Audrey Couineaux, Frédéric Ablitzer, François Gautier
The cristal Baschet is a musical instrument created during the 1950’s by Bernard and Francois Baschet. It is composed of a large number of glass rods arranged in a chromatic scale. The sound produced results of vibrations induced by friction between wet fingers and the glass rods. Each glass rod is connected to an assembly of threaded shafts and a mass. Mechanical properties of this assembly determine the pitch of the note. Then vibrations are transmitted to large metal panels or cones that act as radiating elements. The manufacturing and tuning of this instrument is based on empirical knowledge and involves many parameters whose effects are not clearly understood. One of the encountered problems is the difficulty to produce sound in the high register of the instrument. In an attempt to understand the influences of these parameters on playability, a minimal physical model of the cristal Baschet is developed. It focuses on the interaction between the finger and the isolated resonator. The dynamic behavior is described by a set of modes obtained from a finite element model or from experimental modal analysis. The musician’s gesture is described by two control parameters: the velocity of the finger along the glass rod and the normal force applied by the finger on the rod. To describe the interaction between the finger and the resonator, a friction law is implemented. The influence of different parameters is studied by means of linear stability analysis and time-domain simulations. Specific criteria are developed to highlight the role of design parameters on playability.
{"title":"Minimal physical model of the cristal Baschet","authors":"Audrey Couineaux, Frédéric Ablitzer, François Gautier","doi":"10.1051/aacus/2023041","DOIUrl":"https://doi.org/10.1051/aacus/2023041","url":null,"abstract":"The cristal Baschet is a musical instrument created during the 1950’s by Bernard and Francois Baschet. It is composed of a large number of glass rods arranged in a chromatic scale. The sound produced results of vibrations induced by friction between wet fingers and the glass rods. Each glass rod is connected to an assembly of threaded shafts and a mass. Mechanical properties of this assembly determine the pitch of the note. Then vibrations are transmitted to large metal panels or cones that act as radiating elements. The manufacturing and tuning of this instrument is based on empirical knowledge and involves many parameters whose effects are not clearly understood. One of the encountered problems is the difficulty to produce sound in the high register of the instrument. In an attempt to understand the influences of these parameters on playability, a minimal physical model of the cristal Baschet is developed. It focuses on the interaction between the finger and the isolated resonator. The dynamic behavior is described by a set of modes obtained from a finite element model or from experimental modal analysis. The musician’s gesture is described by two control parameters: the velocity of the finger along the glass rod and the normal force applied by the finger on the rod. To describe the interaction between the finger and the resonator, a friction law is implemented. The influence of different parameters is studied by means of linear stability analysis and time-domain simulations. Specific criteria are developed to highlight the role of design parameters on playability.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"123 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135010237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Florian Kraxberger, Eric Kurz, Werner Weselak, Gernot Kubin, Manfred Kaltenbacher, Stefan Schoder
Porous acoustic absorbers have excellent properties in the low-frequency range when positioned in room edges, therefore they are a common method for reducing low-frequency reverberation. However, standard room acoustic simulation methods such as ray tracing and mirror sources are invalid for low frequencies in general which is a consequence of using geometrical methods, yielding a lack of simulation tools for these so-called edge absorbers. In this article, a validated finite element simulation model is presented, which is able to predict the effect of an edge absorber on the acoustic field. With this model, the interaction mechanisms between room and absorber can be studied by high-resolved acoustic field visualizations in both room and absorber. The finite element model is validated against transfer function data computed from impulse response measurements in a reverberation chamber in style of ISO 354. The absorber made of Basotect ® is modeled using the Johnson-Champoux-Allard-Lafarge model, which is fitted to impedance tube measurements using the four-microphone transfer matrix method. It is shown that the finite element simulation model is able to predict the influence of different edge absorber configurations on the measured transfer functions to a high degree of accuracy. The evaluated third-octave band error exhibits deviations of 3.3–4.1 dB computed from third-octave band averaged spectra.
{"title":"A validated finite element model for room acoustic treatments with edge absorbers","authors":"Florian Kraxberger, Eric Kurz, Werner Weselak, Gernot Kubin, Manfred Kaltenbacher, Stefan Schoder","doi":"10.1051/aacus/2023044","DOIUrl":"https://doi.org/10.1051/aacus/2023044","url":null,"abstract":"Porous acoustic absorbers have excellent properties in the low-frequency range when positioned in room edges, therefore they are a common method for reducing low-frequency reverberation. However, standard room acoustic simulation methods such as ray tracing and mirror sources are invalid for low frequencies in general which is a consequence of using geometrical methods, yielding a lack of simulation tools for these so-called edge absorbers. In this article, a validated finite element simulation model is presented, which is able to predict the effect of an edge absorber on the acoustic field. With this model, the interaction mechanisms between room and absorber can be studied by high-resolved acoustic field visualizations in both room and absorber. The finite element model is validated against transfer function data computed from impulse response measurements in a reverberation chamber in style of ISO 354. The absorber made of Basotect ® is modeled using the Johnson-Champoux-Allard-Lafarge model, which is fitted to impedance tube measurements using the four-microphone transfer matrix method. It is shown that the finite element simulation model is able to predict the influence of different edge absorber configurations on the measured transfer functions to a high degree of accuracy. The evaluated third-octave band error exhibits deviations of 3.3–4.1 dB computed from third-octave band averaged spectra.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135010271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
An optimization method is proposed to find mask parameters of a brass player coming from a one degree of freedom lip model, with only constant mouth pressure and periodic mouthpiece pressure as input data, and a cost function relying on the waveform and the frequency of the signal. It delivers a set of parameters called 𝒞-admissible, which is a subset of all mask parameters that allow the inverse problem to be well defined up to an acceptable precision. Values for the mask parameters are found that give a good aproximation of real signals, with an error on the playing frequency of less than 5 cents for some notes. The evolution of the mask parameters is assessed during recordings with real musicians playing bend notes and their effects on the playing frequency are compared to the theoretical change on a model.
{"title":"Brass player’s mask parameters obtained by inverse method","authors":"S. Maugeais, J. Gilbert","doi":"10.1051/aacus/2023022","DOIUrl":"https://doi.org/10.1051/aacus/2023022","url":null,"abstract":"An optimization method is proposed to find mask parameters of a brass player coming from a one degree of freedom lip model, with only constant mouth pressure and periodic mouthpiece pressure as input data, and a cost function relying on the waveform and the frequency of the signal. It delivers a set of parameters called 𝒞-admissible, which is a subset of all mask parameters that allow the inverse problem to be well defined up to an acceptable precision. Values for the mask parameters are found that give a good aproximation of real signals, with an error on the playing frequency of less than 5 cents for some notes. The evolution of the mask parameters is assessed during recordings with real musicians playing bend notes and their effects on the playing frequency are compared to the theoretical change on a model.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"25 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80107840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
F. Margnat, Wagner J. Gonçalves da Silva Pinto, C. Noûs
New data and review of the spanwise coherence length is provided for flows over cylinders of different cross-sections: circular of diameter d, and rectangular of sectional aspect ratios (breadth (b) to height (d) ratio AR = b/d) of 1, 2 and 3. In the present measurements, the body has both d and spanwise length of 70d fixed, and the Reynolds number (based on d) range 6000–27,000 is covered. Two-point data are obtained from two hot-wire probes, one fixed in the symmetry plane and the other moving on the corresponding spanwise axis. Their position in a cross plane are deduced from preliminary measurement of the mean flow with a single probe, allowing fair comparisons between the different geometries and the introduction of uncertainty bars on coherence length values. At all tested regimes, a very good agreement is noticed between velocity-based and pressure-based coherence experimental data. Coherence length definitions are revisited, and the aeroacoustically consistent, integral length definition is selected, allowing fair synthesis of literature data into a single chart and empirical functions. Definitions for coherence decay models (e.g. Gaussian or Laplacian) are also adapted so that coherence length and coherence integral shall be equivalent. This preliminary work on coherence data and its spanwise integration enables transparent regressions and model selection. Generally, the Gaussian model is relevant for the lift peak, while the coherence exhibits a Laplacian decay at harmonics. On average, at peak Strouhal number, the coherence length for the circular and square cylinders is of 5d while it is of the order of 15d for the rectangular sections. It is concluded that the flow over those latter geometries is still a two-dimensional dynamics at the tone frequency. These values are almost preserved over the tested Reynolds number range. Coherence length value at harmonics is extensively documented. Spanwise coherence length is also discussed as an ingredient of acoustic efficiency.
{"title":"Cylinder aeroacoustics: experimental study of the influence of cross-section shape on spanwise coherence length","authors":"F. Margnat, Wagner J. Gonçalves da Silva Pinto, C. Noûs","doi":"10.1051/aacus/2022061","DOIUrl":"https://doi.org/10.1051/aacus/2022061","url":null,"abstract":"New data and review of the spanwise coherence length is provided for flows over cylinders of different cross-sections: circular of diameter d, and rectangular of sectional aspect ratios (breadth (b) to height (d) ratio AR = b/d) of 1, 2 and 3. In the present measurements, the body has both d and spanwise length of 70d fixed, and the Reynolds number (based on d) range 6000–27,000 is covered. Two-point data are obtained from two hot-wire probes, one fixed in the symmetry plane and the other moving on the corresponding spanwise axis. Their position in a cross plane are deduced from preliminary measurement of the mean flow with a single probe, allowing fair comparisons between the different geometries and the introduction of uncertainty bars on coherence length values. At all tested regimes, a very good agreement is noticed between velocity-based and pressure-based coherence experimental data. Coherence length definitions are revisited, and the aeroacoustically consistent, integral length definition is selected, allowing fair synthesis of literature data into a single chart and empirical functions. Definitions for coherence decay models (e.g. Gaussian or Laplacian) are also adapted so that coherence length and coherence integral shall be equivalent. This preliminary work on coherence data and its spanwise integration enables transparent regressions and model selection. Generally, the Gaussian model is relevant for the lift peak, while the coherence exhibits a Laplacian decay at harmonics. On average, at peak Strouhal number, the coherence length for the circular and square cylinders is of 5d while it is of the order of 15d for the rectangular sections. It is concluded that the flow over those latter geometries is still a two-dimensional dynamics at the tone frequency. These values are almost preserved over the tested Reynolds number range. Coherence length value at harmonics is extensively documented. Spanwise coherence length is also discussed as an ingredient of acoustic efficiency.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"314 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74949353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
M. Kaltenbacher, J. Kergomard, M. Gaborit, Thierry Scotti, A. Ruimy
{"title":"Acta Acustica: State of art and achievements after 3 years","authors":"M. Kaltenbacher, J. Kergomard, M. Gaborit, Thierry Scotti, A. Ruimy","doi":"10.1051/aacus/2023003","DOIUrl":"https://doi.org/10.1051/aacus/2023003","url":null,"abstract":"","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"11 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72826291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Hongmei Hu, S. Ausili, B. Williges, Jonas Klug, Rebecca C. Felsheim, D. Vickers, Mathias Dietz
Bilateral cochlear implants (CIs) greatly improve spatial hearing acuity for CI users, but substantial gaps still exist compared to normal-hearing listeners. For example, CI users have poorer localization skills, little or no binaural unmasking, and reduced spatial release from masking. Multiple factors have been identified that limit binaural hearing with CIs. These include degradation of cues due to the various sound processing stages, the viability of the electrode-neuron interface, impaired brainstem neurons, and deterioration in connectivity between different cortical layers. To help quantify the relative importance and inter-relationship between these factors, computer models can and arguably should be employed. While models exploring single stages are often in good agreement with selected experimental data, their combination often does not yield a comprehensive and accurate simulation of perception. Here, we combine information from CI sound processing with computational auditory model stages in a modular and open-source framework, resembling an artificial bilateral CI user. The main stages are (a) binaural signal generation with optional head-related impulse response filtering, (b) generic CI sound processing not restricted to a specific manufacturer, (c) electrode-to-neuron transmission, (d) binaural interaction, and (e) a decision model. The function and the outputs of different model stages are demonstrated with examples of localization experiments. However, the model framework is not tailored to a specific dataset. It offers a selection of sound coding strategies and allows for third-party model extensions or substitutions; thus, it is possible to employ the model for a wide range of binaural applications and even for educational purposes.
{"title":"A model framework for simulating spatial hearing of bilateral cochlear implant users","authors":"Hongmei Hu, S. Ausili, B. Williges, Jonas Klug, Rebecca C. Felsheim, D. Vickers, Mathias Dietz","doi":"10.1051/aacus/2023036","DOIUrl":"https://doi.org/10.1051/aacus/2023036","url":null,"abstract":"Bilateral cochlear implants (CIs) greatly improve spatial hearing acuity for CI users, but substantial gaps still exist compared to normal-hearing listeners. For example, CI users have poorer localization skills, little or no binaural unmasking, and reduced spatial release from masking. Multiple factors have been identified that limit binaural hearing with CIs. These include degradation of cues due to the various sound processing stages, the viability of the electrode-neuron interface, impaired brainstem neurons, and deterioration in connectivity between different cortical layers. To help quantify the relative importance and inter-relationship between these factors, computer models can and arguably should be employed. While models exploring single stages are often in good agreement with selected experimental data, their combination often does not yield a comprehensive and accurate simulation of perception. Here, we combine information from CI sound processing with computational auditory model stages in a modular and open-source framework, resembling an artificial bilateral CI user. The main stages are (a) binaural signal generation with optional head-related impulse response filtering, (b) generic CI sound processing not restricted to a specific manufacturer, (c) electrode-to-neuron transmission, (d) binaural interaction, and (e) a decision model. The function and the outputs of different model stages are demonstrated with examples of localization experiments. However, the model framework is not tailored to a specific dataset. It offers a selection of sound coding strategies and allows for third-party model extensions or substitutions; thus, it is possible to employ the model for a wide range of binaural applications and even for educational purposes.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"37 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88034237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
This study presents a method of adding to clean speech signals a controlled degree of “musical” noise distortions that mimic typical artefacts of speech enhancement systems. The resulting distorted speech signals were evaluated with respect to listening effort and sound quality in subjective listening tests and via model predictions. Both subjective ratings and model prediction outcomes covered the entire rating scale from “excellent”/ “no effort” to “bad”/ “extreme effort”, respectively, in a consistent way. The proposed method proved to be useful for systematic assessments of “musical” noise distortions for the conditions tested in this study.
{"title":"Method to control the amount of “musical” noise for speech quality assessments","authors":"J. Gößwein, B. Kollmeier, J. Rennies","doi":"10.1051/aacus/2023016","DOIUrl":"https://doi.org/10.1051/aacus/2023016","url":null,"abstract":"This study presents a method of adding to clean speech signals a controlled degree of “musical” noise distortions that mimic typical artefacts of speech enhancement systems. The resulting distorted speech signals were evaluated with respect to listening effort and sound quality in subjective listening tests and via model predictions. Both subjective ratings and model prediction outcomes covered the entire rating scale from “excellent”/ “no effort” to “bad”/ “extreme effort”, respectively, in a consistent way. The proposed method proved to be useful for systematic assessments of “musical” noise distortions for the conditions tested in this study.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"44 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74554154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
The comparison of head-related transfer functions (HRTFs), e.g., for validating different acquisition methods, requires a meaningful way of quantifying HRTF differences – a problem to which literature offers no standardized approach. This impedes the comparability and interpretability of studies. The present work therefore addresses the lack of proper understanding of the behavior of commonly used distance metrics by applying seven metrics to individually measured and approximated HRTF datasets. Covering a variety of spectral deviations, we perform both intra-individual comparisons (contrasting different levels of spectral detail for the same individual) and inter-individual comparisons (assessing metric reactions to non-individual cue differences). The metrics exhibit selective reactions to distinct spectral alterations. Particularly, the results demonstrate that spectrally localized errors go undetected by five out of seven metrics. Further analysis emphasizes inconsistencies in metric correlation patterns. These observations highlight the need for a multi-dimensional metric, capturing various types of HRTF differences for a proper assessment of errors.
{"title":"Examining the interrelation behavior of distance metrics for head-related transfer function evaluation: a case study","authors":"S. Doma, N. Brožová, J. Fels","doi":"10.1051/aacus/2023028","DOIUrl":"https://doi.org/10.1051/aacus/2023028","url":null,"abstract":"The comparison of head-related transfer functions (HRTFs), e.g., for validating different acquisition methods, requires a meaningful way of quantifying HRTF differences – a problem to which literature offers no standardized approach. This impedes the comparability and interpretability of studies. The present work therefore addresses the lack of proper understanding of the behavior of commonly used distance metrics by applying seven metrics to individually measured and approximated HRTF datasets. Covering a variety of spectral deviations, we perform both intra-individual comparisons (contrasting different levels of spectral detail for the same individual) and inter-individual comparisons (assessing metric reactions to non-individual cue differences). The metrics exhibit selective reactions to distinct spectral alterations. Particularly, the results demonstrate that spectrally localized errors go undetected by five out of seven metrics. Further analysis emphasizes inconsistencies in metric correlation patterns. These observations highlight the need for a multi-dimensional metric, capturing various types of HRTF differences for a proper assessment of errors.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"21 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90694718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Previous studies have discussed six pre-Sabine quantifiable guidelines employed in room acoustic design: voice directivity, audience rake, “echo theory”, stage acoustics, reverberation, and length, width, and height ratios. Around the turn of the 18th century, these notions led to two shapes that were theoretically regarded optimal for rooms with acoustical demands: ellipse and semi-circle. The first of these shapes to be tested was the ellipse in the design for the Iffland Theatre (1802–1817). As the resulting acoustics were notoriously poor, contemporary architects and acousticians discussed the grounds for the failed acoustics as well as possible corrections. Multiple subsequent halls were also based on lessons learned from this acoustic failure. As part of this archaeoacoustics research, geometric acoustic numerical simulations were employed to estimate the actual and renovated room acoustic conditions. Three configurations of the hall have been reconstructed. Results show that the hall’s shape led to sound focusing and that the rounded proscenium arch likely induced echoes. Proposed solutions of the time to increase the scattering or absorption appear unlikely to have solved the observed acoustic problems.
{"title":"An archaeoacoustic study on shape: the case study of the Iffland Theatre’s history (1802–1817)","authors":"Barteld N.J. Postma, Brian F.G. Katz","doi":"10.1051/aacus/2023046","DOIUrl":"https://doi.org/10.1051/aacus/2023046","url":null,"abstract":"Previous studies have discussed six pre-Sabine quantifiable guidelines employed in room acoustic design: voice directivity, audience rake, “echo theory”, stage acoustics, reverberation, and length, width, and height ratios. Around the turn of the 18th century, these notions led to two shapes that were theoretically regarded optimal for rooms with acoustical demands: ellipse and semi-circle. The first of these shapes to be tested was the ellipse in the design for the Iffland Theatre (1802–1817). As the resulting acoustics were notoriously poor, contemporary architects and acousticians discussed the grounds for the failed acoustics as well as possible corrections. Multiple subsequent halls were also based on lessons learned from this acoustic failure. As part of this archaeoacoustics research, geometric acoustic numerical simulations were employed to estimate the actual and renovated room acoustic conditions. Three configurations of the hall have been reconstructed. Results show that the hall’s shape led to sound focusing and that the rounded proscenium arch likely induced echoes. Proposed solutions of the time to increase the scattering or absorption appear unlikely to have solved the observed acoustic problems.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135448479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Introduction : For composite structures, delamination usually occurs at the interface. Ultrasonic guided waves have been widely used to detect the delamination. However, most researches focus on the measurement of the delamination length along the interface, and the measurement of the delamination thickness is less studied. Method : In this paper, based on the characteristic that the Stoneley wave only propagates along the interface, the reflection coefficient of interaction between Stoneley wave and delamination is used to measure the delamination thickness. The effects of delamination thickness and frequency on the reflection coefficient are investigated via dividing integral region and reciprocity theorem. Some experimental validations are carried out on two aluminum-steel bilayered composite plates with different delamination thickness. Results : It is found the reflection coefficient increases linearly at first, then its rate of increase slows down gradually, and finally becomes stable, in theory. And the experimental results can verify the theoretical relationship between the reflection coefficients and the delamination thickness. Conclusion : The variation of reflection coefficient provides a reference for the measurement of delamination thickness in Stoneley-wave-based non-destructive testing.
{"title":"Delamination thickness measurement based on Stoneley wave in bilayered composite structure","authors":"Tao Zhou, Ming-hang Li, Bing Li","doi":"10.1051/aacus/2023054","DOIUrl":"https://doi.org/10.1051/aacus/2023054","url":null,"abstract":"Introduction : For composite structures, delamination usually occurs at the interface. Ultrasonic guided waves have been widely used to detect the delamination. However, most researches focus on the measurement of the delamination length along the interface, and the measurement of the delamination thickness is less studied. Method : In this paper, based on the characteristic that the Stoneley wave only propagates along the interface, the reflection coefficient of interaction between Stoneley wave and delamination is used to measure the delamination thickness. The effects of delamination thickness and frequency on the reflection coefficient are investigated via dividing integral region and reciprocity theorem. Some experimental validations are carried out on two aluminum-steel bilayered composite plates with different delamination thickness. Results : It is found the reflection coefficient increases linearly at first, then its rate of increase slows down gradually, and finally becomes stable, in theory. And the experimental results can verify the theoretical relationship between the reflection coefficients and the delamination thickness. Conclusion : The variation of reflection coefficient provides a reference for the measurement of delamination thickness in Stoneley-wave-based non-destructive testing.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135610250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
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