Applied AcousticsPub Date : 2025-07-10DOI: 10.1016/j.apacoust.2025.110928
F. Caccia , L. Galimberti , L. Abergo , A. Savino , A. Zanotti , M. Parsani , A. Guardone
{"title":"Quasi-compact model for accurate noise prediction of complex rotor configurations","authors":"F. Caccia , L. Galimberti , L. Abergo , A. Savino , A. Zanotti , M. Parsani , A. Guardone","doi":"10.1016/j.apacoust.2025.110928","DOIUrl":"10.1016/j.apacoust.2025.110928","url":null,"abstract":"<div><div>The design of urban air mobility systems requires fast yet accurate aerodynamic and acoustic analyses of propeller interactions. Low-fidelity solvers relying on compact F1A formulations are commonly used, but the compact acoustic assumption does not hold for loading noise produced by unsteady inflows. This study introduces a quasi-compact acoustic model applied to isolated and tandem interacting propellers comparing its performance against other hybrid solvers. The quasi-compact model propagates the local chord-wise and span-wise pressure jump distribution computed with a non-linear vortex-lattice aerodynamic solution to far-field observers. Compact models simplify this by using the span-wise distribution only. Reference solutions are generated by propagating high-fidelity CFD pressure fields to far-field observers using the same Ffowcs Williams-Hawkings solver. Results demonstrate that the compact formulation achieves convergence only for isolated propellers, whereas the quasi-compact formulation can provide converged solutions also with rotor-rotor interactions and compares better with the reference high-fidelity data.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"240 ","pages":"Article 110928"},"PeriodicalIF":3.4,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588304","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}
Applied AcousticsPub Date : 2025-07-09DOI: 10.1016/j.apacoust.2025.110931
Abdulkadir Gulsen , Burak Kolukisa , Mustafa Etcil , Umut Caliskan , Hafız Muhammad Numan Zafar , Munise Didem Demirbas , Ahmet Turan Ozdemir , Burcu Bakir-Gungor
{"title":"Investigating strain rate effects on damage mechanisms in hybrid laminated composites using acoustic emission","authors":"Abdulkadir Gulsen , Burak Kolukisa , Mustafa Etcil , Umut Caliskan , Hafız Muhammad Numan Zafar , Munise Didem Demirbas , Ahmet Turan Ozdemir , Burcu Bakir-Gungor","doi":"10.1016/j.apacoust.2025.110931","DOIUrl":"10.1016/j.apacoust.2025.110931","url":null,"abstract":"<div><div>Hybrid composites, which combine distinct fiber types such as carbon, basalt, and aramid, provide a synergistic balance of strength, stiffness, impact resistance, and energy dissipation, making them appealing for critical applications in aerospace, automotive, and other high-performance industries. Monitoring damage progression in these composites is vital for ensuring structural integrity and preventing catastrophic failures. Acoustic emission (AE) serves as a powerful, noninvasive technique for real-time structural health monitoring, capturing the transient stress waves generated when damage events occur. This study utilizes AE to examine the influence of strain rate on damage modes in carbon/basalt/aramid hybrid composites under three-point bending. An unsupervised feature selection based on Laplacian scores is employed to identify the most relevant AE features with damage modes, while SHapley Additive Explanations (SHAP) are used to evaluate the correlation between AE features and strain rates. The correlation analysis results indicate that peak frequency (PF) serves as a key indicator, demonstrating significant shifts at higher strain rates. Gaussian Mixture Model (GMM) clustering is used to analyze hybrid composites by examining clustered AE signals based on selected features identified through Laplacian scores, with Silhouette scores employed to determine the optimal number of clusters. This study highlights the role of AE in understanding fiber interactions and damage evolution, offering valuable insights into the mechanical performance and optimization of carbon/basalt/aramid hybrid composite structures.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"240 ","pages":"Article 110931"},"PeriodicalIF":3.4,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144580267","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}
{"title":"An interpretable frequency-enhanced domain adaptive network for cross-domain fault diagnosis of rotating machinery","authors":"Yazhou Zhang , Xiaoqiang Zhao , Zhenrui Peng , Yongyong Hui , Rongrong Xu , Peng Chen","doi":"10.1016/j.apacoust.2025.110934","DOIUrl":"10.1016/j.apacoust.2025.110934","url":null,"abstract":"<div><div>The performance of domain adaptive fault diagnosis methods can be limited under noisy environments and variable operating conditions, and existing domain adaptive methods lack interpretability. Therefore, to address the above issues, an interpretable frequency-enhanced domain adaptive network (IFEDAN) for cross-domain fault diagnosis of rotating machinery is proposed in this paper. First, the time-domain signals are converted into the frequency domain using the Fast Fourier Transform (FFT) to enhance the representation of frequency-domain fault features. Additionally, the Morlet wavelet is introduced in the initial layer of the model for weight initialization, which enhances the model’s ability to capture fault features. Then, a frequency-enhanced residual block is designed, which not only helps the model to capture more transferable features, but also further enhances the useful features from both local and global perspectives. Finally, Entropy Maximum Mean Difference (EMMD) loss is designed. EMMD uses the entropy value to determine the bandwidth of the Gaussian kernel, which enhances the stability of the training and decision boundaries. Validation is performed on the public dataset, the roller gear (RG) dataset and the Lanzhou University of Technology (LUT) dataset. The results show that IFEDAN has excellent cross-domain diagnostic performance. When performing cross-domain diagnosis between different datasets, the average diagnosis accuracy of IFEDAN reaches 93.81 %, which is higher than the comparison methods.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"240 ","pages":"Article 110934"},"PeriodicalIF":3.4,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144580266","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}
Applied AcousticsPub Date : 2025-07-09DOI: 10.1016/j.apacoust.2025.110933
Giulia Fratoni, Dario D'Orazio
{"title":"Boundary conditions for hybrid simulations in a rectangular environment with sound-absorbing ceiling","authors":"Giulia Fratoni, Dario D'Orazio","doi":"10.1016/j.apacoust.2025.110933","DOIUrl":"10.1016/j.apacoust.2025.110933","url":null,"abstract":"<div><div>Acoustic numerical models facilitate sound field prediction in challenging real-world scenarios, such as environments with non-uniform sound absorption distribution. The accuracy of their results strongly depends on the reliability of boundary conditions required as input data. Research has largely covered analytical models of pressure-based boundary conditions for wave-based simulation techniques. However, accessible lists of frequency-dependent acoustic impedances remain limited compared to the energy-based datasets widely available in the literature. Consequently, random-incidence absorption coefficients are often converted into complex surface impedances through non-unique processes. This work explores the potential discrepancies between the input data of a wave-based finite-element model (hybridized with ray-tracing), and the energy-based coefficients employed in analytical predictions and geometrical acoustics simulations. The 3D model of an existing rectangular space with a highly sound-absorbing surface (the ceiling) is a suitable test environment for this investigation. Room criteria obtained with in-field acoustic measurements, i.e., reverberation time and speech clarity, are the experimental reference data throughout the work. Focusing on the air-backed sound-absorbing tiles at the suspended ceiling, results reveal gaps in input data, suggesting a potential percentage of discrepancies between the analytical formula and numerical models' input data up to 25% at low-mid frequencies (125 Hz - 250 Hz - 500 Hz).</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"240 ","pages":"Article 110933"},"PeriodicalIF":3.4,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144580268","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}
{"title":"Thermoacoustics of CVD graphene","authors":"E.V. Boyko , D.V. Smovzh , D.V. Sorokin , A.A. Pilnik , N.K. Maxim","doi":"10.1016/j.apacoust.2025.110920","DOIUrl":"10.1016/j.apacoust.2025.110920","url":null,"abstract":"<div><div>For the first time, direct experimental evidence of the thermoacoustic effect is presented. The results of studies conducted using atomic force microscopy showed that the amplitude of mechanical vibrations of the thermoacoustic transducer does not exceed 161 nm at a sound pressure level of 65 dB at a distance of 2 cm and a frequency of 3 kHz. Mechanical oscillations with such an amplitude at the specified frequency cannot provide the observed level of sound pressure. This indicates that mechanical oscillations do not significantly contribute to the formation of the sound field generated by the thermoacoustic transducer based on a graphene-glass composite. Consequently, the primary mechanism of sound generation in the studied system is the thermoacoustic effect rather than mechanical vibrations of the substrate. It has also been established for the first time that the non-uniform heating and size of the CVD graphene crystallites influence the sound generation process only on scales comparable to the size of graphene crystallites and, under conditions typical for the use of graphene thermophones, do not have a decisive effect on the thermoacoustic effect.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"240 ","pages":"Article 110920"},"PeriodicalIF":3.4,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144572710","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}
Applied AcousticsPub Date : 2025-07-07DOI: 10.1016/j.apacoust.2025.110919
Shuhan Liu , Raphaël Pile , Robin Petit , Joséphine Pérot-Le Gal , Olivier Thomas , Simon Benacchio
{"title":"Prediction of the elastic film effect on sound attenuation of custom molded solid earplugs using transfer matrices","authors":"Shuhan Liu , Raphaël Pile , Robin Petit , Joséphine Pérot-Le Gal , Olivier Thomas , Simon Benacchio","doi":"10.1016/j.apacoust.2025.110919","DOIUrl":"10.1016/j.apacoust.2025.110919","url":null,"abstract":"<div><div>In this paper, an analytical model of the air-conducted sound propagation in an earplug equipped with a film filter is proposed to explain and predict its acoustic attenuation. The model is developed using the transfer matrix (TM) method under the plane wave assumption, with the elastic film modeled as a prestressed circular plate based on the Kirchhoff-Love theory. This film is coupled with multiple interconnected air cavities to form the TM model of the earplug. The validity and limitations of the model are assessed through comparisons with numerical simulations using the finite element (FE) method. The predicted resonant frequencies deviate by less than 2% within the audible frequency band. The TM model is therefore considered useful to conduct parametric studies in order to provide a physical understanding of the predicted sound attenuation of film filters, as well as their optimization. The influence of the film parameters, such as mass, surface tension, and cavity geometrical parameters on the earplugs' sound attenuation is analyzed both qualitatively and quantitatively, with a focus on amplitude and characteristic frequencies.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"240 ","pages":"Article 110919"},"PeriodicalIF":3.4,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144571152","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}
Applied AcousticsPub Date : 2025-07-07DOI: 10.1016/j.apacoust.2025.110923
Lizhi Xiong , Kuangang Fan , Jiajun Huang , Zhongru Liu , Aigen Fan
{"title":"Adaptive filtering of UAV acoustic signals based on MFDE-LOF fundamental frequency filtering and PSO-VMD harmonic reconstruction","authors":"Lizhi Xiong , Kuangang Fan , Jiajun Huang , Zhongru Liu , Aigen Fan","doi":"10.1016/j.apacoust.2025.110923","DOIUrl":"10.1016/j.apacoust.2025.110923","url":null,"abstract":"<div><div>The rapid proliferation of drone technology has significantly impacted public security, necessitating the development of advanced Unmanned Aerial Vehicle (UAV) filtering techniques. This paper proposes an innovative adaptive filtering method for UAV acoustic signals in diverse noisy environments. Optimizing the Local Outlier Factor (LOF) parameters of Multiscale Fluctuation Dispersion Entropy (MFDE) scatterplots enables the removal of outlier points, thereby filtering out noise fundamental frequencies in the Time-frequency spectrum. Furthermore, Variational Mode Decomposition (VMD) with Particle Swarm Optimization (PSO)-optimized parameters is utilized to adjust the center frequency and bandwidth, enabling precise separation of acoustic signals. Intrinsic Mode Functions (IMFs) are selected based on the harmonic characteristics of UAVs for signal reconstruction, achieving adaptive filtering. Experimental results utilizing three UAVs with nine distinct noise types demonstrate notable performance enhancements, with the average Signal-to-Noise Ratio (SNR) increasing by approximately 5 dB, 8 dB, and 12 dB under 0 dB, -5 dB, and -10 dB noise conditions respectively, while spectral Cosine Similarity (CS) improves by about 0.4, 0.5, and 0.6 on average.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"240 ","pages":"Article 110923"},"PeriodicalIF":3.4,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144571335","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}
Applied AcousticsPub Date : 2025-07-07DOI: 10.1016/j.apacoust.2025.110924
Kelan Kuang , Feiran Yang , Mou Wang , Jun Yang
{"title":"Low-complexity bone conduction-aided speech enhancement leveraging sub-band and full-band architecture","authors":"Kelan Kuang , Feiran Yang , Mou Wang , Jun Yang","doi":"10.1016/j.apacoust.2025.110924","DOIUrl":"10.1016/j.apacoust.2025.110924","url":null,"abstract":"<div><div>This paper presents a low-complexity speech enhancement model that jointly utilizes sub-band and full-band features of bone-conducted (BC) and air-conducted (AC) speech. A two-step speech enhancement procedure is considered. In the first step, the proposed model estimates a set of gains of pre-defined sub-bands to enhance the spectral envelope of noisy AC speech, whereas in the second step, the proposed model estimates a set of coefficients to apply deep filtering to the output of the previous step. Specifically, sub-band gains and deep filtering coefficients are estimated from sub-band and full-band features of both AC and BC speech by two sets of encoder-decoder. Additionally, attention-based feature fusion modules are employed to fuse features of AC and BC at an early and intermediate stage. The multiply-accumulate operations per second of the proposed model are 40.3 M, which is lower than that of most existing BC-aided speech enhancement methods. Experimental results on AC and BC speech recorded from 109 individuals demonstrate that the proposed model effectively balances the noise reduction performance and the computational complexity.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"240 ","pages":"Article 110924"},"PeriodicalIF":3.4,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144571154","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}
Applied AcousticsPub Date : 2025-07-07DOI: 10.1016/j.apacoust.2025.110911
Yaakov Buchris , Yaniv Aluma , Roee Diamant
{"title":"Source localization in the presence of depth-varying sound speed: A test case for sperm whales","authors":"Yaakov Buchris , Yaniv Aluma , Roee Diamant","doi":"10.1016/j.apacoust.2025.110911","DOIUrl":"10.1016/j.apacoust.2025.110911","url":null,"abstract":"<div><div>Sperm whales (<em>Physeter macrocephalus</em>) are the largest of the toothed whales, amongst the deepest divers and are distributed worldwide. They are the focus of intensive biological research for distribution analysis, behavioral studies and, more recently, for language processing through Project CETI. Of particular interest for the latter is the study of their mobility patterns and distribution ranges, which requires knowledge of their location. In this paper, we offer a passive acoustic monitoring (PAM) approach for the localization of Sperm whales through arrays of receivers deployed from surface moorings. Our scheme performs adaptive beamforming for localization, and takes into account the varying sound speed in water and the whale's mobility. A series of stability tests increase the accuracy of positioning. Numerical results investigate the effect of system parameters, varying sound speed, number of moorings and number of receiving elements. Results from real sea experiments replaying sperm whale vocalizations in deep water across the Dominica Island demonstrate the practicality of our approach and its robustness for varying signal to noise ratios and range. To ensure reproducibility, we provide our implementation code.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"240 ","pages":"Article 110911"},"PeriodicalIF":3.4,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144571337","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}
{"title":"Enhancing acoustic comfort for earplug users: objective and subjective evaluation of bone-conducted sound with meta-earplugs incorporating Helmholtz resonators","authors":"Kévin Carillo , Franck Sgard , Olivier Dazel , Olivier Doutres","doi":"10.1016/j.apacoust.2025.110929","DOIUrl":"10.1016/j.apacoust.2025.110929","url":null,"abstract":"<div><div>Passive earplugs are commonly used to protect workers from excessive noise exposure, but they often result in discomfort. The occlusion effect (OE) is a major discomfort that corresponds to an increased perception of bone-conducted sound at low frequencies. Objectively, the OE is associated with an increase in the sound pressure level generated in the earcanal under bone-conducted stimulation. Inspired by metamaterials, “<em>meta</em>-earplugs” incorporating Helmholtz resonators have been developed to minimize this phenomenon, and their effectiveness has been validated using artificial ears in the authors’ prior work. In this study, 34 participants evaluated the effectiveness of <em>meta</em>-earplugs in reducing the OE. Three configurations of the <em>meta</em>-earplug were tested alongside a commercial foam earplug. Objective measurements of both OE and sound attenuation were conducted. Participants also completed a questionnaire evaluating their perception of low-frequency sound amplification and the judgement of the naturalness of their own voice while speaking with the earplugs. On average, the results demonstrate that <em>meta</em>-earplugs reduced the objective OE by up to 20 dB below 1 kHz. Additionally, the perception of low-frequency sound amplification decreased by 2 points, while voice naturalness judgement increased by 2 points, both assessed on a 7-point Likert scale. Using linear mixed-effects models, it was found that the perception of low-frequency sound amplification was primarily driven by the objective OE at 125 Hz, while voice naturalness was also significantly influenced by the objective OE at 4 kHz and the psychosocial characteristic of familiarity with the experimenter. Overall, <em>meta</em>-earplugs were preferred by 85 % of the participants.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"240 ","pages":"Article 110929"},"PeriodicalIF":3.4,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144571153","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}