Enhancing low-frequency sound absorption of micro-perforated panel absorbers by combining parallel mechanical impedance

Xiaodan, Zhao; Wang, Xin; Yu, Yong-jie

doi:10.1016/j.apacoust.2017.10.001

Cited by 30 publications

(8 citation statements)

References 4 publications

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“…It is made of 2-mm thick steel plate with symmetrically placed holes of 2.5-mm diameter in 5-mm grid to eliminate electromagnetic field propagation to the surrounding space (control room with operator console, etc.). Such a perforated surface successfully attenuates low-frequency sound if its wavelength is much larger than perforation thickness and diameter [ 13 , 14 ]. The orifice together with the backing air cavity forms a Helmholtz resonator whose frequency of sound absorption depends on size of these acoustic elements [ 15 ].…”

Section: Subject and Methodsmentioning

confidence: 99%

Vibration and Noise in Magnetic Resonance Imaging of the Vocal Tract: Differences between Whole-Body and Open-Air Devices

Přibil

Přibilová

Frollo

2018

Sensors

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This article compares open-air and whole-body magnetic resonance imaging (MRI) equipment working with a weak magnetic field as regards the methods of its generation, spectral properties of mechanical vibration and acoustic noise produced by gradient coils during the scanning process, and the measured noise intensity. These devices are used for non-invasive MRI reconstruction of the human vocal tract during phonation with simultaneous speech recording. In this case, the vibration and noise have negative influence on quality of speech signal. Two basic measurement experiments were performed within the paper: mapping sound pressure levels in the MRI device vicinity and picking up vibration and noise signals in the MRI scanning area. Spectral characteristics of these signals are then analyzed statistically and compared visually and numerically.

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Section: Subject and Methodsmentioning

confidence: 99%

Vibration and Noise in Magnetic Resonance Imaging of the Vocal Tract: Differences between Whole-Body and Open-Air Devices

Přibil

Přibilová

Frollo

2018

Sensors

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“…Another way was to use multi-layer structural composite materials with series. 22 The multi-layer structural sound absorption composite materials were prepared by flame retardant micro-slit panel, flax felt, and air cavity sequentially. The flax felt was close to the micro-slit panel to obtain the multi-layer structural composite materials.…”

Section: Design Of Multi-layer Structural Sound Absorption Composite Materialsmentioning

confidence: 99%

Sound absorption properties of multi-layer structural composite materials based on waste corn husk fibers

Lyu

Guo

et al. 2020

Journal of Engineered Fibers and Fabrics

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In order to find a reasonable way to use the waste corn husk, waste degummed corn husk fibers were used as reinforcing material in one type of composite material. And polylactic acid particles were used as matrix material. The composite materials were prepared by mixing and hot-pressing process, and they were processed into the micro-slit panel. Then, the multi-layer structural sound absorption composite materials were prepared sequentially by micro-slit panel, air cavity, and flax felt. Finally, the sound absorption properties of the multi-layer structural composite materials were studied by changing flax felt thickness, air cavity depth, slit rate, and thickness of micro-slit panel. As the flax felt thickness varied from 0 to 10 mm in 5 mm increments, the peak of sound absorption coefficient shifted to low frequency. The sound absorption coefficient in the low frequency was improved with the air cavity depth varied from 0 to 10 mm in 5 mm increments. With the slit rate increased from 3% to 7% in 2% increments, the peak of sound absorption coefficient shifted to high frequency. With the thickness of micro-slit panel increased from 2 to 6 mm in 2 mm increments, the sound absorption bandwidth was broaden, and the peak of sound absorption coefficient was increased and shifted to low frequency. Results showed that the highest sound absorption coefficient of the multi-layer structural composite materials was about 1 under the optimal process conditions.

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“…Meanwhile, movement between adjacent mediator molecules can produce viscous and friction forces, causing the energy wave to be dissipated after being converted into thermal energy (Kishor and Pawar, 2019). Along with the advancement of materials science, more and more composite materials have also been applied in the field of noise and vibration absorption (Dunne et al, 2017;Yang and Sheng, 2017;Zhao et al, 2018;Yang et al, 2019;Xie et al, 2020). Carbon nanocomposites, such as carbon nanofibers, carbon nanotubes, and graphenes, have become the most promising vibration and noise absorption composites, owing to their favorable compatibilities, excellent sound and vibration absorption properties, and wide wave absorption frequency band.…”

Section: Vibration and Noise Reduction Based On The Property Of Soundmentioning

confidence: 99%

Carbon Nanomaterials: A New Sustainable Solution to Reduce the Emerging Environmental Pollution of Turbomachinery Noise and Vibration

Jia

Miu

et al. 2020

Front. Chem.

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The vibration and noise that resulted from turbomachinery, such as fans, compressors, and centrifugal pumps, are known to bring considerable disturbance and pollution to the machine itself, the environment, and the operators. Hence, how to cope with the vibration and noise has become a recent research focus. With the advancement of materials science, more and more new nanomaterials have been applied in the field of noise and vibration reduction. To be specific, carbon-based nanomaterials, such as carbon fibers, carbon nanotubes, and graphenes, have achieved outstanding results. Carbon nanocomposites, such as carbon nanofibers, carbon nanotubes, and graphenes, are characterized by their low densities, high strengths, and high elastic moduli, all of which made carbon nanocomposites the most promising vibration and noise-reduction composites, thanks to their damping properties, compatibilities, noise and vibration absorption qualities, and wide wave-absorbing frequency bands. In light of this, this paper summarizes the progresses and application prospects of such carbon nanocomposites as carbon nanofibers, carbon nanotubes, and graphenes in the field of turbomachinery vibration and noise reduction.

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Enhancing low-frequency sound absorption of micro-perforated panel absorbers by combining parallel mechanical impedance

Cited by 30 publications

References 4 publications

Vibration and Noise in Magnetic Resonance Imaging of the Vocal Tract: Differences between Whole-Body and Open-Air Devices

Vibration and Noise in Magnetic Resonance Imaging of the Vocal Tract: Differences between Whole-Body and Open-Air Devices

Sound absorption properties of multi-layer structural composite materials based on waste corn husk fibers

Carbon Nanomaterials: A New Sustainable Solution to Reduce the Emerging Environmental Pollution of Turbomachinery Noise and Vibration

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