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-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 Electrostrictive Modal Actuation of Conical Shells

2008 ◽  
Author(s):  
H. S. Tzou ◽  
W. K. Chai
Keyword(s):  
Conical Shell ◽  
Open Loop ◽  
Natural Mode ◽  
Solid Rocket Motor ◽  
Control Effect ◽  
Loop Control ◽  
Modal Expansion ◽  
Control Actions ◽  
Spatially Distributed ◽  
Control Equation

Horns, nozzles and load carrying structures of rockets, e.g., inter-stage joint, satellite-rocket joint, solid rocket motor case, etc., are usually made of circular conical shell sections. This study is to investigate distributed electrostrictive actuation and to evaluate spatially distributed microscopic control actions of distributed electrostrictive actuator segments bonded on conical shell surfaces. Mathematical model and open-loop control equations of a generic conical shell are defined first, followed by simplification to a free-free truncated conical shell section with segmented electrostrictive actuators. Natural mode shape functions are defined based on the Donnell-Mushtati-Vlasov approximation; independent modal control equation is derived by the modal expansion. Distributed control actions induced by the electrostrictive actuator segments are evaluated in the modal domain and the total control effect can be divided into four microscopic control actions: the longitudinal/circumferential membrane and bending control actions. Detailed parametric analyses of two mode groups indicate that 1) magnitudes of control actions comply with the quadratic increase with respect to control voltages and 2) the circumferential membrane control action is the most dominating component in the total shell control effect. Also, the spatially distributed modal actuation plots can be used to locate the most effective locations and/or regions of electrostrictive actuators placed on the shell surface.

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.

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 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.

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.

Modal Voltages and Distributed Signal Analysis of Conical Shells of Revolution

2001 ◽  
Author(s):  
H. S. Tzou ◽  
W. K. Chai ◽  
D. W. Wang
Keyword(s):  
Conical Shell ◽  
Signal Analysis ◽  
Turbine Blades ◽  
Piezoelectric Sensor ◽  
High Signal ◽  
Shells Of Revolution ◽  
Conical Shells ◽  
Double Curvature ◽  
Shell Models ◽  
Spatially Distributed

Abstract Conical shells and components are widely used as nozzles, injectors, rocket fairings, turbine blades, etc. Dynamic and vibration characteristics of conical shells have been investigated over the years. In this paper, electromechanics and distributed sensing phenomena of a generic double-curvature shell and a conical shell are discussed, and governing sensing signal-displacement equations are derived. Spatially distributed modal voltages and signal generations of conical shells laminated with distributed piezoelectric sensor layers or neurons are investigated based on the Donnel-Mushtari-Valsov theory. Distributed modal voltages and their various signal components of conical shell models reveal that the dominating signal component among the four contributing signal components is the circumferential membrane component. This dominance is even more significant for lower shell modes and/or deep shells. In general, high strain regions result in high signal magnitudes. Accordingly, the spatially distributed signal patterns — the modal voltages — clearly represent the modal dynamic and strain characteristics of conical shells.

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.

Evaluating actuator distributions in simply supported truncated thin conical shell with embedded piezoelectric layers

2018 ◽  
Vol 29 (12) ◽  
pp. 2641-2659 ◽  
Author(s):  
Rasa Jamshidi ◽  
Ali A Jafari
Keyword(s):  
Conical Shell ◽  
Piezoelectric Layer ◽  
Cone Angle ◽  
Expansion Method ◽  
Longitudinal Direction ◽  
Modal Expansion ◽  
Simply Supported ◽  
Modal Expansion Method ◽  
Layer Segmentation ◽  
Distributed Actuator

In this investigation, distributed modal actuator forces of simply supported truncated conical shell embedded by a piezoelectric layer are studied. Piezoelectric layer is distributed on the conical shell surface as actuators. Three types of distributions are considered: longitudinal, circumferential, and diagonal distributions. First, electromechanical equations of the conical shell with embedded piezoelectric actuator layer are extracted. Then modal expansion method is used to define independent modal characteristics of the conical shell. For each kind of distribution, three case studies are considered and evaluated. Results showed that in the longitudinal and diagonal distributed actuator, membrane force in the longitudinal direction is the dominant force and in the circumferential distributed actuator, the membrane force in the circumferential direction is the dominant force. The effects of cone angle, piezoelectric thickness, and piezoelectric layer segmentation on modal forces of each distributed actuator are also studied. In circumferential distributed actuator, modal forces increase as the cone angle increases. This phenomenon in the longitudinal and diagonal distributed actuator is almost reversed. The piezoelectric layer segmentation effect on the modal forces distribution is also evaluated, and it showed that this phenomenon has a critical effect on the modal forces distribution.

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