The present investigation was motivated by a noticeable high-pressure pulsations and vibrations during commissioning of a centrifugal compressor on a high-pressure natural gas transmission system. During commissioning, the gas from the compressor discharge is recycled back to compressor inlet through a recycle line turning the gas flow from the main discharge line into a smaller diameter side branch, thus creating a deadleg due to the closure of a check valve farther downstream on the main discharge line. To better understand and characterize the flow generated pulsations due turning flow into side branches, an experimental setup was constructed on ambient air to test three side-branch to main pipe diameter ratios (d/D), nominally: 1.0, 0.75 and 0.5, over a wide range of mean flow velocities. Experimental results of the normalized pulsation pressure amplitudes (P*) vs. Strouhal number characterized the flow-acoustic field for the three d/D ratios and for acoustically tuned and detuned systems. It was found that P* decreases as d/D decreases for acoustically tuned systems. The highest P* was achieved with d/D = 1 which reached a value of 3.543 at St = 0.1376. At lower d/D = 0.762, the maximum value of P* decreased to 1.173 at a slightly lower St number of approximately 0.1. In the case of d/D = 0.5132, the normalized pressure P* was further reduced to a very low value of 0.2462 at a wider range of St number. Acoustically tuned system is characterized by having the highest anti-nodal point of acoustic velocity oscillation at the Tee-junction location in the axial direction of the main pipe, with minimum acoustic leakage into the side branch. When the system is acoustically detuned, i.e., when the axial acoustic velocity oscillations at the Tee-junction is reduced, the strength of the local acoustic source at the junction is also reduced resulting in a lower peak normalized pressure amplitude at the deadleg. The peak amplitudes of pressure pulsations occur at frequencies exactly matching the deadleg 1/4 wavelength resonance, whether it is tuned or detuned with respect to the inlet section. That is, the peak frequencies tracked the changes in the deadleg length and was not influenced by the inlet section acoustic resonance characteristics. This led to the postulation that the main driver of the flow-generated pulsations, i.e., the acoustic source is associated with the high-shear area of the flow facing the deadleg at the trailing edge of the Tee-junction rather than the ‘vortex bubble’ due to flow separation at the leading edge of the side branch.
本研究的动机是在高压天然气输送系统的离心压缩机调试过程中出现明显的高压脉动和振动。在调试期间，来自压缩机排放物的气体通过一条循环管线回流到压缩机进口，将来自主排放物管线的气体流转化为直径更小的侧分支，从而由于主排放物管线下游的止回阀关闭而造成死腿。为了更好地理解和表征由于转向侧支管而产生的流动脉动，在环境空气中建立了一个实验装置，在广泛的平均流速范围内测试三个侧支与主管道直径比(d/ d)，名义为1.0,0.75和0.5。归一化脉动压力幅值(P*)与Strouhal数的实验结果表征了三个d/ d比以及声学调谐和非调谐系统的流声场。在声学调谐系统中，P*随着d/ d的减小而减小。当d/ d = 1时P*最高，St = 0.1376时P*为3.543。当d/ d = 0.762时，P*的最大值降至1.173,St数略低，约为0.1。当d/ d = 0.5132时，在较大的St数范围内，归一化压力P*进一步减小到0.2462的极低值。声调谐系统的特点是在主管道轴向的tee结位置声速振荡的抗节点最高，侧支路的声泄漏最小。当系统声学失谐时，即当tee结处的轴向声速振荡减小时，结处局部声源的强度也会减小，从而导致死腿处的归一化压力振幅峰值降低。压力脉动的峰值幅值发生在与死腿1/4波长共振完全匹配的频率上，无论它相对于入口部分是调谐的还是调谐的。即峰值频率跟踪死腿长度的变化，不受进口截面声学共振特性的影响。这导致了一种假设，即流动产生脉动的主要驱动因素，即声源与tee结尾缘面向死腿的流动的高剪切区域有关，而不是与侧分支前缘由于流动分离而产生的“涡泡”有关。
{"title":"Measurements of Pulsation Generated Due to Turning Flow Into Side Branches of Different Diameter Ratios","authors":"K. Botros, H. Satish","doi":"10.1115/imece2021-69111","DOIUrl":"https://doi.org/10.1115/imece2021-69111","url":null,"abstract":"\u0000 The present investigation was motivated by a noticeable high-pressure pulsations and vibrations during commissioning of a centrifugal compressor on a high-pressure natural gas transmission system. During commissioning, the gas from the compressor discharge is recycled back to compressor inlet through a recycle line turning the gas flow from the main discharge line into a smaller diameter side branch, thus creating a deadleg due to the closure of a check valve farther downstream on the main discharge line. To better understand and characterize the flow generated pulsations due turning flow into side branches, an experimental setup was constructed on ambient air to test three side-branch to main pipe diameter ratios (d/D), nominally: 1.0, 0.75 and 0.5, over a wide range of mean flow velocities. Experimental results of the normalized pulsation pressure amplitudes (P*) vs. Strouhal number characterized the flow-acoustic field for the three d/D ratios and for acoustically tuned and detuned systems. It was found that P* decreases as d/D decreases for acoustically tuned systems. The highest P* was achieved with d/D = 1 which reached a value of 3.543 at St = 0.1376. At lower d/D = 0.762, the maximum value of P* decreased to 1.173 at a slightly lower St number of approximately 0.1. In the case of d/D = 0.5132, the normalized pressure P* was further reduced to a very low value of 0.2462 at a wider range of St number. Acoustically tuned system is characterized by having the highest anti-nodal point of acoustic velocity oscillation at the Tee-junction location in the axial direction of the main pipe, with minimum acoustic leakage into the side branch. When the system is acoustically detuned, i.e., when the axial acoustic velocity oscillations at the Tee-junction is reduced, the strength of the local acoustic source at the junction is also reduced resulting in a lower peak normalized pressure amplitude at the deadleg. The peak amplitudes of pressure pulsations occur at frequencies exactly matching the deadleg 1/4 wavelength resonance, whether it is tuned or detuned with respect to the inlet section. That is, the peak frequencies tracked the changes in the deadleg length and was not influenced by the inlet section acoustic resonance characteristics. This led to the postulation that the main driver of the flow-generated pulsations, i.e., the acoustic source is associated with the high-shear area of the flow facing the deadleg at the trailing edge of the Tee-junction rather than the ‘vortex bubble’ due to flow separation at the leading edge of the side branch.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84466965","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}
Chang Liu, Xu Mao, Chang Wang, J. Heredia Juesas, J. Martinez-Lorenzo
Contrary to the active detection methods, the passive sound source localization technologies only rely on the differences among the signals recorded by different receivers to localize the object generating the sound wave, without the knowledge of the sound source profile and excitation time. Time domain investigation methods have been widely applied in the analysis of sound source tracking, which greatly suffers from the high ambient noise problems. Instead, this paper applies an imaging method based on frequency domain cross-coherence (FDCC) operation to reconstruct the source to alleviate the effect of noise. The experimental results show the reliability of this method to recover the source in 3D. Moreover, a parabolic reflector is proposed to further increase the measurement amplitude and signal to noise ratio. The FDCC method successfully localizes the source even if the propagation path of the sound wave is disturbed by the reflector.
{"title":"Real-Time Sound Source Localization Using a Parabolic Reflector","authors":"Chang Liu, Xu Mao, Chang Wang, J. Heredia Juesas, J. Martinez-Lorenzo","doi":"10.1115/imece2021-70385","DOIUrl":"https://doi.org/10.1115/imece2021-70385","url":null,"abstract":"\u0000 Contrary to the active detection methods, the passive sound source localization technologies only rely on the differences among the signals recorded by different receivers to localize the object generating the sound wave, without the knowledge of the sound source profile and excitation time. Time domain investigation methods have been widely applied in the analysis of sound source tracking, which greatly suffers from the high ambient noise problems. Instead, this paper applies an imaging method based on frequency domain cross-coherence (FDCC) operation to reconstruct the source to alleviate the effect of noise. The experimental results show the reliability of this method to recover the source in 3D. Moreover, a parabolic reflector is proposed to further increase the measurement amplitude and signal to noise ratio. The FDCC method successfully localizes the source even if the propagation path of the sound wave is disturbed by the reflector.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83195825","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. Sabat, G. Leveque, Y. Pennec, D. Torrent, B. Djafari-Rouhani
In our work, we are interested in the effect of coupling between Helmholtz resonators using the finite element model. We show that the coupling between two spheres leads to two peaks of resonance at low frequencies. One of them is symmetric and corresponds to a mono-polar breathing mode. The second one is anti-symmetric and behaves like a dipole. Consequently, the first one produces an isotropic wave in the far pressure field, while the second produces a directional propagation wave. Therefore, by changing the distance and / or the orientation between the resonators, we aim to manipulate and control the direction of the acoustic wave at specific frequencies.
{"title":"Effect of Coupled Helmholtz Resonators on Sound Control","authors":"R. Sabat, G. Leveque, Y. Pennec, D. Torrent, B. Djafari-Rouhani","doi":"10.1115/imece2021-70333","DOIUrl":"https://doi.org/10.1115/imece2021-70333","url":null,"abstract":"\u0000 In our work, we are interested in the effect of coupling between Helmholtz resonators using the finite element model. We show that the coupling between two spheres leads to two peaks of resonance at low frequencies. One of them is symmetric and corresponds to a mono-polar breathing mode. The second one is anti-symmetric and behaves like a dipole. Consequently, the first one produces an isotropic wave in the far pressure field, while the second produces a directional propagation wave. Therefore, by changing the distance and / or the orientation between the resonators, we aim to manipulate and control the direction of the acoustic wave at specific frequencies.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82286397","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}
Jiewei Lin, Rui Zhang, Qidi Zhou, Junhong Zhang, Gengyi Lin
Sound quality (SQ) plays important role in automobile competitiveness, in which the high frequency characteristics of tones are prominent when internal combustion engines are replaced by fuel cells or batteries. Hence, it is of great significance to explore the influence of tones on the SQ of such electric vehicles. At the moment, the prominence of tones is concerned but the influence of tones in different frequency ranges is not comprehensively considered. Meanwhile, there are some researches on the masking effect of background noise, but they are insufficient. To address these issues, the SQs of four types of vehicles (van, SUV, pure electric car, fuel cell heavy truck) are studied. The prominence ratio (PR) is found to be effective in the evaluation of tones SQ. The influence of tones on subjective evaluation is explored from two dimensions of “audible” and “irritable”. The results show that whether tones can be “audible” and “irritable” are related to the masking effect of background noise and the frequency distribution. Meanwhile, the PR limits of tones are obtained in different frequencies under various working conditions and operating modes.
{"title":"Research on Tone Quality for Vehicles Considering the Masking Effect","authors":"Jiewei Lin, Rui Zhang, Qidi Zhou, Junhong Zhang, Gengyi Lin","doi":"10.1115/imece2021-72907","DOIUrl":"https://doi.org/10.1115/imece2021-72907","url":null,"abstract":"\u0000 Sound quality (SQ) plays important role in automobile competitiveness, in which the high frequency characteristics of tones are prominent when internal combustion engines are replaced by fuel cells or batteries. Hence, it is of great significance to explore the influence of tones on the SQ of such electric vehicles. At the moment, the prominence of tones is concerned but the influence of tones in different frequency ranges is not comprehensively considered. Meanwhile, there are some researches on the masking effect of background noise, but they are insufficient. To address these issues, the SQs of four types of vehicles (van, SUV, pure electric car, fuel cell heavy truck) are studied. The prominence ratio (PR) is found to be effective in the evaluation of tones SQ. The influence of tones on subjective evaluation is explored from two dimensions of “audible” and “irritable”. The results show that whether tones can be “audible” and “irritable” are related to the masking effect of background noise and the frequency distribution. Meanwhile, the PR limits of tones are obtained in different frequencies under various working conditions and operating modes.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82899963","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}
We present a complete thermodynamic analogy of statistical energy analysis (SEA) using entropy and energy for both linear and nonlinear coupled systems. We will use Khinchin’s Entropy as our statistical entropy definition from statistical mechanics. This framework allows for the restrictive assumptions of linearity to be removed from this analysis method. We will use the classical definition of entropy to relate entropy to Vibrational Temperature. Using Khinchin’s statistical definition of entropy for a vibrating system, we will define a Vibrational Temperature as a function of energy. Hence, we will derive all that is necessary to construct the SEA power flow equation along with the transient coupling loss factors without any linearity assumption. With this method one can expand SEA to nonlinear transient coupled systems. We will verify our proposed method using Monte Carlo Simulation and published analytical closed form solutions.
{"title":"Statistical Energy Analysis of Vibrating Structures With Energy and Entropy","authors":"Elise M. Hough, Z. Sotoudeh","doi":"10.1115/imece2021-69640","DOIUrl":"https://doi.org/10.1115/imece2021-69640","url":null,"abstract":"\u0000 We present a complete thermodynamic analogy of statistical energy analysis (SEA) using entropy and energy for both linear and nonlinear coupled systems. We will use Khinchin’s Entropy as our statistical entropy definition from statistical mechanics. This framework allows for the restrictive assumptions of linearity to be removed from this analysis method. We will use the classical definition of entropy to relate entropy to Vibrational Temperature. Using Khinchin’s statistical definition of entropy for a vibrating system, we will define a Vibrational Temperature as a function of energy. Hence, we will derive all that is necessary to construct the SEA power flow equation along with the transient coupling loss factors without any linearity assumption. With this method one can expand SEA to nonlinear transient coupled systems. We will verify our proposed method using Monte Carlo Simulation and published analytical closed form solutions.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90045722","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}
Adhesively bonded joints are gaining popularity among automotive industries due to their light-weight, cost-effective, and multi-material joining solutions. Adhesively bonded joints not only yield light-weighted structures but also provide a more uniform stress distribution than riveted joints resulting in higher fatigue life. However, due to their complex damage mechanism it is not easy to analytically predict the transition between crack initiation, propagation and failure of the joint. To improve the confidence of crack detection and estimation in adhesively bonded lap-joint, this paper proposes a numerical guided wave modal analysis to better understand the fatigue damage. From initial experiments it was found that the crack inside adhesive lap-joints increases at different rates depending on the state of the damage and can be modelled according to the paris-paris law. However, accurate estimation of the transition from crack initiation and crack propagation until total failure is non-trivial. In this paper, a series of finite element simulations are conducted to understand the modal behavior of guided waves at various damage states of the lap-joint and extract the most useful features indicative of transition form from crack initiation and crack propagation. Extracted features shall be used in various prognosis models to improve the remaining-useful-life prediction.
{"title":"Numerical Modal Sensitivity Analysis for Fatigue Damage Accumulation in Adhesively Bonded Lap-Joint","authors":"R. Palanisamy, P. Banerjee, M. Haq, Y. Deng","doi":"10.1115/imece2021-73587","DOIUrl":"https://doi.org/10.1115/imece2021-73587","url":null,"abstract":"\u0000 Adhesively bonded joints are gaining popularity among automotive industries due to their light-weight, cost-effective, and multi-material joining solutions. Adhesively bonded joints not only yield light-weighted structures but also provide a more uniform stress distribution than riveted joints resulting in higher fatigue life. However, due to their complex damage mechanism it is not easy to analytically predict the transition between crack initiation, propagation and failure of the joint. To improve the confidence of crack detection and estimation in adhesively bonded lap-joint, this paper proposes a numerical guided wave modal analysis to better understand the fatigue damage. From initial experiments it was found that the crack inside adhesive lap-joints increases at different rates depending on the state of the damage and can be modelled according to the paris-paris law. However, accurate estimation of the transition from crack initiation and crack propagation until total failure is non-trivial. In this paper, a series of finite element simulations are conducted to understand the modal behavior of guided waves at various damage states of the lap-joint and extract the most useful features indicative of transition form from crack initiation and crack propagation. Extracted features shall be used in various prognosis models to improve the remaining-useful-life prediction.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89173939","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}
Mario Escarcega, Savannah Bradley, Gabriel Campos, Parker Randall, Luke Strebe, Hamed Momeni, A. Ebrahimkhanlou
Reinforced concrete corrosion can be monitored by the acoustic emissions produced by transient mechanical waves of corrosion and damage events. This study aims to use 3D-printed one-way valves to relieve the corrosion-induced internal pressure on concrete structures. This valve is designed in such a way that it can be simply installed to existing structures to increase corrosion resistance in the concrete structure and extend the service life. The impressed current technique is a common technique used to rapidly corrode reinforced concrete samples. To corrode the concrete samples, current was passed through the internal steel strand and copper mesh. This study also investigated the use of an Internet-of-Things device to continuously monitor corrosion in steel-reinforced concrete samples in order to determine the effectiveness of the designed valves. Pressure testing revealed that the designed valves were against backflow and cracked at very low pressure. It was ideal that the valves cracked at a lower pressure so as to release pressure constantly while preventing further corrosion in backflow. This type of valve will prevent reinforced concrete surface cracking and extend the service life of concrete structures by releasing internal pressure build-up without allowing foreign materials to further corrode the steel reinforcement.
{"title":"Corrosion Monitoring and Mitigation in Reinforced Concrete Structures Using Novel 3D-Printed Valves and Internet-of-Things Approach","authors":"Mario Escarcega, Savannah Bradley, Gabriel Campos, Parker Randall, Luke Strebe, Hamed Momeni, A. Ebrahimkhanlou","doi":"10.1115/imece2021-72141","DOIUrl":"https://doi.org/10.1115/imece2021-72141","url":null,"abstract":"\u0000 Reinforced concrete corrosion can be monitored by the acoustic emissions produced by transient mechanical waves of corrosion and damage events. This study aims to use 3D-printed one-way valves to relieve the corrosion-induced internal pressure on concrete structures. This valve is designed in such a way that it can be simply installed to existing structures to increase corrosion resistance in the concrete structure and extend the service life. The impressed current technique is a common technique used to rapidly corrode reinforced concrete samples. To corrode the concrete samples, current was passed through the internal steel strand and copper mesh. This study also investigated the use of an Internet-of-Things device to continuously monitor corrosion in steel-reinforced concrete samples in order to determine the effectiveness of the designed valves. Pressure testing revealed that the designed valves were against backflow and cracked at very low pressure. It was ideal that the valves cracked at a lower pressure so as to release pressure constantly while preventing further corrosion in backflow. This type of valve will prevent reinforced concrete surface cracking and extend the service life of concrete structures by releasing internal pressure build-up without allowing foreign materials to further corrode the steel reinforcement.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73766262","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 paper, a vibration-based method, called wavelet entropy time series, for non-destructive testing of carbon fiber specimens is introduced and demonstrated experimentally. The wavelet transform of vibration signals, acquired after an impact excitation of the specimen, is combined with Shannon’s informational entropy to quantify a trend in the disorder of the signal. Notions such as wavelet entropy, wavelet entropy time series are defined and utilized to assist in structural health monitoring. The scientific merit of the method was investigated both experimentally and computationally. Wavelet entropy time series was able to identify patterns in the complexity of signals making the method suitable for other signal processing applications, outside the scope of non-destructive testing.
{"title":"Spatial Localization of Air Inclusions in Carbon Fiber T-Beam, by Use of Wavelet Entropy Time Series From Hammer Tap Test","authors":"Spyridon Brouzas, I. Georgiou","doi":"10.1115/imece2021-67591","DOIUrl":"https://doi.org/10.1115/imece2021-67591","url":null,"abstract":"\u0000 In this paper, a vibration-based method, called wavelet entropy time series, for non-destructive testing of carbon fiber specimens is introduced and demonstrated experimentally. The wavelet transform of vibration signals, acquired after an impact excitation of the specimen, is combined with Shannon’s informational entropy to quantify a trend in the disorder of the signal. Notions such as wavelet entropy, wavelet entropy time series are defined and utilized to assist in structural health monitoring. The scientific merit of the method was investigated both experimentally and computationally. Wavelet entropy time series was able to identify patterns in the complexity of signals making the method suitable for other signal processing applications, outside the scope of non-destructive testing.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74059599","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}
This paper presents the Electromechanical Impedance Spectroscopy (EMIS) method employing a novel piezoelectric wafer active sensor (PWAS) with sub-resonators, which can generate additional resonant peaks to enhance the impedance signature. In order to develop an in-depth understanding of the mechanism behind the sub-resonator effects, an analytical investigation is conducted first. The theoretical solution for the impedance of the new sub-resonator PWAS transducer is derived. Furthermore, numerical simulations are carried out to demonstrate the effectiveness of the new transducer to create additional resonant peaks. Harmonic analysis of coupled field finite element (FEM) models is conducted. Material degradations are modeled by altering the material properties like density and elastic modulus. Comparative investigations are carried out with both conventional PWAS transducers and sub-resonator PWAS transducers. EMI damage indices based on the spectral amplitude and frequency variation features are used to quantify the material degradation and simultaneously prove the superiority of the sub-resonator PWAS over the conventional PWAS. Additionally, a high-damping dog-bone specimen is employed to conduct the creep experiment lasting for twenty-four hours with a recording interval of two hours. The impedance spectra are obtained by the Bode-100 impedance analyzer. The experimental results further demonstrate the improved sensitivity of the sub-resonator transducer, which is in good agreement with the theoretical and numerical findings. The paper finishes with summary, concluding remarks, and suggestions for future work.
{"title":"High-Damping Viscoelastic Material Monitoring Using Sub-Resonator Enhanced Electro-Mechanical Impedance Spectroscopy","authors":"Runye Lu, Yanfeng Shen","doi":"10.1115/imece2021-71172","DOIUrl":"https://doi.org/10.1115/imece2021-71172","url":null,"abstract":"\u0000 This paper presents the Electromechanical Impedance Spectroscopy (EMIS) method employing a novel piezoelectric wafer active sensor (PWAS) with sub-resonators, which can generate additional resonant peaks to enhance the impedance signature. In order to develop an in-depth understanding of the mechanism behind the sub-resonator effects, an analytical investigation is conducted first. The theoretical solution for the impedance of the new sub-resonator PWAS transducer is derived. Furthermore, numerical simulations are carried out to demonstrate the effectiveness of the new transducer to create additional resonant peaks. Harmonic analysis of coupled field finite element (FEM) models is conducted. Material degradations are modeled by altering the material properties like density and elastic modulus. Comparative investigations are carried out with both conventional PWAS transducers and sub-resonator PWAS transducers. EMI damage indices based on the spectral amplitude and frequency variation features are used to quantify the material degradation and simultaneously prove the superiority of the sub-resonator PWAS over the conventional PWAS. Additionally, a high-damping dog-bone specimen is employed to conduct the creep experiment lasting for twenty-four hours with a recording interval of two hours. The impedance spectra are obtained by the Bode-100 impedance analyzer. The experimental results further demonstrate the improved sensitivity of the sub-resonator transducer, which is in good agreement with the theoretical and numerical findings. The paper finishes with summary, concluding remarks, and suggestions for future work.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74578937","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}
Triply Poly Minimal Surfaces (TPMS) are three dimensional periodic lattice structures with a trigonometric relationship in their unit cell that can be implemented for acoustic applications including acoustic metamaterials and Phononic crystals. The necessity and demand in the ultrasound and acoustic industry for new materials pave the way to investigate further mechanical wave research into the different shape of engineered metamaterials that usually does not exist in nature for different purposes. This paper presents a design pipeline for Schwarz Primitive acoustic metamaterial from the mathematically driven stage of computational design of the unit cell with the utilization of finite element method to simulate the Phononic bandgaps, acoustic pressure, wave propagations, sound pressure levels, and sound transmission loss. The effect of periodic, Floquet, symmetry, & dipole boundary conditions as well as the effect of the upstream and downstream numerical domain extension on the final transmission loss signal in the simulations are compared. These numerical evaluations are important for future experimental acoustic measurement in the different impedance tubes with different microphone positions and sample setups. Finally, the initial stage of additive manufacturing using Stereolithography 3D printing technology for the fabrication of TPMS sample to compare the numerical data with experimental acoustic data is addressed as well as its potential applications to use in the different industries.
{"title":"Implementation of Triply Poly Minimal Surfaces in Design of Phononic Crystals and Acoustic Metamaterials","authors":"Daniel Saatchi, I. Oh","doi":"10.1115/imece2021-72624","DOIUrl":"https://doi.org/10.1115/imece2021-72624","url":null,"abstract":"\u0000 Triply Poly Minimal Surfaces (TPMS) are three dimensional periodic lattice structures with a trigonometric relationship in their unit cell that can be implemented for acoustic applications including acoustic metamaterials and Phononic crystals. The necessity and demand in the ultrasound and acoustic industry for new materials pave the way to investigate further mechanical wave research into the different shape of engineered metamaterials that usually does not exist in nature for different purposes. This paper presents a design pipeline for Schwarz Primitive acoustic metamaterial from the mathematically driven stage of computational design of the unit cell with the utilization of finite element method to simulate the Phononic bandgaps, acoustic pressure, wave propagations, sound pressure levels, and sound transmission loss. The effect of periodic, Floquet, symmetry, & dipole boundary conditions as well as the effect of the upstream and downstream numerical domain extension on the final transmission loss signal in the simulations are compared. These numerical evaluations are important for future experimental acoustic measurement in the different impedance tubes with different microphone positions and sample setups. Finally, the initial stage of additive manufacturing using Stereolithography 3D printing technology for the fabrication of TPMS sample to compare the numerical data with experimental acoustic data is addressed as well as its potential applications to use in the different industries.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79246451","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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