Static flow resistivity measurements based on the ISO 10534.2 standard impedance tube

Tao, Jianmin; Wang, Ping; Qiu, Xiaojun

doi:10.1016/j.buildenv.2015.06.001

Cited by 19 publications

(18 citation statements)

References 15 publications

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“…In this method, the open porosity of specimen is prior known, and an impedance tube measurement backed with hard termination and microphone is necessary. Recently, an acoustical method for measuring the airflow resistance with impedance tube has been established according to the standard of ISO 10534-2 [6]. In this method, the specific acoustic impedance on the front side of specimen is measured by transfer function method.…”

Section: Alternating Airflow Methodsmentioning

confidence: 99%

“…According to reported studies, airflow resistance is stable when frequency tends to zero, which is generally called static airflow resistance. It plays a critical role in calculating various acoustic parameters of fibrous materials, such as characteristic impedance, propagation constant and sound absorption coefficient [6]. In 1985, Ingard and Dear [7] have reported an experimental method to test the dynamic airflow resistance through a standing wave tube and two microphones.…”

Section: Introductionmentioning

confidence: 99%

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Airflow resistance of acoustical fibrous materials: Measurements, calculations and applications

Tang

Xiong

2018

Journal of Industrial Textiles

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The acoustic performance of fibrous materials is mainly determined by its airflow resistance, and it is a parameter of the resistance that the airflow meets through the materials. This paper has summarized the recent advances on the measurements, calculations and applications of airflow resistance. Firstly, different methods for airflow resistance measurements are presented, mainly including the direct airflow method, alternating airflow method and acoustical method. We have summarized the development history, current status and industrial applications of these methods. Secondly, this paper has summarized the models of calculating airflow resistance. Most of these empirical models are based on the characteristic parameters of fibrous materials, for instance bulk density, fiber diameter, porosity and thickness. Thirdly, this review has gathered the applications of airflow resistance in sound absorption and noise control. It is a crucial parameter in the prediction of both normal incidence sound absorption and reverberation chamber sound absorption. In conclusion, this review has concluded with some perspectives for the measurements, calculations and applications of airflow resistance.

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Section: Alternating Airflow Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Airflow resistance of acoustical fibrous materials: Measurements, calculations and applications

Tang

Xiong

2018

Journal of Industrial Textiles

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“…Calculation formula for static flow resistivity of the porous material is shown in Equation (9) [27]. Here, μ was viscosity of the air; σ0 was static flow resistivity of original porous metal; D0 was average aperture of the pores in the original porous metal.…”

Section: Theoretical Modelingmentioning

confidence: 99%

Preparation and Characterization of Gradient Compressed Porous Metal for High-Efficiency and Thin-Thickness Acoustic Absorber

et al. 2019

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Increasing absorption efficiency and decreasing total thickness of the acoustic absorber is favorable to promote its practical application. Four compressed porous metals with compression ratios of 0%, 30%, 60%, and 90% were prepared to assemble the four-layer gradient compressed porous metals, which aimed to develop the acoustic absorber with high-efficiency and thin thickness. Through deriving structural parameters of thickness, porosity, and static flow resistivity for the compressed porous metals, theoretical models of sound absorption coefficients of the gradient compressed porous metals were constructed through transfer matrix method according to the Johnson–Champoux–Allard model. Sound absorption coefficients of four-layer gradient compressed porous metals with the different permutations were theoretically analyzed and experimentally measured, and the optimal average sound absorption coefficient of 60.33% in 100–6000 Hz was obtained with the total thickness of 11 mm. Sound absorption coefficients of the optimal gradient compressed porous metal were further compared with those of the simple superposed compressed porous metal, which proved that the former could obtain higher absorption efficiency with thinner thickness and fewer materials. These phenomena were explored by morphology characterizations. The developed high-efficiency and thin-thickness acoustic absorber of gradient compressed porous metal can be applied in acoustic environmental detection and industrial noise reduction.

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“…According to the classical Johnson-Champoux-Allard model [22][23][24], major acoustic characteristic parameters for the porous material were porosity and static flow resistivity. Although the porosity is easy to obtain, it is difficult to accurately measure the static flow resistivity [3,8,[25][26][27]. Therefore, identification of the acoustic characteristic parameters, which included the porosity and static flow resistivity, were conducted through the cuckoo search algorithm [28,29] based on the experimental data of the sound absorption coefficient of the porous metal in this study.…”

Section: Introductionmentioning

confidence: 99%

Identification of Acoustic Characteristic Parameters and Improvement of Sound Absorption Performance for Porous Metal

Yang

Shen

Duan

et al. 2020

Metals

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Porous metal is widely used in the fields of sound absorption and noise reduction, and it is a critical procedure to identify acoustic characteristic parameters and to improve sound absorption performances. Based on the constructed theoretical sound absorption model and experimental data, acoustic characteristic parameters of the porous metal were identified through the cuckoo search identification algorithm, and their reliabilities were certified through comparing with these labeled parameters and further experimental validation. By adding the microperforated metal panel in front of the porous metal, a composite sound-absorbing structure was formed, which aimed to improve the sound absorption performance of the original porous metal by optimizing the parameters. Finite element simulation and a standing wave tube measurement were conducted to validate the effectiveness and practicability of the optimal composite sound-absorbing structure. Consistencies among theoretical predictions, simulation results, and experimental data proved the effectiveness of the identification and optimization method. When the target frequency ranges were 100–1000 Hz, 100–2000 Hz, 100–3000 Hz, and 100–4000 Hz. Actual average sound absorption coefficients of the optimal composite structures were 0.5154, 0.6369, 0.6770, and 0.7378, respectively, which exhibited the obvious improvements with a tiny increase in the occupied space and a small addition in weight.

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Static flow resistivity measurements based on the ISO 10534.2 standard impedance tube

Cited by 19 publications

References 15 publications

Airflow resistance of acoustical fibrous materials: Measurements, calculations and applications

Airflow resistance of acoustical fibrous materials: Measurements, calculations and applications

Preparation and Characterization of Gradient Compressed Porous Metal for High-Efficiency and Thin-Thickness Acoustic Absorber

Identification of Acoustic Characteristic Parameters and Improvement of Sound Absorption Performance for Porous Metal

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