Micro-Control Actions of Actuator Patches Laminated on Hemispherical Shells

2002 ◽  
Author(s):  
P. Smithmaitrie ◽  
H. S. Tzou
Keyword(s):  
Distributed Control ◽  
Pressure Vessels ◽  
Control Force ◽  
Control Effect ◽  
Control Effectiveness ◽  
Control Actions ◽  
Spatially Distributed ◽  
Membrane Bending ◽  
Control Forces ◽  
Electromechanical Actuation

Spherical shell-type structures and components appear in many engineering systems, such as radar domes, pressure vessels, storage tanks, etc. This study is to evaluate the micro-control actions and distributed control effectiveness of segmented actuator patches laminated on hemispheric shells. Mathematical models and governing equations of the hemispheric shells laminated with distributed actuator patches are presented first, followed by formulations of distributed control forces and micro-control actions including meridional/circumferential membrane and bending control components. Due to difficulties in analytical solution procedures, assumed mode shape functions based on the bending approximation theory are used in the modal control force expressions and analyses. Spatially distributed electromechanical actuation characteristics resulting from various meridional and circumferential actions are evaluated. Distributed control forces, patch sizes, actuator locations, micro-control actions, and normalized control authorities of a free-floating hemispheric shell are analyzed in a case study. Parametric analysis indicates that 1) the control forces and membrane/bending components are mode and location dependent and 2) the meridional/circumferential membrane control actions dominate the overall control effect.

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.

Actuator Placement and Control Efficiency of Paraboloidal Shell Structures

2001 ◽  
Author(s):  
H. S. Tzou ◽  
J. H. Ding
Keyword(s):  
Distributed Control ◽  
Communication Systems ◽  
Design Parameters ◽  
Control Force ◽  
Shells Of Revolution ◽  
Control Effect ◽  
Membrane Bending ◽  
High Control ◽  
Control Forces ◽  
And Control

Abstract Paraboloidal shells of revolution are commonly used in communication systems, precision opto-mechanical systems and aerospace structures. This study is to investigate the precision distributed control effectiveness of paraboloidal shells laminated with segmented actuator patches. Mathematical models of the paraboloidal shells laminated with distributed actuator layers subjected to mechanical, temperature, and control forces are presented first, followed by formulations of distributed control forces with their contributing meridional/circumferential membrane and bending control components using an assumed mode shape function. Studies of actuator placements, control forces, contributing components, and normalized control authorities of paraboloidal shells are carried out. These forces and membrane/bending components basically exhibit distinct modal characteristics influenced by shell geometries and other design parameters. Analyses suggest that the membrane contributed components dominate the overall control effect. Locations with larger normalized forces indicate the areas with high control efficiencies, i.e., larger induced control force per unit actuator area. With limited actuators, placing actuators at those locations would lead to the maximal control effects.

scholarly journals Spatially Filtered Vibration Control of Cylindrical Shells

1996 ◽  
Vol 3 (4) ◽  
pp. 269-278 ◽  
Author(s):  
H.S. Tzou ◽  
J.P. Zhong
Keyword(s):  
Control Force ◽  
Control Effectiveness ◽  
Natural Modes ◽  
Control Actions ◽  
Spatially Distributed ◽  
Control Forces ◽  
Piezoelectric Shell ◽  
Laminated Cylindrical Shell ◽  
Plane Membrane ◽  
Distributed Actuator

Distributed actuators offer spatially distributed actuations and they are usually effective to multiple modes of a continuum. Spatially filtered distributed vibration controls of a laminated cylindrical shell and a piezoelectric shell are investigated, and their control effectivenesses are evaluated in this study. In general, there are two control actions, the in-plane membrane control forces and the counteracting control moments, induced by the distributed actuator in the laminated shell. There is only an in-plane circumferential control force in the piezoelectric shell. Analyses suggest that in either case the control actions are effective in odd natural modes and ineffective in even modes. Spatially filtered control effectiveness and active damping of both shells are studied.

Actuator Placement and Micro-Actuation Efficiency of Adaptive Paraboloidal Shells

2003 ◽  
Vol 125 (4) ◽  
pp. 577-584 ◽  
Author(s):  
H. S. Tzou ◽  
J. H. Ding
Keyword(s):  
Communication Systems ◽  
Design Parameters ◽  
Shells Of Revolution ◽  
Control Effect ◽  
Control Effectiveness ◽  
Membrane Bending ◽  
High Control ◽  
Control Forces ◽  
And Control ◽  
Actuator Placement

Paraboloidal shells of revolution are commonly used in communication systems, precision opto-mechanical systems and aerospace structures. This study is to investigate the precision distributed control effectiveness of adaptive paraboloidal shells laminated with segmented actuator patches. Mathematical models of the paraboloidal shells laminated with distributed actuator layers subjected to mechanical, temperature, and control forces are presented first. Then, formulations of distributed actuating forces with their contributing micro-meridional/circumferential membrane and bending components are derived using an assumed mode shape function. Studies of actuator placements, actuator induced control forces, micro-contributing components, and normalized actuation authorities of paraboloidal shells are carried out. These forces and membrane/bending components basically exhibit distinct modal characteristics influenced by shell geometries and other design parameters. Analyses suggest that the membrane-contributed components dominate the overall control effect. Locations with larger normalized forces indicate the areas with high control efficiencies, i.e., larger induced actuation force per unit actuator area. With limited actuators, placing actuators at those locations would lead to the maximal control effects of paraboloidal shells.

Micro-Control Characteristics of Conical Shell Sections

2003 ◽  
Author(s):  
W. K. Chai ◽  
H. S. Tzou ◽  
K. Higuchi
Keyword(s):  
Distributed Control ◽  
Conical Shell ◽  
Turbine Blades ◽  
Unit Weight ◽  
Solid Rocket Motor ◽  
Control Actions ◽  
Load Carrying ◽  
Spatially Distributed ◽  
Control Forces ◽  
Distributed Actuator

Rocket fairings, turbine blades, load carrying structure for solid rocket motor case, inter-stage joint, satellite-rocket joint etc., usually take the shape of conical shell sections. Conical shell has a large load carrying capacity per unit weight due to its high-strength, high-rigidity and light-weight properties. This paper is to evaluate spatially distributed microscopic control characteristics of distributed actuator patches bonded on conical shell surfaces. The converse effect of piezoelectric materials has been recognized as one of the best electromechanical effects for precision distributed control applications. The resultant control forces and micro-control actions induced by the distributed actuators depend on applied voltages, geometrical (e.g., spatial segmentation and shape) and material (i.e., various actuator materials) properties [8]. Mathematical models and modal domain governing equations of the conical shell section laminated with distributed actuator patches are presented first, followed by the formulations of distributed control forces and micro-control actions which can be refined to longitudinal/circumferential membrane and bending control components. Spatially distributed electromechanical microscopic actuation characteristics and control effects resulting from various longitudinal/circumferential actions of actuator patches are then evaluated.

Spatial Microscopic Actuations of Shallow Conical Shell Sections

2005 ◽  
Vol 11 (11) ◽  
pp. 1397-1411 ◽  
Author(s):  
W. K. Chai ◽  
J. G. Dehaven ◽  
H. S. Tzou
Keyword(s):  
Distributed Control ◽  
Conical Shell ◽  
High Performance ◽  
Piezoelectric Materials ◽  
Structural Systems ◽  
Solid Rocket Motor ◽  
Control Actions ◽  
Spatially Distributed ◽  
Control Forces ◽  
Distributed Actuator

In recent years there has been an interest in distributed control of shell structures because of its extensive applications in high performance structural systems. Conical shells are relevant to components of structural systems such as engine nozzles, interstage joints, satellite–rocket joints, load carrying structures for solid rocket motor cases, etc. In this paper we evaluate the spatially distributed microscopic control characteristics of distributed actuator patches laminated on conical shell surfaces. Piezoelectric materials have always been utilized for precision distributed control applications due to their converse effect. The resultant control forces and micro-control actions induced by distributed piezoelectric actuators depend on applied voltages, geometrical (e.g. spatial segmentation and shape) and material (i.e. various actuator materials) properties. Mathematical models and modal domain governing equations of the conical shell section laminated with distributed actuator patches are presented first, followed by the formulations of distributed control forces and micro-control actions, which can be refined to longitudinal and circumferential membrane/bending control components. We then evaluate the spatially distributed electromechanical microscopic actuation characteristics and control effects resulting from various longitudinal/circumferential actions of actuator patches.

Micro-Actuations and Location Sensitivity of Actuator Patches Laminated on Toroidal Shells

2002 ◽  
Author(s):  
H. S. Tzou ◽  
W. K. Chai ◽  
D. W. Wang
Keyword(s):  
Distributed Control ◽  
Piezoelectric Materials ◽  
Critical Issue ◽  
Toroidal Shell ◽  
Control Actions ◽  
Spatially Distributed ◽  
Control Forces ◽  
And Control ◽  
Actuator Placement ◽  
Toroidal Shells

Toroidal shell structure has been proposed for components of inflatable space structures and telescope etc. Thus, distributed control of toroidal shells becomes a critical issue in precision maneuver, operation, and reliability. The converse effect of piezoelectric materials has made it one of the best candidates for distributed control actuators. The resultant control forces and micro-control actions induced by the distributed actuators depend on applied voltages, geometrical (e.g., spatial segmentation and shape) and material (i.e., various actuator materials) properties of the actuators. The purpose of this analysis is to study the location effects of actuator placement and to evaluate the micro-control actions imposed upon toroidal shell structures. Mathematical models and governing equations of the toroidal shells laminated with distributed actuator patches are presented first, followed by formulations of distributed control forces and micro-control actions including meridional/circumferential membrane and bending control components. Spatially distributed electromechanical microscopic actuation characteristics and control effects resulting from various meridional and circumferential actions are evaluated.

Micro-Control Actions of Segmented Actuators on Shallow Paraboloidal Shell Reflectors

2002 ◽  
Author(s):  
S.-S. Lih ◽  
G. Hickey ◽  
J. H. Ding ◽  
H. S. Tzou
Keyword(s):  
Distributed Control ◽  
Design Guidelines ◽  
Shell Structures ◽  
Natural Mode ◽  
Shells Of Revolution ◽  
Control Effect ◽  
Control Cost ◽  
Control Actions ◽  
Control Forces ◽  
Paraboloidal Shell

Shallow paraboloidal shells of revolution are common components for reflectors, mirrors, etc. This study is to investigate the micro-control actions and distributed control effectiveness of precision paraboloidal shell structures laminated with segmented actuator patches. Mathematical models and governing equations of the paraboloidal shells laminated with distributed actuator layers segmented into patches are presented first, followed by formulations of distributed control forces and micro-control actions including meridional/circumferential membrane and bending control components based on an assumed mode shape function and the Taylor series expansion. Distributed control forces, patch sizes, actuator locations, micro-control actions, and normalized control authorities of a shallow paraboloidal shell are then analyzed in a case study. Analysis indicates that 1) the control forces and membrane/bending components are mode and location dependent, 2) the meridional/circumferential membrane control actions dominate the overall control effect, 3) there are optimal actuator locations resulting in the maximal control effects at the minimal control cost for each natural mode. The analytical results provide generic design guidelines for actuator placement on precision shallow paraboloidal shell structures.

Micro-Control Actions and Location Sensitivity of Actuator Patches Laminated on Toroidal Shells

2004 ◽  
Vol 126 (2) ◽  
pp. 284-297 ◽  
Author(s):  
H. S. Tzou ◽  
W. K. Chai ◽  
D. W. Wang
Keyword(s):  
Distributed Control ◽  
Piezoelectric Materials ◽  
Spatial Location ◽  
Critical Issue ◽  
Shell Structures ◽  
Toroidal Shell ◽  
Control Actions ◽  
Spatially Distributed ◽  
Control Forces ◽  
Toroidal Shells

Toroidal shell structures have been proposed for components of inflatable telescopes and space structures, etc. over the years. Thus, distributed control of toroidal shells becomes a critical issue in precision maneuver, operation, and reliability. The converse effect of piezoelectric materials has made it one of the best candidates for distributed actuators. The resultant control forces and micro-control actions induced by the distributed actuators depend on applied voltages, geometrical (e.g., spatial segmentation and shape) and material (i.e., various actuator materials) properties of the actuators. The purpose of this analysis is to study the spatial location effects of actuator placement and to evaluate the micro-control actions imposed upon toroidal shell structures. Mathematical models and governing equations of the toroidal shells laminated with distributed actuator patches are presented first, followed by formulations of distributed control forces and micro-control actions including meridional/circumferential membrane and bending control components. Spatially distributed electromechanical microscopic actuation characteristics and control effects resulting from various meridional and circumferential actions of actuator patches at various shell locations are evaluated.

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.

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