Micro-Sensor Electromechanics and Distributed Signal Analysis of Piezo(electric)-Elastic Spherical Shells

Mechanics of Advanced Materials and Structures

Lee

Arnold

2004

172

Many electroactive functional materials have been used in small-and microscale transducers and precision mechatronic control systems for years. It was not until the mid-1980s that scientists started integrating electroactive materials with large-scale structures as in situ sensors and/or actuators, thus introducing the concept of smart materials, smart structures, and structronic systems. This paper provides an overview of present smart materials and their sensor/actuator/structure applications. Fundamental multifield optomagnetopiezoelectric-thermoelastic behaviors and novel transducer technologies applied to complex multifield problems involving elastic, electric, temperature, magnetic, light, and other interactions are emphasized. Material histories, characteristics, material varieties, limitations, sensor/actuator/structure applications, and so forth of piezoelectrics, shape-memory materials, electro-and magnetostrictive materials, electro-and magnetorheological fluids, polyelectrolyte gels, superconductors, pyroelectrics, photostrictive materials, photoferroelectrics, magneto-optical materials, and so forth are thoroughly reviewed. INTRODUCTIONThe concepts of smart, intelligent, and adaptive materials and structures originated in the mid-1980s in an attempt to describe the newly emerging research area of integrating electroactive functional materials into large-scale structures as in situ sensors and actuators. Previously, electroactive materials had only been used in small-and microscale transducers and precision mechatronic (mechanical + electronic) control systems. The general perception of smart, intelligent, and adaptive materials or structures implies an ability to be clever, sharp, active, fashionable, and sophisticated. However, in reality, materials or structures can never achieve true intelligence or reasoning without the addition of artificial intelligence

Section: Piezoelectric Materialsmentioning

confidence: 99%

Smart Materials, Precision Sensors/Actuators, Smart Structures, and Structronic Systems

Mechanics of Advanced Materials and Structures

Lee

Arnold

2004

172

“…where Y p is the actuator elastic modulus; d 3i is the piezoelectric strain constant; r a i defines the distance measured from the neutral surface to the mid-plane of the actuator patch (i.e., the moment arm); f a is the imposed control voltage determined by control algorithms (e.g., openloop or closed-loop control) [14,15]. Substituting the control forces and moments into the system equations of the spherical shell/actuator system and imposing the bending approximation theory [8], i.e., N ff ¼ N cc ¼ N fc ¼ 0; yields the simplified governing equations:…”

Section: Segmented Distributed Actuator Patches On Spherical Shellmentioning

confidence: 99%

“…Natural frequencies of a shallow spherical shell and a thin hemisphere shell with free boundary condition have been investigated and experimentally verified [6,7]. Dynamic modal sensing characteristics, distributed modal voltages, and micro-signal components of spherical shells of revolution laminated with distributed piezoelectric sensor layers were recently investigated [8]. Actuations of spherical shells with piezoceramic actuators were also studied [9][10][11], so the conical shells and deep paraboloidal shells [12,13].…”

Section: Introductionmentioning

confidence: 99%

Micro-Control Actions of Actuator Patches Laminated on Hemispherical Shells

Smithmaitrie

2002

Design Engineering

Self Cite

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.

“…Distributed sensing of various shell structures using piezoelectric materials has been investigated over the years [1]. Sensing signals induced by the piezoelectric patches on shells with various shapes, such as ring, circular cylindrical, spherical, conical, paraboloidal and toroidal shells, etc., were derived and their sensing behaviors including the spatial distribution and the component domination were also studied [2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Neural signals on adaptive paraboloidal cylindrical shells

2011 Symposium on Piezoelectricity, Acoustic Waves and Device Applications (SPAWDA)

2011

Paraboloidal cylindrical shells are commonly used as key components in communication antennas, space reflectors, solar collectors, etc. This study focuses on analysis of distributed sensing signals induced by piezoelectric sensors on a flexible simply-supported paraboloidal cylindrical shell panel. The PVDF layer fully laminated on the shell panel is segmented into infinitesimal patches to investigate the characteristic of distributed neural sensing signals. The transverse vibration is only considered since it is the dominant vibration component for paraboloidal cylindrical shells. A new mode shape function of the transverse vibration that satisfies the simply-supported boundary condition is derived. The shell whose meridian height and radial distance are the same is studied as a standard case. The curvature effect is the most primary fact that influence the piezoelectric signal generation. The modal neural signal reaches maximal at the ridge (high-curvature region) when the mode n is odd and inclines to the ridge region with oven modes.