This paper presents a Nonlinear Electromechanical Impedance Spectroscopy (NEMIS) methodology for the comprehensive monitoring of carbon fiber reinforced composite (CFRC) laminates. This method can obtain structural impedance spectra and capture nonlinear ultrasonic features for damage detection, combining the merits of the conventional EMIS and the nonlinear ultrasonic techniques. A comparative illustration between the conventional EMIS and NEMIS is presented. Various damage types and damage mechanisms of CFRC laminates are reviewed. Numerical investigation on a reduced-order 1-D Contact Acoustic Nonlinearity (CAN) model are conducted to demonstrate the chirp-induced nonlinear features. Furthermore. a finite element (FE) model is established to verify the feasibility of the NEMIS for damage detection. The macro-scale damage types are modeled by the changes of material properties, while the incipient damage like delamination is simulated by setting the contact interfacing condition between the laminate debonding areas. Correspondingly, the chirp-based impedance spectra are employed to detect the macro-scale damage via the deviation of resonance peaks, while the nonlinear features, such as higher harmonics and wave modulation are utilized to monitor the delamination. Two damage indices are developed to quantify the severity of both the macro and incipient damage. This paper finishes with conclusion and suggestions for future work.
{"title":"Nonlinear Electro-Mechanical Impedance Spectroscopy for Comprehensive Monitoring of Carbon Fiber Reinforced Composite Laminates","authors":"Runye Lu, Yanfeng Shen","doi":"10.1115/imece2022-94882","DOIUrl":"https://doi.org/10.1115/imece2022-94882","url":null,"abstract":"\u0000 This paper presents a Nonlinear Electromechanical Impedance Spectroscopy (NEMIS) methodology for the comprehensive monitoring of carbon fiber reinforced composite (CFRC) laminates. This method can obtain structural impedance spectra and capture nonlinear ultrasonic features for damage detection, combining the merits of the conventional EMIS and the nonlinear ultrasonic techniques. A comparative illustration between the conventional EMIS and NEMIS is presented. Various damage types and damage mechanisms of CFRC laminates are reviewed. Numerical investigation on a reduced-order 1-D Contact Acoustic Nonlinearity (CAN) model are conducted to demonstrate the chirp-induced nonlinear features. Furthermore. a finite element (FE) model is established to verify the feasibility of the NEMIS for damage detection. The macro-scale damage types are modeled by the changes of material properties, while the incipient damage like delamination is simulated by setting the contact interfacing condition between the laminate debonding areas. Correspondingly, the chirp-based impedance spectra are employed to detect the macro-scale damage via the deviation of resonance peaks, while the nonlinear features, such as higher harmonics and wave modulation are utilized to monitor the delamination. Two damage indices are developed to quantify the severity of both the macro and incipient damage. This paper finishes with conclusion and suggestions for future work.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"125 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74832994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Arjunan, R. Swindell, Arindam Ghosh, D. Karczub, Nick Horder, J. A. Mann
Reduction of the fatigue risk presented by acoustically induced vibration in flare header systems using mitigations that either reduce dynamic stress concentration effects or the level of vibration are of considerable interest to designers and plant operators. Assessments of the relative performance of different types of pipe fittings in reducing dynamic stress levels are presented based on the evaluation of data from full-scale laboratory tests of a pressure-relief system. A modal-analysis based finite-element methodology is also developed so that predictions may be extended to other piping arrangements that vary in thickness, size or connection type. The pipe fittings considered in the test are Pipet®, fabricated tee (Stub-on arrangement), sockolet (small-bore branch connections only), full-wrap reinforced fabricated Tee and Sweepolet®. For the finite-element method reducing tee connection is considered in addition. The test system produced significant levels of both turbulent-induced vibration (FIV) and acoustically induced vibration (AIV), which required differentiation of stress evaluations for the low-frequency FIV region and the mid-to-high frequency AIV region. The relative performance of mitigations (through selection of the type of pipe fitting) was found to be particularly relevant in the low-frequency FIV region. The reductions in dynamic stress and vibration of small-bore branch connections from installation of clamped bracing are also presented. The results show that the use of reducing Tees and full-wrap reinforcements for Stub-on connections for tailpipe and sub-header branch connections provide significant mitigation of dynamic stress and improvement of fatigue life over the use of Pipet® and Stub-on fittings. However, for the Sweepolet® connection which was expected to provide similar improvement the benefits are not fully realized in the 10S configuration.
{"title":"Acoustically Induced Vibration Mitigation","authors":"R. Arjunan, R. Swindell, Arindam Ghosh, D. Karczub, Nick Horder, J. A. Mann","doi":"10.1115/imece2022-93947","DOIUrl":"https://doi.org/10.1115/imece2022-93947","url":null,"abstract":"\u0000 Reduction of the fatigue risk presented by acoustically induced vibration in flare header systems using mitigations that either reduce dynamic stress concentration effects or the level of vibration are of considerable interest to designers and plant operators. Assessments of the relative performance of different types of pipe fittings in reducing dynamic stress levels are presented based on the evaluation of data from full-scale laboratory tests of a pressure-relief system. A modal-analysis based finite-element methodology is also developed so that predictions may be extended to other piping arrangements that vary in thickness, size or connection type. The pipe fittings considered in the test are Pipet®, fabricated tee (Stub-on arrangement), sockolet (small-bore branch connections only), full-wrap reinforced fabricated Tee and Sweepolet®. For the finite-element method reducing tee connection is considered in addition. The test system produced significant levels of both turbulent-induced vibration (FIV) and acoustically induced vibration (AIV), which required differentiation of stress evaluations for the low-frequency FIV region and the mid-to-high frequency AIV region. The relative performance of mitigations (through selection of the type of pipe fitting) was found to be particularly relevant in the low-frequency FIV region. The reductions in dynamic stress and vibration of small-bore branch connections from installation of clamped bracing are also presented. The results show that the use of reducing Tees and full-wrap reinforcements for Stub-on connections for tailpipe and sub-header branch connections provide significant mitigation of dynamic stress and improvement of fatigue life over the use of Pipet® and Stub-on fittings. However, for the Sweepolet® connection which was expected to provide similar improvement the benefits are not fully realized in the 10S configuration.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"69 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79314883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nashmin Yeganeh, I. Makarov, Snorri Steinn Stefánsson Thors, Hafliði Ásgeirsson, Á. Kristjánsson, R. Unnþórsson
This study presents a new design of a wearable vibrotactile device — a tactile sleeve consisting of three voice coil actuators (Model: Lofelt L5). The device was made within an R&D project aimed at developing a wearable for enhancing the music perception of cochlear implant recipients. The aim is to provide tactile stimulation in addition to the cochlear implant stimulation — generating an audio-tactile music experience. We also present the results of an experiment performed to investigate whether the sleeve can be used to identify songs from tactile stimulation and investigate the effects of different encodings. Five short music segments were used, and the tactile stimulation provided by each voice coil actuator conveyed song information (Bass or drum). Participants had intact hearing. At the beginning of the experiment, the participants listened to one song via headphones. Afterward, they were presented with various tactile encodings of the songs in random order. Their task was to identify the encoding of the song that was played. In this experiment, an investigation of the best combination of information from the bass versus drums was conducted. The results confirm that the sleeve can provide tactile stimulation that can be used to identify songs without audio. The results also provide insights into which encodings are most useful for conveying music.
{"title":"Vibrotactile Sleeve to Improve Music Enjoyment of Cochlear Implant Users","authors":"Nashmin Yeganeh, I. Makarov, Snorri Steinn Stefánsson Thors, Hafliði Ásgeirsson, Á. Kristjánsson, R. Unnþórsson","doi":"10.1115/imece2022-95591","DOIUrl":"https://doi.org/10.1115/imece2022-95591","url":null,"abstract":"\u0000 This study presents a new design of a wearable vibrotactile device — a tactile sleeve consisting of three voice coil actuators (Model: Lofelt L5). The device was made within an R&D project aimed at developing a wearable for enhancing the music perception of cochlear implant recipients. The aim is to provide tactile stimulation in addition to the cochlear implant stimulation — generating an audio-tactile music experience. We also present the results of an experiment performed to investigate whether the sleeve can be used to identify songs from tactile stimulation and investigate the effects of different encodings. Five short music segments were used, and the tactile stimulation provided by each voice coil actuator conveyed song information (Bass or drum). Participants had intact hearing. At the beginning of the experiment, the participants listened to one song via headphones. Afterward, they were presented with various tactile encodings of the songs in random order. Their task was to identify the encoding of the song that was played. In this experiment, an investigation of the best combination of information from the bass versus drums was conducted. The results confirm that the sleeve can provide tactile stimulation that can be used to identify songs without audio. The results also provide insights into which encodings are most useful for conveying music.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"68 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76763107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yongna Shen, G. Shen, Pengcheng Gan, Junjiao Zhang, Yilin Yuan
In order to clarify the detection range of acoustic emission technology for the tank bottom plate inspection, the attenuation characteristics of AE signal from lead-break on the tank bottom plate are investigated in this work. First the attenuation of AE signals from the lead-break on the upper surface of the tank bottom plate and that from the lead-break on the lower surface of the tank bottom plate are studied and compared when the tank is empty, which indicates that the upper surface corrosion of the tank bottom plate is much easier to detect than the lower surface corrosion. The weld perpendicular to the AE transport direction contributed much to the attenuation of the AE signals from tank floor. Then, the influence of liquid level on the attenuation and transport path of AE signals from tank bottom plate are investigated when water is added into the tank with a level of 10cm and 70cm, respectively. The liquid changes both the attenuation trend and the transport path of AE signals.
{"title":"Research on the Attenuation Characteristics of Acoustic Emission From Corrosion of Tank Bottom Plate","authors":"Yongna Shen, G. Shen, Pengcheng Gan, Junjiao Zhang, Yilin Yuan","doi":"10.1115/imece2022-96869","DOIUrl":"https://doi.org/10.1115/imece2022-96869","url":null,"abstract":"\u0000 In order to clarify the detection range of acoustic emission technology for the tank bottom plate inspection, the attenuation characteristics of AE signal from lead-break on the tank bottom plate are investigated in this work. First the attenuation of AE signals from the lead-break on the upper surface of the tank bottom plate and that from the lead-break on the lower surface of the tank bottom plate are studied and compared when the tank is empty, which indicates that the upper surface corrosion of the tank bottom plate is much easier to detect than the lower surface corrosion. The weld perpendicular to the AE transport direction contributed much to the attenuation of the AE signals from tank floor. Then, the influence of liquid level on the attenuation and transport path of AE signals from tank bottom plate are investigated when water is added into the tank with a level of 10cm and 70cm, respectively. The liquid changes both the attenuation trend and the transport path of AE signals.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78555706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fault detection techniques in metal additive manufacturing (AM) have explored a variety of monitoring methods to flag anomalies as they occur during the sintering process. Although many in-situ techniques are able to adeptly detect these abnormalities, several utilize machine learning black box methods that do not easily transfer to varying print geometries. An approach that is adaptable to a multitude of geometries holds an advantage in determining anomalies for more complex cross-sections and raster patterns. To address this lack of a geometry agnosticism, we propose a method that detects faults using the frequency content of the melt pool image response through an unsupervised approach. Scan line length and scan speed extracted from known geometry can be translated to associated frequencies via a spectrogram. We examine three specific geometries to determine detection performance on each by comparing the frequency content to the nominal response. A deviation from the expected performance will signify that an anomaly has occurred. We verify this approach is feasible for fault detection and is accurate in detecting anomalies that are hard to observe in the image time series. A feasible geometry agnostic method and the current interpretability will be discussed in this paper. The results reached in this paper strongly indicate that the approach is promising, has potential for improvement, and that a geometrically independent method is sensible. With further work, a generic algorithm applicable on any geometry will be achievable.
{"title":"Unsupervised Online Anomaly Detection of Metal Additive Manufacturing Processes via a Statistical Time-Frequency Domain Approach","authors":"Alvin Chen, F. Kopsaftopoulos, Sandipan Mishra","doi":"10.1115/imece2022-94486","DOIUrl":"https://doi.org/10.1115/imece2022-94486","url":null,"abstract":"\u0000 Fault detection techniques in metal additive manufacturing (AM) have explored a variety of monitoring methods to flag anomalies as they occur during the sintering process. Although many in-situ techniques are able to adeptly detect these abnormalities, several utilize machine learning black box methods that do not easily transfer to varying print geometries. An approach that is adaptable to a multitude of geometries holds an advantage in determining anomalies for more complex cross-sections and raster patterns. To address this lack of a geometry agnosticism, we propose a method that detects faults using the frequency content of the melt pool image response through an unsupervised approach. Scan line length and scan speed extracted from known geometry can be translated to associated frequencies via a spectrogram. We examine three specific geometries to determine detection performance on each by comparing the frequency content to the nominal response. A deviation from the expected performance will signify that an anomaly has occurred. We verify this approach is feasible for fault detection and is accurate in detecting anomalies that are hard to observe in the image time series. A feasible geometry agnostic method and the current interpretability will be discussed in this paper. The results reached in this paper strongly indicate that the approach is promising, has potential for improvement, and that a geometrically independent method is sensible. With further work, a generic algorithm applicable on any geometry will be achievable.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74797008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, an improved mathematical representation of a drill-string assembly is developed to provide an alternative assessment on vibration irregularities proliferating downhole due to bit-rock interference. Lateral vibrations receive particular attention due to their high frequency content which alter the dynamic response of the drill-string, instigate casing damage, and impede optimal penetration rates. The response of the drill-string is captured by synthesizing compatible stationary bit excitations, via an auto-regressive digital filter, and implementing Monte Carlo simulation, while the power spectral density function is approximated to elucidate the dynamic characteristics during drilling. Formulating adequate physical parameters for the equation of motion implies incorporating a finite element technique, where the flexibility of the drill-string and elastic characteristics of the well-bore are accounted for. In conjunction with the stochastic nature of the excitation, the mathematical representation accounts for rig structural parameters, drilling fluid circulating within annulus/casing extremities, and a nonlinearity exhibited through a contact force generated between the well-bore and drill-string segment. To address the nature of the nonlinearity, the method of statistical linearization is incorporated to establish an equivalent linear system.
{"title":"Development of an Improved Mathematical Representation Which Captures the Nonlinear Dynamic Behavior of a Drill-String Assembly","authors":"Eleazar Marquez","doi":"10.1115/imece2022-95551","DOIUrl":"https://doi.org/10.1115/imece2022-95551","url":null,"abstract":"\u0000 In this study, an improved mathematical representation of a drill-string assembly is developed to provide an alternative assessment on vibration irregularities proliferating downhole due to bit-rock interference. Lateral vibrations receive particular attention due to their high frequency content which alter the dynamic response of the drill-string, instigate casing damage, and impede optimal penetration rates. The response of the drill-string is captured by synthesizing compatible stationary bit excitations, via an auto-regressive digital filter, and implementing Monte Carlo simulation, while the power spectral density function is approximated to elucidate the dynamic characteristics during drilling. Formulating adequate physical parameters for the equation of motion implies incorporating a finite element technique, where the flexibility of the drill-string and elastic characteristics of the well-bore are accounted for. In conjunction with the stochastic nature of the excitation, the mathematical representation accounts for rig structural parameters, drilling fluid circulating within annulus/casing extremities, and a nonlinearity exhibited through a contact force generated between the well-bore and drill-string segment. To address the nature of the nonlinearity, the method of statistical linearization is incorporated to establish an equivalent linear system.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"82 5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88055793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Chukovenkova, Andrei N. Zagrai, H. Halliday, Joshua Toddy, Nylana J. Murphy
Additive manufacturing (AM) process has different parameters, their combination, and powder composition which could affect the mechanical properties of printed material. The layer by layer manufacturing approach influences microstructure of the material, and hence, the anisotropy of the mechanical properties. Also, defects such as porosity or cracks could be caused by non-optimized printing parameters. In order avoid wasting of sample while inferring mechanical properties of the printed material, it beneficial to utilize the nondestructive evaluation (NDE) methods. Implementation of NDE methods for additively manufactured parts plays a great role in evaluating and ensuring the reliability of the printed part. In this work, ultrasonic technique was utilized to determine the elastic properties and anisotropy of additively manufactured AlSi10Mg and conventionally fabricated Al 6061 samples. An ultrasonic measurement approach which allowed for the accurate measurement of the material properties was established and implemented. Longitudinal and shear transducers were used and the sound speed was calculated by analyzing the position of the arrived pulses in the pulse-echo configuration. Elastic properties were calculated from the longitudinal and shear sound speeds and measured density. Also, the correlation between elastic properties and sample’s location within the printed block, and spatial distribution of the elastic properties were explored.
{"title":"Ultrasonic Characterization of AlSi10Mg Specimens Printed By Direct Energy Deposition Technology","authors":"M. Chukovenkova, Andrei N. Zagrai, H. Halliday, Joshua Toddy, Nylana J. Murphy","doi":"10.1115/imece2022-96236","DOIUrl":"https://doi.org/10.1115/imece2022-96236","url":null,"abstract":"\u0000 Additive manufacturing (AM) process has different parameters, their combination, and powder composition which could affect the mechanical properties of printed material. The layer by layer manufacturing approach influences microstructure of the material, and hence, the anisotropy of the mechanical properties. Also, defects such as porosity or cracks could be caused by non-optimized printing parameters.\u0000 In order avoid wasting of sample while inferring mechanical properties of the printed material, it beneficial to utilize the nondestructive evaluation (NDE) methods. Implementation of NDE methods for additively manufactured parts plays a great role in evaluating and ensuring the reliability of the printed part.\u0000 In this work, ultrasonic technique was utilized to determine the elastic properties and anisotropy of additively manufactured AlSi10Mg and conventionally fabricated Al 6061 samples.\u0000 An ultrasonic measurement approach which allowed for the accurate measurement of the material properties was established and implemented. Longitudinal and shear transducers were used and the sound speed was calculated by analyzing the position of the arrived pulses in the pulse-echo configuration. Elastic properties were calculated from the longitudinal and shear sound speeds and measured density. Also, the correlation between elastic properties and sample’s location within the printed block, and spatial distribution of the elastic properties were explored.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88760212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dirac cones in the band structures of highly symmetric phononic crystal lattices have been extensively studied to produce unique acoustic phenomena. Traditionally, these interesting phenomena produced by Dirac cones occur at fixed frequencies, which cannot be adapted unless significant lattice material or geometric changes occur. To create tunable phononic structures, researchers have successfully utilized Miura-origami to modulate phononic inclusions between discrete high symmetry Bravais lattice configurations. However, the origami transformation between Bravais lattices is a continuous process, meaning that between the high symmetry Bravais lattices, the structure will transform into low symmetry lattices, which are largely unexplored. In this work, we study the perturbation of a hexagonal phononic lattice away from high symmetry. Interestingly, we see the Dirac cone at the K point of the Brillouin zone for the hexagonal lattice persist through the lattice modulation, despite loss of symmetry. Using this insight, we propose an origami phononic structure capable of continuous adjustment and refinement of Dirac cone frequency. Ultimately, we demonstrate continuous Dirac cone modulation for beam forming with the proposed origami phononic structure.
{"title":"Continuous Dirac Cone Evolution in Modulated Phononic Crystal","authors":"Megan Hathcock, B. Popa, Kon-Well Wang","doi":"10.1115/imece2022-95839","DOIUrl":"https://doi.org/10.1115/imece2022-95839","url":null,"abstract":"\u0000 Dirac cones in the band structures of highly symmetric phononic crystal lattices have been extensively studied to produce unique acoustic phenomena. Traditionally, these interesting phenomena produced by Dirac cones occur at fixed frequencies, which cannot be adapted unless significant lattice material or geometric changes occur. To create tunable phononic structures, researchers have successfully utilized Miura-origami to modulate phononic inclusions between discrete high symmetry Bravais lattice configurations. However, the origami transformation between Bravais lattices is a continuous process, meaning that between the high symmetry Bravais lattices, the structure will transform into low symmetry lattices, which are largely unexplored. In this work, we study the perturbation of a hexagonal phononic lattice away from high symmetry. Interestingly, we see the Dirac cone at the K point of the Brillouin zone for the hexagonal lattice persist through the lattice modulation, despite loss of symmetry. Using this insight, we propose an origami phononic structure capable of continuous adjustment and refinement of Dirac cone frequency. Ultimately, we demonstrate continuous Dirac cone modulation for beam forming with the proposed origami phononic structure.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89767888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ultrasonic guided-wave (UGW) NDT technology is an efficient means for damage identification and has been applied widely in the field of detection for pipelines, railway tracks, ships and aircrafts. Besides, the dispersion curves of the guided waves in a square steel pipe are indispensable references for the integrity test of continuous structural components, which represent the frequency dependence of guided wave velocities. Unfortunately, the complete dispersion curve of ultrasonic waves in square steel pipes cannot be solved by the traditional finite element modal analysis method. To address the problem, the semi-analytical finite element (SAFE) method was used to obtain the ultrasonic guided wave dispersion curves in a square steel pipe, on this basis, a UGW-based NDT strategy is proposed. Firstly, triangular elements are adopted to perform the finite element discretization on the cross-section of the square steel pipe, and the guided wave is assumed to be in a harmonic motion along the wave propagation direction. Then, the wave equation of the ultrasonic guided waves propagating in the square steel pipe is deduced theoretically, through solving the characteristic equation, the wave number and frequency can be obtained, and the relation between the frequency and phase velocity & group velocity is obtained; thus, the dispersion curves can be plotted, which can be used to analyze the vibration characteristics of the guided wave modes. Afterwards, the optimal excitation frequency, excitation direction and excitation location are selected based on dispersion property for the different damage modes of the square steel pipe. Lastly, the proposed damage identification method is validated through numerical simulation. The results show that the dispersion curves of square steel pipe solved with the semi-analytical finite element method are in good agreement with the simulated result, besides, for the damage on the square steel pipe surface, the reflected guided wave package can identify the damage location effectively under the selected excitation.
{"title":"Ultrasonic Guided Waves Nondestructive Damage Detection for Square Steel Pipe Based on Semi-Analytical Finite Element Method","authors":"Tingting Yang, Wensong Zhou","doi":"10.1115/imece2022-97130","DOIUrl":"https://doi.org/10.1115/imece2022-97130","url":null,"abstract":"\u0000 Ultrasonic guided-wave (UGW) NDT technology is an efficient means for damage identification and has been applied widely in the field of detection for pipelines, railway tracks, ships and aircrafts. Besides, the dispersion curves of the guided waves in a square steel pipe are indispensable references for the integrity test of continuous structural components, which represent the frequency dependence of guided wave velocities. Unfortunately, the complete dispersion curve of ultrasonic waves in square steel pipes cannot be solved by the traditional finite element modal analysis method.\u0000 To address the problem, the semi-analytical finite element (SAFE) method was used to obtain the ultrasonic guided wave dispersion curves in a square steel pipe, on this basis, a UGW-based NDT strategy is proposed. Firstly, triangular elements are adopted to perform the finite element discretization on the cross-section of the square steel pipe, and the guided wave is assumed to be in a harmonic motion along the wave propagation direction. Then, the wave equation of the ultrasonic guided waves propagating in the square steel pipe is deduced theoretically, through solving the characteristic equation, the wave number and frequency can be obtained, and the relation between the frequency and phase velocity & group velocity is obtained; thus, the dispersion curves can be plotted, which can be used to analyze the vibration characteristics of the guided wave modes. Afterwards, the optimal excitation frequency, excitation direction and excitation location are selected based on dispersion property for the different damage modes of the square steel pipe. Lastly, the proposed damage identification method is validated through numerical simulation. The results show that the dispersion curves of square steel pipe solved with the semi-analytical finite element method are in good agreement with the simulated result, besides, for the damage on the square steel pipe surface, the reflected guided wave package can identify the damage location effectively under the selected excitation.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86212370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effects of aircraft flight speed and fan face pressure variations on sound propagation from an axisymmetric commercial supersonic engine inlet were studied using numerical methods. A computational fluid dynamics (CFD) model of the inlet was constructed in Ansys Fluent. The results of this model were then used as inputs for the aeroacoustic solver, ACTRAN, and used to calculate far field radiated noise. Using this process, a parametric study was conducted varying two parameters: the approach Mach number from 0.35 to 0.55 in increments of 0.0125, and the fan face back pressures from −10 kPa to −40 kPa in increments of 1 kPa. It was found that variations in free stream Mach number resulted in approximate variations of 2 dB on radiated acoustics while variations in fan face pressure resulted in up to 5 dB of change. These variations were found to be frequency dependent with the largest variations happening over a frequency range of approximately 3 kHz to 5 kHz and again from 6 kHz to 8 kHz. These results indicate combinations of flight speed and fan pressure to avoid in flight to reduce overall noise reaching the ground.
{"title":"Variation of Sound Directivity From a Supersonic Nacelle","authors":"Mitchell L. Sugar, Paul E. Slaboch","doi":"10.1115/imece2022-96515","DOIUrl":"https://doi.org/10.1115/imece2022-96515","url":null,"abstract":"\u0000 The effects of aircraft flight speed and fan face pressure variations on sound propagation from an axisymmetric commercial supersonic engine inlet were studied using numerical methods. A computational fluid dynamics (CFD) model of the inlet was constructed in Ansys Fluent. The results of this model were then used as inputs for the aeroacoustic solver, ACTRAN, and used to calculate far field radiated noise. Using this process, a parametric study was conducted varying two parameters: the approach Mach number from 0.35 to 0.55 in increments of 0.0125, and the fan face back pressures from −10 kPa to −40 kPa in increments of 1 kPa. It was found that variations in free stream Mach number resulted in approximate variations of 2 dB on radiated acoustics while variations in fan face pressure resulted in up to 5 dB of change. These variations were found to be frequency dependent with the largest variations happening over a frequency range of approximately 3 kHz to 5 kHz and again from 6 kHz to 8 kHz. These results indicate combinations of flight speed and fan pressure to avoid in flight to reduce overall noise reaching the ground.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82797429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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