Experimental evaluation on acoustic impedance and sound absorption performances of porous foams with additives with Helmholtz number

Guan, Yiheng; Zhao, Dan; Low, Thien Sen

doi:10.1016/j.ast.2021.107120

Cited by 28 publications

(11 citation statements)

References 33 publications

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“…Though the absorption coefficients at 125 Hz, 250 Hz, 1500 Hz, and 3000 Hz are also enhanced with periodic cavities, the improvement effect could be neglected due to the relative small values at these frequencies. This frequency-dependent improvement effects due to the multiple scattering between cavities can be explained using Fabry–Pérot resonance 19,20 : Fabry–Pérot resonance occurs at a frequency at which a sound wave transmitted by a voided layer becomes a resonance condition through constructive interference due to multiple scattering of waves between voided layers. At low frequencies below 500 Hz, the silicone rubber foam hardly exhibits sound absorption performance, which should be the result of the wave-passing behavior caused by the scattering effect for long wavelength.…”

Section: Resultsmentioning

confidence: 99%

“…The porous liquid silicone rubber material prepared by introducing a foaming agent into the liquid silicone rubber has the advantages of softness, light weight, high resilience rate, controllable cell size and density, easy implementation, corrosion resistance, weather resistance, etc., which is suitable for sound absorption and noise reduction in most indoor and outdoor environments. 13,15,16,[18][19][20][21] Additionally, introducing chemical foaming agents into the liquid silicone rubber, such as foaming agents or pore formers, foamed material with countless cells could be prepared after different processes. Different types of cell structures (closed, open, and mixed cell structures) could be achieved by adjusting the hydrogen-containing silicone oil, and the cell size can also be tailored.…”

Section: Introductionmentioning

confidence: 99%

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Improved low-frequency sound absorption of porous silicone rubber resonance sheet with periodic cavities

Peng

Zhao

Cheng

et al. 2022

Journal of Low Frequency Noise, Vibration and Active Control

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Since the development of advanced sound absorption material is highly critical in noise control applications, anechoic coatings, and acoustic metamaterials, both fabrication technology and structure design are significant in the achievement of broadband and strong absorption performance in the low sound frequency range. In this work, the silicone rubber resonance absorption sheet with periodic cavities is prepared via inserting cylindrical steel strips with different diameters into the non-vulcanized colloid. Effects of size and arrangement of cavities on the sound absorption properties, as well as the corresponding mechanical properties, are investigated and discussed. Results indicate that periodic pattern designs could further improve the low-frequency sound absorption performance of silicone rubber foams, and increasing the cavity diameter could significantly improve the sound absorption efficiency of the prepared samples in the middle- and low-frequency range from 125 to 2000 Hz. Particularly, increasing the number of the layered cavities could also improve the sound absorption efficiency. The consumption of sound energy in the prepared silicone rubber resonance sheet is discussed, which could be attributed to the synergistic effect in different spatial scales.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Improved low-frequency sound absorption of porous silicone rubber resonance sheet with periodic cavities

Peng

Zhao

Cheng

et al. 2022

Journal of Low Frequency Noise, Vibration and Active Control

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“…Compared to the two-room method, the impedance tube method is cheaper and has fewer space requirements [ 29 ]. Therefore, the impedance tube method has been widely applied in STL tests of materials and structures [ 30 ].…”

Section: Experimental Studymentioning

confidence: 99%

Influence of Magnetic Field on Sound Transmission Loss of the Unit Filled with Magnetorheological Fluid

Wang

2022

Materials

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To explore the feasibility of applying magnetorheological fluids (MRFs) in the field of noise control, the influence of the magnetic field intensity and direction on the sound transmission loss (STL) of a unit filled with MRF (MRF unit) were investigated in this study. First, two types of test sample containing the MRF unit were designed and fabricated. The magnetic field applied to the MRF was provided by the permanent magnets used in pairs. The direction of the magnetic field was perpendicular or parallel to the direction of the sound wave propagation. The distribution of the magnetic field intensity of the two types of test samples was simulated using magnetostatic finite element analysis and validated with the magnetic field intensity measured using a Teslameter. For comparison, test samples containing air and water units were also prepared. Then, the STL of the two types of test samples were measured under different magnetic field intensities using the impedance tube method. Finally, the STL curves of the two types of test samples were presented, and the influence of magnetic field intensity and direction on the STL were discussed. The results demonstrate that the magnetic field direction has a significant influence on the STL of the MRF unit. In addition, when the magnetic field direction is parallel to the sound propagation direction, the STL of the test sample containing MRF unit significantly increases with the increase of the magnetic field intensity at low and middle frequencies.

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“…In addition, Guan et al 8 conducted a series of experiments to evaluate the noise damping performance of PU foam, ceramic fiber, concrete, and silica gel with different density, thickness, or porous structure. This work clarified how to optimize the acoustic damping performance of porous foams.…”

Section: Introductionmentioning

confidence: 99%

“…Arjunan et al 14,15 found that the metal foam combination structure with cavity thickness can improve the sound absorption performance, and increasing the air chamber helped to expand the frequency range of the absorption peak. Zhao et al 8,16 proposed a modified design of a Helmholtz resonator by implementing a rigid baffle in its cavity, and improved the acoustic impedance and sound absorption performances of porous foams with additives in Helmholtz.…”

Section: Introductionmentioning

confidence: 99%

Study on sound absorption performance of resonance structure for aluminum–polyurethane foam composite and plexiglass

Yuan

Fang

Liu

et al. 2022

Journal of Low Frequency Noise, Vibration and Active Control

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Low-frequency noise control in substations (converter stations) has received extensive attention. The sound absorption performance of a single material is limited. In the paper, aluminum–polyurethane (Al–PU) foam composite materials were prepared by impregnating method. The microstructure and composition of PU and Al–PU composite foam were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that aluminum particles can be well adhered to the skeleton of PU foams, and the sound absorption coefficient of Al–PU foams at 50 Hz–315 Hz was greatly improved. Meanwhile, the resonance structures of Al–PU foams and plexiglass were further constructed. The sound absorption coefficient of different resonance structures was different, and the performance of the resonance structure with 10 mm back cavity and front hole was the best.

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Experimental evaluation on acoustic impedance and sound absorption performances of porous foams with additives with Helmholtz number

Cited by 28 publications

References 33 publications

Improved low-frequency sound absorption of porous silicone rubber resonance sheet with periodic cavities

Improved low-frequency sound absorption of porous silicone rubber resonance sheet with periodic cavities

Influence of Magnetic Field on Sound Transmission Loss of the Unit Filled with Magnetorheological Fluid

Study on sound absorption performance of resonance structure for aluminum–polyurethane foam composite and plexiglass

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