Durability, Acoustic Performance and Process Efficiencies of Absorbent Fibers for Muffler Filling

Cofer, Cameron G.; Bielert, Friedrich; Kullmann, Thomas

doi:10.4271/1999-01-1655

Cited by 4 publications

(1 citation statement)

References 1 publication

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“…The sound absorption characteristics of fiber materials are well established in the literature (Cofer et al, 1999). The recent improvements in their properties combined with their broadband acoustic dissipation characteristics make such materials potentially desirable for implementation in silencers.…”

Section: Introductionmentioning

confidence: 99%

Acoustic Attenuation Performance of Perforated Absorbing Silencers

Selamet¹,

Lee²,

Ji³

et al. 2001

SAE Technical Paper Series

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The acoustic attenuation performance of a single-pass, perforated concentric silencer filled with continuous strand fibers is investigated theoretically and experimentally. One-dimensional analytical and threedimensional boundary element methods are employed to predict the acoustic attenuation in the absence of mean flow. Measured complex characteristic impedance and wave number are used to account for the wave propagation through absorbing fiber. The perforation impedance facing the fiber is also presented in terms of the complex characteristic impedance and wave number. The effects of perforate duct porosity and the fiber density are examined. Comparisons of predictions with the experiments illustrate the need for multidimensional analysis at higher frequencies, while the one-dimensional treatment provides a reasonable accuracy at lower frequencies, as expected. The study also shows a significant improvement in the acoustic attenuation of the silencer due to fiber absorption.

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Section: Introductionmentioning

confidence: 99%

Acoustic Attenuation Performance of Perforated Absorbing Silencers

Selamet¹,

Lee²,

Ji³

et al. 2001

SAE Technical Paper Series

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Acoustic attenuation of hybrid silencers

Selamet

Lee

Huff

2003

Journal of Sound and Vibration

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Using Response Surface for Searching the Nearly Optimal Parameters Combination of the Foam Concrete Muffler

2022

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A car muffler is a device to improve car noise emission. Some conventional mufflers use layers of glass fiber as a material to absorb noise. However, filling glass fiber is an environmentally unfriendly work, mainly manually filling with chop strand fiber. This research selected a composite material of glass fiber and foam concrete to replace chop strand fiber to avoid this hazard and maintain the muffler’s good noise reduction performance. A response surface methodology with a two-way factorial experimental design repeated the center point twice is performed. The density of the foamed concrete and the weight of the glass fiber is being considered in order to determine the nearly optimal combination of the values in two factors. The response variable is the loudness sensation in Sone of the noise generated from the muffler. At present, the lowest loudness sensation from the two-way factorial design is 16.6494 Sones, which occurred for a muffler with a formula combination of a density of 0.2 g/cm3 and 40 g of glass fiber. The significance of this paper is the presentation of a new application of foam concrete to the green muffler design. To the best of our knowledge, this unique area has never been tackled in the material application of concrete. We have discovered that foam concrete indeed does an excellent job in terms of noise reduction as compared with that of a market muffler.

show abstract

Durability, Acoustic Performance and Process Efficiencies of Absorbent Fibers for Muffler Filling

Cited by 4 publications

References 1 publication

Acoustic Attenuation Performance of Perforated Absorbing Silencers

Acoustic Attenuation Performance of Perforated Absorbing Silencers

Acoustic attenuation of hybrid silencers

Using Response Surface for Searching the Nearly Optimal Parameters Combination of the Foam Concrete Muffler

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