M. Sunar
King Fahd University of Petroleum and Minerals
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Applied Mechanics Reviews | 1994
S. S. Rao; M. Sunar
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Applied Mechanics Reviews | 1999
M. Sunar; S. S. Rao
25.00 Purchase Learn about subscription and purchase options Topics: Piezoelectricity , Flexible structures , Piezoelectric materials , Vibration measurement Your Session has timed out. Please sign back in to continue. About ASME Digital Collection Email Alerts Library Service Center ASME Membership Contact Us Publications Permissions /Reprints Privacy Policy Terms of Use
AIAA Journal | 2002
M. Sunar; Ahmed Z. Al-Garni; M. H. Ali; Ramazan Kahraman
Due to their special characteristics, piezoelectric materials can be used in distributed behavior sensing and control of flexible structures. These materials are usually incorporated with the precision sensing and control of highly adaptive intelligent structures. Many theoretical, numerical, and experimental research activities treating piezoelectricity in sensing and control of various flexible structures have been carried out over the last decade. This survey article aims at collecting the recent research studies in this important field. It contains 336 references which are classified according to their applications. A brief theory and history of piezoelectricity is also presented.
AIAA Journal | 1997
M. Sunar; S. S. Rao
Linearconstitutiveequationsofa thermopiezomagneticmedium involving mechanical, electrical, magnetic, and thermal e elds are presented with the aid of a thermodynamic potential. A thermopiezomagnetic medium can be formed by bonding together a piezoelectric and magnetostrictive composite. Two energy functionals are dee ned. It is shown via Hamilton’ s principle that these functionals yield the equations of motion for the mechanical e eld, Maxwell’ s equilibrium equations for the electrical and magnetic e elds, and the generalized heat equation for the thermal e eld. Finite element equations for the thermopiezomagnetic media are obtained by using the linear constitutive equations in Hamilton’ s principle together with the e nite element approximations. The e nite element equations are utilized on an example two-layer smartstructure, which consistsof a piezoceramic (barium titanate ) layer at the bottom and a magnetoceramic (cobalt ferrite ) layer at the top. An electrostatic e eld applied to the piezoceramic layer causes strain in the structure. This strain then produces magnetic e eld in the magnetoceramic layer.
AIAA Journal | 1996
M. Sunar; S. S. Rao
The quasistatic thermopiezoelectricity equations are used to include thermal effects in piezoelectric sensing and control systems. The ® nite element equations are developed for thermopiezoelectric sensor and actuator design. Static and dynamic case studies are carried out to observe the temperature effects in the piezoelectric control systems. Thermal effects are also included in the piezoelectric actuator location problem for the cantilever beamlike problems. It is found that the displacements caused by the temperature effects are important in the precision sensing and control of distributed systems by piezoelectric materials. It is also concluded that for the cantilever beamlike problems, in the presence of a uniformly distributed thermal ® eld, the thermopiezoelectric actuators are to be located closer to the ® xed end for a more effective control of structural oscillations.
AIAA Journal | 1997
M. Sunar; S. S. Rao
Two dimensional thin rectangular elements with pseudointernal degrees of freedom are used to develop the finite element model of piezoelectric materials. The internal DOF are for the better representation of bending moments generated by the feedback piezoelectric voltage and are condensed to the physical nodal DOF using the Guyan reduction technique. The control efficiency effect of the location of the piezoelectric actuator pair on the beam is studied
AIAA Journal | 1993
M. Sunar; S. S. Rao
The quasistatic thermopiezoelectricity equations are used to include thermal effects in piezoelectric sensing and control systems. The ® nite element equations are developed for thermopiezoelectric sensor and actuator design. Static and dynamic case studies are carried out to observe the temperature effects in the piezoelectric control systems. Thermal effects are also included in the piezoelectric actuator location problem for the cantilever beamlike problems. It is found that the displacements caused by the temperature effects are important in the precision sensing and control of distributed systems by piezoelectric materials. It is also concluded that for the cantilever beamlike problems, in the presence of a uniformly distributed thermal ® eld, the thermopiezoelectric actuators are to be located closer to the ® xed end for a more effective control of structural oscillations.
Computer Methods in Applied Mechanics and Engineering | 2001
M. Sunar; S. J. Hyder; B.S. Yilbas
A methodology is developed for the optimal selection of state and input weighting matrices, Q and R, respectively, of the linear quadratic regulator (LQR) method in the integrated design of structures/controls. An optimal control problem is set up in such a way that design variables are the diagonal entries of Q and R; the objective function is the trace of the solution matrix to the algebraic Riccati equation of the LQR method, P matrix; and constraints are imposed on the closed-loop eigenvalues to satisfy minimum stability conditions for the control system. The procedure finds the optimal diagonal Q and I? that enables the actively controlled system to meet the prespecified stability and performance bounds. Furthermore, the resulting Q and R yield the minimum possible performance index and hence the control effort is substantially reduced. The proposed method is integrated with a substructure decomposition scheme which results in substantial savings on the numerical computations with very little loss in the accuracy of the original system response. It is found that for trusslike space structures, the proposed optimization scheme is mostly affected by the changes in the diagonal terms of R and the changes in the velocity diagonal terms of Q of the controlled system. The method is expected to be very useful for large-scale systems and is illustrated with the help of two example problems.
Computers & Structures | 1993
M. Sunar; S. S. Rao
A robust design methodology is presented for the control of flexible structures by the use of piezoelectric actuators. The finite element modeling and analysis of the piezoelectric media are carried out via Hamiltons principle. Finite element equations are utilized for the piezoelectric control of flexible structures subject to dynamic disturbances. Various configurations of piezoelectric actuator pairs mounted on cantilever beam structures are considered for illustration purposes. The dimensions as well as the locations of the actuator pairs are assumed to be design variables varying within certain limits. Taguchi methodology is employed to these piezoelectrically controlled structures as a robust design technique in order to investigate the effects of the design variables on the control performance. Within the ranges considered in this study, it is concluded that the piezoelectric actuator pairs with larger sizes usually perform better in attenuating the structural vibrations. For the actuator pair location, the actuator pairs close to the fixed end result in better performance characteristics.
Journal of Adhesion Science and Technology | 2004
Mamdouh A. Al-Harthi; Ramazan Kahraman; B.S. Yilbas; M. Sunar; B. J. Abdul Aleem
Abstract A design approach is presented to uniquely couple passive and active control designs of structures and to solve the resultant problem using multiobjective optimization techniques. Passive control is realized through structural modifications while active control is accomplished by negative state feedback control to drive the characteristic poles of the system into a desired region in the complex plane. It is observed that it is advantageous to use multiobjective optimization strategies to better correlate between passive and active control designs thereby providing the designer with a powerful tool in finding a good balance between possibly conflicting practical control limitations.