Precision Microscopic Actuations of Parabolic Cylindrical Shell Reflectors

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
S. D. Hu ◽  
H. Li ◽  
H. S. Tzou
Keyword(s):  
Cylindrical Shell ◽  
Piezoelectric Actuator ◽  
Cylindrical Shells ◽  
Active Vibration Control ◽  
Modal Control ◽  
Control Force ◽  
Signal Collection ◽  
Shell Panel ◽  
Active Vibration ◽  
Radar Antennas

An open parabolic cylindrical shell panel plays a key role in radial signal collection, reflection, and/or transmission applied to radar antennas, space reflectors, solar collectors, etc. Active vibration control can suppress unexpected fluctuation and maintain its precision surface and operations. This study aims to investigate the distributed active actuation behavior of adaptive open parabolic cylindrical shell panels using piezoelectric actuator patches. Dynamic equations of parabolic cylindrical shells laminated with piezoelectric actuator patches are presented first. Then, the actuator induced modal control force is defined based on a newly derived mode shape function. As the actuator area varies due to the curvature change, the normalized actuation effectiveness (i.e., modal control force per unit actuator area) is further evaluated. When the actuator area shrinks to infinitesimal, the expression of microscopic local modal control force is obtained to predict the spatial microscopic actuation behavior on parabolic cylindrical shells. The total control force and its three components exhibit distinct characteristics with respect to shell geometries, modes, and actuator properties. Analyzes suggest that the control force contributed by the membrane force component dominates the total actuation effect. The bending-contributed component increases with the corresponding mode number, while the membrane-contributed component decreases. Actuation effectiveness of two shell geometries, from shallow to deep, and actuator sizes are evaluated. Analysis of optimal actuator locations reveals that actuators placed at the maximal shell curvature are more effective and maximize the control effects.

Distributed Actuation Effectiveness of Flexible Parabolic Cylindrical Panels

2012 ◽  
Author(s):  
S. D. Hu ◽  
H. Li ◽  
H. S. Tzou
Keyword(s):  
Active Vibration Control ◽  
Cylindrical Panel ◽  
Modal Control ◽  
Control Force ◽  
Control Effect ◽  
Control Effectiveness ◽  
Cylindrical Panels ◽  
Total Control ◽  
Shell Panel ◽  
Active Vibration

Open parabolic cylindrical panel plays a key role in radial collection and transmission applied to radar antennas, space reflectors, solar collectors, etc. Piezoelectric active vibration control can suppress unexpected fluctuation and maintain precision surface and operations. This study aims to investigate the distributed actuation behavior of adaptive open parabolic cylindrical panels using piezoelectric actuator patches. Motion equations of parabolic cylindrical panels laminated with a piezoelectric patch is presented first. Then, the actuator induced modal control force is derived with an assumed mode shape function. As the area of actuator patch varies due to the curvature change, the normalized actuation effectiveness (i.e., modal control force divided by actuator area) is further evaluated. When the actuator area shrinks to infinitesimal, the expression of microscopic point modal control force is obtained to theoretically predict the actuation distribution behavior. The actuation behaviors of the total control force and its components exhibit distinct characteristics with respect to shell geometries, modes and actuator properties. Analyses show that the control force component contributed by the membrane force dominates the total control effect. The bending-contributed component increases with corresponding vibration mode number, while the membrane-contributed component decreases. Three shell geometries from shallow to deep are evaluated in case studies. Analysis of optimal actuator location shows that actuators are preferred to locate where the curvature of shell panel is larger in order to maximize the control effectiveness.

scholarly journals Active Vibration Control of a Fluid-Conveying Functionally Graded Cylindrical Shell using Piezoelectric Material

2020 ◽  
Vol 319 ◽  
pp. 03003
Author(s):  
Dan Wang ◽  
Changqing Bai ◽  
Hongyan Zhang
Keyword(s):  
Cylindrical Shell ◽  
Vibration Control ◽  
Piezoelectric Actuator ◽  
Active Vibration Control ◽  
Coupled System ◽  
Functionally Graded ◽  
Governing Equations ◽  
Velocity Feedback ◽  
Active Vibration ◽  
Piezoelectric Voltage

Active vibration control of a smart FG (functionally graded) cylindrical shell conveying fluid in thermal environment is studied theoretically by using a laminated piezoelectric actuator. Velocity feedback control law is implemented to activate the piezoelectric actuator. Considering the electric-thermo-fluid-structure interaction effect, a nonlinear dynamic model of the smart fluid-conveying FG cylindrical shell is developed based on Hamilton’s principle and von-Karman type geometrical nonlinear relationship. The inviscid, incompressible, isentropic and irrotational fluid is coupled into governing equations using the linearized potential theory. The Galerkin’s method is used to obtain the nonlinear governing equations of motion of the coupled system. The multiple time scales approach is applied to solve the resulting governing equations for analysing the nonlinear dynamic characteristics of the coupled system. The influence of fluid flow velocity, feedback control gains of piezoelectric voltage, external excitation and material properties of FGM on the frequency-response curves of system are investigated. The results indicate that the piezoelectric voltage is an effective controlling parameter for vibration control of the system, and the flow velocity can effect significantly the vibration amplitude and nonlinearity of the coupled system.

Fuzzy Controller for Active Vibration Control of Cylindrical Shells

2017 ◽  
Author(s):  
Hua Li ◽  
Kaiming Hu
Keyword(s):  
Fuzzy Logic ◽  
Vibration Control ◽  
Fuzzy Logic Controller ◽  
Fuzzy Controller ◽  
Cylindrical Shells ◽  
Active Vibration Control ◽  
Control Force ◽  
Engineering Structures ◽  
Model Control ◽  
Active Vibration

Cylindrical shells are widely used engineering structures, such as pipelines, tubes, submarine shells, etc. The active vibration control of these structures are important methods for ensuring their performance. In this paper, a fuzzy logic controller was proposed for the active vibration control of cylindrical shells. Piezoelectric actuators were laminated on the shell surface for the generation of control force. Then, the mathematical model of the model control force were given based the inverse piezoelectric effects and modal summation method. The transfer equation of the controlled system was derived from the modal equation. The fuzzy logic controller was then designed, in which the centroid method was used for defuzification. The proposed controller was then implemented in Matlab/Simulink environment, followed by case studies to evaluate its performance. Numerical results shown the effectiveness of fuzzy logic controller on active vibration of smart cylindrical shells. For all evaluated cases, more than 33% of amplitude reduction were achieved.

Spatial Actuation Effectiveness of Segmented Actuators on Parabolic Cylindrical Panels

2012 ◽  
Author(s):  
S. D. Hu ◽  
H. Li ◽  
H. S. Tzou
Keyword(s):  
Shape Control ◽  
Cylindrical Panel ◽  
Design Parameters ◽  
Modal Control ◽  
Control Force ◽  
Optimal Position ◽  
Meridional Direction ◽  
Cylindrical Panels ◽  
Active Vibration ◽  
Control Forces

With the distinct capability of line-focusing, open parabolic cylindrical panels are commonly used as key components of radar antennas, space reflectors, solar collectors, etc. These structures suffer unexpected vibrations from the fluctuation of base structure, non-uniform heating and air flow. The unwanted vibration will reduce the surface reflecting precision and even result in structure damages. To explore active vibration and shape control of parabolic cylindrical panels, this study focuses on actuation effectiveness induced by segmented piezoelectric patches laminated on a flexible parabolic cylindrical panel. The mathematical model of a parabolic cylindrical panel laminated with distributed actuators is formulated. The segmentation technique is developed and applied to parabolic cylindrical panels, and the piezoelectric layer is segmented uniformly in the meridional direction. The distributed actuator patches induced modal control forces are evaluated. As the area of actuator patch varies in the meridional direction, modal control force divided by actuator area, i.e., actuation effectiveness, is investigated. Spatial actuation effectiveness, including its membrane and bending components are evaluated with respect to design parameters: actuator size and position, shell curvature, shell thickness and vibration mode in case studies. The actuation component induced by the membrane force in the meridional direction mainly contributes to the total actuation effectiveness for lower modes. Average and cancellation effect of various actuator sizes and the optimal actuator position are also discussed. Results suggest that for odd vibration modes, the maximal actuation effectiveness locates at the ridge of the panel; while for even modes, the peak/valley closest to the ridge is the optimal position to obtain the maximal actuation effectiveness. A segmentation scheme of the meridian interval angle 0.0464rad for the investigated standard panel is a preferred tradeoff between the actuation effectiveness and practical feasibility. The modal actuation effectiveness increases with the shell curvature, whereas decreases when the shell thickens.

Active Vibration Control of a Triple Flexible Structures Combined With Actuators

1995 ◽  
Author(s):  
Kazuto Seto ◽  
Yoshihiro Toba ◽  
Fumio Doi
Keyword(s):  
Vibration Control ◽  
Large Scale ◽  
Active Vibration Control ◽  
Flexible Structures ◽  
Low Frequency ◽  
Tall Buildings ◽  
Control Force ◽  
Active Vibration ◽  
Strong Winds ◽  
Lq Control

Abstract In order to realize living comfort of tall buildings by reducing the vibration of higher floors by strong winds, this paper proposes a new method of vibration control for flexible structures with a large scale. The higher a tall building the lower its natural frequency. Since obtaining sufficient force to control the lower frequency vibrations of tall buildings is a difficult task, controlling the vibration of ultra-tall buildings using active dynamic absorbers is nearly impossible. This problem can be overcome by placing actuators between a pair of two or three ultra-tall buildings and using the vibrational force of each building to offset the vibrational movement of its paired mate. Therefore, it is able to obtain enough control force under the low frequency when the proposed method is used. In this paper, a reduced-order model expressed by 2DOF system under taking into consideration for preventing spillover instability is applied to control each flexible structure. The LQ control theory is applied to the design of such a control system. The effectiveness of this method is demonstrated theoretically as well as experimentally.

The influences of magnetostrictive layers on active vibration control of laminated composite rotating cylindrical shells based on first-order shear deformation theory

2019 ◽  
Vol 233 (13) ◽  
pp. 4606-4619 ◽  
Author(s):  
Shahin Mohammadrezazadeh ◽  
Ali Asghar Jafari
Keyword(s):  
Vibration Control ◽  
Shear Deformation ◽  
Deformation Theory ◽  
Cylindrical Shells ◽  
Active Vibration Control ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
First Order ◽  
Vibration Responses ◽  
Active Vibration

In this paper for the first time, active vibration control of rotating laminated composite cylindrical shells embedded with magnetostrictive layers as actuators by means of first-order shear deformation theory is studied. Vibration equations of the rotating shell are extracted using Hamilton principle considering the effects of initial hoop tension, Coriolis, and centrifugal forces. The vibration differential equations are reduced to algebraic ones through Galerkin method. The validity of the study is proved by the comparison of some results with the literature results. Eventually, the influence of several parameters on damping characteristics and vibration responses are investigated in detail.

Magnetostrictive Microactuations and Modal Sensitivities of Thin Magnetoelastic Shells

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
W. K. Chai ◽  
H. S. Tzou ◽  
S. M. Arnold ◽  
H.-J. Lee
Keyword(s):  
Cylindrical Shell ◽  
Transverse Mode ◽  
Control Force ◽  
Control Actions ◽  
Spatially Distributed ◽  
Longitudinal Bending ◽  
Shell Panel ◽  
Magnetostrictive Actuator ◽  
Membrane Bending ◽  
Control Forces

This study is to evaluate distributed microscopic actuation characteristics and control actions of segmented magnetostrictive actuator patches laminated on a flexible cylindrical shell panel. A mathematical model and its modal domain governing equations of the cylindrical shell panel laminated with distributed magnetostrictive actuator patches are presented first, followed by the formulation of distributed magnetostrictive control forces and microcontrol actions including circumferential membrane∕bending and longitudinal bending control components. Transverse mode shape functions with simply supported boundary conditions are used in the modal control force expressions and the microcontrol action analyses. Control effectives and spatial characteristics of distributed actuators depend on applied magnetic fields and on geometrical (e.g., spatial segmentation, location, and shape) and material (i.e., various actuator materials) properties. Spatially distributed magnetoelectromechanical actuation characteristics contributed by circumferential membrane∕bending and longitudinal bending control actions are investigated. Distributed control forces and microactuations of a magnetostrictive actuator patch at various locations are analyzed, and modal-dependent spatial control effectiveness is evaluated.

Curved piezoactuator model for active vibration control of cylindrical shells

AIAA Journal ◽  
1996 ◽  
Vol 34 (5) ◽  
pp. 1034-1040 ◽  
Author(s):  
Venkata R. Sonti ◽  
James D. Jones
Keyword(s):  
Vibration Control ◽  
Cylindrical Shells ◽  
Active Vibration Control ◽  
Active Vibration
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