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#### Performance of valveless diffuser micropumps under harmonic piezoelectric actuation

, Article 8th Biennial ASME Conference on Engineering Systems Design and Analysis, ESDA2006, Torino, 4 July 2006 through 7 July 2006 ; Volume 2006 , 2006 ; 0791837793 (ISBN); 9780791837795 (ISBN) ; Saidi, M. H ; Mehrabian, A ; Bazargan, M ; Kenarsari, S. D ; Sharif University of Technology
American Society of Mechanical Engineers
2006

Abstract

Valveless piezoelectric micropumps are in wide practical use due to their ability to conduct particles with absence of interior moving mechanical parts. The objective of this paper is to obtain the fluid flow response to actuation frequency of a passive diffuser valve under harmonic pressures. In this regards a 2D model of a micropump valves and chambers is analyzed. The analysis is performed for 10Kpa back pressure on micropump chamber and actuation frequencies within the range of 1Hz to 10 KHz. Results show the highest velocity in the direction of diffuser axis occurs at the narrow diffuser neck while flow direction reverses every half period. For low frequencies, a parabolic velocity...

#### Effect of actuation frequency on the performance of diffuser micropumps

, Article 4th International Conference on Nanochannels, Microchannels and Minichannels, ICNMM2006, Limerick, 19 June 2006 through 21 June 2006 ; Volume 2006 B , 2006 , Pages 725-731 ; 0791847608 (ISBN); 9780791847602 (ISBN) ; Ahmadian, M. T ; Sharif University of Technology
2006

Abstract

Valveless piezoelectric micropumps are in wide practical use due to their ability to conduct particles with absence of interior moving mechanical parts. The objective of this paper is to obtain the fluid flow response to actuation frequency of a passive diffuser valve under harmonic pressures. In this regards a 2D model of a micropump valves and chambers is analyzed. The analysis is performed for 10Kpa back pressure on micropump chamber and actuation frequencies within the range of 1 Hz to 10 KHz. Results show the highest velocity in the direction of diffuser axis occurs at the narrow diffuser neck while flow direction reverses every half period. For low frequencies, a parabolic velocity...

#### Simplified modeling and generalized predictive position control of an ultrasonic motor

, Article ISA Transactions ; Volume 44, Issue 2 , 2005 , Pages 273-282 ; 00190578 (ISSN) ; Haeri, M ; Sharif University of Technology
ISA - Instrumentation, Systems, and Automation Society
2005

Abstract

Ultrasonic motors (USM's) possess heavy nonlinear and load dependent characteristics such as dead-zone and saturation reverse effects, which vary with driving conditions. In this paper, behavior of an ultrasonic motor is modeled using Hammerstein model structure and experimental measurements. Also, model predictive controllers are designed to obtain precise USM position control. Simulation results indicate improved performance of the motor for both set point tracking and disturbance rejection. © 2005 ISA - The Instrumentation, Systems, and Automation Society

#### Nonlinear modeling of piezoelectric layered beams

, Article Active and Passive Smart Structures and Integrated Systems 2007, San Diego, CA, 19 March 2007 through 22 March 2007 ; Volume 6525 , 2007 ; 0277786X (ISSN) ; Jalili, N ; Meghdari, A ; Sharif University of Technology
2007

Abstract

The dynamic equations of piezoelectric benders are studied in this paper, considering nonlinear behavior of piezoceramics. A second order approximation of constitutive equations of piezoceramics is used to account for reversible nonlinearities. Transversal and longitudinal deflections at the tip of the beam and the blocking force as well as sensor equations (output charge as a function of external loads) are obtained under static conditions. The static equations are then used to construct a linear dynamic model for actuation. A Bouc-Wen type hysteresis model is employed in order to account for the irreversible nonlinearities. The final equation of motion is in the form of well-known Hill's...

#### System identification techniques of smart structures with piezoelements

, Article 17th IASTED International Conference on Modelling and Simulation, Montreal, QC, 24 May 2006 through 26 May 2006 ; Volume 2006 , 2006 , Pages 534-539 ; 10218181 (ISSN) ; 0889865949 (ISBN); 9780889865945 (ISBN) ; Yousefi Koma, A ; Khanmirza, E ; Sharif University of Technology
2006

Abstract

Analytical and numerical system identification (system ID) techniques of smart structures with piezoelements are introduced and compared in this paper. Simplicity and low cost of numerical system ID methods developed here make them beneficial in control design and implementation as well as in optimization of location and size of actuators and sensors of the smart structure. The accuracy of these techniques is then verified using analytical system ID, which derives the dynamic model of the structure from differential equations. In the first numerical system ID technique, Finite Element Method (FEM) is employed to model the dynamic system and to obtain the Frequency Response Function (FRF)....

#### A piezoelectric-inhomogeneity system with imperfect interface

, Article International Journal of Engineering Science ; Volume 44, Issue 5-6 , 2006 , Pages 291-311 ; 00207225 (ISSN) ; Tabatabaei, S. M ; Kamali, M. T ; Sharif University of Technology
2006

Abstract

This paper examines the electro-mechanical fields for a circular anisotropic piezoelectric fiber sensor inside an anisotropic piezoelectric or non-piezoelectric elastic matrix with imperfect interface under remote in-plane uniform tension. The interface imperfection is posed on the mechanical fields only. The present formulation admits different boundary value problems in a unified manner, so various fiber-matrix interface conditions are considered: (1) perfect bonding; (2) pure debonding; (3) in-plane pure sliding; (4) out-of-plane pure sliding; (5) full debonding; and (6) partial debonding. An interface condition is modeled by a specific layer of mechanical springs with vanishing...

#### Closed-loop finite element modeling for analysis of smart structures in ansys environment

, Article 2006 ASME International Mechanical Engineering Congress and Exposition, IMECE2006, Chicago, IL, 5 November 2006 through 10 November 2006 ; 2006 ; 10716947 (ISSN); 0791837904 (ISBN); 9780791837900 (ISBN) ; Shahidi, A ; Abedian, A ; Meghdari, A ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2006

Abstract

It would be promising if one can simulate the closed-loop behavior of a smart system in an available FEM software such as "ANSYS". The ANSYS/Multiphysics software has the ability of coupling different physical domains and also modeling smart materials such as piezoelectric and piezoresistives, i.e. it has the capability of modeling smart structures. The dynamic modeling of the controlled structures is then realized by the ANSYS programming tool. This aspect highly facilitates the overall system behavior analysis and at the same time various control methods can be tested without noticing the time consuming structural analysis involved. In this research work, it is tried the mentioned idea to...

#### A new model for dynamic analysis of side mounted diffuser valve micropumps

, Article 8th Biennial ASME Conference on Engineering Systems Design and Analysis, ESDA2006, Torino, 4 July 2006 through 7 July 2006 ; Volume 2006 , 2006 ; 0791837793 (ISBN); 9780791837795 (ISBN) ; Mehrabian, A ; Sharif University of Technology
American Society of Mechanical Engineers
2006

Abstract

Valveless micropumps are widely used due to simple structure, durability and low maintenance. Understanding the fluid-membrane interaction and performance criteria is still a challenging problem for the scientists. In this work, a new model for side mounted valve micropumps is developed to obtain dynamic response of micropump with respect to piezoelectric actuation. The parameters of this model are obtained in terms of actuation frequency and geometrical dimensions of the micropump. Balancing elastic, inertial and damping forces result in the governing equation of the micropump system model. Analytical studies for the bottom mounted valve micropump indicate pump flux is independent of the...

#### Optimal feedback-adaptive feedforward controller for vibration suppression of a cantilever beam using piezo-actuators

, Article 8th Biennial ASME Conference on Engineering Systems Design and Analysis, ESDA2006, Torino, 4 July 2006 through 7 July 2006 ; Volume 2006 , 2006 ; 0791837793 (ISBN); 9780791837795 (ISBN) ; Sayyaadi, H ; Behzad, M ; Sharif University of Technology
American Society of Mechanical Engineers
2006

Abstract

In this paper the combined optimal feedback-adaptive feedforward controller proposed to attain better performance of active vibration suppression of flexible structures subjected to different type of disturbances. The structure considered here is a cantilever beam actuated with a PZT patch actuator. The proposed controller consists of two individual parts, a filtered-x controller as a feedforward part and an optimal linear controller as a feedback part. Recursive Least Square algorithm (RLS) is used for the adaptive filtering scheme in Filtered-x adaptive feedforward controller. LQG optimal controller is also used in the feedback part of the controller. This research investigates the...

#### Modeling and optimization of an elliptical shape ultrasonic motor using combination of finite element method and design of experiments

, Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 12 November 2010 through 18 November 2010, Vancouver, BC ; Volume 8, Issue PARTS A AND B , 2010 , Pages 491-496 ; 9780791844458 (ISBN) ; Akbari, J ; Shahidi, A. R ; Darki, A. A ; Sharif University of Technology
2010

Abstract

Standing-wave ultrasonic motors are a modern class of positioning systems, which are used to deliver a high precision linear or rotary motion with an unlimited stroke. The design process should be performed through an effective optimization algorithm in order to guaranty proper and efficient function of these motors. An optimization method of ultrasonic motors is proposed based on the combination of finite element method and factorial design as a design of experiments in this study. The results show the ability of this method in optimal design of ultrasonic motors especially those which have a complex structure and multi modes operation principle

#### The scattering of P-waves by a piezoelectric particle with FGPM interfacial layers in a polymer matrix

, Article International Journal of Solids and Structures ; Volume 47, Issue 18-19 , 2010 , Pages 2390-2397 ; 00207683 (ISSN) ; Shodja, H. M ; Sharif University of Technology
2010

Abstract

Propagation of P-wave in an unbounded elastic polymer medium which contains a set of nested concentric spherical piezoelectric inhomogeneities is formulated. The polymer matrix is made of Epoxy and is isotropic; each phase of the inhomogeneity is made of a different piezoelectric material and is radially polarized and has spherical isotropy. Note that the individual phases are homogeneous, and all interfaces are perfectly bonded. The scattered displacement and electric potentials in the matrix are expressed in terms of spherical wave vector functions and Legendre functions, respectively. The transmitted displacement and electric potentials within each phase of the piezoelectric particle are...

#### Finding an unknown object by using piezeoelectric material: A finite element approach

, Article 2nd International Conference on Environmental and Computer Science, ICECS 2009, 28 December 2009 through 30 December 2009, Dubai ; 2009 , Pages 156-160 ; 9780769539379 (ISBN) ; Durali, L ; Zareie, S ; Parvari Rad, F ; Sharif University of Technology
IEEE
2009

Abstract

This paper presents a method to determine material of an unknown sample object. The main objective of this study is to design a database for specifying material of an object. We produce the database for different materials which is subjected to different forces. For this purpose we use a Polyvinidilene Fluoride (PVDF) sensor which is a piezoelectric material. Also we study the effect of changing place of sensor on our study. The detailed design was performed using finite element method analysis. Furthermore, if we have an object which we do not know its material by use of this database we can find out what this object is and how much its Yanoung's modules is. This study will be suitable for...

#### Displacement potentials for functionally graded piezoelectric solids

, Article Applied Mathematical Modelling ; Volume 52 , 2017 , Pages 458-469 ; 0307904X (ISSN) ; Eskandari, M ; Ahmadi, S. F ; Sharif University of Technology
Abstract

Two new displacement potential functions are introduced for the general solution of a three-dimensional piezoelasticity problem for functionally graded transversely isotropic piezoelectric solids. The material properties vary continuously along the axis of symmetry of the medium. The four coupled equilibrium equations in terms of displacements and electric potential are reduced to two decoupled sixth- and second-order linear partial differential equations for the potential functions. The obtained results are verified with two limiting cases: (i) a functionally graded transversely isotropic medium, and (ii) a homogeneous transversely isotropic piezoelectric solid. The simplified relations...

#### Design and experimental evaluation of a precise and compact tubular ultrasonic motor driven by a single-phase source

, Article Precision Engineering ; Volume 48 , 2017 , Pages 172-180 ; 01416359 (ISSN) ; Sarhan, A. A. D ; Akbari, J ; Azizi Mardi, N ; Sharif University of Technology
Elsevier Inc
2017

Abstract

A precise and compact tubular ultrasonic motor driven by a single-phase source is proposed and tested in this study. The motor is designed by modeling a motor stator in FEM software. The motor fabricated according to the design is tested experimentally and its working characteristics including speed and torque are measured and presented. The maximum speed and torque of the motor are 59 rpm and 0.28 mN m at 80 Vpp of applied voltage. The proposed motor possesses advantages such as a simple and compact structure with application in the fields of robotics, space, medical devices and high-resolution stages, among others. The proposed motor is a good candidate for applications where accurate...

#### Frequency domain identification of a tapered beam embedded by piezoelectric layer

, Article 2016 International Conference on Advanced Mechatronic Systems, ICAMechS 2016, 30 November 2016 through 3 December 2016 ; 2017 , Pages 312-317 ; 23250682 (ISSN); 9781509053469 (ISBN) ; Ahranjani, F. F ; Kamankesh, Z ; Sharif University of Technology
IEEE Computer Society
2017

Abstract

This study is conducted aiming to identify the dynamics of a tapered beam, embedded by piezoelectric layer. Narrowing the tip of the beam equipped with piezoelectric patches leads to optimize the output power after excitation by the frequency sweep input. An accelerometer is installed on the beam base, which measures the acceleration that is applied to the system. Piezoelectric sensors also measure the generated voltage. The experimental test data is handled through CIFER software, using Fourier transform and Bode plot in the frequency domain, to obtain appropriate transfer functions. MATLAB is used for nonlinear simulation and validation of discrete transfer functions by a set of data that...

#### Optimization of the shaping function of a tapered piezoelectric energy harvester using tabu continuous ant colony system

, Article Journal of Intelligent Material Systems and Structures ; Volume 30, Issue 20 , 2019 , Pages 3025-3035 ; 1045389X (ISSN) ; Rahimi, G. H ; Saraygord Afshari, S ; Sharif University of Technology
SAGE Publications Ltd
2019

Abstract

During the past years, the development of piezoelectric energy harvesters is extensively increased for providing the required energy of sensor nodes. It has been proven that changing the beam’s cross-section along its length direction may lead to extract more power with less mass. In this article, a hybrid metaheuristic algorithm called tabu continuous ant colony system is employed to optimize the tapered piezoelectric energy harvester in a fast and course manner. The exponential and fourth-order polynomial functions are considered as shaping functions for tapering the beam’s width along its length direction. An experiment is also set up to evaluate the performance of the optimization...

#### Using piezoelectric materials to control the dynamic response of a thin rectangular plate under moving mass

, Article 11th East Asia-Pacific Conference on Structural Engineering and Construction, EASEC-11, Taipei, 19 November 2008 through 21 November 2008 ; January , 2008 ; Rofooei, F. R ; Sharif University of Technology
2008

Abstract

The governing differential equation of motion for an undamped thin rectangular plate with a number of bonded piezoelectric patches on its surface, and arbitrary boundary conditions are derived using Hamilton's principle. A moving mass traveling on an arbitrary trajectory acts as an external excitation for the system. The effect of moving mass inertia is considered using all the out-of-plane translational acceleration components. The method of eigenfunction expansion is used to decouple the equation of motion into a number of coupled ordinary differential equations. A classical closed loop optimal control algorithm is employed to suppress the dynamic response of the system by determining the...

#### Fatigue damage detection in large thin wall plate based on ultrasonic guided wave by using a piezoelectric sensor network

, Article 29th Congress of the International Council of the Aeronautical Sciences, ICAS 2014 ; 2014 ; Abedian, A ; Sharif University of Technology
Abstract

Today, structural Health monitoring is a major concern in the engineering community. Multisite fatigue damage, hidden cracks and corrosion in hard-to-reach locations are among the major flaws encountered in today's extensive diagnosis and/or prognosis of aircraft structures. Ultrasonic waves, lamb waves are particularly advantageous because of their propagation at large distances with little damp in thin-wall structures. In this paper a new rectangular shape array of embedded piezoelectric sensors is developed to detect some damages in large planar structures. An artificial neural network is trained to identify the damage state and its location. Output signals of each sensor due to various...

#### Electromechanical modeling and analytical investigation of nonlinearities in energy harvesting piezoelectric beams

, Article International Journal of Mechanics and Materials in Design ; 2016 , Pages 1-16 ; 15691713 (ISSN) ; Ahmadian, M. T ; Zohoor, H ; Sharif University of Technology
Springer Netherlands
2016

Abstract

Piezoelectric materials are extensively applied for vibrational energy harvesting especially in micro-scale devices where other energy conversion mechanisms such as electromagnetic and electrostatic methods encounter fabrication limitations. A cantilevered piezoelectric bimorph beam with an attached proof (tip) mass for the sake of resonance frequency reduction is the most common structure in vibrational harvesters. According to the amplitude and frequency of applied excitations and physical parameters of the harvester, the system may be pushed into a nonlinear regime which arises from material or geometric nonlinearities. In this study nonlinear dynamics of a piezoelectric bimorph harvester...

#### Electromechanical modeling and analytical investigation of nonlinearities in energy harvesting piezoelectric beams

, Article International Journal of Mechanics and Materials in Design ; Volume 13, Issue 4 , 2017 , Pages 499-514 ; 15691713 (ISSN) ; Ahmadian, M. T ; Zohoor, H ; Sharif University of Technology
Abstract

Piezoelectric materials are extensively applied for vibrational energy harvesting especially in micro-scale devices where other energy conversion mechanisms such as electromagnetic and electrostatic methods encounter fabrication limitations. A cantilevered piezoelectric bimorph beam with an attached proof (tip) mass for the sake of resonance frequency reduction is the most common structure in vibrational harvesters. According to the amplitude and frequency of applied excitations and physical parameters of the harvester, the system may be pushed into a nonlinear regime which arises from material or geometric nonlinearities. In this study nonlinear dynamics of a piezoelectric bimorph harvester...