Modelling, Simulation and Data Analysis in Acoustical Problems–Volume 3

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Acoustics and Vibrations".

Deadline for manuscript submissions: 31 December 2024 | Viewed by 15356

Special Issue Editors


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Guest Editor
Civil Engineering Department, University of Salerno, 4084 Fisciano, SA, Italy
Interests: acoustics; environmental acoustics; room acoustics; field measurements; modeling and simulation; data analysis
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
Civil Engineering Department, University of Salerno, 84084 Fisciano, SA, Italy
Interests: modeling and simulation; data analysis; programming; acoustics; field measurements

Special Issue Information

Dear Colleagues,

We are pleased to announce the third edition of the Special Issue on “Modeling, Simulation, and Data Analysis in Acoustical Problems”. The success of the previous editions and the growing interest in the related topics encouraged us to announce and start the third edition of the Special Issue.

The general framework suggests that modeling and simulation in acoustical problems, as well as data analysis, are attracting an increased amount of interest today. Thanks to modern computational techniques that allow us to rapidly perform calculations, also in real time, a strong development of predictive models has been observed in recent years.

This Special Issue is aimed at the collection of original research papers on theoretical and applicative studies on acoustics modeling, simulation, and data analysis. An interdisciplinary approach is encouraged. Research topics to be considered for a valid submission are all the issues related to the following topics (but not limited to them):

  • Modeling and simulation in environmental acoustics;
  • Modeling and simulation in room acoustics;
  • Modeling and simulation in musical acoustics;
  • Online and offline data analysis;
  • Predictive model implementation and validation;
  • Residuals and error evaluation and statistics;
  • Signal analysis and parameter evaluation.

Prof. Dr. Claudio Guarnaccia
Dr. Domenico Rossi
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Applied Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • acoustics
  • vibration
  • environmental acoustics
  • room acoustics
  • modeling
  • simulation
  • data analysis
  • error evaluation and metrics

Published Papers (11 papers)

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Research

13 pages, 4258 KiB  
Article
Resonant Acoustic Metamaterials
by Gino Iannace, Giovanni Amadasi, Antonella Bevilacqua, Maria Cairoli and Amelia Trematerra
Appl. Sci. 2024, 14(12), 5080; https://doi.org/10.3390/app14125080 - 11 Jun 2024
Viewed by 185
Abstract
Acoustic applications of metamaterials have rapidly developed over the past few decades. The sound attenuation provided by metamaterials is due to the interaction between soundwaves and scatterers organized into a reticular grid, with a peak attenuation at a specific frequency band that is [...] Read more.
Acoustic applications of metamaterials have rapidly developed over the past few decades. The sound attenuation provided by metamaterials is due to the interaction between soundwaves and scatterers organized into a reticular grid, with a peak attenuation at a specific frequency band that is highly dependent on the scatterers’ diameter and reticular geometric organization of installation. In this article, the scatterer types chosen for the experiments are represented by a 2D shape, which are cylindrical solid-wood bars of 15 mm diameter and empty cylindrical bars of 20 mm diameter. Acoustic measurements were conducted in a semi-anechoic chamber to identify the specific frequency at which the highest insertion loss (IL) was registered. A second experiment was conducted by creating holes of 5 mm diameter on the external surface of the empty bars; in this way, it registered a higher sound attenuation. In particular, the resonant system characterized with holes, in combination with the attenuation given by 2D scatterer metamaterials, increased the sound attenuation for the frequency range between 1 kHz and 10 kHz. Full article
20 pages, 4403 KiB  
Article
Improving Low-Frequency Panel Absorbers with Two-Dimensional Acoustic Black Hole
by Michael Funk, Mehmet Sait Özer and M. Ercan Altinsoy
Appl. Sci. 2024, 14(4), 1338; https://doi.org/10.3390/app14041338 - 6 Feb 2024
Viewed by 815
Abstract
Many rooms struggle with the absorption of low-frequency sound due to its long wavelengths. The integration of existing solutions into these spaces is often challenging due to their intricate installations and large depths. To address this problem, a new type of resonance absorber [...] Read more.
Many rooms struggle with the absorption of low-frequency sound due to its long wavelengths. The integration of existing solutions into these spaces is often challenging due to their intricate installations and large depths. To address this problem, a new type of resonance absorber has been developed: the Distributed Mode Absorber (DMA). It consists of a thin vibrating front panel and a volume of enclosed air behind it. This straightforward structure can be utilized to create acoustically functional furniture that can be seamlessly incorporated into rooms. This article is devoted to the structural optimization of the DMA front panel, using the Acoustic Black Hole (ABH) effect known within structural dynamics. A numerical model is constructed using a Finite Element Analysis (FEA) and examined numerically. Several geometric parameters of the ABH are studied with regard to their influence on the vibrations of the front panel. Prototypes are developed and manufactured based on these insights. The quality of the numerical model is verified during the subsequent validation. Finally, the sound absorption of the improved DMA is compared with that of the reference DMA. Full article
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15 pages, 6465 KiB  
Article
Simulation Analysis of Acoustic Radiation from Force Excitation of Foam-Filled Stiffened Sandwich Panels
by Bin Li, Ning Wang, Haoyang Ding, Zilai Zheng, Wenjian Kuang and Langlang Wei
Appl. Sci. 2023, 13(19), 10733; https://doi.org/10.3390/app131910733 - 27 Sep 2023
Viewed by 715
Abstract
To tackle the influence of foam filling on the sound radiation performance of reinforced sandwich panels, this study employs a combined approach of experiments and simulations to investigate the factors that impact the sound radiation performance in the 1–2000 Hz mid–low frequency range. [...] Read more.
To tackle the influence of foam filling on the sound radiation performance of reinforced sandwich panels, this study employs a combined approach of experiments and simulations to investigate the factors that impact the sound radiation performance in the 1–2000 Hz mid–low frequency range. The aim is to determine how the parameters of foam impact the sound radiation performance of foam-filled reinforced sandwich panels. The results indicate that changes in the acoustic parameters of the foam have a weak effect on the frequency corresponding to the peak sound radiation power and the non-peak frequency range sound radiation performance of the sandwich panel, while significantly impacting the peak sound radiation power. Among them, porosity has the least influence on sound radiation performance, whereas static flow resistivity and tortuosity factors have a greater influence on peak sound radiation performance. The reduction in thermal characteristic length and the increase in static flow resistivity can both enhance the sound radiation performance of the panel, while the impact of tortuosity factor and viscous characteristic length on panel sound radiation performance depends on the frequency range. Full article
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17 pages, 9524 KiB  
Article
Analysis of Vibration and Acoustic Radiation Characteristics of Reinforced Laminated Cylindrical Shell Structure
by Bin Li, Ning Wang, Ying Tian, Wenjian Kuang, Langlang Wei and Zilai Zheng
Appl. Sci. 2023, 13(17), 9617; https://doi.org/10.3390/app13179617 - 25 Aug 2023
Cited by 1 | Viewed by 861
Abstract
This paper investigates the acoustic radiation characteristics of reinforced laminated cylindrical shell structures in the medium-low frequency range (1~1000 Hz) of aircrafts, submarines, and deepwater thrusters by combining simulation analysis and experimental testing. The research focuses on reinforced laminated plates, where experimental setup [...] Read more.
This paper investigates the acoustic radiation characteristics of reinforced laminated cylindrical shell structures in the medium-low frequency range (1~1000 Hz) of aircrafts, submarines, and deepwater thrusters by combining simulation analysis and experimental testing. The research focuses on reinforced laminated plates, where experimental setup is established to measure structural modal parameters and structural acoustic power, and a finite element model is developed to verify the reliability of the finite element modeling method through comparison with experimental and simulation results. Simultaneously, a finite element model of the reinforced laminated cylindrical shell structure is established, and finite element simulation analysis is conducted to investigate the effects of different reinforcement methods, reinforcement quantities, reinforcement lengths, and reinforcement thicknesses on the acoustic radiation characteristics of the structure. The results indicate that in the frequency range of 1~1000 Hz, ribbed reinforcement exhibits better performance in reducing structural noise radiation compared to longitudinal reinforcement. With the increase in reinforcement quantity and thickness, the structural acoustic radiation decreases. Meanwhile, with the increase in reinforcement length, the overall sound power level of the structure shows a trend of first increasing and then decreasing. Full article
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18 pages, 2892 KiB  
Article
Analysis of the Effect of Temperature on the Sound Transmission Loss of a Curved Plate
by Guowei Zhang, Jianmin Ge, Shiquan Cheng, Tianyu Zhao and Shu Liu
Appl. Sci. 2023, 13(16), 9116; https://doi.org/10.3390/app13169116 - 10 Aug 2023
Viewed by 789
Abstract
Curved structures are used in many engineering applications. Temperature affects the performance of structural vibration and acoustics and can damage the equipment when its effects are severe. A theoretical model of the sound transmission loss (STL) of a simply supported curved plate considering [...] Read more.
Curved structures are used in many engineering applications. Temperature affects the performance of structural vibration and acoustics and can damage the equipment when its effects are severe. A theoretical model of the sound transmission loss (STL) of a simply supported curved plate considering the effect of temperature was established. Moreover, a numerical solution was obtained using the modal superposition method. The finite element results were compared to validate the theoretical model. The effects of temperature and acoustic loading on the modal frequency and STL were considered, and the variation laws of the radius of curvature, opening angle, and loss factor on the STL were analyzed. The results showed that the modal frequency increased with decreasing temperature, the frequency ratio of the same-order modal frequency varied approximately linearly with temperature, and the trough of the STL shifted toward high frequencies. The pitch angle substantially influenced the STL, whereas the azimuth angle was negligible. A larger radius increased the effect of temperature. In addition, an increase in the opening angle formed an aggregation of STL at (1, 1)-order modal frequencies. The loss factor affects only the amplitude of the trough position of the STL. Therefore, the proposed theoretical model can aid in the vibroacoustic design of curved plates in a thermal environment. Full article
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15 pages, 3232 KiB  
Article
Construction of Half Masks for the Respiratory Tract Protection and the Speech Intelligibility Assessed from the Measured Suppression of Sound
by Krzysztof Nowacki, Wojciech Marczak, Karolina Łakomy and László Almásy
Appl. Sci. 2023, 13(15), 8644; https://doi.org/10.3390/app13158644 - 27 Jul 2023
Viewed by 691
Abstract
Half masks (a.k.a. filtering facepieces, FFP) are personal protective equipment against dust in a work environment. Their filtration efficiency is legally regulated. Occupational safety and health services have not paid enough attention to speech disruption caused by FFPs, even though the latter could [...] Read more.
Half masks (a.k.a. filtering facepieces, FFP) are personal protective equipment against dust in a work environment. Their filtration efficiency is legally regulated. Occupational safety and health services have not paid enough attention to speech disruption caused by FFPs, even though the latter could impair verbal communication and result in discomfort or increased risk of accidents. This study deals with the objective differences in speech suppression between masks of various construction belonging to the same filtration class, FFP2, and equipped with exhalation valves. We applied an objective method of white noise attenuation, suggested in our previous work. Its uniqueness lies in the fact that the acoustic apparati are applied in the whole procedure, and no human speakers/listeners participation is required. We compared seven types of masks: three moulded, one moulded with folded elements, two folded horizontally, and one vertically. We determined attenuation caused by the masks in 1/3 octave-wide bands with centre frequency from 100 Hz to 20 kHz. All the studied FFPs attenuated sound waves in a frequency range responsible for 80–90% of the perceived speech intelligibility. The attenuations of moulded masks were ca. 3 dB higher in 1–16 kHz bands than those of folded ones. The moulded mask with foldable parts for better fitting the face suppressed the high-pitch tones considerably more than the other masks. These observations were confirmed quantitatively by the cluster analysis based on the Euclidean distances between the acoustic spectra. Full article
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18 pages, 5400 KiB  
Article
Calibration and Validation of a Measurements-Independent Model for Road Traffic Noise Assessment
by Domenico Rossi, Aurora Mascolo and Claudio Guarnaccia
Appl. Sci. 2023, 13(10), 6168; https://doi.org/10.3390/app13106168 - 18 May 2023
Cited by 3 | Viewed by 1584
Abstract
The assessment of road traffic noise is very important for the health of people living in urban areas. Noise is usually assessed by field measurements, and predictive models play an important role when experimental data are not available. Nevertheless, when they are based [...] Read more.
The assessment of road traffic noise is very important for the health of people living in urban areas. Noise is usually assessed by field measurements, and predictive models play an important role when experimental data are not available. Nevertheless, when they are based on regression techniques, predictive models suffer from the drawback of strong dependence on the calibration data. In this paper, the authors present a regressive model calibrated on computed noise levels without the need for field measurements. The independence from field measurements makes the model flexible and adjustable for any road traffic condition possible. A multilinear regression technique is applied to establish the correlation between the computed equivalent noise levels and several independent variables, including, among others, traffic flow and distance. The model is then validated on a large field measurement database to check its efficiency in terms of prediction accuracy. The validation is performed both via error distribution analysis and using different error metrics. The results are encouraging, showing that the model provides good results in terms of the average error (less than 2 dBA) and is not susceptible to the presence of outliers in the input data that correspond to unconventional conditions of the traffic flow. Full article
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13 pages, 3138 KiB  
Article
Performance Analysis of Different Gun Silencers
by Artūras Kilikevičius, Vytautas Giedraitis, Kristina Kilikevičienė, Jonas Matijošius, Jaroslaw Selech, Gytis Buckiūnas and Mirosław Rucki
Appl. Sci. 2023, 13(7), 4426; https://doi.org/10.3390/app13074426 - 30 Mar 2023
Cited by 2 | Viewed by 4242
Abstract
With the rapid development of the military industry and the increasing focus on the safety of those in these fields, there is an increasing search for solutions to existing and emerging weapons for the user and the environment. In this case, components for [...] Read more.
With the rapid development of the military industry and the increasing focus on the safety of those in these fields, there is an increasing search for solutions to existing and emerging weapons for the user and the environment. In this case, components for firearm suppression are used to reduce the effects of noxious impulse sound, to minimize the severity of the weapon’s recoil to the user’s body, and maintain important accuracy, maneuverability and other parameters. The analysis and investigation of silencer designs can provide essential values for acoustic characteristics that reduce risk in real situations. The gun silencer analysis was performed in two steps. The modeling processes of the silencer configuration were performed to choose the optimal construction, and the main parameters were selected, including different angles and forms of the tilt. The angle of inclination of the partitions was changed to 60° and 135°. Due to the reduced results observed in the last zones with closed cavities and created additional configurations, the number of partitions was shortened by three partitions and the angle of inclination was adjusted to 60°; the simulation of the initial variant was also supplemented with 135° partitions. The second step was an experimental validation of the optimal tilt angle and form according to the modeling data. The silencer was found to achieve a sound pressure damping value and the sound pressure level during the shot was reduced to below a dangerous level. The search to find the optimal configurations will lead to the parameters of production and efficiency. Full article
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25 pages, 51470 KiB  
Article
Structural and Vibro-Acoustics Optimization of a Car Body Rear Part
by Roberto Citarella, Tommaso Landi, Luca Caivano, Giuseppe D’Errico, Francesca Raffa, Mario Romano and Enrico Armentani
Appl. Sci. 2023, 13(6), 3552; https://doi.org/10.3390/app13063552 - 10 Mar 2023
Viewed by 1466
Abstract
The perceived vibro-acoustic comfort, inside the passenger compartment, under driving conditions, is strictly related to the car body torsional behavior. The aim of this work was to identify which parts of a car body most influence the first torsional mode, in order to [...] Read more.
The perceived vibro-acoustic comfort, inside the passenger compartment, under driving conditions, is strictly related to the car body torsional behavior. The aim of this work was to identify which parts of a car body most influence the first torsional mode, in order to modify them and acquire an increase in such car body natural frequency. It was also intended to exploit the great potential of 3D printing that allows an increase in the complexity of component shapes, with an acceptable compromise with respect to production costs. A design and material (from steel to aluminum) change of a car body rear part, which was identified as the structural part of the car body with the most relevant impact on the frequency of the first torsional mode, was assessed in terms of structural and vibro-acoustic performances. In particular, with the constraint of increasing the structural and vibro-acoustic performances and, at the same time, minimize the weight of the structure itself, geometric, structural (e.g., type of connections), and material changes of the car body rear part were assessed. Working on a car model dating back to 2008, which was already compliant with structural and vibro-acoustic regulatory norms, an increase of 2 Hz on the first torsional mode frequency of the Trimmed Body model was obtained. In parallel, a weight reduction in the optimized components was also gained. It was also requested to lower the cabin sound pressure levels, optimizing the vibro-acoustic transfer functions from the accelerations at engine mounts and suspension attachment points to the cabin inside. It was shown how the combined use of advanced topological and structural optimization tools, with the capabilities of an unconventional manufacturing technology, such as 3D printing in aluminum, could guarantee an increase in the vibro-acoustics and structural car performances, also gaining a weight reduction. Full article
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16 pages, 7839 KiB  
Article
Investigation of Ultrasonic Velocity and Transmission Losses in Graphite Rods Based on Numerical Simulation and Experiment
by Mi Li and Jianjun He
Appl. Sci. 2023, 13(5), 3329; https://doi.org/10.3390/app13053329 - 6 Mar 2023
Viewed by 1772
Abstract
The depth of electrodes inserted into the charge plays a vital role in controlling the submerged arc furnace. Therefore, we used ultrasound waves reflected from the electrode tip to estimate the depth of electrodes inserted into the charge. However, graphite’s ultrasonic velocity and [...] Read more.
The depth of electrodes inserted into the charge plays a vital role in controlling the submerged arc furnace. Therefore, we used ultrasound waves reflected from the electrode tip to estimate the depth of electrodes inserted into the charge. However, graphite’s ultrasonic velocity and transmission loss are the basis for establishing an ultrasonic measurement system. Thus, we expected to improve our understanding of them through numerical simulations and experimental measurements. First, we proposed an ultrasonic detection method to estimate the electrode length by embedding graphite rods in Söderberg electrodes. Then, we developed a 3D finite element model in COMSOL for wave transmission in the graphite rod. The wave transmission through 20 and 40 cm graphite rods was simulated using finite element models. The transmission loss, sound pressure, intensity, and displacement distribution of the sound wave passing through the graphite electrode were calculated. To verify the simulation calculation results, we further conducted an acoustic experiment. The results showed that transmission loss varies significantly with frequency. When the frequency was between 25 and 55 kHz, the transmission loss of the graphite rod was slight. At 47 kHz, the transmission loss was 1.837 dB/m. Full article
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15 pages, 7414 KiB  
Article
Effect of Controlled Muscle Activation in a Unilateral Vocal Fold Polyp Setting on Vocal Fold Vibration
by Mingjun Ji, Boquan Liu, Jack Jiang, Matthew R. Hoffman, Jinwei Lan and Jin Fang
Appl. Sci. 2022, 12(23), 12486; https://doi.org/10.3390/app122312486 - 6 Dec 2022
Cited by 1 | Viewed by 1303
Abstract
Unilateral vocal fold polyps can lead to incomplete glottal closure and irregular vocal fold vibration. Depending on polyp size and resulting dysphonia severity, voice therapy or surgery may be recommended. As part of voice therapy, patients may learn how to optimize intrinsic and [...] Read more.
Unilateral vocal fold polyps can lead to incomplete glottal closure and irregular vocal fold vibration. Depending on polyp size and resulting dysphonia severity, voice therapy or surgery may be recommended. As part of voice therapy, patients may learn how to optimize intrinsic and extrinsic laryngeal muscle use to mitigate benign lesion effects, increase vocal efficiency, and improve voice quality. In this study, we used a low-dimensional mass model with a simulated unilateral vocal fold polyp and varied intra-laryngeal muscle activity to simulate vocal fold vibration across varied conditions. Differing muscle activation has different effects on frequency, periodicity, and intensity. Accordingly, learning how to optimize muscle activity in a unilateral polyp setting may help patients achieve the best possible periodic and most efficiently produced voice in the context of abnormal vocal fold morphology. Full article
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