Yo-Seb Choi, Suk-Yoon Hong, Jee-hun Song, H. Kwon, J. Kang
To comply with noise regulations in residential areas, low-noise electrical transformers must be developed. However, it is difficult to accurately reflect the frequency characteristics of the transformer, which have a large influence on the noise produced, because the high voltage and current make it impossible to experimentally measure the internal excitation forces involved. In this paper, we propose a new method using an experimental apparatus for estimating the internal excitation forces experienced by transformers whose results accurately reflect the actual frequency characteristics of the transformer. To estimate the excitation force, the pressure distribution data outside the enclosure of a transformer was experimentally measured by the experimental apparatus based on a beamforming method, and the transfer function from the excitation source to the noise radiation was derived numerically. The excitation force was then derived using the pressure distribution data and transfer function. Based on the estimated excitation force, the contribution of each vibration transmission path was derived using transfer path analysis with integrated transfer function matrix as a basis for creating an effective noise reduction plan. The noise reduction plan based on our method was able to reduce transformer noise sufficiently to meet the noise standard set in standard transformer export contracts.
{"title":"Power transformer excitation force estimation for load noise reduction using experimental apparatus based on beamforming theory","authors":"Yo-Seb Choi, Suk-Yoon Hong, Jee-hun Song, H. Kwon, J. Kang","doi":"10.3397/1/37706","DOIUrl":"https://doi.org/10.3397/1/37706","url":null,"abstract":"To comply with noise regulations in residential areas, low-noise electrical transformers must be developed. However, it is difficult to accurately reflect the frequency characteristics of the transformer, which have a large influence on the noise produced, because the high voltage and\u0000 current make it impossible to experimentally measure the internal excitation forces involved. In this paper, we propose a new method using an experimental apparatus for estimating the internal excitation forces experienced by transformers whose results accurately reflect the actual frequency\u0000 characteristics of the transformer. To estimate the excitation force, the pressure distribution data outside the enclosure of a transformer was experimentally measured by the experimental apparatus based on a beamforming method, and the transfer function from the excitation source to the noise\u0000 radiation was derived numerically. The excitation force was then derived using the pressure distribution data and transfer function. Based on the estimated excitation force, the contribution of each vibration transmission path was derived using transfer path analysis with integrated transfer\u0000 function matrix as a basis for creating an effective noise reduction plan. The noise reduction plan based on our method was able to reduce transformer noise sufficiently to meet the noise standard set in standard transformer export contracts.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41987476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Attachment of constrained layer dampers and dynamic vibration absorbers (DVAs) on rails are two effective passive control methods used for mitigating vibration and noise of railways at the source. An integrated passive control method in which constrained layer dampers and DVAs were simultaneously attached on the rail was proposed to attenuate the vibration and noise of the rail in a broad frequency range and to suppress the maximum vibration emitted by the first pinned-pinned resonance of the rail. The design method for the integrated application was developed based on the optimum design theory of DVA for multiple-degree-of-freedom damping structures. The vibration and noise reduction properties of the integrated control method were analyzed using a vibroacoustic model established based on the sequential finite element method–boundary element method and evaluated through laboratory tests. The results show that the integrated control method fully demonstrates the advantages of the two passive vibration control methods, which can improve the longitudinal transmission loss of the rail by 5.3 dB/m at the first pinned-pinned resonant frequency and reduce the maximum acoustic power of the rail by 7.8 dB(A) as well as achieve an overall rail noise reduction of 4.0 dB(A) within 3000 Hz. The vibration and noise reduction properties of the integrated control method are improved as the mass ratio increases in the frequency range above 600 Hz. The test results show that the integrated control method decreases the rail web vibration and rail noise by more than 40%.
{"title":"Integrated design of passive control methods for mitigating vibration and noise of rails in high-speed railway","authors":"Rixin Cui","doi":"10.3397/1/37707","DOIUrl":"https://doi.org/10.3397/1/37707","url":null,"abstract":"Attachment of constrained layer dampers and dynamic vibration absorbers (DVAs) on rails are two effective passive control methods used for mitigating vibration and noise of railways at the source. An integrated passive control method in which constrained layer dampers and DVAs were\u0000 simultaneously attached on the rail was proposed to attenuate the vibration and noise of the rail in a broad frequency range and to suppress the maximum vibration emitted by the first pinned-pinned resonance of the rail. The design method for the integrated application was developed based\u0000 on the optimum design theory of DVA for multiple-degree-of-freedom damping structures. The vibration and noise reduction properties of the integrated control method were analyzed using a vibroacoustic model established based on the sequential finite element method–boundary element method\u0000 and evaluated through laboratory tests. The results show that the integrated control method fully demonstrates the advantages of the two passive vibration control methods, which can improve the longitudinal transmission loss of the rail by 5.3 dB/m at the first pinned-pinned resonant frequency\u0000 and reduce the maximum acoustic power of the rail by 7.8 dB(A) as well as achieve an overall rail noise reduction of 4.0 dB(A) within 3000 Hz. The vibration and noise reduction properties of the integrated control method are improved as the mass ratio increases in the frequency range above\u0000 600 Hz. The test results show that the integrated control method decreases the rail web vibration and rail noise by more than 40%.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47818847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Resistant mufflers are commonly used in the wide band noise control of the exhaust of tractor internal combustion engines due to their simple structure, broadband frequency performance and long service life. In this paper, a corrugated perforated pipe muffler was proposed based on an improved design of a straight-through perforated pipe muffler to reduce the exhaust noise of internal combustion engines. The acoustic attenuation performance of the corrugated perforated tube muffler under the action of nonuniform flow and a temperature gradient was predicted by using the one-way flow-acoustic coupling method, which combines computational fluid dynamics and the acoustic finite element method. The pressure loss and self-noise of the corrugated perforated tube muffler were compared with those of the straight-through perforated tube muffler. The influence of the structural parameters of the corrugated perforated tube mufflers on the transmission loss was analyzed. The significance level of the perforation diameter, peak height, distance between adjacent peaks, and peak width on the transmission loss of the corrugated perforated tube muffler was studied by multiple linear regression analysis.
{"title":"Case study: Numerical study of the noise reduction characteristics of corrugated perforated pipe mufflers","authors":"Z. Hou, Tanghong Xu, Zhijun Zhang, Jiyu Sun","doi":"10.3397/1/37702","DOIUrl":"https://doi.org/10.3397/1/37702","url":null,"abstract":"Resistant mufflers are commonly used in the wide band noise control of the exhaust of tractor internal combustion engines due to their simple structure, broadband frequency performance and long service life. In this paper, a corrugated perforated pipe muffler was proposed based on an\u0000 improved design of a straight-through perforated pipe muffler to reduce the exhaust noise of internal combustion engines. The acoustic attenuation performance of the corrugated perforated tube muffler under the action of nonuniform flow and a temperature gradient was predicted by using the\u0000 one-way flow-acoustic coupling method, which combines computational fluid dynamics and the acoustic finite element method. The pressure loss and self-noise of the corrugated perforated tube muffler were compared with those of the straight-through perforated tube muffler. The influence of the\u0000 structural parameters of the corrugated perforated tube mufflers on the transmission loss was analyzed. The significance level of the perforation diameter, peak height, distance between adjacent peaks, and peak width on the transmission loss of the corrugated perforated tube muffler was studied\u0000 by multiple linear regression analysis.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47416012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Yıldız, Aytekin Özkan, Halil Ateş, Ahmet Ayvaz, Traki Küçük
The acoustic comfort level of a passenger vehicle is one of the most critical factors that affect customer preferences before purchasing. Recent studies on refining the engine noise lead to a more evident panorama for tire and wind noise due to the elimination of the masking effect of the engine. Furthermore, replacing the internal combustion engine with the electric motor will also push road noise to be the primary noise factor in vehicles. In this study, the road noise phenomenon is analyzed for both structure-borne and air-borne paths. Transfer path analyses and panel contribution analyses were performed on a reference vehicle to identify the main paths of road noise. Solutions to improve road noise levels were determined accordingly. Finally, improvements were confirmed by physical tests and subjective evaluations.
{"title":"Case study: Mitigation of the road noise of a passenger vehicle by determination of critical paths via transfer path analysis","authors":"M. Yıldız, Aytekin Özkan, Halil Ateş, Ahmet Ayvaz, Traki Küçük","doi":"10.3397/1/37701","DOIUrl":"https://doi.org/10.3397/1/37701","url":null,"abstract":"The acoustic comfort level of a passenger vehicle is one of the most critical factors that affect customer preferences before purchasing. Recent studies on refining the engine noise lead to a more evident panorama for tire and wind noise due to the elimination of the masking effect\u0000 of the engine. Furthermore, replacing the internal combustion engine with the electric motor will also push road noise to be the primary noise factor in vehicles. In this study, the road noise phenomenon is analyzed for both structure-borne and air-borne paths. Transfer path analyses and panel\u0000 contribution analyses were performed on a reference vehicle to identify the main paths of road noise. Solutions to improve road noise levels were determined accordingly. Finally, improvements were confirmed by physical tests and subjective evaluations.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":"1 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41661690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The rotating source identifier (ROSI) beamforming method is a method designed for localizing rotating noise sources in a uniform flow based on out-of-flow acoustic pressure field measurement data. It has been developed for sources moving along a circular trajectory, such as turbomachinery blades. The original ROSI method processes the measured acoustic signals over a long time segment to reconstruct the noise sources, providing time-averaged results for each noise source. By doing so, it does not take into consideration certain features of the noise sources, such as the directivity of the trailing edge and leading-edge noise sources. A further development of the ROSI method is presented herein, which separates the sound-pressure signal of one revolution into multiple segments. In this way, the beamforming maps can provide one with a better understanding of the differences between the noise sources as a function of angular position. This method will be referred to herein as the segmented ROSI method. The goal of this further development is to improve the capability of the method in identifying the position-dependent modulations of the various noise sources as they are moving along their trajectories, rotating around the axis. The investigation presents the theory behind the new segmented ROSI method along with simulation and measurement-based test cases which help in comparing the new method to the original ROSI method. The results show that the novel method provides a strong tool for investigating turbomachinery noise sources that vary along segments of their trajectories. It is therefore expected that the tool will be useful in cases that look at turbomachinery from an angle and cases where the loading of the blades changes as a function of angular position.
{"title":"Segmented ROSI method: Beamforming method for investigating turbomachinery noise sources along segmented trajectories","authors":"Haitian Zhang, Bálint Kocsis, Csaba Horváth","doi":"10.3397/1/37705","DOIUrl":"https://doi.org/10.3397/1/37705","url":null,"abstract":"The rotating source identifier (ROSI) beamforming method is a method designed for localizing rotating noise sources in a uniform flow based on out-of-flow acoustic pressure field measurement data. It has been developed for sources moving along a circular trajectory, such as turbomachinery\u0000 blades. The original ROSI method processes the measured acoustic signals over a long time segment to reconstruct the noise sources, providing time-averaged results for each noise source. By doing so, it does not take into consideration certain features of the noise sources, such as the directivity\u0000 of the trailing edge and leading-edge noise sources. A further development of the ROSI method is presented herein, which separates the sound-pressure signal of one revolution into multiple segments. In this way, the beamforming maps can provide one with a better understanding of the differences\u0000 between the noise sources as a function of angular position. This method will be referred to herein as the segmented ROSI method. The goal of this further development is to improve the capability of the method in identifying the position-dependent modulations of the various noise sources as\u0000 they are moving along their trajectories, rotating around the axis. The investigation presents the theory behind the new segmented ROSI method along with simulation and measurement-based test cases which help in comparing the new method to the original ROSI method. The results show that the\u0000 novel method provides a strong tool for investigating turbomachinery noise sources that vary along segments of their trajectories. It is therefore expected that the tool will be useful in cases that look at turbomachinery from an angle and cases where the loading of the blades changes as a\u0000 function of angular position.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42767168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, transverse vibrations and acoustic radiation of an all-edges-free baffled rectangular thin plate are examined by Rayleigh's formulation. While the Rayleigh-Ritz method is applicable for a wide variety of boundary condition combinations, in this study, the method is used for evaluating the modal characteristics of an all edges free plate. Acoustic pressure levels are calculated by Rayleigh's acoustic formula for a free field. This study provides a quick formula for those who are interested in calculating the sound pressure of a baffled plate on a specific point for a free field while only requiring the vibration of the surface to be expressed in terms of 2D power series. The results obtained from the formula are compared with the finite element analysis results.
{"title":"On the acoustic radiation of all edges free rectangular thin plate","authors":"F. Ertürk, H. Erol","doi":"10.3397/1/37703","DOIUrl":"https://doi.org/10.3397/1/37703","url":null,"abstract":"In this study, transverse vibrations and acoustic radiation of an all-edges-free baffled rectangular thin plate are examined by Rayleigh's formulation. While the Rayleigh-Ritz method is applicable for a wide variety of boundary condition combinations, in this study, the method is used\u0000 for evaluating the modal characteristics of an all edges free plate. Acoustic pressure levels are calculated by Rayleigh's acoustic formula for a free field. This study provides a quick formula for those who are interested in calculating the sound pressure of a baffled plate on a specific\u0000 point for a free field while only requiring the vibration of the surface to be expressed in terms of 2D power series. The results obtained from the formula are compared with the finite element analysis results.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44489219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Yamin, Z. Yousaf, Khalid Mahmood Bhatt, Muhammad Ibrahim
Constant exposure of noise to the auditory system of the agricultural tractor opera- tor can cause physical and psychological problems. A field study was conducted in the Faisalabad and Narowal districts of Pakistan to examine the spread of tractor noise and its psychological effects on the safety of tractor operators driving tractors without cabins and other noise reduction measures. Four of the most common imple- ments used in Pakistan, including land scraper, cultivator, disk harrow and seed drill, were used to detect the changes in tractor noise at two speeds of 5.3 km/h and 10.6 km/h in all four directions. Lowest noise was produced during the field operation of the seed drill at a mean noise value of 81.9 dB(A) among all four implements. Disk harrow and cultivator were found to be the most noisy implement, and during oper- ation, the tractor operator was directly exposed to high noise levels of 86.9 dB(A) and 84.9 dB(A), respectively. This noise pollution caused psychological problems in agri- cultural tractor operators, as demonstrated by the highly positive correlations of de- pression, aggression, anxiety and stress. This trend had a negative effect on their social interactions relative to the comparable population of office employees. In or- der to mitigate the adverse health effects, tractor operators must be equipped with sound proof cabins or at least ear plugs because of direct exposure to high noise levels. Furthermore, a safe distance of 48 m or at least a warning distance of 26 m from the tractor must be maintained by farm workers.
{"title":"Noise exposure and its impact on psychological health of agricultural tractor operators","authors":"M. Yamin, Z. Yousaf, Khalid Mahmood Bhatt, Muhammad Ibrahim","doi":"10.3397/1/376947","DOIUrl":"https://doi.org/10.3397/1/376947","url":null,"abstract":"Constant exposure of noise to the auditory system of the agricultural tractor opera- tor can cause physical and psychological problems. A field study was conducted in the Faisalabad and Narowal districts of Pakistan to examine the spread of tractor noise and its psychological effects\u0000 on the safety of tractor operators driving tractors without cabins and other noise reduction measures. Four of the most common imple- ments used in Pakistan, including land scraper, cultivator, disk harrow and seed drill, were used to detect the changes in tractor noise at two speeds of 5.3\u0000 km/h and 10.6 km/h in all four directions. Lowest noise was produced during the field operation of the seed drill at a mean noise value of 81.9 dB(A) among all four implements. Disk harrow and cultivator were found to be the most noisy implement, and during oper- ation, the tractor operator\u0000 was directly exposed to high noise levels of 86.9 dB(A) and 84.9 dB(A), respectively. This noise pollution caused psychological problems in agri- cultural tractor operators, as demonstrated by the highly positive correlations of de- pression, aggression, anxiety and stress. This trend had\u0000 a negative effect on their social interactions relative to the comparable population of office employees. In or- der to mitigate the adverse health effects, tractor operators must be equipped with sound proof cabins or at least ear plugs because of direct exposure to high noise levels. Furthermore,\u0000 a safe distance of 48 m or at least a warning distance of 26 m from the tractor must be maintained by farm workers.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42252695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Jiang, Xiang Liu, Stephany Y. Xu, Shangyu Zhang
In this paper, the efficacy of porous ceiling treatment to reduce noise levels inside a typical tunnel is examined with a validated modal-based prediction method. It is found that, for a point source, the effect of increasing porous ceiling thickness on sound pressure level (SPL) attenuation along the tunnel is limited. A porous ceiling with thickness of 0.3 m is comparable with an infinite porous ceiling in middle and high frequency ranges. For a line source, the effect of ceiling thickness on SPL reduc- tion in this typical tunnel is limited. Sound pressure level reduction of 4 dBA is real- ized with 0.3 m porous ceiling, which is the same as infinite ceiling and only 1 dBA smaller than the theoretically optimized value. These results suggest that, in the event only ceiling treatment is considered, 0.3 m porous material is sufficient for noise re- duction in this typical tunnel.
{"title":"Prediction and analysis of sound field in long enclosures with a modal-based method","authors":"C. Jiang, Xiang Liu, Stephany Y. Xu, Shangyu Zhang","doi":"10.3397/1/376949","DOIUrl":"https://doi.org/10.3397/1/376949","url":null,"abstract":"In this paper, the efficacy of porous ceiling treatment to reduce noise levels inside a typical tunnel is examined with a validated modal-based prediction method. It is found that, for a point source, the effect of increasing porous ceiling thickness on sound pressure level (SPL) attenuation\u0000 along the tunnel is limited. A porous ceiling with thickness of 0.3 m is comparable with an infinite porous ceiling in middle and high frequency ranges. For a line source, the effect of ceiling thickness on SPL reduc- tion in this typical tunnel is limited. Sound pressure level reduction of\u0000 4 dBA is real- ized with 0.3 m porous ceiling, which is the same as infinite ceiling and only 1 dBA smaller than the theoretically optimized value. These results suggest that, in the event only ceiling treatment is considered, 0.3 m porous material is sufficient for noise re- duction in this\u0000 typical tunnel.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45689221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, the vibration signal of planetary gear with amplitude, frequency and phase modulation is studied. The proposed mathematical model is employed to in- vestigate the modulation behavior of planetary gear. Based on this model, the ampli- tude modulation (AM) sidebands are analyzed to verify the correctness of theoretical calculation by Inalpolat and Kahraman. Then, the frequency modulation (FM) side- bands and phase modulation (PM) sidebands are also illustrated through an exam- ple analysis. The effects of parameters of planetary gear such as number of planets, teeth of sun and planet phasing relationships on the AM, FM and PM sidebands are analyzed. Finally, the specific expression of transmission error, time-varying mesh stiffness and dynamic mesh force including gear manufacturing error is developed. Time history signal and acceleration spectra of gear mesh interface excitations including AM, FM and PM are investigated for the meshes of sun-planet and ring- planet. The results show that gear parameters have important influence on the mod- ulation behavior. Additionally, manufacturing errors can be introduced to predict the sidebands of planetary gear. The amplitude, frequency and phase modulation study are extremely significant for the noise and vibration reduction, especially the fault diagnosis of planetary gear
{"title":"Vibration signal analysis of planetary gear with amplitude, frequency and phase modulation","authors":"Hai-Zhen Sun, Wei Liu","doi":"10.3397/1/376946","DOIUrl":"https://doi.org/10.3397/1/376946","url":null,"abstract":"In this paper, the vibration signal of planetary gear with amplitude, frequency and phase modulation is studied. The proposed mathematical model is employed to in- vestigate the modulation behavior of planetary gear. Based on this model, the ampli- tude modulation (AM) sidebands are\u0000 analyzed to verify the correctness of theoretical calculation by Inalpolat and Kahraman. Then, the frequency modulation (FM) side- bands and phase modulation (PM) sidebands are also illustrated through an exam- ple analysis. The effects of parameters of planetary gear such as number of planets,\u0000 teeth of sun and planet phasing relationships on the AM, FM and PM sidebands are analyzed. Finally, the specific expression of transmission error, time-varying mesh stiffness and dynamic mesh force including gear manufacturing error is developed. Time history signal and acceleration spectra\u0000 of gear mesh interface excitations including AM, FM and PM are investigated for the meshes of sun-planet and ring- planet. The results show that gear parameters have important influence on the mod- ulation behavior. Additionally, manufacturing errors can be introduced to predict the sidebands\u0000 of planetary gear. The amplitude, frequency and phase modulation study are extremely significant for the noise and vibration reduction, especially the fault diagnosis of planetary gear","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":"1 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41396637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A micro-perforated panel absorber (MPPA) can reduce noise without the use of sound-absorbing materials. It is made of various materials and is poten- tially applicable in a variety of fields. However, the application of MPPAs is limited owing to the narrow absorption band. In a previous study, to enhance the sound- absorption performance of MPPAs, we proposed a parallel arrangement of multi- layer MPPAs. Based on the results of this previous study, we carried out the present study to apply an MPPA to the curve squeal noise of railways. Squeal noise, which occurs at approximately 500 to 5000 Hz, has high-level peaks. We designed and fabricated an MPPAwith the proposed structure according to the characteris- tics of the squeal noise. The noise reduction was analyzed after an MPPA barrier was installed in the field with a curve radius of 120 m. The reduction in noise level was approximately 17 dB(A) on the first floor and approximately 7 dB(A) on the fourth floor of the building. At 630 to 5000 Hz, the noise reduction level was at least approximately 5 dB(A). To analyze the noise absorption effect of the MPPA bar- rier, a simulation was carried out and subsequently verified by comparing the measurement results with the simulation results. In the simulation, the difference in noise reduction level between the MPPA and reflective barrier was analyzed. The noise reduction level of the MPPA barrier was approximately 7.5 dB(A) higher than that of the reflective barrier on the second and third floors of the build- ing at 630 to 5000 Hz. These results support the viability of MPPA application in re- ducing noise from curve squeal noise.
{"title":"Application of a micro-perforated panel absorber to reduce the curve squeal noise of railways","authors":"Woong-yong Lee, Jae-chul Kim, H. Noh","doi":"10.3397/1/376948","DOIUrl":"https://doi.org/10.3397/1/376948","url":null,"abstract":"A micro-perforated panel absorber (MPPA) can reduce noise without the use of sound-absorbing materials. It is made of various materials and is poten- tially applicable in a variety of fields. However, the application of MPPAs is limited owing to the narrow absorption band. In a previous\u0000 study, to enhance the sound- absorption performance of MPPAs, we proposed a parallel arrangement of multi- layer MPPAs. Based on the results of this previous study, we carried out the present study to apply an MPPA to the curve squeal noise of railways. Squeal noise, which occurs at approximately\u0000 500 to 5000 Hz, has high-level peaks. We designed and fabricated an MPPAwith the proposed structure according to the characteris- tics of the squeal noise. The noise reduction was analyzed after an MPPA barrier was installed in the field with a curve radius of 120 m. The reduction in noise\u0000 level was approximately 17 dB(A) on the first floor and approximately 7 dB(A) on the fourth floor of the building. At 630 to 5000 Hz, the noise reduction level was at least approximately 5 dB(A). To analyze the noise absorption effect of the MPPA bar- rier, a simulation was carried out and\u0000 subsequently verified by comparing the measurement results with the simulation results. In the simulation, the difference in noise reduction level between the MPPA and reflective barrier was analyzed. The noise reduction level of the MPPA barrier was approximately 7.5 dB(A) higher than that\u0000 of the reflective barrier on the second and third floors of the build- ing at 630 to 5000 Hz. These results support the viability of MPPA application in re- ducing noise from curve squeal noise.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47094701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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