Acoustic Transduction - Materials and Devices, Period 31 July 1996 to 31 December 1997, Annual Report. Volume 4

Acoustic Transduction - Materials and Devices, Period 31 July 1996 to 31 December 1997, Annual Report. Volume 4
Author:
Publisher:
Total Pages: 0
Release: 1998
Genre:
ISBN:

Transducer Studies have continued to exploit the excellent sensitivity and remarkable versatility of the cymbal type flextensional element. Initial studies of a small cymbal arrays show excellent promise in both send and receive modes, and larger arrays are now under construction for tests at ARL. New studies in constrained layer vibration damping and in flow noise reduction are yielding exciting new results.

Acoustic Transduction - Materials and Devices, Period 31 July 1996 to 31 December 1997, Annual Report

Acoustic Transduction - Materials and Devices, Period 31 July 1996 to 31 December 1997, Annual Report
Author: Kenji Uchino
Publisher:
Total Pages: 162
Release: 1998
Genre:
ISBN:

This paper reviews recent developments of ultrasonic motors using piezoelectric resonant vibrations. Following the historical background, ultrasonic motors using the standing and traveling waves are introduced. Driving principles and motor characteristics are explained in comparison with the conventional electromagnetic motors. After a brief discussion on speed and thrust calculation, finally, reliability issues of ultrasonic motors are described.

Acoustic Transduction - Materials and Devices, Period 31 July 1996 to 31 December 1997, Annual Report

Acoustic Transduction - Materials and Devices, Period 31 July 1996 to 31 December 1997, Annual Report
Author: Kenji Uchino
Publisher:
Total Pages: 169
Release: 1998
Genre:
ISBN:

In Actuator Studies, an important advance in piezoelectric generated noise control now permits wider use of acoustic emission as a reliability diagnostic technique. Joint studies with NRL, Washington have developed a completely new d15 driven torsional actuator and the CAV program element has designed an exciting high strain high force inchworm. Finite element analysis continues to be an important tool for understanding the more complex composite structures and their beam forming capability in water. Thin and Thick Thin Film Studies are gearing up to provide the material base for micro-tonpilz arrays. New exploitation of ultra sensitive strain and permittivity measurements is providing the first reliable data of electrostriction in simple solids, and suggesting new modes for separating the polarizability contributors in dielectrics and electrostrictors.

Acoustic Transduction - Materials and Devices, Period 31 July 1996 to 31 December 1997, Annual Report

Acoustic Transduction - Materials and Devices, Period 31 July 1996 to 31 December 1997, Annual Report
Author: Kenji Uchino
Publisher:
Total Pages: 164
Release: 1998
Genre:
ISBN:

In Material Studies, undoubtedly major breakthroughs have occurred in the ultra- high strain relaxor ferroelectric systems. Earlier reports of unusual piezoelectric activity in single crystal perovskite relaxors have been amply confirmed in the lead zinc niobate: lead titanate, and lead magnesium niobate : lead titanate systems for compositions of rhombohedral symmetry close to the Morphotropic Phase Boundary (MPB) in these solid solutions. Analysis of the unique properties of 001 field poled rhombohedral ferroelectric crystals suggests new intrinsic mechanisms for high strain and carries the first hints of how to move from lead based compositions. A major discovery of comparable importance is a new mode of processing to convert PVDF:TrFE copolymer piezoelectric into a relaxor ferroelectric in which electrostrictive strains of 4% have been demonstrated at high fields. Both single crystal and polymer relaxors appear to offer energy densities almost order of magnitude larger than in earlier polycrystal ceramic actuators. Transducer Studies have continued to exploit the excellent sensitivity and remarkable versatility of the cymbal type flextensional element. Initial studies of a small cymbal arrays show excellent promise in both send and receive modes, and larger arrays are now under construction for tests at ARL. New studies in constrained layer vibration damping and in flow noise reduction are yielding exciting new results. In Actuator Studies, an important advance in piezoelectric generated noise control now permits wider use of acoustic emission as a reliability diagnostic technique. Joint studies with NRL, Washington have developed a completely new d15 driven torsional actuator and the CAV program element has designed an exciting high strain high force inchworm. Finite element analysis continues to be an important tool for understanding the more complex composite structures and their beam forming capability in water.

Acoustic Transduction - Materials and Devices, Period 31 July 1996 to 31 December 1997, Annual Report

Acoustic Transduction - Materials and Devices, Period 31 July 1996 to 31 December 1997, Annual Report
Author: Kenji Uchino
Publisher:
Total Pages: 159
Release: 1998
Genre:
ISBN:

The overarching project objective is the development of acoustic transduction materials and devices of direct relevance to Navy needs and with application in commercial products. The initial focus of studies is upon high performance sensors and high authority high strain actuators. This objective also carries the need for new materials, new device designs, improved drive and control strategies and a continuing emphasis upon reliability under a wide range of operating conditions. In Material Studies, undoubtedly major breakthroughs have occurred in the ultra- high strain relaxor ferroelectric systems. Earlier reports of unusual piezoelectric activity in single crystal perovskite relaxors have been amply confirmed in the lead zinc niobate : lead titanate, and lead magnesium niobate : lead titanate systems for compositions of rhombohedral symmetry close to the Morphotropic Phase Boundary (MPB) in these solid solutions. Analysis of the unique properties of 001 field poled rhombohedral ferroelectric crystals suggests new intrinsic mechanisms for high strain and carries the first hints of how to move from lead based compositions. A major discovery of comparable importance is a new mode of processing to convert PVDF:TrFE copolymer piezoelectric into a relaxor ferroelectric in which electrostrictive strains of 4% have been demonstrated at high fields. Both single crystal and polymer relaxors appear to offer energy densities almost order of magnitude larger than in earlier polycrystal ceramic actuators. Transducer Studies have continued to exploit the excellent sensitivity and remarkable versatility of the cymbal type flextensional element. Initial studies of a small cymbal arrays show excellent promise in both send and receive modes, and larger arrays are now under construction for tests at ARL. New studies in constrained layer vibration damping and in flow noise reduction are yielding exciting new results.

Acoustic Transduction - Materials and Devices, Period 31 July 1996 to 31 December 1997, Annual Report

Acoustic Transduction - Materials and Devices, Period 31 July 1996 to 31 December 1997, Annual Report
Author:
Publisher:
Total Pages: 200
Release: 1998
Genre:
ISBN:

In Material Studies, undoubtedly major breakthroughs have occurred in the ultra- high strain relaxor ferroelectric systems. Earlier reports of unusual piezoelectric activity in single crystal perovskite relaxors have been amply confirmed in the lead zinc niobate : lead titanate, and lead magnesium niobate : lead titanate systems for compositions of rhombohedral symmetry close to the Morphotropic Phase Boundary (MPB) in these solid solutions. Analysis of the unique properties of 001 field poled rhombohedral ferroelectric crystals suggests new intrinsic mechanisms for high strain and carries the first hints of how to move from lead based compositions. A major discovery of comparable importance is a new mode of processing to convert PVDF:TrFE copolymer piezoelectric into a relaxor ferroelectric in which electrostrictive strains of 4% have been demonstrated at high fields. Both single crystal and polymer relaxors appear to offer energy densities almost order of magnitude larger than in earlier polycrystal ceramic actuators.

Piezoelectric Energy Harvesting

Piezoelectric Energy Harvesting
Author: Alper Erturk
Publisher: John Wiley & Sons
Total Pages: 377
Release: 2011-04-04
Genre: Technology & Engineering
ISBN: 1119991358

The transformation of vibrations into electric energy through the use of piezoelectric devices is an exciting and rapidly developing area of research with a widening range of applications constantly materialising. With Piezoelectric Energy Harvesting, world-leading researchers provide a timely and comprehensive coverage of the electromechanical modelling and applications of piezoelectric energy harvesters. They present principal modelling approaches, synthesizing fundamental material related to mechanical, aerospace, civil, electrical and materials engineering disciplines for vibration-based energy harvesting using piezoelectric transduction. Piezoelectric Energy Harvesting provides the first comprehensive treatment of distributed-parameter electromechanical modelling for piezoelectric energy harvesting with extensive case studies including experimental validations, and is the first book to address modelling of various forms of excitation in piezoelectric energy harvesting, ranging from airflow excitation to moving loads, thus ensuring its relevance to engineers in fields as disparate as aerospace engineering and civil engineering. Coverage includes: Analytical and approximate analytical distributed-parameter electromechanical models with illustrative theoretical case studies as well as extensive experimental validations Several problems of piezoelectric energy harvesting ranging from simple harmonic excitation to random vibrations Details of introducing and modelling piezoelectric coupling for various problems Modelling and exploiting nonlinear dynamics for performance enhancement, supported with experimental verifications Applications ranging from moving load excitation of slender bridges to airflow excitation of aeroelastic sections A review of standard nonlinear energy harvesting circuits with modelling aspects.