Non-Uniform Control Moments Induced by a Skew-Quad Actuator Design Applied to Plate Controls

2009 ◽  
Author(s):  
Jing Jiang ◽  
Hong-Hao Yue ◽  
Zong-Quan Deng ◽  
Horn-Sen Tzou
Keyword(s):  
Piezoelectric Materials ◽  
Flexible Structures ◽  
Variation Method ◽  
Modal Control ◽  
Control Effectiveness ◽  
Control Actions ◽  
Distributed Structures ◽  
Control Forces ◽  
Parametric Analyses ◽  
Actuator Design

Distributed vibration control of flexible structures using piezoelectric materials has been extensively studied for decades. A number of design configurations of distributed actuators with uniform control forces and moments have been investigated to improve modal control effectiveness of distributed structures, e.g., shells and plates. In this study, a new skew-quad actuator design which consists of four pieces of mono-axial piezoelectric actuator is proposed and evaluated. Due to the uneven boundary conditions of each region, this new actuator can induce non-uniform control forces and moments. Based on the variation method, the non-uniform distribution of the actuator induced forces and moments are defined. The coupling equation of a simply supported plate laminated with this new design is derived; distributed control action resulting from the non-uniform control moments is also defined in the modal domain. The actuator induced control actions are calculated respectively on a square plate and a rectangle plate, and the effects of varying actuator size are also evaluated. These control effects of the skew-quad actuator are compared with those of a multi-DOF actuator. Parametric analyses suggest that due to the non-uniform control moments, the new skew-quad actuator induces better modal control actions in certain plate modes as compared with the multi-DOF actuator. This new skew-quad actuator has great potential to improve control effects to other shell structures.

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.

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.

Cylindrical Shell Control With Center- and Corner-Placed Photostrictive Skew-Quad Actuators

2010 ◽  
Author(s):  
Jing Jiang ◽  
Hong-Hao Yue ◽  
Zong-Quan Deng ◽  
Horn-Sen Tzou
Keyword(s):  
Cylindrical Shell ◽  
High Energy ◽  
Negative Control ◽  
Control Effectiveness ◽  
Actuator System ◽  
Control Forces ◽  
And Control ◽  
Paired Design ◽  
Actuator Design ◽  
Photostrictive Actuators

Light-driven photostrictive actuators can induce control actions capable of wireless non-contact actuation and control of precision structures and systems. Conventional distributed actuators laminated on shells and plates usually introduce only uniform control forces and moments. Structural actuation and control based on uniform control forces and moments have been investigated for over two decades. This paper is to exploit a new photostrictive actuator design, i.e., a skew-quad (SQ) actuator system and this new distributed SQ system laminated on shells and plates can introduce non-uniform control forces and moments. The new SQ actuator system is composed of four pieces of photostrictive materials and inner two edges of each piece are bonded to a cross fixture. Under the irradiation of high-energy lights, each piece generates non-uniform control forces and moments, due to its uneven nonsymmetrical boundary conditions. Modal actuation characteristics of a cylindrical shell coupled with a center-placed and corner-placed skew-quad actuator system are evaluated respectively. A paired-design regulating positive/negative control forces of each actuator region is proposed to improve the control effectiveness of the center-located skew-quad actuator system. Parametric analysis proves improved control effectiveness of unsymmetrical shell modes.

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.

Cylindrical Shell Control With Center- and Corner-Placed Photostrictive Skew-Quad Actuator Systems

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
J. Jiang ◽  
H. H. Yue ◽  
Z. Q. Deng ◽  
H. S. Tzou
Keyword(s):  
Cylindrical Shell ◽  
High Energy ◽  
Negative Control ◽  
Control Effectiveness ◽  
Actuator System ◽  
Control Forces ◽  
And Control ◽  
Paired Design ◽  
Actuator Design ◽  
Photostrictive Actuators

Light-driven photostrictive actuators can induce control actions for wireless non-contact actuation and control of precision structures and systems. Conventional distributed actuators laminated on shells and plates usually only introduce uniform control forces and moments. Structural actuation and control based on uniform control forces and moments have been investigated for over two decades. This paper is to exploit a new photostrictive actuator design, i.e., a skew-quad (SQ) actuator system. This new distributed SQ actuator system laminated on shells and plates can introduce non-uniform control forces and moments. The new SQ actuator system is composed of four pieces of photostrictive materials and the inner two edges of each piece are bonded to a cross fixture. Under the irradiation of high-energy lights, each piece generates non-uniform control forces and moments, due to its uneven non-symmetrical boundary conditions. Modal actuation characteristics of a cylindrical shell coupled with the center-placed and corner-placed SQ actuator systems are evaluated respectively. A paired-design regulating positive/negative control forces of each actuator region is also proposed and evaluated to improve the control effectiveness of the center-located SQ actuator system. Parametric analysis proves improved control effectiveness of unsymmetrical shell modes.

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.

WPT-based modal control on distributed structures with MRF-04K damper

2011 ◽  
Vol 17 (6) ◽  
pp. 397-403
Author(s):  
Wei Lin ◽  
Zhongxian Li ◽  
Genming Zhang ◽  
Pengyun Huang
Keyword(s):  
Modal Control ◽  
Distributed Structures

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.

The Method of Successive Decrease and the Concept of Harmonic Wave Filter in Structural Wave Control

1995 ◽  
Author(s):  
Dajun Wang ◽  
Quan Wang ◽  
A. Y. T. Leung
Keyword(s):  
Vibration Control ◽  
Structural Control ◽  
Natural Frequencies ◽  
Control Method ◽  
Harmonic Wave ◽  
Flexible Structures ◽  
Modal Control ◽  
Large Space ◽  
Wave Filter ◽  
Wave Control

Abstract Most of the available vibration control methods for flexible structures are based on the modal control method, which, however, sometimes meets with problems. For examples, the problem of spillover has not been solved adequately. And, for flexible large space structures with closely spaced natural frequencies, it is very difficult to use modal method to treat vibration control problems because the modes corresponding to closely spaced and repeated frequencies can not be computed accurately. In recent years, the method of structural wave control has been developed, but it has not been studied sufficiently. The object of this paper is an attempt to solve some of the existing problems raised due to the application of the modal control method. A wave control method — the method of successive decrease is set up at first, which is aimed at one harmonic wave. Then, a new design method in wave control is proposed, based on the above method. The problem of control spillover is analyzed and the concept of harmonic wave filter is introduced. As an example, the problem of the control of structures with closely spaced natural frequencies is treated by both the method of modal control and the method of successive decrease. The numerical results show that the method of successive decrease is more effective than the method of modal control. It proves that the method of successive decrease and the concept of harmonic wave filter is promising in solving the problems of structural control.

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