Microperforated insertion units: An alternative strategy to design microperforated panels

Pfretzschner, Jaime; Cobo, Pedro; Simón, Francisco; Cuesta, María; Fernández, Alejandro

doi:10.1016/j.apacoust.2005.05.005

Cited by 37 publications

(31 citation statements)

References 8 publications

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“…As the MPP is made from a panel, it provides several advantages, such as being non-fibrous, non-abrasive, and non-polluting. Several works have been conducted concerning the improvement of sound absorption performance of the MPP, e.g., by arranging it to be a double-leaf (Sakagami et al, 2006), by increasing its thickness (Pfretzner and Cobo, 2006), and by modifying its hole geometry (Sakagami et al, 2008). This paper proposes the insertion of an MPP within a double-panel partition.…”

Section: Introductionmentioning

confidence: 99%

Sound Transmission Loss of A Double-Leaf Partition with Micro-Perforated Plate Insertion under Diffuse Field Incidence

Putra¹,

Ismail²,

Ayob³

2013

Int J Automot Mech Eng

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In noise control applications, a double-leaf partition has been applied widely as a lightweight structure for noise insulation, such as in car doors, train bodies, and aircraft fuselages. Unfortunately, the insulation performance deteriorates significantly at massair-mass resonance due to coupling between the panels and the air in the gap. This paper investigates the effect of a micro-perforated panel (MPP), inserted in the conventional double-panel partition, on sound transmission loss at troublesome resonant frequencies. It is found that the transmission loss improves at this resonance if the MPP is located at a distance of less than half that of the air gap. A mathematical model is derived for the diffuse field incidence of acoustic loading.

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Section: Introductionmentioning

confidence: 99%

Sound Transmission Loss of A Double-Leaf Partition with Micro-Perforated Plate Insertion under Diffuse Field Incidence

Putra¹,

Ismail²,

Ayob³

2013

Int J Automot Mech Eng

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“…Since for optimal absorption the perforation diameter should be less than 1 mm, the resulting low thickness of the panel would constrain its mechanical implementation in such a two-layer absorber configuration. Pfretzschner et al (2006) proposed an alternative methodology to construct more structurally robust MPPs, combining a thick panel with large perforations with a thinner one highly perforated. The passive absorption of such an extended absorber has already been measured, at normal incidence (Pfretzschner et al, 2006), at low angles of incidence in a free field (Cobo et al, 2006a), and in a reverberation room (Cobo et al, 2006b).…”

Section: Hybrid Passive-active Absorber In Anechoic Roommentioning

confidence: 99%

“…Pfretzschner et al (2006) proposed an alternative methodology to construct more structurally robust MPPs, combining a thick panel with large perforations with a thinner one highly perforated. The passive absorption of such an extended absorber has already been measured, at normal incidence (Pfretzschner et al, 2006), at low angles of incidence in a free field (Cobo et al, 2006a), and in a reverberation room (Cobo et al, 2006b). The current research is concerned with the design of the active absorber as well as the hybrid passive-active absorption measurements.…”

Section: Hybrid Passive-active Absorber In Anechoic Roommentioning

confidence: 99%

Hybrid passive-active absorption of a microperforated panel in free field conditions

Cobo

Cuesta

2007

The Journal of the Acoustical Society of America

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Although hybrid passive-active absorption in impedance tubes has been widely analyzed, its study in more realistic conditions remains to be accomplished. This letter describes the practical measurement of the passive-active absorption coefficient in a free field. The passive absorber consists of a microperforated panel backed by an air cavity and a wooden panel. A multichannel active system controls the sound pressure in a reduced cell behind the absorber. Measured absorption coefficients between 200 and 400Hz account for 0.2–0.4 and 0.72–0.75, in the passive and active cases, respectively, and above 500Hz both are comparable.

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“…To deal with that, some studies have been done by modifying the form of pores in order to improve the performance e.g. tapered holes [9,10] for micro-perforated insertion units (MIU) [11]. Even though that can deal with the thicker panel effect on MPP but it still poses a difficulty from the practical point of view e.g.…”

Section: Introductionmentioning

confidence: 99%

Study on inhomogeneous perforation thick micro-perforated panel sound absorbers

Prasetiyo¹,

Sarwono²,

Sihar³

2016

J. MECH. ENG. SCI.

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Micro-perforated panel (MPP) sound absorbers are usually made of a thin panel and have narrow absorption bandwidth. This drawback causes the application of MPP to be limited. In this paper, the possibility of realizing wider absorption bandwidth MPP with sufficient structural strength is investigated. For this, multi-MPP (resonator) arranged in parallel to form an inhomogeneous perforation MPP is introduced to widen the absorption bandwidth. The thickness of MPP must be 1.5 times higher than perforation diameter or more in order to have appropriate strength. The characteristics of corresponding absorption coefficients are studied parametrically using theoretical models as thick panels can reduce the MPP's performance. It is found that the absorption bandwidth of thicker panels with inhomogeneous perforation approach can be at least twice times of classical MPP. The problem of reduced peak absorption coefficient in a thick panel can be avoided by keeping the acoustic resistance value around 1± 0.5 Rayls. Compared with homogeneous MPP, inter-resonator interaction exists in the inhomogeneous perforation thick MPP that causes the overall absorption to become higher due to the increasing of the acoustic resistance as well as the shifting of peak resonance following residual acoustic reactance. The measurement results confirm all of the characteristics.

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Microperforated insertion units: An alternative strategy to design microperforated panels

Cited by 37 publications

References 8 publications

Sound Transmission Loss of A Double-Leaf Partition with Micro-Perforated Plate Insertion under Diffuse Field Incidence

Sound Transmission Loss of A Double-Leaf Partition with Micro-Perforated Plate Insertion under Diffuse Field Incidence

Hybrid passive-active absorption of a microperforated panel in free field conditions

Study on inhomogeneous perforation thick micro-perforated panel sound absorbers

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