This research presents a thorough evaluation of the reverberation room at Acoustics Laboratory in National Institute of Standards (NIS) according to the related international standards. The evaluation aims at examining the room performance and exploring its effectiveness in the frequency range from 125 Hz to 10000 Hz according to the international standard requirements. The room, which was designed and built several years ago, is an irregular rectangular shape free from diffusers. Its volume is about 158.84 m, which meets the requirement of the ISO 354 standard Lmax < 1.9V . Cut-off frequencies of one and one-third octave are 63 Hz and 100 Hz respectively; however Schroder frequency is 400 Hz. Calculations of cut-off frequency and modal density showed adequate modes that give acceptable uniformity starting comfortably from frequency of 125 Hz. The room has a reverberation time that is suitable for its size over the frequency range of interest. The room sound absorption surface area and its sound absorption coefficient satisfy the criteria given in ISO 3741 and ISO 354. There is an accepted diffuse sound field inside the room due to the standard deviation of measured sound level, which is less than 1.5 dB over all the frequency range. The only exception was 125 Hz which may be due to a lack of diffusivity of the sound field at this frequency. The evaluation proves that the NIS reverberation room is in full agreement with the international standards, which in turns qualifies the room to host measurements inside without concerns.
{"title":"Performance Evaluation and Effectiveness of the Reverberation Room","authors":"Mohamed Abd-elbasseer, Hatem Kh Mohamed","doi":"10.32604/SV.2021.09417","DOIUrl":"https://doi.org/10.32604/SV.2021.09417","url":null,"abstract":"This research presents a thorough evaluation of the reverberation room at Acoustics Laboratory in National Institute of Standards (NIS) according to the related international standards. The evaluation aims at examining the room performance and exploring its effectiveness in the frequency range from 125 Hz to 10000 Hz according to the international standard requirements. The room, which was designed and built several years ago, is an irregular rectangular shape free from diffusers. Its volume is about 158.84 m, which meets the requirement of the ISO 354 standard Lmax < 1.9V . Cut-off frequencies of one and one-third octave are 63 Hz and 100 Hz respectively; however Schroder frequency is 400 Hz. Calculations of cut-off frequency and modal density showed adequate modes that give acceptable uniformity starting comfortably from frequency of 125 Hz. The room has a reverberation time that is suitable for its size over the frequency range of interest. The room sound absorption surface area and its sound absorption coefficient satisfy the criteria given in ISO 3741 and ISO 354. There is an accepted diffuse sound field inside the room due to the standard deviation of measured sound level, which is less than 1.5 dB over all the frequency range. The only exception was 125 Hz which may be due to a lack of diffusivity of the sound field at this frequency. The evaluation proves that the NIS reverberation room is in full agreement with the international standards, which in turns qualifies the room to host measurements inside without concerns.","PeriodicalId":49496,"journal":{"name":"Sound and Vibration","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86518751","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}
A. Askari, A. Salehi Sahl Abadi, Alimardan Alinia, M. Pourjaafar, Aref Honairi Haghighi, Elham Akhlaghi Pirposhteh
{"title":"Prioritizing and Providing Sound Pollution Control Strategies at the CPF of North Azadegan Oilfield Project","authors":"A. Askari, A. Salehi Sahl Abadi, Alimardan Alinia, M. Pourjaafar, Aref Honairi Haghighi, Elham Akhlaghi Pirposhteh","doi":"10.32604/sv.2021.016662","DOIUrl":"https://doi.org/10.32604/sv.2021.016662","url":null,"abstract":"","PeriodicalId":49496,"journal":{"name":"Sound and Vibration","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73225529","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}
V. Sekar, S. Y. E. Noum, A. Putra, S. Sivanesan, Kok Chun Chin, Y. Wong, D. H. Kassim
This paper presents the development and performance of micro-perforated panels (MPP) from natural fiber reinforced composites. The MPP is made of Polylactic Acid (PLA) reinforced with Oil Palm Empty Fruit Bunch Fiber (OPEFBF). The investigation was made by varying the fiber density, air gap, and perforation ratio to observe the effect on the Sound Absorption Coefficient (SAC) through the experiment in an impedance tube. It is found that the peak level of SAC is not affected, but the peak frequency shifts to lower frequency when the fiber density is increased. This phenomenon might be due to the presence of porosity in the inner wall of the holes. Increasing or decreasing the air gap and perforation ratio shifts the peaks of acoustic absorption either way.
{"title":"Acoustic Properties of Micro-Perforated Panels Made from Oil Palm Empty Fruit Bunch Fiber Reinforced Polylactic Acid","authors":"V. Sekar, S. Y. E. Noum, A. Putra, S. Sivanesan, Kok Chun Chin, Y. Wong, D. H. Kassim","doi":"10.32604/sv.2021.014916","DOIUrl":"https://doi.org/10.32604/sv.2021.014916","url":null,"abstract":"This paper presents the development and performance of micro-perforated panels (MPP) from natural fiber reinforced composites. The MPP is made of Polylactic Acid (PLA) reinforced with Oil Palm Empty Fruit Bunch Fiber (OPEFBF). The investigation was made by varying the fiber density, air gap, and perforation ratio to observe the effect on the Sound Absorption Coefficient (SAC) through the experiment in an impedance tube. It is found that the peak level of SAC is not affected, but the peak frequency shifts to lower frequency when the fiber density is increased. This phenomenon might be due to the presence of porosity in the inner wall of the holes. Increasing or decreasing the air gap and perforation ratio shifts the peaks of acoustic absorption either way.","PeriodicalId":49496,"journal":{"name":"Sound and Vibration","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91215633","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}
N. Dhobale, S. Mulik, R. Jegadeeshwaran, A. Patange
{"title":"Supervision of Milling Tool Inserts using Conventional and Artificial Intelligence Approach: A Review","authors":"N. Dhobale, S. Mulik, R. Jegadeeshwaran, A. Patange","doi":"10.32604/sv.2021.014224","DOIUrl":"https://doi.org/10.32604/sv.2021.014224","url":null,"abstract":"","PeriodicalId":49496,"journal":{"name":"Sound and Vibration","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87923315","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}
Mohammad Javad Jafari, M. Niknam Sharak, A. Khavanin, T. Ebadzadeh, M. Fazlali, Rohollah Fallah Madvari
{"title":"Improving the Morphological Parameters of Aluminum Foam for Maximum Sound Absorption Coefficient using Genetic Algorithm","authors":"Mohammad Javad Jafari, M. Niknam Sharak, A. Khavanin, T. Ebadzadeh, M. Fazlali, Rohollah Fallah Madvari","doi":"10.32604/sv.2021.09729","DOIUrl":"https://doi.org/10.32604/sv.2021.09729","url":null,"abstract":"","PeriodicalId":49496,"journal":{"name":"Sound and Vibration","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76783921","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}
{"title":"Combined Signal Processing Based Techniques and Feed Forward Neural Networks for Pathological Voice Detection and Classification","authors":"T. Jayasree, S. Shia","doi":"10.32604/sv.2021.011734","DOIUrl":"https://doi.org/10.32604/sv.2021.011734","url":null,"abstract":"","PeriodicalId":49496,"journal":{"name":"Sound and Vibration","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73408177","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 article, time fractional Fornberg-Whitham equation of He’s fractional derivative is studied. To transform the fractional model into its equivalent differential equation, the fractional complex transform is used and He’s homotopy perturbation method is implemented to get the approximate analytical solutions of the fractional-order problems. The graphs are plotted to analysis the fractional-order mathematical modeling.
{"title":"He’s Homotopy Perturbation Method and Fractional Complex Transform for Analysis Time Fractional Fornberg-Whitham Equation","authors":"Yanni Zhang, J. Pang","doi":"10.32604/sv.2021.014445","DOIUrl":"https://doi.org/10.32604/sv.2021.014445","url":null,"abstract":"In this article, time fractional Fornberg-Whitham equation of He’s fractional derivative is studied. To transform the fractional model into its equivalent differential equation, the fractional complex transform is used and He’s homotopy perturbation method is implemented to get the approximate analytical solutions of the fractional-order problems. The graphs are plotted to analysis the fractional-order mathematical modeling.","PeriodicalId":49496,"journal":{"name":"Sound and Vibration","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76504799","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}
Al Munawir, A. Putra, I. Prasetiyo, Wan Mohd Farid Wan Mohamad, S. Herawan
Statistical Energy Analysis (SEA) is a well-known method to analyze the flow of acoustic and vibration energy in a complex structure. This study investigates the application of the corrected SEA model in a non-reverberant acoustic space where the direct field component from the sound source dominates the total sound field rather than a diffuse field in a reverberant space which the classical SEA model assumption is based on. A corrected SEA model is proposed where the direct field component in the energy is removed and the power injected in the subsystem considers only the remaining power after the loss at first reflection. Measurement was conducted in a box divided into two rooms separated by a partition with an opening where the condition of reverberant and non-reverberant can conveniently be controlled. In the case of a non-reverberant space where acoustic material was installed inside the wall of the experimental box, the signals are corrected by eliminating the direct field component in the measured impulse response. Using the corrected SEA model, comparison of the coupling loss factor (CLF) and damping loss factor (DLF) with the theory shows good agreement.
{"title":"Corrected Statistical Energy Analysis Model in a Non-Reverberant Acoustic Space","authors":"Al Munawir, A. Putra, I. Prasetiyo, Wan Mohd Farid Wan Mohamad, S. Herawan","doi":"10.32604/sv.2021.015938","DOIUrl":"https://doi.org/10.32604/sv.2021.015938","url":null,"abstract":"Statistical Energy Analysis (SEA) is a well-known method to analyze the flow of acoustic and vibration energy in a complex structure. This study investigates the application of the corrected SEA model in a non-reverberant acoustic space where the direct field component from the sound source dominates the total sound field rather than a diffuse field in a reverberant space which the classical SEA model assumption is based on. A corrected SEA model is proposed where the direct field component in the energy is removed and the power injected in the subsystem considers only the remaining power after the loss at first reflection. Measurement was conducted in a box divided into two rooms separated by a partition with an opening where the condition of reverberant and non-reverberant can conveniently be controlled. In the case of a non-reverberant space where acoustic material was installed inside the wall of the experimental box, the signals are corrected by eliminating the direct field component in the measured impulse response. Using the corrected SEA model, comparison of the coupling loss factor (CLF) and damping loss factor (DLF) with the theory shows good agreement.","PeriodicalId":49496,"journal":{"name":"Sound and Vibration","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82209281","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}
Saqlain Abbas, Fucai Li, Zulkarnain Abbas, Taufeeq Ur Rehman Abbasi, Xiaotong Tu, R. Pasha
Structural health monitoring (SHM) is recognized as an ef fi cient tool to interpret the reliability of a wide variety of infrastructures. To identify the structural abnormality by utilizing the electromechanical coupling property of piezoelectric transducers, the electromechanical impedance (EMI) approach is preferred. However, in real-time SHM applications, the monitored structure is exposed to several varying environmental and operating conditions (EOCs). The previous study has recognized the temperature variations as one of the serious EOCs that affect the optimal performance of the damage inspection process. In this framework, an experimental setup is developed in current research to identify the presence of fatigue crack in stainless steel (304) beam using EMI approach and estimate the effect of temperature variations on the electrical impedance of the piezoelectric sensors. A regular series of experiments are executed in a controlled temperature environment (25°C – 160°C) using 202 V1 Constant Temperature Drying Oven Chamber (Q/TBXR20-2005). It has been observed that the dielectric constant ð " 33 T Þ which is recognized as the temperature-dependent constant of PZT sensor has suf fi ciently in fl uenced the electrical impedance signature. Moreover, the effective frequency shift (EFS) approach is optimized in term of signi fi cant temperature compensation for the current impedance signature of PZT sensor relative to the reference signature at the extended frequency bandwidth of the developed measurement system with better outcomes as compared to the previous literature work. Hence, the current study also deals ef fi ciently with the critical issue of the width of the frequency band for temperature compensation based on the frequency shift in SHM. The results of the experimental study demonstrate that the proposed methodology is quali fi ed for the damage inspection in real-time monitoring applications under the temperature variations. It is capable to exclude one of the major reasons of false fault diag-nosis by compensating the consequence of elevated temperature at extended frequency bandwidth in SHM.
结构健康监测(SHM)被认为是解释各种基础设施可靠性的有效工具。为了利用压电换能器的机电耦合特性来识别结构异常，首选采用机电阻抗(EMI)方法。然而，在实时SHM应用中，被监测的结构暴露于几种不同的环境和操作条件(eoc)中。在以往的研究中，温度变化是影响损伤检测过程最佳性能的重要影响因素之一。在此框架下，在目前的研究中建立了一个实验装置，利用电磁干扰方法识别不锈钢(304)梁中疲劳裂纹的存在，并估计温度变化对压电传感器电阻抗的影响。使用202 V1恒温干燥箱(Q/TBXR20-2005)在受控温度环境(25°C - 160°C)中进行常规系列实验。研究发现介电常数33 T Þ作为PZT传感器的温度相关常数，充分影响了PZT传感器的电阻抗特征。此外，对有效频移(EFS)方法进行了优化，对PZT传感器的电流阻抗特征在扩展的测量系统带宽下相对于参考特征进行了显著的温度补偿，与以往的文献工作相比效果更好。因此，本研究也有效地解决了SHM中基于频移的温度补偿的关键频段宽度问题。实验结果表明，该方法适用于温度变化下的实时监测损伤检测。该方法通过补偿SHM扩展带宽下温度升高的后果，能够排除误诊断的主要原因之一。
{"title":"Experimental Study of Effect of Temperature Variations on the Impedance Signature of PZT Sensors for Fatigue Crack Detection","authors":"Saqlain Abbas, Fucai Li, Zulkarnain Abbas, Taufeeq Ur Rehman Abbasi, Xiaotong Tu, R. Pasha","doi":"10.32604/SV.2021.013754","DOIUrl":"https://doi.org/10.32604/SV.2021.013754","url":null,"abstract":"Structural health monitoring (SHM) is recognized as an ef fi cient tool to interpret the reliability of a wide variety of infrastructures. To identify the structural abnormality by utilizing the electromechanical coupling property of piezoelectric transducers, the electromechanical impedance (EMI) approach is preferred. However, in real-time SHM applications, the monitored structure is exposed to several varying environmental and operating conditions (EOCs). The previous study has recognized the temperature variations as one of the serious EOCs that affect the optimal performance of the damage inspection process. In this framework, an experimental setup is developed in current research to identify the presence of fatigue crack in stainless steel (304) beam using EMI approach and estimate the effect of temperature variations on the electrical impedance of the piezoelectric sensors. A regular series of experiments are executed in a controlled temperature environment (25°C – 160°C) using 202 V1 Constant Temperature Drying Oven Chamber (Q/TBXR20-2005). It has been observed that the dielectric constant ð \" 33 T Þ which is recognized as the temperature-dependent constant of PZT sensor has suf fi ciently in fl uenced the electrical impedance signature. Moreover, the effective frequency shift (EFS) approach is optimized in term of signi fi cant temperature compensation for the current impedance signature of PZT sensor relative to the reference signature at the extended frequency bandwidth of the developed measurement system with better outcomes as compared to the previous literature work. Hence, the current study also deals ef fi ciently with the critical issue of the width of the frequency band for temperature compensation based on the frequency shift in SHM. The results of the experimental study demonstrate that the proposed methodology is quali fi ed for the damage inspection in real-time monitoring applications under the temperature variations. It is capable to exclude one of the major reasons of false fault diag-nosis by compensating the consequence of elevated temperature at extended frequency bandwidth in SHM.","PeriodicalId":49496,"journal":{"name":"Sound and Vibration","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81969674","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}
Pub Date : 2020-12-31DOI: 10.1515/9780822374824-001
{"title":"Introduction Closed Grooves, Open Ears","authors":"","doi":"10.1515/9780822374824-001","DOIUrl":"https://doi.org/10.1515/9780822374824-001","url":null,"abstract":"","PeriodicalId":49496,"journal":{"name":"Sound and Vibration","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2020-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79017317","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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