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Saturday, November 7, 2020 | History

3 edition of Interior noise reduction by alternate resonance tuning found in the catalog.

Interior noise reduction by alternate resonance tuning

Interior noise reduction by alternate resonance tuning

six month progress report

by

  • 96 Want to read
  • 29 Currently reading

Published by Dept. of Mechanical Engineering and Materials Design, Duke University in Durham, N.C .
Written in English

    Subjects:
  • Airplanes -- Soundproofing.

  • Edition Notes

    Statementprepared by Donald B. Bliss, James A. Gottwald, Jeffrey W. Bryce.
    SeriesNASA contractor report -- NASA CR-181189.
    ContributionsGottwald, James A., Bryce, Jeffrey W., United States. National Aeronautics and Space Administration.
    The Physical Object
    FormatMicroform
    Pagination1 v.
    ID Numbers
    Open LibraryOL15393349M


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Interior noise reduction by alternate resonance tuning Download PDF EPUB FB2

Get this from a library. Interior noise reduction by alternate resonance tuning: six month progress report. [Donald B Bliss; James A Gottwald; Jeffrey W Bryce; United States. National Aeronautics and Space Administration.].

Get this from a library. Aircraft interior noise reduction by alternate resonance tuning: semi-annual progress report for the period ending June, [Donald B Bliss; Jet Propulsion Laboratory (U.S.);]. Provided these adjacent panels are acoustically compact, the resulting cancellation causes the interior acoustic modes to be cut off, and therefore be nonpropagating and evanescent.

This interior noise reduction method, called Alternate Resonance Tuning (ART), is being investigated theoretically and experimentally. Progress to date is : Donald B. Bliss, James A. Gottwald, Jeffrey W.

Bryce. Aircraft interior noise reduction by alternate resonance tuning. By James A. Gottwald and Donald B. Bliss.

Abstract. Model problem development and analysis continues with the Alternate Resonance Tuning concept. Various topics are presently at different stages of completion and are described.

These topics included optimization of panel mass Author: James A. Gottwald and Donald B. Bliss. An interior noise reduction called alternate resonance tuning (ART) is described both theoretically and experimentally.

Problems dealing with tuning single paneled wall structures for optimum noise reduction using the ART methodology are presented, and three theoretical problems are : James A. Gottwald and Donald B. Bliss. Aircraft interior noise reduction by alternate resonance.

Model problem development and analysis continues with the Alternate Resonance Tuning (ART) concept. The various topics described are presently at different stages of completion: investigation of the effectiveness of the ART concept under an external propagating pressure field associated with propeller passage by the fuselage; analysis of ART performance with a double panel wall mounted in a.

This interior noise reduction method, called Alternate Resonance Tuning (ART), is currently being investigated both theoretically and experimentally. This new concept has potential application to reducing interior noise due to the propellers in advanced turboprop aircraft.

The focus is on a noise control method which considers aircraft fuselages lined with panels alternately tuned to frequencies above and below the frequency that must be attenuated. An interior noise reduction called alternate resonance tuning (ART) is described both theoretically and experimentally.

Problems dealing with tuning single paneled wall structures for optimum noise reduction using. This interior noise reduction method, called Alternate Resonance Tuning (ART), is described in this thesis both theoretically and experimentally.

Problems presented herein deal with tuning single paneled wall structures for optimum noise reduction using the ART tuning methodology, and three theoretical problems are analyzed. Get this from a library. Aircraft interior noise reduction by alternate resonance tuning: progress report for the period ending December, [Donald B Bliss; United States.

National Aeronautics and Space Administration.;]. sound quality of vehicle interior noise: a challenge for the NVH-engineers’, Int. Vehicle Noise and Vibration, Vol. 1, Nos. 1/2, pp– Biographical notes: Dr.-Ing. Klaus Genuit was born in Düsseldorf in He studied electronic engineering from to and economics until at the Technical University of Aachen.

Get this from a library. Aircraft interior noise reduction by alternate resonance tuning: one year progress report. [James A Gottwald; Donald B Bliss; United States. National Aeronautics and.

Engine noise; Road noise, i.e. the noise transferred into the car from the tires rolling on the road; Wind noise; Besides these, you will have noise from other mechanical functions in the car, such as ventilation.

And you may also hear different squeaks and rattles from the interior. But the focus here will be on engine, road and wind noise. David Thompson, in Railway Noise and Vibration, Concluding remarks.

Vehicle interior noise is a complex problem to which this chapter has only given a brief introduction. All the sources described in the rest of the book apply to interior noise, so that noise control techniques described elsewhere apply equally to interior noise.

Achieving adequate low‐frequency transmission loss through lightweight flexible paneled walls is an important problem, particularly for interior noise reduction of propeller aircraft. Alternate resonance tuning (ART) is a new method of blocking sound transmission through such structures by controlling the dynamics of the wall panels.

Adjacent acoustically compact panels are designed to. Aircraft interior noise reduction by alternate resonance tuning [microform]: progress report for the pe Aircraft interior noise reduction by alternate resonance tuning [microform]: semi-annual progress repor Definition of technology aircraft noise levels and the methodology for assessing airplane noise imp.

Due to its potential application in reducing interior cabin noise and reduction of structural vibration, acoustic emission control has been a growing research area. For cabin noise reduction active control of the structural vibration of the cabin shell is a good alternative method [3].

The tuning of an acoustic resonator, in terms of its Helmholtz frequency and the internal resistance, is investigated for the control of a narrowband noise in an acoustic enclosure.

This paper extends our previous work on the resonance control to a more general scenario in which the noise generated may be either close to, far away from, or in. A solution to the low‐frequency noise reduction problem associated with panel/frame structures is proposed by way of tailoring the structural mode shapes associated with individual panels.

The panel is shown to be a poor acoustic radiator when the panel dynamics are altered by tailoring the structural mode shapes. This is achieved by choosing appropriate panel stiffness and mass distributions.

The interior and exterior disturbing noise will need to be minimized, while interior driving noise, actuation noise and communication/audio acoustics can be designed as shown in Fig. The vibration and ride quality are also tested in all vehicle operating conditions.

Download: Download full-size image; Benchmarked vehicle noise. The most commonly applied noise control techniques are based on the use of passive technologies such as resonators.

Since ancient times, resonators have been used for several acoustical applications. In this section, the tuning of the Helmholtz frequency on the reduction of the narrowband noise in an enclosure is investigated.

A rectangular enclosure with L x = mm, L y = mm, L z = mm is used in the calculation. An acoustic monopole source and an observer point are located at (, 59, 0)mm and (, 70, )mm, respectively, both being arbitrarily chosen.

ations, our proposal, called resonance tuning, changes the fre-quency of current variations away from the resonance band to a non-resonant frequency to be absorbed by the power supply.

Because inductive noise is a resonance problem, resonance tun-ing reacts only to repeated variations in the resonance band, and not to isolated variations.

the frequency of the unwanted noise changes from the tuned value, the noise reduction is diminished. Past efforts at active tuning of Helmholtz resonators resulted in limited tuning capability and significant mechanical complexity (Bedout, ).

This work considers a system that. American Institute of Aeronautics and Astronautics Sunrise Valley Drive, Suite Reston, VA Why Clients Love dB-BLoc. dB-Bloc is a stock item that will drop ship to the door step of your project site within days upon order.

The rolls will be heavy, weighing in at nearly pounds per roll. For more than 25 years, we have been selling this layering treatment to thousands of satisfied customers who today enjoy a more sound insulated space by soundproofing walls. INTERIOR ROOM ACOUSTICS This section addresses problems such as excessively loud rooms, boominess, dead spots, echoes and more.

It explains how room size, shape and surface materials all affect interior acoustics and how they can be altered to more accurately reflect musical sound in your rehearsal rooms. MECHANICAL NOISE Whooshing ventilation. 20 Evaluating Methods for Determining Interior Noise Levels Used in Airport Sound Insulation Programs finalize the noise reduction calculation, two corrections are then applied: a correction to account for the specific noise â signatureâ of aircraft and a correction to account for the reverberant field created when noise from the loudspeaker.

Method and apparatus for a reinforced skin structure such as an aircraft fuselage which has reduced interior cabin noise. The reinforced skin structure according to the present invention, includes a frame assembly which has a plurality of spaced apart frame members and an outer skin mounted on the frame assembly.

A plurality of inner panels, which generally defines an interior compartment, are. Aircraft Interior Noise Reduction by Alternate Resonance Tuning Progress Report for the period ending June, Dr. Donald B. Bliss et al: A 41 page study of Alternate Resonance Tuning, alteration of fuselage structure to alter its resonance with sound sources and quiet noise.

MB: The Radiation of Sound from a Propeller at Angle. This interior noise reduction method, called Alternate Resonance Tuning (ART), is currently being investigated both theoretically and experimentally.

This new concept has potential application to. The purpose of this work is to study computationally the possibility of the application of a hybrid active noise control technique for magnetic resonance imaging (MRI) acoustic noise reduction.

He has also developed a method called Alternate Resonance Tuning (ART) to prevent low frequency sound transmission into flexible wall enclosures, with applications to aircraft interior noise.

He also conducts research on mathematical homogenization applied to structural acoustic systems, and on general boundary conditions for bulk-reacting.

Mechanical Engineering and Materials Science People. The overall noise level from most unsilenced engine exhaust systems varies from about dBA to dBA, when measured 1 meter from the pipe outlet. The noise level does not always align with the power rating of the generator as you can see by this next graph.

Exhaust noise can also be affected by engine turbochargers and after-coolers. It is. Flowmaster SUV performance mufflers are a larger version of Flowmaster's famous 50 series mufflers, and are designed specifically for trucks, SUVs, and large displacement car engines.

They feature a special tuning chamber that reduces interior resonance, while their larger case improves sound control and optimizes exhaust flow. (45). Resonance occurs in many different systems, including strings, air columns, and atoms. Resonance is the driven or forced oscillation of a system at its natural frequency.

At resonance, energy is transferred rapidly to the oscillating system, and the amplitude of its oscillations grows until the system can no longer be described by Hooke’s law.

The resonator comprises a resonance box and a tuning pipe, wherein the resonance box is spanned on the exhaust pipe which passes through the resonance box, and the tuning pipe is arranged on the exhaust pipe in the box and is positioned wholly inside the resonance box.

Noise reduction of rotary mowers using an acoustical helmholtz resonator. On the other hand, improvement of gear accuracy and/or vehicle interior noise increases sensitivity to manufacturing variation.

It tends to appear noisiness by transmission unit variation. To prevent such gear noise problem, we made detailed investigation by both several tests and simulation, i.e.

noise measurement, shaker test, running gear. The Nissan Sentra receives some important updates for Among them is the addition of the new Sentra SR Turbo and Sentra NISMO trims.

They are powered by a L turbocharged 4-cylinder making horsepower and mated to either a 6-speed manual or Xtronic continuously variable transmission.PGL is not specific as to which of these three treatment outcomes is consistent with FAA noise reduction goals; however, it does state, â The measurement of interior noise levels is an average for all habitable spaces in a particular residential unit.â 12 This is consistent with the consensus of programs and the FAA offices that the.

Reactive Muffler Noise Canceling Strategies. Former Indy Car racer and Midget Auto Racing Hall of Fame driver Billy Boat explains the strategy behind his company’s noise canceling concepts. “We consider two basic noise canceling concepts when designing mufflers for B&B Exhaust systems,” says Boat.

“Reactive and absorption.