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Modeling the acoustic signature of an Ocean Explorer class autonomous underwater vehicle

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Date Issued:
2000
Summary:
Autonomous Underwater Vehicles (AUV) rely on acoustics for a number of mission functions such as communications (Acoustic Modem) and vision (Forward and Side Looking Sonars). The AUV acoustic signature (self-noise and vibration) can thus interfere with AUV operations. Additionally, underwater measurements such as turbulence measurements can be contaminated by interference between the AUV generated acoustics pressures and the low pressures of the turbulence. In this thesis a Finite Element and Boundary Element approach is developed to characterize the self-noise (vibration and radiated sound pressure) of a simplified FAU Ocean Explorer AUV. Mechanical excitation from the "podule", which contains the motors for the propulsion and motion control, is assumed in the analysis. The low frequency (less than 1Khz) results are dominated by two types of modes. One type associated with the motion of the "podule" as a rigid body on the vibration isolation supports that connects it to the rest of the AUV structure. The second type is associated with local structural deformations of the "podule", support frame, and AUV hull. Modifying the stiffness of the supports reduces the frequency of the rigid body modes of the "podule", but does not influence the frequencies of the local structural deformations of the "podule" and the rest of the AUV. Decreasing the stiffness of the supports should result in a reduced AUV acoustic signature.
Title: Modeling the acoustic signature of an Ocean Explorer class autonomous underwater vehicle.
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Name(s): Debiesme, Francois-Xavier.
Florida Atlantic University, Degree grantor
Cuschieri, Joseph M., Thesis advisor
Type of Resource: text
Genre: Electronic Thesis Or Dissertation
Issuance: monographic
Date Issued: 2000
Publisher: Florida Atlantic University
Place of Publication: Boca Raton, Fla.
Physical Form: application/pdf
Extent: 106 p.
Language(s): English
Summary: Autonomous Underwater Vehicles (AUV) rely on acoustics for a number of mission functions such as communications (Acoustic Modem) and vision (Forward and Side Looking Sonars). The AUV acoustic signature (self-noise and vibration) can thus interfere with AUV operations. Additionally, underwater measurements such as turbulence measurements can be contaminated by interference between the AUV generated acoustics pressures and the low pressures of the turbulence. In this thesis a Finite Element and Boundary Element approach is developed to characterize the self-noise (vibration and radiated sound pressure) of a simplified FAU Ocean Explorer AUV. Mechanical excitation from the "podule", which contains the motors for the propulsion and motion control, is assumed in the analysis. The low frequency (less than 1Khz) results are dominated by two types of modes. One type associated with the motion of the "podule" as a rigid body on the vibration isolation supports that connects it to the rest of the AUV structure. The second type is associated with local structural deformations of the "podule", support frame, and AUV hull. Modifying the stiffness of the supports reduces the frequency of the rigid body modes of the "podule", but does not influence the frequencies of the local structural deformations of the "podule" and the rest of the AUV. Decreasing the stiffness of the supports should result in a reduced AUV acoustic signature.
Identifier: 9780599640818 (isbn), 15764 (digitool), FADT15764 (IID), fau:12517 (fedora)
Collection: FAU Electronic Theses and Dissertations Collection
Note(s): College of Engineering and Computer Science
Thesis (M.S.)--Florida Atlantic University, 2000.
Subject(s): Oceanographic submersibles
Underwater acoustics
Acoustic models
Held by: Florida Atlantic University Libraries
Persistent Link to This Record: http://purl.flvc.org/fcla/dt/15764
Sublocation: Digital Library
Use and Reproduction: Copyright © is held by the author, with permission granted to Florida Atlantic University to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
Use and Reproduction: http://rightsstatements.org/vocab/InC/1.0/
Host Institution: FAU
Is Part of Series: Florida Atlantic University Digital Library Collections.