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Proceedings Paper

Acoustic signature reduction using feedback of piezoelectric layers
Author(s): Johan Hamberg; Anders Malmgren
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Paper Abstract

The possibilities of using dynamic feedback of piezoelectric layers for controlling the acoustic properties of a surface are investigated. The investigation shows that in principle it is possible to achieve desired properties (e.g. no reflection, artificial transparency or simultaneous transmission and reception of information) using a single piezo-electric layer. The layer then operates both as a sensor and as an actuator. This approach can be described as controlling the boundary conditions of the acoustic field. The study shows that this will work well, also in practice, if the material has an electromechanic coupling factor that is large enough. Explicit controllers for these cases are given. However, for the values of electro-mechanic coupling factors of available materials, the above construction is not suitable for practical purposes, due to non-robustness. Therefore, the possibility of using multiple layers is also investigated. It turns out that a two layer construction can achieve the properties of a single layer with large electro-mechanic coupling factor. For the specific problem of achieving no reflection, an explicit construction of a realistic controller is given. Requirements of robust stability and limited voltage amplitudes imply that low reflection cannot be achieved at low and high frequencies. However for a large frequency interval, it is possible to obtain low reflection. It is shown that both the gain and phase margins are infinite with this controller. Our work makes extensive use of the Redheffer star-product for systematic modeling, analysis and synthesis of the system and the regulator.

Paper Details

Date Published: 19 June 2000
PDF: 11 pages
Proc. SPIE 3984, Smart Structures and Materials 2000: Mathematics and Control in Smart Structures, (19 June 2000); doi: 10.1117/12.388757
Show Author Affiliations
Johan Hamberg, Swedish Defense Research Establishment (Sweden)
Anders Malmgren, Swedish Defense Research Establishment (Sweden)

Published in SPIE Proceedings Vol. 3984:
Smart Structures and Materials 2000: Mathematics and Control in Smart Structures
Vasundara V. Varadan, Editor(s)

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