thermo-elastic equations, TED is obtained for...
[ 4 ] - Mechanical Behavior of a FGM Capacitive Micro-Beam Subjected to a Heat Source
This paper presents mechanical behavior of a functionally graded (FG) cantilever micro-beam subjected to a nonlinear electrostatic pressure and thermal moment considering effects of material length scale parameters. Material properties through the beam thickness direction are graded. The top surface of the micro-beam is made of pure metal and the bottom surface from a mixture of metal and ceram...
[ 5 ] - Dynamic Characteristics and Vibrational Response of a Capacitive Micro-Phase Shifter
The objective of this paper is to control the phase shifting by applying a bias DC voltage and changing the mechanical characteristics in electrostatically-actuated micro-beams. This problem can be more useful in the design of micro-phase shifters, which has not generally been investigated their mechanical behavior. By presenting a mathematical modeling, Galerkin-based step by step linearizatio...
[ 6 ] - Mechanical Behavior of an Electrostatically-Actuated Microbeam under Mechanical Shock
In this paper static and dynamic responses of a fixed-fixed microbeam to electrostatic force and mechanical shock for different cases have been studied. The governing equations whose solution holds the answer to all our questions about the mechanical behavior is the nonlinear elasto-electrostatic equations. Due to the nonlinearity and complexity of the derived equations analytical solution are ...
[ 7 ] - Study of Volumetric Flow Rate of a Micropump Using a Non-classical Elasticity Theory
The purpose of this research is to study the mechanical behavior of a micropump with clamped circular diaphragm which is the main component of drug delivery systems. In this paper, the non-linear governing equations of the circular microplate using Kirchhoff thin plate theory was been extracted based on the modified couple stress (MCST) and classical (CT) theories. Then, the non-linear equation...
[ 8 ] - Quality Factor of Free In-plane Vibration of a Fully Clamped Rectangular Micro-plate
Thermo-elastic damping is a significant dissipation mechanism in high quality factor microstructures. In this paper, thermo-elastic damping of the in-plane vibration of fully clamped rectangular micro-plates has been studied. The governing equation of the micro-plate motion and heat conduction equation were derived. Then, The Galerkin method has been used to solve the coupled heat-displacement ...
[ 9 ] - Stabilization of Electrostatically Actuated Micro-pipe Conveying Fluid Using Parametric Excitation
This paper investigates the parametric excitation of a micro-pipe conveying fluid suspended between two symmetric electrodes. Electrostatically actuated micro-pipes may become unstable when the exciting voltage is greater than the pull-in value. It is demonstrated that the parametric excitation of a micro-pipe by periodic (ac) voltages may have a stabilizing effect and permit an increase of the...
[ 10 ] - Couple Stress Effect on Micro/Nanocantilever-based Capacitive Gas Sensor
Micro/nanocantilevers have been employed as sensors in many applications including chemical and biosensing. Due to their high sensitivity and potential for scalability, miniature sensing systems are in wide use and will likely become more prevalent in micro/nano-electromechanical systems (M-NEMSs). This paper is mainly focused on the use of sensing systems that employ micro/nano-size cantilever...
[ 11 ] - Vibration Analysis of Circular Magneto-Electro-Elastic Nano-plates Based on Eringen s Nonlocal Theory
The present work mainly studies the free vibration of circular magneto-electro-elastic (MEE) nano-plates based on the Kirchhoff’s plate theory within the framework of nonlocal elasticity theory to account for the small scale effect. The MEE nano-plate studied here is considered to be fully clamped and subjected to the external magnetic and electric potentials. Using nonlocal constitutive relati...
[ 12 ] - Design of Direct Exponential Observers for Fault Detection of Nonlinear MEMS Tunable Capacitor
In this paper a novel method is proposed for construction of an exponential observer for nonlinear system. The presented method is based on direct solution of dynamic error without any linearzing of nonlinear terms. Necessary and sufficient conditions for construction of direct observer are presented. Stability of the observer is checked using Lyapunov theorem. Also the ability of this observer...
[ 13 ] - Application of Thau Observer for Fault Detection of Micro Parallel Plate Capacitor Subjected to Nonlinear Electrostatic Force
This paper investigates the fault detection of a micro parallel plate capacitor subjected to nonlinear electrostatic force. For this end Thau observer, which has good ability in fault detection of nonlinear system has been presented and governing nonlinear dynamic equation of the capacitor has been presented. Upper and lower threshold for fault detection have been obtained. The robustness of th...
[ 14 ] - Investigation of Thermoelastic Damping in the Longitudinal Vibration of a Micro Beam
In the design of high Quality factor (Q) micro or nano beam resonators, different dissipation mechanisms may have damaging effects on the quality factor. One of the major dissipation mechanisms is the thermoelastic damping (TED) that needs an accurate consideration for prediction. In this paper, thermoelastic damping of the longitudinal vibration of a homogeneous micro beam with both ends clamp...
[ 15 ] - Static Pull-in Analysis of Capacitive FGM Nanocantilevers Subjected to Thermal Moment using Eringen’s Nonlocal Elasticity
This paper aims to investigate the pull-in phenomenon of functionally graded (FG) capacitive nanocantilevers subjected to an electrostatic force and thermal moment due to an applied voltage and thermal shock considering intermolecular force within the framework of nonlocal elasticity theory to account for the small scale effect. The FG nano-beam is made of mixture of metal and ceramic which the...
[ 16 ] - Effect of Length-scale Parameter on Pull-in Voltage and Natural Frequency of a Micro-plate
This paper deals with the effect of the intrinsic material length-scale parameter on the stability and natural frequency of a rectangular micro-plate for two different cases; fully clamped and fully simply supported. A variational formulation based on Hamilton’s principle and the modified couple stress theory is used to obtain the nonlinear governing equation of a micro-plate incorporating the ...
[ 17 ] - Thermo-Elastic Damping in Nano-beam Resonators Based on Nonlocal Theory
In this article thermoelastic damping in nano-beam resonators is investigated based on nonlocal theory of elasticity and the Euler-Bernoulli beam assumptions. The governing equation of deflection of the beam is obtained from shear and moment resultants and stress–strain relationship of the nonlocal elasticity model and also the governing equations of thermoelastic damping are established by usi...
[ 18 ] - Mechanical Response of a Piezoelectrically Sandwiched Nano-Beam Based on the Non-Local Theory
This article deals with the mechanical analysis of a fixed-fixed nano-beam based on nonlocal elasticity theory. The nano-beam is sandwiched with two piezoelectric layers through it’s upper and lower sides. The electromechanical coupled equations governing the problem are derived based nonlocal theory considering to Euler-Bernoulli beam assumptions and based on the nonlocal piezoelectricity acco...
[ 19 ] - STATIC AND DYNAMIC RESPONSE OF CARBON NANOTUBE-BASED NANOTWEEZERS
In this paper static and dynamic response of nanotweezers composed of two carbon nanotube (CNT) arms are investigated. Taking into account a continuum model and considering the electrostatic actuation as well as the presence of the van der Waals forces, the static nonlinear equations are solved by a step by step linearization and Galerkin projection method. Simulating the closing dynamics of a ...
[ 20 ] - Generating and Focusing the Ultrasound Waves Using Elastomer-based Capacitive Micro-Speakers
Ultrasound wave is a kind of waves with the frequency higher than the human audible frequency. Although ultrasound was first used for military identification purposes, it has been used for decades for various other applications, especially medical applications. Medical applications of ultrasound include diagnostic and therapeutic applications, such as for the treatment of cancer. In this paper,...
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