Pub Date : 2026-02-02DOI: 10.1016/j.apacoust.2026.111241
Jinpeng Liu , Chao Zhang , Dejiang Shang
Current research on the active control of low-frequency omnidirectional noise from underwater structures remains limited. Most studies concentrate on control system algorithms, with insufficient attention to the specific mechanisms governing acoustic field control. To address this gap, this study applies the minimum space square sound pressure method to control the low-frequency radiated acoustic field of a typical cylindrical shell structure and analyze sound field control mechanism. The approach follows a control strategy aimed at minimizing the total radiated energy of the acoustic field in space. Numerical simulations and lake experiments are conducted. The results show that the low-frequency radiated acoustic field of the cylindrical shell can be effectively controlled using this method. The findings clarify the mechanism of low-frequency active control, which operates through three pathways: reducing the output power of the primary sound source, enabling energy absorption by the secondary sound source, and the combined effect of both, and clearly establish how the energy is reduced in the sound field control process. This investigation of the acoustic field control mechanism provides a theoretical foundation for optimizing active control systems.
{"title":"Active noise control mechanism for the low-frequency sound field of a cylindrical shell","authors":"Jinpeng Liu , Chao Zhang , Dejiang Shang","doi":"10.1016/j.apacoust.2026.111241","DOIUrl":"10.1016/j.apacoust.2026.111241","url":null,"abstract":"<div><div>Current research on the active control of low-frequency omnidirectional noise from underwater structures remains limited. Most studies concentrate on control system algorithms, with insufficient attention to the specific mechanisms governing acoustic field control. To address this gap, this study applies the minimum space square sound pressure method to control the low-frequency radiated acoustic field of a typical cylindrical shell structure and analyze sound field control mechanism. The approach follows a control strategy aimed at minimizing the total radiated energy of the acoustic field in space. Numerical simulations and lake experiments are conducted. The results show that the low-frequency radiated acoustic field of the cylindrical shell can be effectively controlled using this method. The findings clarify the mechanism of low-frequency active control, which operates through three pathways: reducing the output power of the primary sound source, enabling energy absorption by the secondary sound source, and the combined effect of both, and clearly establish how the energy is reduced in the sound field control process. This investigation of the acoustic field control mechanism provides a theoretical foundation for optimizing active control systems.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"247 ","pages":"Article 111241"},"PeriodicalIF":3.4,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146096207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-02DOI: 10.1016/j.apacoust.2026.111245
Gildean do N. Almeida, Andrey B. da Silva, Rafael R. Goes, Erasmo F. Vergara, Arcanjo Lenzi
The duality between sound insulation and air ventilation currently represents one of the most promising research areas in applied acoustical physics and noise control. In this context, this paper presents the design of a metamaterial that enables air ventilation and sound attenuation over a wide frequency band. The unit cell consists of a square aperture loaded with two combinations of periodic Fabry-Pérot-type scatterers. The transfer matrix method approach is adopted to evaluate the structure’s behavior under normal wave incidence, while the radiation impedance is used to assess its behavior under diffuse incidence. Theoretical and experimental results show that high sound transmission loss values ( dB) in different frequency bands are possible due to the bandgap property; furthermore, this magnitude can be easily defined through the periodicity of the scatterers. In addition, the characteristic of air ventilation of the structure was experimentally demonstrated, showing a maximum airflow reduction of and a flow resistivity of Pasm−2. Using a full-scale panel, we demonstrated that the low transmissibility of energy that is incident diffusely on the structure is due to physical-geometric effects, that is, due to local resonances and interactions between scatterers. The structure was then evaluated as an enclosure for a refrigerator noise source; consequently, broadband noise attenuation was achieved, demonstrating the effectiveness of the design. Finally, this work contributes to advances in the field of noise control through ventilated metamaterials.
{"title":"Study of broadband noise control by a ventilated metamaterial based on Fabry-Pérot scatterers","authors":"Gildean do N. Almeida, Andrey B. da Silva, Rafael R. Goes, Erasmo F. Vergara, Arcanjo Lenzi","doi":"10.1016/j.apacoust.2026.111245","DOIUrl":"10.1016/j.apacoust.2026.111245","url":null,"abstract":"<div><div>The duality between sound insulation and air ventilation currently represents one of the most promising research areas in applied acoustical physics and noise control. In this context, this paper presents the design of a metamaterial that enables air ventilation and sound attenuation over a wide frequency band. The unit cell consists of a square aperture loaded with two combinations of periodic Fabry-Pérot-type scatterers. The transfer matrix method approach is adopted to evaluate the structure’s behavior under normal wave incidence, while the radiation impedance is used to assess its behavior under diffuse incidence. Theoretical and experimental results show that high sound transmission loss values (<span><math><mo>></mo><mn>29</mn></math></span> dB) in different frequency bands are possible due to the bandgap property; furthermore, this magnitude can be easily defined through the periodicity of the scatterers. In addition, the characteristic of air ventilation of the structure was experimentally demonstrated, showing a maximum airflow reduction of <span><math><mn>40</mn><mo>,</mo><mn>0</mn><mi>%</mi></math></span> and a flow resistivity of <span><math><mi>σ</mi><mo>≈</mo><mn>6.04</mn></math></span> Pa<span><math><mo>⋅</mo></math></span>s<span><math><mo>⋅</mo></math></span>m<sup>−2</sup>. Using a full-scale panel, we demonstrated that the low transmissibility of energy that is incident diffusely on the structure is due to physical-geometric effects, that is, due to local resonances and interactions between scatterers. The structure was then evaluated as an enclosure for a refrigerator noise source; consequently, broadband noise attenuation was achieved, demonstrating the effectiveness of the design. Finally, this work contributes to advances in the field of noise control through ventilated metamaterials.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"247 ","pages":"Article 111245"},"PeriodicalIF":3.4,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146096208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-28DOI: 10.1016/j.apacoust.2026.111239
Ignasi Nou-Plana , Adrian Teaca , Giovanni Zambon , Rosa Ma Alsina-Pagès
Understanding underwater soundscapes is essential for assessing the impacts of maritime noise pollution on marine environments. Characterizing these soundscapes is crucial both for evaluating current noise impacts and for developing future mitigation strategies. Several datasets have been published focusing on the acoustic signatures of common vessel types; however, most remain restricted to a single location, are not fully open to the public, and lack scalable storage or dissemination tools. The DeuteroNoise Dataset addresses these gaps; an open-access corpus that pairs long-duration, calibrated hydrophone recordings with time-synchronised Automatic Identification System data to document coastal vessel noise and contrasting natural soundscapes at three European sites: the Catalan coast, the Venice Lagoon, and the western Black Sea. Six short-term fixed-station campaigns conducted since December 2023 have produced nearly 700 h of publicly available continuous audio with more than 11 h of labelled audio. Each recorded and identified event is correlated with the ship’s identity, position, and speed metadata; the dataset therefore spans cargo vessel traffic, workboats, leisure craft, and non-anthropogenic background sounds. Vessel types are categorized and linked to their acoustic signatures, facilitating analyses of soundscape dynamics and ecological impact. Built on PostgreSQL with a FastAPI backend, and served through an interactive web interface, the dataset offers a scalable platform for large-scale retrieval and exploration. By integrating calibrated, multi-basin recordings with vessel metadata in an openly accessible, scalable framework. The DeuteroNoise Dataset represents the first resource of its kind in Europe, enabling robust cross-regional comparisons, supporting the development of AI-based classification models, advancing ecological research on anthropogenic noise, and setting a new benchmark for underwater soundscape monitoring worldwide.
{"title":"The DeuteroNoise dataset: An open, calibrated, multi-basin resource for vessel noise and natural soundscapes in European coastal waters","authors":"Ignasi Nou-Plana , Adrian Teaca , Giovanni Zambon , Rosa Ma Alsina-Pagès","doi":"10.1016/j.apacoust.2026.111239","DOIUrl":"10.1016/j.apacoust.2026.111239","url":null,"abstract":"<div><div>Understanding underwater soundscapes is essential for assessing the impacts of maritime noise pollution on marine environments. Characterizing these soundscapes is crucial both for evaluating current noise impacts and for developing future mitigation strategies. Several datasets have been published focusing on the acoustic signatures of common vessel types; however, most remain restricted to a single location, are not fully open to the public, and lack scalable storage or dissemination tools. The DeuteroNoise Dataset addresses these gaps; an open-access corpus that pairs long-duration, calibrated hydrophone recordings with time-synchronised Automatic Identification System data to document coastal vessel noise and contrasting natural soundscapes at three European sites: the Catalan coast, the Venice Lagoon, and the western Black Sea. Six short-term fixed-station campaigns conducted since December 2023 have produced nearly 700 h of publicly available continuous audio with more than 11 h of labelled audio. Each recorded and identified event is correlated with the ship’s identity, position, and speed metadata; the dataset therefore spans cargo vessel traffic, workboats, leisure craft, and non-anthropogenic background sounds. Vessel types are categorized and linked to their acoustic signatures, facilitating analyses of soundscape dynamics and ecological impact. Built on PostgreSQL with a FastAPI backend, and served through an interactive web interface, the dataset offers a scalable platform for large-scale retrieval and exploration. By integrating calibrated, multi-basin recordings with vessel metadata in an openly accessible, scalable framework. The DeuteroNoise Dataset represents the first resource of its kind in Europe, enabling robust cross-regional comparisons, supporting the development of AI-based classification models, advancing ecological research on anthropogenic noise, and setting a new benchmark for underwater soundscape monitoring worldwide.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"246 ","pages":"Article 111239"},"PeriodicalIF":3.4,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-28DOI: 10.1016/j.apacoust.2026.111235
Salomé Wanty , Etienne Parizet , Nicolas Totaro , Martin Glesser
Electric motors have become a part of our daily lives, making the question of their noise essential for our acoustic comfort. The sound they emit is often described as tonal or whistling due to the presence of many harmonics, one source of which is a power supply technique called pulse width modulation (PWM). During the design process, auralization models can be used to evaluate the effect of PWM harmonics on sound quality. Engineering-grade models, which are based on simplifying assumptions, are used in the early stages of design when little input data is available. With these models, a direct perceptual comparison between measured and simulated sounds would inevitably reveal significant differences. However, if the model can reliably predict the perceptual sound space, it can be a valuable tool for assessing sound quality. This paper presents a methodology to evaluate the capability of a simplified engineering model to simulate the main attributes of PWM noise. To this end, the authors implemented an auralization model to synthesize the noise emitted by an electric motor from its supply signals. Some sound stimuli were collected from measurements and simulations to conduct a perceptual experiment. The measured and simulated sounds were evaluated separately within two sets of stimuli. The experiment included similarity and pleasantness evaluations. Comparing the results obtained by Individual Difference Scaling (INDSCAL) showed great coherence between the two sound sets, suggesting that the simulated stimuli were evaluated similarly to the measured stimuli. Pleasantness ratings yielded the same result. Therefore, the auralization model appears to reliably reproduce the main sound dimensions underlying the perception of PWM noise.
{"title":"Perceptual evaluation of an auralization model for pulse width modulation noise","authors":"Salomé Wanty , Etienne Parizet , Nicolas Totaro , Martin Glesser","doi":"10.1016/j.apacoust.2026.111235","DOIUrl":"10.1016/j.apacoust.2026.111235","url":null,"abstract":"<div><div>Electric motors have become a part of our daily lives, making the question of their noise essential for our acoustic comfort. The sound they emit is often described as tonal or whistling due to the presence of many harmonics, one source of which is a power supply technique called pulse width modulation (PWM). During the design process, auralization models can be used to evaluate the effect of PWM harmonics on sound quality. Engineering-grade models, which are based on simplifying assumptions, are used in the early stages of design when little input data is available. With these models, a direct perceptual comparison between measured and simulated sounds would inevitably reveal significant differences. However, if the model can reliably predict the perceptual sound space, it can be a valuable tool for assessing sound quality. This paper presents a methodology to evaluate the capability of a simplified engineering model to simulate the main attributes of PWM noise. To this end, the authors implemented an auralization model to synthesize the noise emitted by an electric motor from its supply signals. Some sound stimuli were collected from measurements and simulations to conduct a perceptual experiment. The measured and simulated sounds were evaluated separately within two sets of stimuli. The experiment included similarity and pleasantness evaluations. Comparing the results obtained by Individual Difference Scaling (INDSCAL) showed great coherence between the two sound sets, suggesting that the simulated stimuli were evaluated similarly to the measured stimuli. Pleasantness ratings yielded the same result. Therefore, the auralization model appears to reliably reproduce the main sound dimensions underlying the perception of PWM noise.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"246 ","pages":"Article 111235"},"PeriodicalIF":3.4,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-28DOI: 10.1016/j.apacoust.2026.111244
Thi Hai Duong Ninh, Wei Zeng, Martin Francis Lambert, Nhu Cuong Do, Chengcheng Yin
Sewer overflows due to blockages are significant challenges for water utilities worldwide, as these events pose substantial risks of disruption and contamination to society, the economy, and the environment. Accurately detecting blockages in sewer systems is essential to mitigate such incidents. This paper investigates the use of paired acoustic sensors in combination with a paired-impulse response function (paired-IRF) technique to detect, locate, and estimate sewer blockages, helping to prevent sewer overflow risks. Laboratory tests were conducted on both clean and blocked pipes with varying blockage types and severities. The acoustic responses of these pipes were analysed to distinguish between unobstructed and obstructed conditions. The paired IRF extracted was then applied to identify blockage locations and estimate blockage sizes. The presence of paired spikes in the paired-IRF trace serves as clear evidence of blockages within the tested sewer pipe, including those caused by tree root and solid materials. The technique accurately identified both the location and size of blockages, showing strong agreement with actual conditions observed during experiments. These findings express that the acoustic-based paired-IRF approach is a reliable method for blockage detection in sewer systems, enabling water utilities to take informed and timely actions before issues lead to environmental or public health impacts.
{"title":"Proactive blockage detection in sewer pipes using paired acoustic sensors: An experimental study","authors":"Thi Hai Duong Ninh, Wei Zeng, Martin Francis Lambert, Nhu Cuong Do, Chengcheng Yin","doi":"10.1016/j.apacoust.2026.111244","DOIUrl":"10.1016/j.apacoust.2026.111244","url":null,"abstract":"<div><div>Sewer overflows due to blockages are significant challenges for water utilities worldwide, as these events pose substantial risks of disruption and contamination to society, the economy, and the environment. Accurately detecting blockages in sewer systems is essential to mitigate such incidents. This paper investigates the use of paired acoustic sensors in combination with a paired-impulse response function (paired-IRF) technique to detect, locate, and estimate sewer blockages, helping to prevent sewer overflow risks. Laboratory tests were conducted on both clean and blocked pipes with varying blockage types and severities. The acoustic responses of these pipes were analysed to distinguish between unobstructed and obstructed conditions. The paired IRF extracted was then applied to identify blockage locations and estimate blockage sizes. The presence of paired spikes in the paired-IRF trace serves as clear evidence of blockages within the tested sewer pipe, including those caused by tree root and solid materials. The technique accurately identified both the location and size of blockages, showing strong agreement with actual conditions observed during experiments. These findings express that the acoustic-based paired-IRF approach is a reliable method for blockage detection in sewer systems, enabling water utilities to take informed and timely actions before issues lead to environmental or public health impacts.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"246 ","pages":"Article 111244"},"PeriodicalIF":3.4,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-28DOI: 10.1016/j.apacoust.2026.111243
Louise Chiocchetti , David Marx , Vincent Valeau , François Ollivier , Régis Marchiano
This work investigates, using a microphone array, the localization of aeroacoustic sources resulting from the interaction of a flow with rods. In similar investigations in the literature, arrays often have a planar geometry and the spatial region in which acoustic sources are searched is a plane parallel to that of the array. However, the sources are not always distributed in such a plane. Moreover, aeroacoustic sources resulting from flow-obstacle interaction are often dipoles, and for some complex geometries, the dipoles’ orientation can vary in space, such as for curved obstacles or arrangements of rods with different orientations. In order to identify such dipoles, this work uses a three-dimensional array composed of four flat arrays, forming a tunnel of 1024 microphones around the open vein of an anechoic wind tunnel. Microphone signals are processed by an inverse beamforming technique to identify equivalent dipole sources producing the measured sound field at the array, using classical Tikhonov regularization. Taking advantage of the acoustic compactness of the cross-section of the rods located in the flow, the dipoles are sought along the axis of the rods, with a spacing of the order of the vortex shedding coherence length. The technique does not require any prior assumption on dipole orientation. Results from simulated or experimental data are presented to assess the effectiveness of the method, in the cases of a rectilinear rod and a bent rod forming a ring.
{"title":"Three-dimensional microphone array for the reconstruction of compact dipole aeroacoustic sources with spatially varying orientation","authors":"Louise Chiocchetti , David Marx , Vincent Valeau , François Ollivier , Régis Marchiano","doi":"10.1016/j.apacoust.2026.111243","DOIUrl":"10.1016/j.apacoust.2026.111243","url":null,"abstract":"<div><div>This work investigates, using a microphone array, the localization of aeroacoustic sources resulting from the interaction of a flow with rods. In similar investigations in the literature, arrays often have a planar geometry and the spatial region in which acoustic sources are searched is a plane parallel to that of the array. However, the sources are not always distributed in such a plane. Moreover, aeroacoustic sources resulting from flow-obstacle interaction are often dipoles, and for some complex geometries, the dipoles’ orientation can vary in space, such as for curved obstacles or arrangements of rods with different orientations. In order to identify such dipoles, this work uses a three-dimensional array composed of four flat arrays, forming a tunnel of 1024 microphones around the open vein of an anechoic wind tunnel. Microphone signals are processed by an inverse beamforming technique to identify equivalent dipole sources producing the measured sound field at the array, using classical Tikhonov regularization. Taking advantage of the acoustic compactness of the cross-section of the rods located in the flow, the dipoles are sought along the axis of the rods, with a spacing of the order of the vortex shedding coherence length. The technique does not require any prior assumption on dipole orientation. Results from simulated or experimental data are presented to assess the effectiveness of the method, in the cases of a rectilinear rod and a bent rod forming a ring.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"246 ","pages":"Article 111243"},"PeriodicalIF":3.4,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-28DOI: 10.1016/j.apacoust.2026.111238
Yilei Fu , Qixiang Zhang , Zhiliang Hong , Guangyu Zhang , Xiaoyu Wang
Acoustic impedance is a key parameter for characterizing liner performance, and the development of time-domain impedance models facilitates the analysis of transient problems in complex acoustic environments. This study introduces a broadband impedance implementation within the two-dimensional time-domain boundary element method and further extends it to transfer impedance for modeling non-locally reacting liners. Validation through representative numerical and experimental cases demonstrates that the broadband impedance model can accurately capture the frequency-dependent characteristics of liners, and exhibits broader applicability to both locally and non-locally reacting liners. The results confirm that the proposed method offers clear advantages in terms of physical fidelity and numerical robustness, providing an efficient tool for liner design and noise reduction optimization in complex acoustic fields.
{"title":"Implementation of broadband acoustic impedance for locally and non-locally reacting perforated plate liners in a time-domain boundary element method","authors":"Yilei Fu , Qixiang Zhang , Zhiliang Hong , Guangyu Zhang , Xiaoyu Wang","doi":"10.1016/j.apacoust.2026.111238","DOIUrl":"10.1016/j.apacoust.2026.111238","url":null,"abstract":"<div><div>Acoustic impedance is a key parameter for characterizing liner performance, and the development of time-domain impedance models facilitates the analysis of transient problems in complex acoustic environments. This study introduces a broadband impedance implementation within the two-dimensional time-domain boundary element method and further extends it to transfer impedance for modeling non-locally reacting liners. Validation through representative numerical and experimental cases demonstrates that the broadband impedance model can accurately capture the frequency-dependent characteristics of liners, and exhibits broader applicability to both locally and non-locally reacting liners. The results confirm that the proposed method offers clear advantages in terms of physical fidelity and numerical robustness, providing an efficient tool for liner design and noise reduction optimization in complex acoustic fields.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"246 ","pages":"Article 111238"},"PeriodicalIF":3.4,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-27DOI: 10.1016/j.apacoust.2026.111237
Jiwan Kim, Yerin Shim, Wonju Jeon
We propose an acoustic metasurface that achieves low-frequency broadband absorption with tunable target frequencies via mechanically adjustable apertures. The metasurface consists of sub-wavelength Helmholtz resonators, each integrating an aperture into the neck rim without increasing overall thickness. By adjusting aperture closure ratios, geometrical asymmetry between adjacent resonators induces hybrid resonance, yielding perfect absorption. Compared with the design without apertures, the proposed structure lowers resonance frequency and widens bandwidth while maintaining deep sub-wavelength thickness. A theoretical model is developed to calculate the frequency-dependent effective impedance of the metasurface by rigorously accounting for thermo-viscous losses in narrow apertures. This model provides a physics-based framework for selecting aperture closure ratios to ensure impedance matching at arbitrary frequencies. To demonstrate practical feasibility, a metasurface sample with iris-diaphragm-inspired apertures is fabricated using three-dimensional printing, and its absorption performance is experimentally validated using impedance tube measurements. Experimental results confirm perfect absorption at a selected frequency within a tunable range from 400 to 540 Hz. Furthermore, combining multiple unit cells extends the design to broadband absorption, achieving 90% absorption over a one-third octave band (390–485 Hz). Given its compactness and tunability, the metasurface offers an effective solution for low-frequency noise control under dynamically varying spectral conditions.
{"title":"Tunable acoustic metasurface for low-frequency broadband absorption via asymmetric adjustable apertures","authors":"Jiwan Kim, Yerin Shim, Wonju Jeon","doi":"10.1016/j.apacoust.2026.111237","DOIUrl":"10.1016/j.apacoust.2026.111237","url":null,"abstract":"<div><div>We propose an acoustic metasurface that achieves low-frequency broadband absorption with tunable target frequencies via mechanically adjustable apertures. The metasurface consists of sub-wavelength Helmholtz resonators, each integrating an aperture into the neck rim without increasing overall thickness. By adjusting aperture closure ratios, geometrical asymmetry between adjacent resonators induces hybrid resonance, yielding perfect absorption. Compared with the design without apertures, the proposed structure lowers resonance frequency and widens bandwidth while maintaining deep sub-wavelength thickness. A theoretical model is developed to calculate the frequency-dependent effective impedance of the metasurface by rigorously accounting for thermo-viscous losses in narrow apertures. This model provides a physics-based framework for selecting aperture closure ratios to ensure impedance matching at arbitrary frequencies. To demonstrate practical feasibility, a metasurface sample with iris-diaphragm-inspired apertures is fabricated using three-dimensional printing, and its absorption performance is experimentally validated using impedance tube measurements. Experimental results confirm perfect absorption at a selected frequency within a tunable range from 400 to 540 Hz. Furthermore, combining multiple unit cells extends the design to broadband absorption, achieving 90% absorption over a one-third octave band (390–485 Hz). Given its compactness and tunability, the metasurface offers an effective solution for low-frequency noise control under dynamically varying spectral conditions.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"246 ","pages":"Article 111237"},"PeriodicalIF":3.4,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-27DOI: 10.1016/j.apacoust.2026.111248
Weiguo Chen, Xiaobin Hong, Dingmin Yang, Jiangbo Chen, Zhi Li
Ultrasonic guided wave is susceptible to nonlinear effects in the instrument measurement chain during damage detection, generating multi-harmonic interference signals that affect the accuracy of damage signature identification. To address this issue, a multi-bandgap metamaterial structure design method is proposed, which utilizes multiple bandgaps to suppress multi-harmonic interference signals. First, a genetic algorithm fitness function is designed to optimize six metamaterial configurations, successfully obtaining a stepped square pillarlike metamaterial with dual bandgaps of 120 kHz (2nd harmonic) and 180 kHz (3rd harmonic). Simulation and experimental results demonstrate that the designed metamaterial allows the 60 kHz fundamental frequency to pass with slight attenuation, while achieving a strong suppression effect on the 2nd and 3rd harmonic components. Finally, in ultrasonic guided wave testing experiments on specimens containing fatigue microcrack with a width of 5–10 μm, the multi-bandgap metamaterial effectively suppressed the instrument’s inherent harmonic noise, highlighting the nonlinear harmonics induced by the microcrack, providing a reliable basis for early microcrack identification. This study demonstrates the significant advantages of multi-bandgap metamaterial in multi-frequency wave control, frequency selectivity and microdamage detection, highlighting the important potential of metamaterial in the field of structural health monitoring.
{"title":"Multi-bandgap metamaterial-based suppression of nonlinear multi-harmonic signals in ultrasonic guided wave","authors":"Weiguo Chen, Xiaobin Hong, Dingmin Yang, Jiangbo Chen, Zhi Li","doi":"10.1016/j.apacoust.2026.111248","DOIUrl":"10.1016/j.apacoust.2026.111248","url":null,"abstract":"<div><div>Ultrasonic guided wave is susceptible to nonlinear effects in the instrument measurement chain during damage detection, generating multi-harmonic interference signals that affect the accuracy of damage signature identification. To address this issue, a multi-bandgap metamaterial structure design method is proposed, which utilizes multiple bandgaps to suppress multi-harmonic interference signals. First, a genetic algorithm fitness function is designed to optimize six metamaterial configurations, successfully obtaining a stepped square pillarlike metamaterial with dual bandgaps of 120 kHz (2nd harmonic) and 180 kHz (3rd harmonic). Simulation and experimental results demonstrate that the designed metamaterial allows the 60 kHz fundamental frequency to pass with slight attenuation, while achieving a strong suppression effect on the 2nd and 3rd harmonic components. Finally, in ultrasonic guided wave testing experiments on specimens containing fatigue microcrack with a width of 5–10 μm, the multi-bandgap metamaterial effectively suppressed the instrument’s inherent harmonic noise, highlighting the nonlinear harmonics induced by the microcrack, providing a reliable basis for early microcrack identification. This study demonstrates the significant advantages of multi-bandgap metamaterial in multi-frequency wave control, frequency selectivity and microdamage detection, highlighting the important potential of metamaterial in the field of structural health monitoring.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"246 ","pages":"Article 111248"},"PeriodicalIF":3.4,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-27DOI: 10.1016/j.apacoust.2026.111247
Chunhao Li , Cong Niu , Xiao Li , Guohao Zhang , Chuanjie Hu , Daxing Dong , Yangyang Fu
Acoustic metacages have been widely studied for noise insulation and reduction, but existing designs lack dynamic tunability, limiting their ability to support acoustic information transport. In this work, we propose a tunable acoustic metacage based on dual-layer metagratings to realize efficient dynamic switching between sound insulation and transmission. The dual-layer metagrating is designed with binary phase elements, providing a simple and robust method to modify the phase gradient of the acoustic metacage. By twisting the dual-layer metagratings, we achieve a dynamic transition between sound insulation and transmission through the 0th-order diffraction, governed by the parity-dependent diffraction law. We further design and experimentally demonstrate a tunable acoustic metacage that exhibits effective switching functionality for both sound insulation and transmission within the frequency range of 3.1 kHz to 4.0 kHz. Experimental results confirm the effective ventilation capability for both functionalities. With its simple design and tunable properties, the proposed acoustic metacage shows significant potential for applications in both noise reduction and acoustic communication.
{"title":"Tunable dual-layer acoustic metacage for efficient sound insulation and transmission","authors":"Chunhao Li , Cong Niu , Xiao Li , Guohao Zhang , Chuanjie Hu , Daxing Dong , Yangyang Fu","doi":"10.1016/j.apacoust.2026.111247","DOIUrl":"10.1016/j.apacoust.2026.111247","url":null,"abstract":"<div><div>Acoustic metacages have been widely studied for noise insulation and reduction, but existing designs lack dynamic tunability, limiting their ability to support acoustic information transport. In this work, we propose a tunable acoustic metacage based on dual-layer metagratings to realize efficient dynamic switching between sound insulation and transmission. The dual-layer metagrating is designed with binary phase elements, providing a simple and robust method to modify the phase gradient of the acoustic metacage. By twisting the dual-layer metagratings, we achieve a dynamic transition between sound insulation and transmission through the 0th-order diffraction, governed by the parity-dependent diffraction law. We further design and experimentally demonstrate a tunable acoustic metacage that exhibits effective switching functionality for both sound insulation and transmission within the frequency range of 3.1 kHz to 4.0 kHz. Experimental results confirm the effective ventilation capability for both functionalities. With its simple design and tunable properties, the proposed acoustic metacage shows significant potential for applications in both noise reduction and acoustic communication.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"246 ","pages":"Article 111247"},"PeriodicalIF":3.4,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号