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.

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.

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.

Light-Induced Non-Contact Actuation and Control With Photostrictive Actuators

1997 ◽  
Author(s):  
H. S. Tzou ◽  
B. J. Liu
Keyword(s):  
Constitutive Relations ◽  
Cylindrical Shells ◽  
Time History ◽  
Ultra Violet ◽  
High Energy ◽  
Electromechanical Actuators ◽  
Modeling And Analysis ◽  
Control Effectiveness ◽  
Control Forces ◽  
And Control

Abstract Non-contact light activated distributed opto-electromechanical actuators represent a new class of precision distributed actuator which are based on the photodeformation process and controlled by high energy lights, e.g., lasers and ultra-violet lights. Fundamental opto-thermo-electromechancial constitutive relations are discussed and formulations of optically induced control forces and moments introduced. Mathematical modeling and analysis of distributed opto-electromechanical shell actuators are presented. A generic distributed photo-actuation theory is proposed and the closed-loop opto-thermo-electromechancial equations of circular cylindrical shells are derived. The systems equations reveal the couplings among elasticity, photodeformation, pyroelectricity, and thermoelasticity. Active distributed control of flexible cylindrical shells using segmented distributed opto-electromechanical shell actuators are investigated and the control effectiveness is evaluated. Membrane and bending control effects are evaluated. Time history analyses of independent modal control reveal that the Lyapunov control is more effective than the proportional feedback control.

Non Contact Precision Actuation and Optimal Actuator Placement of Hybrid Photostrictive Beam Structronic Systems

2007 ◽  
Author(s):  
Hong-Hao Yue ◽  
Zong-Quan Deng ◽  
Horn-Sen Tzou
Keyword(s):  
Photovoltaic Effect ◽  
Mechanical Strain ◽  
Elastic Beam ◽  
High Energy ◽  
Design Parameters ◽  
Control Electronics ◽  
Control Forces ◽  
And Control ◽  
Converse Piezoelectric Effect ◽  
Photostrictive Actuators

Non-contact wireless actuation offers many advantages to precision control, as compared with conventional hard-wired actuation mechanisms. High-energy laser or ultraviolet lights irradiating on photostrictive materials can induce a photodeformation process involving two fundamental effects: 1) the photovoltaic effect and 2) the converse piezoelectric effect. This photodeformation process transforms photonic energy to mechanical strain/stress that can be directly used for actuation and control applications. With specific design configurations, the photodeformation process of photostrictive actuators can induce various control forces and moments applied to precision manipulation and control of mechatronic and structronic systems. In this study, fundamental photodeformation coupling mechanisms among photo-thermo-electromechanical/control fields are investigated and parametric evaluation of various design parameters of a hybrid photostrictive/elastic beam is conducted. A mathematical model for a laminated beam with segmented photostrictive actuators is defined, followed by photodeformation induced modal control forces and moments of segmented actuators. Characteristics of actuation and control effectiveness of distributed photostrictive actuators at various locations, natural modes and illumination intensities are analyzed in case studies. The most effective actuator location(s) for controlling the first four beam modes are illustrated. Finally, with scheduling light irradiations on various photostrictive actuators, one can control multiple beam modes, allowed by control electronics and material response.

Nonlinear Piezothermoelasticity and Multi-Field Actuations, Part 2: Control of Nonlinear Deflection, Buckling and Dynamics

1997 ◽  
Vol 119 (3) ◽  
pp. 382-389 ◽  
Author(s):  
H. S. Tzou ◽  
Y. H. Zhou
Keyword(s):  
Circular Plate ◽  
Geometrical Nonlinearity ◽  
Nonlinear Effects ◽  
Thermal Buckling ◽  
Control Effect ◽  
Control Moment ◽  
Piezoelectric Layers ◽  
Equivalent Control ◽  
High Control ◽  
And Control

Linear dynamics and distributed control of piezoelectric laminated continua have been intensively investigated in recent years. In this study, dynamics, electromechanical couplings, and control of thermal buckling of a nonlinear piezoelectric laminated circular plate with an initial large deformation are investigated. It is assumed that the transverse nonlinear component is much more prominent than the other two in-plane components—the von Karman type geometrical nonlinearity. In addition, the piezoelectric layers are uniformly distributed on the top and bottom surfaces of the circular plate. Accordingly, the control effect is introduced via an equivalent control moment on the circumference. Dynamic equations and boundary conditions including the elastic and piezoelectric couplings are formulated, and solutions are derived. Active control of plate’s nonlinear deflections, thermal buckling, and natural frequencies using high control voltages are studied, and their nonlinear effects are evaluated.

Piezoelectric Actuation of von Karman Circular Plates With Thermal Deformation and Nonlinear Oscillation

1995 ◽  
Author(s):  
H. S. Tzou ◽  
Y.-H. Zhou
Keyword(s):  
Circular Plate ◽  
Nonlinear Effects ◽  
Thermal Buckling ◽  
Control Effect ◽  
Control Moment ◽  
Von Karman ◽  
Equivalent Control ◽  
High Control ◽  
Von Kármán ◽  
And Control

Abstract Linear dynamics and distributed control of piezoelectric laminated continua have been intensively studied in recent years. In this study, dynamics, electromechanical couplings, and control of thermal buckling of a piezoelectric laminated circular plate with an initial nonlinear large deformation are investigated. It is assumed that the von Karman type geometrically nonlinear deformation is considered. In addition, the piezoelectric layers are uniformly distributed on the top and bottom surfaces of the circular plate. Accordingly, control effect is introduced via an equivalent control moment on the circumference. Dynamic equations and boundary conditions including elastic and piezoelectric couplings are formulated, and solutions are derived. Active control of plate’s nonlinear deflections, thermal buckling, and natural frequencies using high control voltages are studied, and their nonlinear effects are evaluated.

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.

Electro-Dynamics and Micro-Actuation of Ultrasonic Curvilinear Arc Stators

2003 ◽  
Author(s):  
P. Smithmaitrie ◽  
H. S. Tzou
Keyword(s):  
Spherical Surface ◽  
Vibration Characteristics ◽  
Design Parameters ◽  
Natural Mode ◽  
Circular Arc ◽  
Driving Mechanisms ◽  
Circular Arcs ◽  
Membrane Bending ◽  
Control Forces ◽  
Actuator Control

Driving mechanisms basically deliver two fundamental motions, i.e., the linear and the curvilinear motions. A piezoelectric laminated circular arc can serve as a curvilinear arc stator to deliver curvilinear motion on a spherical surface. This study is to evaluate ultrasonic vibration characteristics and microscopic membrane/bending actuation forces of piezoelectric actuators laminated on a curvilinear circular arc. Mathematical model and governing equations of circular arcs bonded with piezoelectric actuator patch are derived, followed by analysis of actuator control forces and moments and microcontrol actions in the modal domain. Study of vibration characteristics is conducted to design optimal actuator configuration, e.g., size and location. Then, distributed control forces and micro-control actions of the curvilinear arc stator are analyzed with respect to key design parameters (i.e., arc radius, arc thickness and actuator thickness). Study of stator vibration behavior clearly suggests an optimal actuator size and location to efficiently excite the desirable ultrasonic natural mode dominated by the micro-bending control action.

Parametric Studies of Photo Deformation and Optical Actuation

1995 ◽  
Author(s):  
H. S. Tzou ◽  
C.-S. Chou
Keyword(s):  
Piezoelectric Effect ◽  
Photovoltaic Effect ◽  
Constitutive Relations ◽  
Design Parameters ◽  
Equivalent Control ◽  
Parametric Studies ◽  
Control Forces ◽  
And Control ◽  
Converse Piezoelectric Effect ◽  
Piezoelectric Characteristics

Abstract Optically driven actuators can introduce remote actuation and control effects without any hard-wire connections. In this study, photostrictive {opto-piezoelectric) characteristics and photodeformation of distributed photostrictive optical actuators are investigated and a parametric study of design parameters is conducted. Photodeformation induced by the photostrictive (opto-piezoelectric) effect (a combination of the photovoltaic effect and the converse piezoelectric effect) is discussed and its two-dimensional (2-D) constitutive relations are presented. 2-D equivalent control forces and moments induced by the photodeformation effect of distributed actuators are formulated, and system governing equations derived. Static and dynamic applications are discussed, and simulation studies of design parameters are conducted and evaluated.

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