Performance of a dual-cup-dual-cushion earmuff design

Du, Yu; Homma, Kenji

doi:10.3397/1.3207866

Cited by 9 publications

(15 citation statements)

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“…Else, erroneous results would be expected. This statement could be supported by the literature where researchers have attempted to develop a robust numerical model to approximate-with high accuracy-the noise attenuation of a given earmuff [28,31,32]. As demonstrated by Boyer et al [28], rigorous experiments would be necessary to obtain important parameters such as the headband force and the cushion dynamic stiffness.…”

Section: Discussionmentioning

confidence: 92%

Low-Frequency Noise Reduction by Earmuffs with Flax Fibre-Reinforced Polypropylene Ear Cups

Ang

Tran

Phillips

et al. 2018

Advances in Acoustics and Vibration

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Soldiers and supporting engineers are frequently exposed to high low-frequency (<500 Hz) cabin noise in military vehicles. Despite the use of commercial hearing protection devices, the risk of auditory damage is still imminent because the devices may not be optimally customised for such applications. This study considers flax fibre-reinforced polypropylene (Flax-PP) as an alternative to the material selection for the ear cups of commercial earmuffs, which are typically made of acrylonitrile butadiene styrene (ABS). Different weaving configurations (woven and nonwoven) and various noise environments (pink noise, cabin booming noise, and firing noise) were considered to investigate the feasibility of the proposed composite earmuffs for low-frequency noise reduction. The remaining assembly components of the earmuff were kept consistent with those of a commercial earmuff, which served as a benchmark for results comparison. In contrast to the commercial earmuff, the composite earmuffs were shown to be better in mitigating low-frequency noise by up to 16.6 dB, while compromising midfrequency acoustical performance. Consequently, the proposed composite earmuffs may be an alternative for low-frequency noise reduction in vehicle cabins, at airports, and at construction sites involving heavy machineries.

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Section: Discussionmentioning

confidence: 92%

Low-Frequency Noise Reduction by Earmuffs with Flax Fibre-Reinforced Polypropylene Ear Cups

Ang

Tran

Phillips

et al. 2018

Advances in Acoustics and Vibration

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“…A is a term accounting for the thickness of the plastic cup. For Sides (2004), A ¼ S o =S i , while for Du and Homma (2009) and other authors, A ¼ 1 and, thus, S o ¼ S i .…”

Section: Lpms Formulationsmentioning

confidence: 94%

“…In the case of a perfect sealing between the cushion and the baffle and the foam insert being removed from the cup, the sound attenuation of the earmuff given by the analytical models (Zwislocki, 1955;Shaw and Thiessen, 1958;Paurobally and Pan, 2000;Sides, 2004;Du and Homma, 2009) can be expressed as…”

Section: Lpms Formulationsmentioning

confidence: 99%

“…The analytical models are usually lumped parameters models (LPMs), such as the one developed by Zwislocki (1955), Shaw and Thiessen (1958), Paurobally and Pan (2000), Sides (2004), Du andHomma (2009), andKalb (2010). They are used to model the sound attenuation of circumaural HPDs at low frequency, typically <1 kHz.…”

Section: Introductionmentioning

confidence: 99%

“…This modeling strategy is useful to approximate the behavior of the earmuff, but it is limited to low frequencies, i.e., below the first acoustic or elastic structural resonance of the system. To overcome this limitation, numerical models based on the finite element method (FEM) or the boundary element method (BEM) have been proposed (Lee et al, 1995;Vergara et al, 2002;Anwar, 2005;James, 2006;Khani et al, 2007;Du and Homma, 2009;Sgard et al, 2010). They are able to predict the vibroacoustic behavior of earmuffs over a large frequency band, typically up to 5 kHz.…”

Section: Introductionmentioning

confidence: 99%

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Low frequency finite element models of the acoustical behavior of earmuffs

Boyer

Doutres

Sgard

et al. 2015

The Journal of the Acoustical Society of America

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This paper compares different approaches to model the vibroacoustic behavior of earmuffs at low frequency and investigates their accuracy by comparison with objective insertion loss measurements recently carried out by Boyer et al. [(2014). Appl. Acoust. 83, 76-85]. Two models based on the finite element (FE) method where the cushion is either modeled as a spring foundation (SF) or as an equivalent solid (ES), and the well-known lumped parameters model (LPM) are investigated. Modeling results show that: (i) all modeling strategies are in good agreement with measurements, providing that the characterization of the cushion equivalent mechanical properties are performed with great care and as close as possible to in situ loading, boundary, and environmental conditions and that the frequency dependence of the mechanical properties is taken into account, (ii) the LPM is the most simple modeling strategy, but the air volume enclosed by the earmuff must be correctly estimated, which is not as straightforward as it may seem, (iii) similar results are obtained with the SF and the ES FE-models of the cushion, but the SF should be preferred to predict the earmuff acoustic response at low frequency since it requires less parameters and a less complex characterization procedure.

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