A Parametric Study of the Acoustic Performance of Resonant Absorbers Made of Micro-perforated Membranes and Perforated Panels

Pan, Lili; Martellotta, Francesco

doi:10.3390/app10051581

Cited by 18 publications

(8 citation statements)

References 36 publications

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“…Although it is not related to 3D printing, Pan and Martellotta [15] performed trial productions of MPP with films of 5.0 mm thickness with microdrills. The hole diameter of their specimens showed a Gaussian distribution from 0.2 to 0.35 mm around the targeted value of 0.3 mm.…”

Section: Sound Absorption Performance Of Mpps and Manufacturing Accuracymentioning

confidence: 99%

The Effect of Deviation Due to the Manufacturing Accuracy in the Parameters of an MPP on Its Acoustic Properties: Trial Production of MPPs of Different Hole Shapes Using 3D Printing

et al. 2020

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In this study, we discuss the effect of the manufacturing accuracy of a microperforated panel (MPP) produced by 3D printers on acoustic properties through measured and calculated results as a pilot study. The manufacturing costs of MPPs have long been one of their shortcomings; however, with recent developments in the manufacturing process, low-cost MPPs are now available. In a further attempt at reducing the cost, 3D printing techniques have recently been considered. Cases of trial production of MPPs manufactured by 3D printing have been reported. When introducing such new techniques, despite the conventional microdrill procedure, manufacturing accuracy can often become an issue. However, there are few studies reporting the effect of manufacturing accuracy on the acoustic properties in the case of 3D-printed MPPs. Considering this situation, in this pilot study, we attempted to produce MPPs with circular and rectangular perforations using a consumer 3D printer of the additive manufacturing type. The hole sizes of the specimens were measured, and the accuracy was evaluated. The normal incidence absorption coefficient and specific impedance were measured using an impedance tube. The measured results were compared with the theoretical values using Guo’s model. Through these basic studies, the MPPs produced by an additive manufacturing 3D printer demonstrated good sound absorption performance; however, due to the large deviations of parameters, the agreement with the theoretical values was not good, which suggests that it is difficult to predict the acoustic properties of MPPs made by a consumer-grade additive manufacturing 3D printer.

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Section: Sound Absorption Performance Of Mpps and Manufacturing Accuracymentioning

confidence: 99%

The Effect of Deviation Due to the Manufacturing Accuracy in the Parameters of an MPP on Its Acoustic Properties: Trial Production of MPPs of Different Hole Shapes Using 3D Printing

et al. 2020

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“…More recently, in a case study on the absorption characteristics of an MPP with distributed hole diameters due to the lower production accuracy, Pan and Martellotta showed that a relatively good prediction of absorption characteristics was possible using the mean hole diameter in the case that the deviation is smaller [15]. On the contrary, Sakagami et al [16] reported a case study of MPPs produced by a 3D printer of nonprofessional use, in which hole diameters were distributed randomly due to the lower production accuracy: It was shown that the predicted values, using the mean hole diameter as the representative diameter in the existing theory, were not in good agreement with the measured results.…”

Section: Introductionmentioning

confidence: 99%

A Basic Study on the Absorption Properties and Their Prediction of Heterogeneous Micro-Perforated Panels: A Case Study of Micro-Perforated Panels with Heterogeneous Hole Size and Perforation Ratio

2021

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Micro-perforated panels (MPPs) are one of the most promising alternatives to conventional porous sound-absorbing materials. Traditionally, the theory of the sound absorption properties of MPPs is based on the assumption that MPPs are a homogeneous material with identical pores at regular intervals. However, in recent years, some MPPs have not met these conditions, and although a variety of designs have been created, their properties and prediction methods were studied in only fewer works. In this paper, considering the wide variety of MPP designs, we made a trial production of heterogeneous MPPs, which are MPPs with holes of different diameters, and studied the prediction method applicable to these MPPs. We measured the normal incidence sound absorption characteristics of those MPPs, backed by a rigid backing and air-cavity in-between, in an impedance tube. The prediction method proposed in this work is to treat the heterogeneous MPPs as combinations of several homogeneous components, and to combine them after applying the existing theory on homogeneous MPPs to each component. As a result, except in a few cases, the measured and predicted values of the absorption properties agreed relatively well. We also found that the arrangement of the holes in the material and the depth of the back cavity affected the agreement between the measured and predicted results.

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“…Nowadays, the interest in sound absorbing materials is growing due to the variety of their possible applications, from room acoustics [1] to environmental noise control [2,3]. Porous and fibrous absorbers [4][5][6] have until now been the most used materials in noise control application because of their high performance-to-cost ratio in the frequency band of interest.…”

Section: Introductionmentioning

confidence: 99%

A Trial Acoustic Improvement in a Lecture Hall with MPP Sound Absorbers and FDTD Acoustic Simulations

et al. 2021

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Sound absorbing micro-perforated panels (MPPs) are being increasingly used because of their high quality in terms of hygiene, sustainability and durability. The present work investigates the feasibility and the performance of MPPs when used as an acoustic treatment in lecture rooms. With this purpose, three different micro-perforated steel specimens were first designed following existing predictive models and then physically manufactured through 3D additive metal printing. The specimens’ acoustic behavior was analyzed with experimental measurements in single-layer and double-layer configurations. Then, the investigation was focused on the application of double-layer MPPs to the ceiling of an existing university lecture hall to enhance speech intelligibility. Numerical simulations were carried out using a full-spectrum wave-based method: a finite-difference time-domain (FDTD) code was chosen to better handle time-dependent signals as the verbal communication. The present work proposes a workflow to explore the suitability of a specific material to speech requirements. The measured specific impedance complex values allowed to derive the input data referred to MPPs in FDTD simulations. The outcomes of the process show the influence of the acoustic treatment in terms of reverberation time (T30) and sound clarity (C50). A systematic comparison with a standard geometrical acoustic (GA) technique is reported as well.

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A Parametric Study of the Acoustic Performance of Resonant Absorbers Made of Micro-perforated Membranes and Perforated Panels

Cited by 18 publications

References 36 publications

The Effect of Deviation Due to the Manufacturing Accuracy in the Parameters of an MPP on Its Acoustic Properties: Trial Production of MPPs of Different Hole Shapes Using 3D Printing

The Effect of Deviation Due to the Manufacturing Accuracy in the Parameters of an MPP on Its Acoustic Properties: Trial Production of MPPs of Different Hole Shapes Using 3D Printing

A Basic Study on the Absorption Properties and Their Prediction of Heterogeneous Micro-Perforated Panels: A Case Study of Micro-Perforated Panels with Heterogeneous Hole Size and Perforation Ratio

A Trial Acoustic Improvement in a Lecture Hall with MPP Sound Absorbers and FDTD Acoustic Simulations

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