Sound power of vibrating cylinders using the radiation resistance matrix and a laser vibrometer

Caleb B. Goates; Cameron B. Jones; Scott D. Sommerfeldt; Jonathan D. Blotter

doi:10.1121/10.0002870

Sound power of vibrating cylinders using the radiation resistance matrix and a laser vibrometer

The Journal of the Acoustical Society of America ◽

10.1121/10.0002870 ◽

2020 ◽

Vol 148 (6) ◽

pp. 3553-3561

Author(s):

Caleb B. Goates ◽

Cameron B. Jones ◽

Scott D. Sommerfeldt ◽

Jonathan D. Blotter

Keyword(s):

Radiation Resistance ◽

Laser Vibrometer ◽

Sound Power ◽

Resistance Matrix

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The Use of Radiation Resistance Measurements to Assess the Noise Characteristics of Machines

Volume 3B: 15th Biennial Conference on Mechanical Vibration and Noise — Acoustics, Vibrations, and Rotating Machines ◽

10.1115/detc1995-0457 ◽

1995 ◽

Author(s):

Everett H. Paddock ◽

Gary H. Koopmann

Keyword(s):

Radiation Resistance ◽

Combustion Engine ◽

Operating Conditions ◽

Surface Radiation ◽

Production Model ◽

Sound Power ◽

Volume Velocity ◽

Noise Characteristics ◽

Low Profile ◽

Resistance Matrix

Abstract An experimental method for assessing the noise characteristics of machines is developed. The method is based on a computation of the radiated sound power of a vibrating structure in terms of its acoustic surface radiation resistance and surface volume velocity. To measure acoustic surface radiation resistance, a probe is developed which consists of a low profile loudspeaker and a small microphone, both of which are moveable over the surface of the structure. As an application of the the method, the sound power produced by two valve covers of a 3.3L V6 internal combustion engine, a current production model and the prototype of a new design, is computed and compared. Based on the probe measurements made on a quiescent engine, a surface resistance matrix was generated for the two valve covers. Measurements of the volume velocity of the valve covers were made at two engine operating conditions: 1800 and 5300 RPM. After combining each of the velocity measurements with the resistance matrix, the results indicate that the prototype valve cover radiates significantly less sound power than the production cover at both operating conditions.

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Experimental validation of determining sound power using acoustic radiation modes and a laser vibrometer

Applied Acoustics ◽

10.1016/j.apacoust.2020.107254 ◽

2020 ◽

Vol 164 ◽

pp. 107254 ◽

Cited By ~ 4

Author(s):

Cameron B. Jones ◽

Caleb B. Goates ◽

Jonathan D. Blotter ◽

Scott D. Sommerfeldt

Keyword(s):

Experimental Validation ◽

Acoustic Radiation ◽

Laser Vibrometer ◽

Sound Power

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Experimental Analysis of Vibration and Radiated Sound Power Reduction Using an Array of Acoustic Black Holes

ASME 2015 Noise Control and Acoustics Division Conference ◽

10.1115/ncad2015-5918 ◽

2015 ◽

Author(s):

Philip A. Feurtado ◽

Stephen C. Conlon

Keyword(s):

Black Hole ◽

Experimental Analysis ◽

Low Frequency ◽

Mode Shapes ◽

Design Parameters ◽

Laser Vibrometer ◽

Sound Power ◽

Radiated Sound ◽

Bending Wave ◽

Radiated Sound Power

The Acoustic Black Hole (ABH) has been developed in recent years as an effective, passive, and lightweight method for attenuating bending wave vibrations in beams and plates. The acoustic black hole effect utilizes a local change in the plate or beam thickness to reduce the bending wave speed and increase the transverse vibration amplitude. Attaching a viscoelastic damping layer to the ABH results in effective energy dissipation and vibration reduction. Surface averaged mobility and radiated sound power measurements were performed on an aluminum plate containing an array of 20 two-dimensional ABHs with damping layers and compared to a similar uniform plate. Detailed laser vibrometer scans of an ABH cell were also performed to analyze the vibratory characteristics of the individual ABHs and compared with mode shapes calculated using Finite Elements. The diameter of the damping layer was reduced in successive steps to experimentally demonstrate the effect of damping layer distribution on the ABH performance. The experimental analysis demonstrated the importance of low order ABH modes in reducing the vibration and radiated sound power of plates with embedded ABHs. The results will be useful for designing the low frequency performance of future ABH systems and describing ABH performance in terms of design parameters.

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