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.

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.

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.

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.

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.

Control of Cylindrical Shell Panels With Input Shaping and Phase Shift of Shape Memory Ring Segments

2005 ◽  
Author(s):  
J. G. DeHaven ◽  
H. S. Tzou
Keyword(s):  
Cylindrical Shell ◽  
Shape Memory ◽  
Free Vibration Analysis ◽  
Harmonic Excitation ◽  
Optimal Placement ◽  
Elastic Cylindrical Shell ◽  
Control Force ◽  
Control Effect ◽  
Longitudinal Modes ◽  
Shell Panel

The purpose of this study is to investigate the control effect from shape memory alloy (SMA) ring segments placed at the desired positions along the length of a cylindrical shell panel. Equations of motion for an elastic cylindrical shell panel are defined first and then used with the assumed mode shape functions for the appropriate boundary conditions in a free vibration analysis. The results from this are used with the generic shell sensing equation to determine the spatial strain distribution. From this, optimal placement of ring segments for each given mnth mode is determined. Through use of the modal expansion method, the open-loop control force induced by the SMA ring segments applied to a cylindrical shell panel is determined next. This evaluation shows that only the odd modes in the circumferential direction can be controlled. Longitudinal modes are controlled via placing a varying number, depending on the mode, of ring segments along the length of the cylindrical shell panel. To predict control effects of the SMA ring segments, the modal participation factor response is determined for an external harmonic excitation applied to the shell along with SMA control force induced to eliminate the unwanted effects. The results show that with proper choice of waveform function for the applied temperature to the SMA ring segments and minor modifications to frequency and phase, the SMA ring segments can control unwanted external vibration.

Actuation of Parabolic Cylindrical Shell Panels With Light-Activated Shape Memory Actuators

2016 ◽  
Author(s):  
Huiyu Li ◽  
Xufang Zhang ◽  
Hornsen Tzou
Keyword(s):  
Cylindrical Shell ◽  
Shape Memory ◽  
Shape Memory Polymer ◽  
Expansion Method ◽  
Modal Control ◽  
Control Force ◽  
Strain Variation ◽  
Modal Expansion ◽  
Control Forces ◽  
Initial Strains

Parabolic cylindrical shell panels are used in optical and aerospace structures. Light-activated shape memory polymer (LaSMP) is a novel smart material and it is capable of offering a non-contact actuation and control in room temperature. In this study, the parabolic cylindrical shell panels laminated with LaSMP actuators are analyzed. Firstly the dynamic equations of the parabolic cylindrical shell panels coupled with the LaSMP actuators are established; the modal control force of LaSMP actuators is derived with the modal expansion method. Then the strain variation of the LaSMP actuators are modeled based on the chemical kinetics. Further, the shape-memory recovery effect of an LaSMP actuator with initial strains is measured in laboratory. The experiment data of strain variation are used to validate the established strain model. Finally, in the case study the modal control forces of LaSMP actuators for the first four shell modes, i.e., the (1,3), (1,4), (2,4) and (2,5) modes are analyzed. The study shows that LaSMP actuators can induce strains not only in the x, Ψ directions but also in the xΨ direction (induced by the warping effect). The reason is that LaSMP actuators are easy to be cut in any shapes and be deformed in any directions. Thus, LaSMP actuators have potential applications for the non-contact vibration control of double-curvature shells.

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.

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.

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.

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