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Numerical and Experimental Study of Sound Power Reduction Performance of Acoustic Black Holes in Rectangular Plates

Unruh, Oliver and Blech, Christopher and Monner, Hans Peter (2015) Numerical and Experimental Study of Sound Power Reduction Performance of Acoustic Black Holes in Rectangular Plates. SAE Noise and Vibration Conference 2015, 22.-25. Juni 2015, Grand Rapids, USA.

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Abstract

Global attenuation of structural velocities is one of the most effective approaches in order to reduce noise emitted by shell structures such as a car roof or aircraft fuselage panels. This global reduction can be achieved by the application of passive damping treatments like constraint layer damping on large fractions of the vibrating surface. The main disadvantage of this approach arises from the fact that it leads to increasing total cost and weight of the structure. To overcome this problem, acoustic black holes can be used to create locations with high vibration amplitudes and low bending waves velocity in order to dissipate the energy of structure borne sound by very limited application of damping treatments. Acoustic black holes are funnel shaped thickness reductions that attract sound radiating bending waves and allow a global vibration reduction by an acceptable use of additional damping. This paper presents the results of a numerical and experimental study of acoustic black holes located on a rectangular plate. The presented work is focused on the influence of size, position and number of acoustic black holes on the acoustic performance. A large number of different configurations of these parameters is studied by finite-element-analysis and evaluated in terms of vibration amplitude and sound power level. In order to confirm simulation results the most efficient configuration is implemented in laboratory setup and characterized in terms of vibrational and acoustic performance.

Item URL in elib:https://elib.dlr.de/102319/
Document Type:Conference or Workshop Item (Speech)
Title:Numerical and Experimental Study of Sound Power Reduction Performance of Acoustic Black Holes in Rectangular Plates
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Unruh, Oliveroliver.unruh (at) dlr.deUNSPECIFIED
Blech, ChristopherUNSPECIFIEDUNSPECIFIED
Monner, Hans PeterUNSPECIFIEDUNSPECIFIED
Date:1 June 2015
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:Sound Radiation, Acoustic Black Holes, Noise Reduction
Event Title:SAE Noise and Vibration Conference 2015
Event Location:Grand Rapids, USA
Event Type:international Conference
Event Dates:22.-25. Juni 2015
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:fixed-wing aircraft
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Structures and Materials
Location: Braunschweig
Institutes and Institutions:Institute of Composite Structures and Adaptive Systems > Adaptronics
Deposited By: Unruh, Oliver
Deposited On:25 Jan 2016 12:11
Last Modified:25 Jan 2016 12:11

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