Applied Acoustics最新文献

{"title":"Physical model experimental study on the infrasound characteristics of bedding slide in rock slope","authors":"Qiao Chen ,&nbsp;Dongming Jia ,&nbsp;Yaobai Sun ,&nbsp;Qingming Xie ,&nbsp;Fenglin Xu ,&nbsp;Rufu Zhou ,&nbsp;Wei Peng ,&nbsp;Jilong Chen ,&nbsp;Jianrong Ma ,&nbsp;Kang Yang","doi":"10.1016/j.apacoust.2024.110364","DOIUrl":"10.1016/j.apacoust.2024.110364","url":null,"abstract":"<div><div>The main focus and challenge of landslide research is always the formation mechanism of bedding rock landslide. Preventing and controlling large-scale landslide is difficult due to high monitoring costs and short warning times, posing a significant challenge for accurate forecasting. In recent years, infrasound monitoring has been widely applied in the field of geological hazards. However, the infrasound characteristics of rock landslide remain unclear, hindering the application and promotion of this technology. Therefore, this study aimed to analyze the infrasound characteristics of bedding rock landslide through a physical model test. Through wavelet decomposition analysis of the experimental infrasound data, the study summarized the infrasound characteristics and energy distribution of rock landslide failure at various stages, as well as analyzed the correlation between the slide process and infrasound signals. The results showed that: (1) Infrasound signals are present in uniform deformation, accelerated deformation, slow sliding and rapid sliding stages of the bedding rock landslide, but the energy distribution is different for each stage, with the most apparent infrasound events occurring during accelerated deformation and rapid sliding stages. (2) During the deformation stage of the rock landslide, the infrasound waveform exhibits sharper features than during the sliding stage, with waveforms during the uniform deformation and slow sliding stages sloping to the right, and waveforms during the accelerated deformation and rapid sliding stages sloping to the left. (3) The infrasound frequencies in each stage are distributed between 0.01 and 20.0 Hz, among which the dominant frequencies in the uniform deformation stage and the slow sliding stage are mainly distributed between 0.01 and 10.0 Hz, and the dominant frequencies in the accelerated deformation stage and the rapid sliding stage are mainly distributed between 10.0 and 20.0 Hz. The findings of this study offer valuable insights for the development and application of rock landslide infrasound monitoring and early warning technology.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142539688","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":"On the accuracy of finite-difference time-domain simulations of head-related transfer functions as a function of model complexity","authors":"Julie Meyer ,&nbsp;Sebastian Prepeliţă ,&nbsp;Lorenzo Picinali","doi":"10.1016/j.apacoust.2024.110353","DOIUrl":"10.1016/j.apacoust.2024.110353","url":null,"abstract":"<div><div>Wave-based numerical tools such as finite-difference time-domain (FDTD) solvers are useful for modeling several acoustic properties and interactions. While these numerical tools are widely used in acoustics, there seems to be less attention to assessing the quality of the produced outputs. However, in order to ensure that the obtained results are reliable, the quantification of the errors present in the simulation results is an essential step. There exists a mathematical process known as solution verification which aims at assessing the accuracy of the computed solutions. A relevant application for the FDTD method is the simulation of head-related transfer functions (HRTFs), since these are relatively complex to acoustically measure on humans. This paper aims at applying the solution verification process on HRTF modeling using the FDTD method to evaluate the accuracy of the simulated HRTF magnitudes with increased human head/torso model complexity. The FDTD-simulated HRTFs are also compared with respect to the similarity/dissimilarity of their spectrum and with respect to the relevance of these spectral variations on sound source localization. The results show that asymptotically extrapolating the FDTD-simulated HRTFs from a series of simulations provides more accurate HRTF predictions when compared to using single FDTD simulations ran on sub-millimeter grids, regardless of the model complexity. Results also demonstrate that the accuracy of the FDTD-simulated HRTF predictions decreases with increased model complexity. The localization performance predictions showed that the largest localization errors were obtained with models with the lowest complexities. Significant differences in predicted sound source localization performance were found between FDTD-simulated results.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultrasonic dry-coupling detection with gradient acoustic impedance match layer","authors":"Donglin Tang ,&nbsp;Sheng Rao ,&nbsp;Chao Ding ,&nbsp;Chao Qin","doi":"10.1016/j.apacoust.2024.110355","DOIUrl":"10.1016/j.apacoust.2024.110355","url":null,"abstract":"<div><div>Ultrasonic dry coupling technology eliminates the need for traditional liquid coupling agents and is critical for detecting advanced materials or coatings that cannot be contaminated by liquid coupling agents. In the conventional dry-coupling technique, sound waves propagate within a multilayer medium of water, dry-coupling material (rubber), and the material being examined (steel). The serious impedance mismatch between multilayer media results in very low ultrasonic transmission efficiency, and the maximum transmission coefficient of sound intensity is only 0.12. To improve the acoustic transmission performance, this paper proposes a dry coupling layer with gradient variation of acoustic impedance, whose impedance varies with an exponential law in the thickness direction. In the first stage, the propagation laws of acoustic waves in multilayer media with varying acoustic impedance gradients were investigated. Boundary impedance mismatch conditions were introduced, and the effects of different acoustic impedance mismatches on the acoustic properties of dry coupling layers were investigated based on acoustic transmission theory analysis. In the second stage, based on the optimized parameters after numerical analysis, the gradient composites were fabricated by centrifugal method, and dry-coupling detection experiments were carried out. Experimental results confirmed that the dry coupling layer with an exponential change in acoustic impedance improved the sound propagation efficiency by 80 % and the −6dB bandwidth of the pulse-echo signal by 20 % compared to rubber.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535984","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":"Unsupervised selection of acoustic indices: An experimental comparison for characterizing unlabeled audio recordings from sub-Andean forest soundscapes","authors":"Ana Lorena Uribe-Hurtado ,&nbsp;Fernando Martínez-Tabares ,&nbsp;Mauricio Orozco-Alzate","doi":"10.1016/j.apacoust.2024.110363","DOIUrl":"10.1016/j.apacoust.2024.110363","url":null,"abstract":"<div><div>We present an experimental comparison of applying six unsupervised (i.e. not relying on class labels) and almost parameterless feature selection methods for ranking acoustic indices. The study is aimed at guiding the practitioner in choosing appropriate acoustic indices when, in absence of class labels, a small but meaningful number of features to characterize soundscapes is desired. Forty acoustic indices were considered, which correspond to seventeen temporal, spectral and soundscape features, along with their basic statistics. Three publicly available soundscape datasets, registered in a sub-Andean forest, were used for the experiments; moreover, several subsets were considered according to the different times of the day. Results reveal that the Acoustic Evenness Index is the most important one in terms of representational power according to the six considered selection criteria, followed by the Acoustic Complexity Index when conditions are relaxed to examine features ranked among the top-five. Besides, the Bioacoustic Index, the Acoustic Diversity Index and the Root Mean Square Energy stand out as important features when characterizing days in their separated parts.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142536043","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":"Ultra-thin low-frequency broadband absorber based on layered coiled channel structure","authors":"Wenli Sun ,&nbsp;Yonghua Wang ,&nbsp;Haidong Yuan ,&nbsp;Wenbo Guo ,&nbsp;Yan Wang ,&nbsp;Jingze Xue ,&nbsp;Huadong Yu","doi":"10.1016/j.apacoust.2024.110358","DOIUrl":"10.1016/j.apacoust.2024.110358","url":null,"abstract":"<div><div>To improve and broaden the performance in absorbing sound waves of metamaterials at the lower and mid-frequency ranges, a layered coiled channel composite structure (LCCS) with deep subwavelengths is proposed in this paper, which extends the acoustic wave propagation paths longitudinally by connecting the Helmholtz resonator channels in each layer and achieves the multistep resonance of the coupling cavities, which results in the cancellation of acoustic energies, reduces the acoustic reflections and scattering, and enhances the absorption performance. A model to simulate theoretical sound absorption and finite elements simulation of the metamaterial were evolved to reveal its potential mechanism<!--> <!-->for absorbing sound. Using the single-variable method to study the impact of altering structural parameters on the effectiveness of sound absorption, it shows good tunability in the target frequency range and obtains four fundamental unit LCCSs having distinct frequency absorption peaks, and designs a multi-unit coupling construction having low frequencies wideband sound absorption performance by connecting them in parallel to realize a large-broadband continuous and high-efficiency sound absorption within the scope of 370–1400 Hz, using a mean peak sound absorption value higher than 0.7. The structure was put together by 3D printing, and the impedance tube method test verified the precision of the simulation’s findings. This study offers a practical means to create lightweight, low-frequency broadband acoustic absorbing metamaterials.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142536042","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":"Characterization of noise sources in two- and three-element high-lift airfoil configurations","authors":"Marinus K. Okoronkwo ,&nbsp;Dominic G. Geneau ,&nbsp;Jessica M. Eburn ,&nbsp;Hadar Ben-Gida ,&nbsp;Oksana Stalnov ,&nbsp;Stéphane Moreau ,&nbsp;Philippe Lavoie","doi":"10.1016/j.apacoust.2024.110354","DOIUrl":"10.1016/j.apacoust.2024.110354","url":null,"abstract":"<div><div>To improve the current understanding of flap noise generation mechanisms in high-lift devices used by small- to large-size commercial aircraft, a detailed study of both two- and three-element configurations of the canonical high-lift 30P30N airfoil has been conducted. Results from unsteady Reynolds-Averaged Navier-Stokes simulations are compared with aerodynamic and acoustic measurements in the hybrid anechoic wind tunnel at the University of Toronto to gain better physical insights into the flow phenomena associated with the noise sources in multi-element configurations. It is shown that the slat element has little impact on the flow in and around the flap and flap gap when the main wing is at the same orientation relative to the incoming flow. Tonal peaks are found both in the flap cove and on the flap, matching the tonal noise produced by the slat when in the three-element configuration. These peaks are present at the flap due to pressure waves that emanate from the slat and propagate downstream. Analysis of the frequency wavenumber spectra of the unsteady pressure along the main element pressure surface shows the existence of forward- and backward-traveling acoustic waves, providing evidence of a feedback loop between the two coves, which amplifies the narrowband tonal peaks in both coves. These tones disappear from the flap when the slat is removed in a two-element configuration, with the flap-cove overall broadband pressure fluctuation levels remaining unchanged.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142536041","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":"A fault diagnosis method for bogie axle box bearing based on sound-vibration multiple signal fusion","authors":"Zejun Zheng,&nbsp;Dongli Song,&nbsp;Weihua Zhang,&nbsp;Chen Jia","doi":"10.1016/j.apacoust.2024.110336","DOIUrl":"10.1016/j.apacoust.2024.110336","url":null,"abstract":"<div><div>The fault diagnosis method of multi-signal fusion is one of the current research trends, which can improve the reliability of diagnosis results. In this paper, the single channel signal is decomposed by multi-channel bandpass filter bank, and a new indicator value is constructed to select the optimal component. A new fusion demodulation method is constructed by using the two signal demodulation methods to extract the characteristic frequency of the single channel signal. Subsequently, the characteristic spectrum of the multi-channel signals is fused to extract the final characteristic frequency. The diagnosis method is verified by the simulation signal and the sound signal and vibration signal collected by the experiment. The results show that the proposed method can reduce the content of noise components in the characteristic spectrum, highlight the fault characteristic frequency, and reflect the superiority of the proposed method compared with other methods. This paper provides guidance for feature extraction of data fusion methods in the future, and provides an effective method for fault diagnosis and condition monitoring of bearings.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142536039","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":"Locating and reconstructing transformer low-frequency noises with a 3D, six-microphone array","authors":"Yazhong Lu ,&nbsp;Sean F. Wu ,&nbsp;Chuanbin Nie ,&nbsp;Wen He","doi":"10.1016/j.apacoust.2024.110351","DOIUrl":"10.1016/j.apacoust.2024.110351","url":null,"abstract":"<div><div>This paper presents diagnosis and analyses of the sound fields radiated from power transformers in 3D space under normal operational conditions. Transformers are crucial components in the power system. Good condition of a transformer is an important factor to ensure safe and reliable operations of the entire power system. Diagnosis and analyses of transformer noise are challenging because of the complexity of the acoustic environment surrounding the power grid. Previous studies have revealed that transformer noise is predominantly concentrated in the low frequency range. This low-frequency nature of transformer noise has made it extremely difficult to pinpoint the precise source locations. The present study shows that by using the Sound Viewer system, which is built on the principles of passive SODAR (Sonic Detection And Ranging) and HELS (Helmholtz Equation Least Squares) methods, we can not only pinpoint the precise locations of noise sources of a transformer, but quantify individual source strengths. Specifically, SODAR enables one to locate multiple sound sources simultaneously in 3D space over the frequency range of 20–20,000 Hz, and the HELS method enables one to reconstruct the acoustic field and acquire the optimal approximation of the acoustic pressure distribution in 3D space, time-averaged acoustic intensities, and time-averaged acoustic powers of the individual acoustic sources. The accuracy in reconstruction depends on the SNR (Signal to Noise Ratio) of the input data. The higher the SNR is, the more accurate the reconstruction becomes. Moreover, by using a spatial filter, we can eliminate the interferences of unwanted sound sources and extract the time-averaged acoustic power of a specific target. This salient feature enables us to perform a source ranking, which can be critical in designing the most cost-effective noise mitigation strategy. Results of the present study demonstrate that this technology can play a significant role in diagnosing and analyzing complex acoustic field in a non-ideal test environment, especially for transformer health monitoring and predictive maintenance in power systems.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142536038","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":"Smooth topological design of lightweight vibro-acoustic sandwich structures by maximizing sound transmission loss","authors":"Jiao Xu ,&nbsp;Jie Hu ,&nbsp;Jiachun Li ,&nbsp;Yugang Li ,&nbsp;Ning Gan ,&nbsp;Meng Tao ,&nbsp;Wenkang Cao","doi":"10.1016/j.apacoust.2024.110347","DOIUrl":"10.1016/j.apacoust.2024.110347","url":null,"abstract":"<div><div>The vibro-acoustic coupling mechanism and its optimization design of lightweight sandwich structures are globally hot research topics. The traditional parameter adjustment approach highly relies on the experience of designers, which makes it difficult to achieve lightweight design while regulating the acoustic insulation performance of sandwich structures at a limited cost. This paper proposes a new dynamic three-field floating projection topology optimization (FPTO) method to conduct vibro-acoustic coupling topological design for lightweight insulated sandwich structures, to achieve superior sound insulation performance by maximizing sound transmission loss with a volume constraint. The effectiveness and accuracy of the proposed method were verified on representative 2D and 3D numerical examples and also validated with impedance tube tests. The results show that novel optimized structures with a smooth boundary for practical applications and superior acoustic insulation performance than conventional designs can be obtained based on the proposed method. For instance, at an optimization target frequency of 1200 Hz, the total sound transmission loss, corresponding to the optimized target sound insulation performance of the 3D sandwich case, showed an improvement from 56.68 dB to 70.8 dB, compared to the common closed honeycomb structures in engineering practice under the equal mass conditions. Moreover, the numerical simulation and experimental results showed good agreement. The study suggests that the dynamic three-field FPTO method is promising for optimizing acoustic and vibration performance in lightweight vibro-acoustic sandwich structures.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142536040","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":"Empirical variational mode extraction and its application in bearing fault diagnosis","authors":"Bin Pang ,&nbsp;Yanjie Zhao ,&nbsp;Changqi Yu ,&nbsp;Ziyang Hao ,&nbsp;Zhenduo Sun ,&nbsp;Zhenli Xu ,&nbsp;Pu Li","doi":"10.1016/j.apacoust.2024.110349","DOIUrl":"10.1016/j.apacoust.2024.110349","url":null,"abstract":"<div><div>Bearing fault signals typically contain rich interference components such as random pulses, harmonics, and environmental noise, posing significant challenges for bearing fault feature identification. Derived from variational mode decomposition (VMD), variational mode extraction (VME) stands out due to its specialized narrowband filtering capabilities, enabling effective extraction of targeted components from complex signals. However, VME’s capability notably depends on two key parameters: the penalty factor, which controls the bandwidth of extracted mode, and the central frequency, determining the frequency band’s center for extraction. An empirical variational mode extraction (EVME) method, inspired by the structure of empirical wavelet transform (EWT), is introduced to guide optimal filtering and demodulation analysis of fault components. Firstly, the effects of central frequency and penalty factor on the filtering characteristics of VME are thoroughly investigated and the mathematical relationship between bandwidth and penalty parameter is established through mathematical simulations. Secondly, a spectrum background scale-space division (SBSSD) method which incorporates adaptive clutter separation (ACS) and scale-space division is proposed to implement an optimal spectrum division, guiding the parameter determination of VME. Finally, each component is recursively extracted by VME from low to high frequencies following the segmentation outcomes of frequency bands. Simulated and experimental validations confirm the capability of EVME for extracting bearing fault features. Furthermore, comparisons with VMD and EWT underscore its superiority.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142536036","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}