Development of an Acoustic Material Database for Vehicle Interior Trims

Liu, Zhengqing; Fard, Mohammad; Jazar, Reza N.

doi:10.4271/2015-01-0046

Cited by 8 publications

(8 citation statements)

References 12 publications

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“…Observing Figure 14a, it is suggested that the sound absorption peak may be moved to a lower frequency. This hypothesis may be supported by studies on other porous media [37,42]. The viscous characteristic length (Λ) describes the viscous effects of the flow [29].…”

Section: Resultsmentioning

confidence: 72%

“…Observing Figure 14a, it is suggested that the sound absorption peak may be moved to a lower frequency. This hypothesis may be supported by studies on other porous media [37,42]. According to Darcy's law (Equation ( 10)), the decrease in porosity may increase the static air flow resistivity (σ) for a given pressure gradient ( → ∇P) and fluid velocity ( → v ) [39].…”

Section: Resultsmentioning

confidence: 79%

“…Given that this variable is also predominantly affected by the ratio of pore volume and superficial area (Equation ( 11)) [44] and recurring to Figure 15a, it may be observed that as the value of this variable increases, there may be an elevation in the sound absorption coefficient. The frequency-dependent dynamic thermal permeability (𝑘 𝜔 ) may be calculated using Equation (13), being dependent on the differentials of pressure and time (𝜕𝑃/𝜕𝑡), porosity (Ф), air thermal conductivity (k) and excess of the temperature inside the cellular The frequency-dependent dynamic thermal permeability (k (ω)) may be calculated using Equation (13), being dependent on the differentials of pressure and time (∂P/∂t), porosity (Φ), air thermal conductivity (k) and excess of the temperature inside the cellular solid (τ) [40,42]. The static thermal permeability (k 0 ) relates thermal effects between the rigid frame and the fluid at low frequencies actuating in the boundary layer, according to Equation ( 13) [45].…”

Section: Resultsmentioning

confidence: 99%

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Vibration Damping and Acoustic Behavior of PU-Filled Non-Stochastic Aluminum Cellular Solids

Carneiro

Puga

Meireles

2021

Metals

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Aluminum-based cellular solids are promising lightweight structural materials considering their high specific strength and vibration damping, being potential candidates for future railway vehicles with enhanced riding comfort and low fuel consumption. The filling of these lattices with polymer-based (i.e., polyurethane) foams may further improve the overall vibration/noise-damping without significantly increasing their density. This study explores the dynamic (i.e., frequency response) and acoustic properties of unfilled and polyurethane-filled aluminum cellular solids to characterize their behavior and explore their benefits in terms of vibration and noise-damping. It is shown that polyurethane filling can increase the vibration damping and transmission loss, especially if the infiltration process uses flexible foams. Considering sound reflection, however, it is shown that polyurethane filled samples (0.27–0.30 at 300 Hz) tend to display lower values of sound absorption coefficient relatively to unfilled samples (0.75 at 600 Hz), is this attributed to a reduction in overall porosity, tortuosity and flow resistivity. Foam-filled samples (43–44 dB at 700–1200 Hz) were shown to be more suitable to reduce sound transmission rather than reflection than unfilled samples (21 dB at 700 Hz). It was shown that the morphology of these cellular solids might be optimized depending on the desired application: (i) unfilled aluminum cellular solids are appropriate to mitigate internal noises due to their high sound absorption coefficient; and (ii) PU filled cellular solids are appropriate to prevent exterior noises and vibration damping due to their high transmission loss in a wide range of frequencies and vibration damping.

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Section: Resultsmentioning

confidence: 72%

“…Observing Figure 14a, it is suggested that the sound absorption peak may be moved to a lower frequency. This hypothesis may be supported by studies on other porous media [37,42]. According to Darcy's law (Equation ( 10)), the decrease in porosity may increase the static air flow resistivity (σ) for a given pressure gradient ( → ∇P) and fluid velocity ( → v ) [39].…”

Section: Resultsmentioning

confidence: 79%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Vibration Damping and Acoustic Behavior of PU-Filled Non-Stochastic Aluminum Cellular Solids

Carneiro

Puga

Meireles

2021

Metals

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“…The porous sound absorbing material (5 mm Nonwoven Fabrics Linen) was cut down to 450 mm by 300 mm to fit the size of the alu minum plate as shown in Figure 1 (b). It has an average density of 140.10 kg/m 3 , flo w resistivity = 181000 N.s/ m 4 , tortuosity = 2.9, porosity = 0.98, v iscous characteristic lengths = 0.000112 m, and thermal characteristic lengths = 0.000224 m. These acoustic material properties were well studied by Liu et al (2015bLiu et al ( , 2016b.…”

Section: Methodsmentioning

confidence: 99%

“…The porous sound absorbing material is treated as a equivalent fluid model with acoustic material properties given by Liu et al (2015b). The propagation of noise in a porous sound absorbing material is fully described by wave impedance and wave number.…”

Section: Porous Sound Absorbing Materials Modelmentioning

confidence: 99%

Prediction of the effect of porous sound-absorbing material inside a coupled plate cavity system

Liu

Fard

Davy

2016

IJVNV

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This paper predicts the acoustic properties of the porous sound absorbing material in a box cavity by conducting a FEM (Finite Element M ethod) analysis, and it verifies the estimated acoustic properties using an appropriate experimental method. The cavity is a rectangular box with five rigid walls and one flexible wall which is an aluminium plate. The porous sound absorbing material is attached to the inner surface of the plate, in order to modify the coupling between the plate inner surface and the air inside the box. The plate is mechanically excited by using an electromagnetic shaker, which is imitating structure-borne noise. The generated noise is recorded by using pressure microphones at the different locations inside the box. The results show that there is good agreement between the FEM prediction and the measurement for the acoustic response at different locations inside the rectangular box. Sound pressure peaks due to cavity modes are effectively reduced by adding porous sound absorbing material. Furthermore, sound level in the cavity is reduced by a similar amount in both the numerical simulation and the measurement, when a porous sound absorbing material is added. The developed FEM model is used to characterize the effects of porous sound absorbing material in reducing the structure-borne radiated noise.

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Sound Package

2018

Noise and Vibration Control in Automotive Bodies

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Development of an Acoustic Material Database for Vehicle Interior Trims

Cited by 8 publications

References 12 publications

Vibration Damping and Acoustic Behavior of PU-Filled Non-Stochastic Aluminum Cellular Solids

Vibration Damping and Acoustic Behavior of PU-Filled Non-Stochastic Aluminum Cellular Solids

Prediction of the effect of porous sound-absorbing material inside a coupled plate cavity system

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