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Monday, August 10, 2020 | History

3 edition of Structure-borne noise estimates for the PTA aircraft found in the catalog.

Structure-borne noise estimates for the PTA aircraft

Structure-borne noise estimates for the PTA aircraft

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Published by National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Division, National Technical Information Service, distributor] in [Washington, DC], [Springfield, Va .
Written in English

    Subjects:
  • Propellers, Aerial.,
  • Airplanes -- Noise.

  • Edition Notes

    Other titlesStructure borne noise estimates for the PTA aircraft.
    StatementJames F. Unruh.
    SeriesNASA contractor report -- 4315., NASA contractor report -- NASA CR-4315.
    ContributionsUnited States. National Aeronautics and Space Administration. Scientific and Technical Information Division.
    The Physical Object
    FormatMicroform
    Pagination1 v.
    ID Numbers
    Open LibraryOL18072596M

      Based on the noise decay data, calculations can be performed to estimate potential noise reduction if absorptive materials are applied to room surfaces, such as the walls and ceiling. Specialized Noise Dosimeters. The HRT maintains super-duty noise dosimeters that are contained in a sealed, waterproof, intrinsically safe metal housing. The noise levels produced by modern aircraft are about 22 dB lower than those of first generation jet aircraft. This reduction has been achieved as a result of the development of turbofan engines with high bypass ratios, liner technology and turbomachinery source noise reduction.

      Aircraft noise has adverse impacts on passengers, airport staff and people living near airports, it thus limits the capacity of regional and international airports throughout the world. Reducing perceived noise of aircraft involves reduction of noise at source, along the propagation path and at the receiver. Effective noise control demands highly s. As for structure-borne noise sources, the international standard of the measurement is appeared recently[3]. But, the qualitative and quantitative representation of their source levels have been actively studied until now[4], although free vibration at mounting points of a machine~ has been commonly used as structure-borne noise source levels.

    Ambient noise must be representative of the acoustical background that exists during the flyover test run. The recorded aircraft noise data is acceptable only if the ambient noise levels, when analyzed in the same way, and quoted in PNL (see A (a)), are at least 20 dB below the maximum PNL of the aircraft.   The key to controlling noise in an aircraft audio system is to fully understand the cause of each type of noise, and to learn to identify them correctly. The aircraft world is a strange mix of.


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Structure-borne noise estimates for the PTA aircraft Download PDF EPUB FB2

Structure-Borne Noise for the PTA Aircraft Estimates James F. Unruh Southwest Research Institute San Antonio, Texas Prepared for Langley Research Center under Contract NAS National Aeronautics and Space Administration Office of Management Scientific.

Get this from a library. Structure-borne noise estimates for the PTA aircraft. [James F Unruh; United States. National Aeronautics and Space Administration. Scientific and Technical Information Division.]. Structure-borne noise estimates for the PTA aircraft.

By James F. Unruh. Abstract. Estimates of the level of in-flight structure-borne noise transmission in the Propfan Test Assessment Aircraft were carried out for the first three blade passage frequencies.

The procedure used combined the frequency response functions of wing strain to cabin Author: James F. Unruh. Structure-borne noise estimates for the PTA aircraft / By James F.

Unruh, Langley Research Center. and Southwest Research Institute. Internet Topics: Aircraft cabins, Propellers, Aerial, Airplanes. Publisher: Washington, D.C.: National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information. Estimates of the level of structure-borne noise transmission in the Propfan Test Assessment (PTA) aircraft were carried out for the first three blade passage frequencies.

The procedure used combined the frequency response functions of cabin sound pressure level to wing strain response obtained during ground test of the PTA aircraft with in-flight measured wing strain response : James F.

Unruh. Knowing the Difference: Airborne Noise vs Structure-Borne Noise No matter what type of sound it is, you’ll want to keep any unwanted noises out of your house.

Whether it’s your neighbors throwing a party, causing a lot or airborne noise, or that new project in your house, causing structure-borne noise, we’re here for all your.

Structure-borne noise estimates for the PTA aircraft / (Washington, D.C.: National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Division.

1. INTRODUCTION Aerospace and aircraft structures are built from many discretely stiffened components. The vibrations induced from power plants, life support systems, thrusters, mechanical equipment, etc.

could generate structure- borne noise in the interior of various aircraft and space transportation vehicles. American Institute of Aeronautics and Astronautics Sunrise Valley Drive, Suite Reston, VA Book. Aug ; Simon J. Newman Structure-borne noise estimates for the PTA aircraft. Estimates of the level of in-flight structure-borne noise transmission in the Propfan Test Assessment.

contributes to the noise inside the aircraft. Thus airborne noise is distinguished from the structure-borne noise that is generated by the vibrations caused e.g. by the operation of the insufficiently balanced elements of the power plants [1]. However, within the aircraft fuselage, especially the large ones, there are significant noise.

The noise levels in the passenger cabin of turbopropeller-driven aircraft are typically higher than the noise levels in comparable turbofan-powered aircraft. The sources of noise in a turboprop aircraft include boundary layer flow noise, structure-borne noise due to. Aircraft propeller induced structure-borne noise A laboratory-based test apparatus employing components typical of aircraft construction was developed that would allow the study of structure-borne noise transmission due to propeller induced wake/vortex excitation of in-wake structural appendages.

The test apparatus was employed to evaluate several aircraft installation effects (power. After flight testing on the PTA aircraft, noise reduction (NR) tests were performed with the enclosure in the Kelly Johnson Research and Development Center Acoustics Laboratory.

Book. Jan In this section, noise sources are presented for the most common machines used in industrial installations. For each case, the mechanism of noise generation is discussed.

Industrial Gas Jets Industrial jet noise probably ranks third as a major cause of hearing damage after that of impact and material handling noise. Review and Evaluation of Aircraft Noise Spectra used to Estimate Noise Level Reduction for Airport Sound Insulation Programs based on the Loudspeaker Test Method.

HMMH Report No. February Prepared for: Federal Aviation Administration – Office of Environment &. How Both Airborne and Structure Borne Noise Are Closely Related.

Here is the major highlight to learn: In our previous learning, the only difference we found is the origin of the noise, where airborne noise generated due to sound source however the structure borne noise is. Aircraft noise also affects people within the aircraft: crew and passengers.

Cabin noise can be studied to address the occupational exposure and the health and safety of pilots and flight attendants. In64 commercial airline pilots were surveyed regarding hearing loss and tinnitus. Inthe NIOSH conducted several noise surveys and health hazard evaluations, and found noise levels.

In a meta-analysis published inan estimate of the relative risk of (95% CI=–) per 5-dB(A) increase in the aircraft noise level during the day (L day,16 h =55 to 72 dB(A)) was calculated for the association between aircraft noise and hypertension. Since then a number of new aircraft noise studies have been carried out.

Engine Induced Structural-Borne Noise in a General Aviation Aircraft This paper describes a study of engine induced structural-borne noise in a single engine light aircraft. Cabin noise and fuselage vibration levels were recorded during ground tests for engine-attached, engine-detached, interior-installed, and interior-removed.

with the aircraft or on platform with in- or out taxiing aircraft. Noise exposure and 6 kHz was used t Exposure measurements were performed inusing a Spark RC, noise dosimeter, (Larson Davis INC, UTUSA). Equivalent personal exposure (Leq) dB (A) during a working day was measured during different working tasks.Aircraft noise exerts an adverse influence on the environment and on people's health, and is also a performance issue.

The aircraft noise problem is a complex topic that covers a number of areas, including passenger cabin and cockpit noise, ramp noise, structure‐borne noise, propulsive system noise, jet noise, airframe noise, etc., each of which requires separate modeling and mitigation.FD DESCRIPTION OF BROADBAND STRUCTURE-BORNE AND AIRBORNE NOISE TRANSMISSION FROM THE POWERTRAIN 1Sottek, Roland*, 1Genuit, Klaus, 2Behler, Gottfried, 2Vorländer, Michael 1 HEAD acoustics GmbH, Germany 2 Institute of Technical Acoustics, RWTH Aachen University, Germany KEYWORDS – Binaural Transfer Path Analysis, reciprocal .