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Sound Transmission Through Primary Bulb Rubber Sealing Systems
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Abstract
Structural sound transmission through primary bulb (PB) sealing systems was investigated. A two-degrees-of-freedom analytical model was developed to predict the sound transmission characteristics of a PB seal assembly. Detailed sound transmission measurements were made for two different random excitations: acoustic and aerodynamic. A reverberation room method was first used, whereby a seal sample installed within a test fixture was excited by a diffuse sound field. A quiet flow facility was then used to create aerodynamic pressure fluctuations which acted as the excitation. The space-averaged input pressure within the pseudo door gap cavity and the sound pressure transmitted on the quiescent side of the seal were obtained in each case for different cavity dimensions, seal compression, and seal designs. The sound transmission predictions obtained from the lumped element model were found to be in reasonable agreement with measured values. The measured noise reduction was found to be very similar for both types of excitation. This confirmed that an acoustic excitation may be used instead of aerodynamic pressure fluctuations for sound transmission measurements, and that the barrier performance of the PB seal was not significantly affected by the presence of a static pressure gradient associated with the mean flow. The wind tunnel method was also found to yield a better signal-to-noise ratio than the reverberation room method.
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Mongeau, L. and Danforth, R., "Sound Transmission Through Primary Bulb Rubber Sealing Systems," SAE Technical Paper 971903, 1997, https://doi.org/10.4271/971903.Also In
References
- George, A.R. “Automobile aeroacoustics,” AIAA Paper 89-1067 1989
- Zorea, S.I. “Aeroacoustic assessment of vehicle door gaps,” Proceedings of Inter-noise 95 289 292 1995
- Lorea, A. Castelluccio, V. Costelli, A. Masoero, M. “A wind-tunnel method for evaluating the aerodynamic noise of cars,” SAE Paper 860215 1986
- Buchheim, R. Dobrzynski, W. Mankua, H. Schwabe, D. “Vehicle interior noise related to aerodynamics,” International Journal of Vehicle Design 3 4 398 410 1982
- Yoshimatsu, H. “Survey of wind noise sources by acoustic intensity measurement,” Proceedings of Second International Congress on Acoustic Intensity 462 470 1985
- Saha, P. Kolano, R.A. “Acoustical performance testing of automotive weatherseals,” SAE Paper 931270 1993
- Mongeau, L. Bezemek, J. Danforth, R. “Pressure fluctuations in flow-excited, door-gap shaped cavities,” SAE Paper 97NV213 1997
- Mongeau, L. Danforth, R. “Laboratory method for evaluating the sound transmission characteristics of primary bulb seals,” SAE Paper 96193, SAE Transactions SP-1147 51 60 1996
- Brown, D.V. Mongeau, L. “The design, construction, and validation of a small, low-speed, quiet wind tunnel with application to noise from the flow over a cavity,” Herrick Laboratories Internal Report No. 204 1995
- ASTM “Standard test method for laboratory measurement of airborne sound transmission loss of building partitions,” ASTM E90 1990
- SAE “Laboratory measurement of the airborne sound barrier performance of automotive materials and assemblies,” SAE recommended practice J1400