Pub Date : 2021-01-01DOI: 10.36336/akustika20214029
J. Smutný, Dušan Janoštík, Viktor Nohál
The aim of the paper is to introduce a less used method for the evaluation of non-stationary and especially transient phenomena in railway structures to the wider professional public. This method may find wide application in many technical and other fields. It is the so-called Hilbert-Huang transform. In this paper, its application in the study of dynamic phenomena occurring in a selected superstructure structure is shown. The calculation procedure of the presented transform differs from traditional tools, which include, for example, the short-term Fourier transform or the Wavelet transform. The paper includes a mathematical analysis and description of this transformation. Furthermore, the paper contains a description of the measurement method used, a discussion of the results obtained and recommendations for practice.
{"title":"THE USE OF THE HILBERT HUANG TRANSFORMATION IN THE TESTING OF RAILWAY STRUCTURES","authors":"J. Smutný, Dušan Janoštík, Viktor Nohál","doi":"10.36336/akustika20214029","DOIUrl":"https://doi.org/10.36336/akustika20214029","url":null,"abstract":"The aim of the paper is to introduce a less used method for the evaluation of non-stationary and especially transient phenomena in railway structures to the wider professional public. This method may find wide application in many technical and other fields. It is the so-called Hilbert-Huang transform. In this paper, its application in the study of dynamic phenomena occurring in a selected superstructure structure is shown. The calculation procedure of the presented transform differs from traditional tools, which include, for example, the short-term Fourier transform or the Wavelet transform. The paper includes a mathematical analysis and description of this transformation. Furthermore, the paper contains a description of the measurement method used, a discussion of the results obtained and recommendations for practice.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70174581","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 : 2021-01-01DOI: 10.36336/akustika202141200
A. Vasilyev
The results of analysis of Russian approaches and of experience of development of methods and of results of experimental research of low-frequency gas dynamic pressure pulsations in pipelines of power plants are described. Peculiarities of Russian standards and of the sanitary norms are considered. According to results of experimental researches is possible to conclude that the maximal vibration levels are observed on the frequencies 31,5 Hz and 40 Hz. The same results were obtained during the measurements of sound pressure level on the same experimental compressor mount. Earlier during the experiments on the same mount it was achieved that the maximal values of low frequency gas pressure pulsations are observed on the frequency 35 Hz. Thus, it was experimentally shown that gas pressure pulsations are making the main contribution into forming of low frequency sound and vibration of compressor mount.
{"title":"ANALYSIS OF METHODS AND PRESENTATION OF RESULTS OF EXPERIMENTAL RESEARCH OF LOW FREQUENCY GAS DYNAMIC PULSATIONS IN PIPELINES OF POWER PLANTS","authors":"A. Vasilyev","doi":"10.36336/akustika202141200","DOIUrl":"https://doi.org/10.36336/akustika202141200","url":null,"abstract":"The results of analysis of Russian approaches and of experience of development of methods and of results of experimental research of low-frequency gas dynamic pressure pulsations in pipelines of power plants are described. Peculiarities of Russian standards and of the sanitary norms are considered. According to results of experimental researches is possible to conclude that the maximal vibration levels are observed on the frequencies 31,5 Hz and 40 Hz. The same results were obtained during the measurements of sound pressure level on the same experimental compressor mount. Earlier during the experiments on the same mount it was achieved that the maximal values of low frequency gas pressure pulsations are observed on the frequency 35 Hz. Thus, it was experimentally shown that gas pressure pulsations are making the main contribution into forming of low frequency sound and vibration of compressor mount.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70175995","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 : 2021-01-01DOI: 10.36336/akustika20214152
A. Vasilyev
The importance of the problem of low-frequency noise and vibration reduction now may be considered as urgent. Increased influence of low-frequency noise and vibration may cause both human health problems and equipment damage. Power plants (internal combustion engines, compressors, heat-exchanges etc.) are one of the main low-frequency noise and vibration sources. The principles of classification of methods of power plants low-frequency noise and vibration reduction are suggested. Author is proposing energetic approach, according of which all the methods and arrangements of reduction may be classified as passive (adaptive and non-adaptive), active and hybrid passive-active. The classification is illustrated by the different examples, including constructions of mufflers and dampers, some of which are developed by author.
{"title":"APPROACHES TO CLASSIFICATION OF REDUCTION METHODS OF LOW FREQUENCY NOISE AND VIBRATION OF POWER PLANTS","authors":"A. Vasilyev","doi":"10.36336/akustika20214152","DOIUrl":"https://doi.org/10.36336/akustika20214152","url":null,"abstract":"The importance of the problem of low-frequency noise and vibration reduction now may be considered as urgent. Increased influence of low-frequency noise and vibration may cause both human health problems and equipment damage. Power plants (internal combustion engines, compressors, heat-exchanges etc.) are one of the main low-frequency noise and vibration sources. The principles of classification of methods of power plants low-frequency noise and vibration reduction are suggested. Author is proposing energetic approach, according of which all the methods and arrangements of reduction may be classified as passive (adaptive and non-adaptive), active and hybrid passive-active. The classification is illustrated by the different examples, including constructions of mufflers and dampers, some of which are developed by author.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70176887","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 : 2021-01-01DOI: 10.36336/akustika20214165
A. Sekacheva, L. Pastukhova, A. Noskov
The article discusses the results of studies of the dynamic parameters of a pipeline connected to a pump, carried out in order to obtain data in full-scale conditions. At this stage of the study, the stationary process of the pump operation, which forms a turbulent flow in the pipeline, was studied. A computational and experimental technique for studying natural frequencies and vibration modes of pipelines of complex spatial configuration has been developed. The adequacy of the developed methods of finite element modeling of dynamic processes in pipeline systems in the frequency range up to 400 Hz has been confirmed.
{"title":"EXPERIMENTAL STUDY OF DYNAMIC PARAMETERS OF COMPLEX PIPELINE SYSTEM","authors":"A. Sekacheva, L. Pastukhova, A. Noskov","doi":"10.36336/akustika20214165","DOIUrl":"https://doi.org/10.36336/akustika20214165","url":null,"abstract":"The article discusses the results of studies of the dynamic parameters of a pipeline connected to a pump, carried out in order to obtain data in full-scale conditions. At this stage of the study, the stationary process of the pump operation, which forms a turbulent flow in the pipeline, was studied. A computational and experimental technique for studying natural frequencies and vibration modes of pipelines of complex spatial configuration has been developed. The adequacy of the developed methods of finite element modeling of dynamic processes in pipeline systems in the frequency range up to 400 Hz has been confirmed.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70177191","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 : 2021-01-01DOI: 10.36336/akustika2021418
V. Krutova, B. Meskhi
The coefficient of vibrational energy loss is a physical and mechanical characteristic, the accuracy of calculation of vibroacoustic characteristics of corresponding machines at the stage of their design to a great extent depends on its value.
{"title":"THEORETICAL STUDY OF THE CLOSED BAR LOOS FACTOR","authors":"V. Krutova, B. Meskhi","doi":"10.36336/akustika2021418","DOIUrl":"https://doi.org/10.36336/akustika2021418","url":null,"abstract":"The coefficient of vibrational energy loss is a physical and mechanical characteristic, the accuracy of calculation of vibroacoustic characteristics of corresponding machines at the stage of their design to a great extent depends on its value.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70177260","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 : 2021-01-01DOI: 10.36336/akustika202141205
A. Vasilyev
The factors influencing on the active noise and vibration control system efficiency of operation and the ways of the system protection improvement are discussed. Analysis of factors decreasing the efficiency of operation of active noise and vibration control systems in ducts is showing that there are such factors as physical characteristics of operating medium (temperature, pressure, moisture, vibrations, dust), masking acoustic and vibrating interferences of other sources of noise and vibration etc., which may significantly reduce the efficiency, reliability and durability of active systems operation. The ways of improvement of protection of the elements of the active noise and vibration control system are discussed. Further improvement of active noise control and vibration system elements protection allows the system to operate with higher efficiency and reliability. Widely, achieving of good results in the solution of this problem helps us to extend the possibilities of active noise and vibration control systems practical application.
{"title":"ANALYSIS OF THE FACTORS DECREASING THE EFFICIENCY OF OPERATION OF ACTIVE NOISE AND VIBRATION CONTROL SYSTEMS IN DUCTS AND THE WAYS OF IMPROVEMENT OF PROTECTION","authors":"A. Vasilyev","doi":"10.36336/akustika202141205","DOIUrl":"https://doi.org/10.36336/akustika202141205","url":null,"abstract":"The factors influencing on the active noise and vibration control system efficiency of operation and the ways of the system protection improvement are discussed. Analysis of factors decreasing the efficiency of operation of active noise and vibration control systems in ducts is showing that there are such factors as physical characteristics of operating medium (temperature, pressure, moisture, vibrations, dust), masking acoustic and vibrating interferences of other sources of noise and vibration etc., which may significantly reduce the efficiency, reliability and durability of active systems operation. The ways of improvement of protection of the elements of the active noise and vibration control system are discussed. Further improvement of active noise control and vibration system elements protection allows the system to operate with higher efficiency and reliability. Widely, achieving of good results in the solution of this problem helps us to extend the possibilities of active noise and vibration control systems practical application.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70176117","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 : 2021-01-01DOI: 10.36336/akustika20214194
M. Butorina, N. Ivanov, Alisa Troshchinina
Construction machinery is one of the most common noise sources in the environment and at the workplace. In Russia about 40% of all occupational injuries and 40% of the loss of working capacity are recorded at the construction sites. The noise levels at the operator’s position exceeds noise limits up to 40 dBA. However, personal hearing protection recommended in Russia can not provide sufficient noise reduction. To reduce construction noise administrative and engineering controls, substitution of noise with the standardization of noise emissions and replacing of noisier equipment with quieter items can be recommended. Administrative measures of noise reduction include reduction of work time, training and audiometric testing. To elaborate engineering controls a method of separation of noise sources with mathematical modelling was proposed. Basing on this method the most effective noise reduction measures were proposed that helped to reduce noise in the cabin of a backhoe by 6-7 dBA.
{"title":"NOISE REDUCTION AT WORKPLACE IN CONSTRUCTION","authors":"M. Butorina, N. Ivanov, Alisa Troshchinina","doi":"10.36336/akustika20214194","DOIUrl":"https://doi.org/10.36336/akustika20214194","url":null,"abstract":"Construction machinery is one of the most common noise sources in the environment and at the workplace. In Russia about 40% of all occupational injuries and 40% of the loss of working capacity are recorded at the construction sites. The noise levels at the operator’s position exceeds noise limits up to 40 dBA. However, personal hearing protection recommended in Russia can not provide sufficient noise reduction. To reduce construction noise administrative and engineering controls, substitution of noise with the standardization of noise emissions and replacing of noisier equipment with quieter items can be recommended. Administrative measures of noise reduction include reduction of work time, training and audiometric testing. To elaborate engineering controls a method of separation of noise sources with mathematical modelling was proposed. Basing on this method the most effective noise reduction measures were proposed that helped to reduce noise in the cabin of a backhoe by 6-7 dBA.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70176961","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 : 2021-01-01DOI: 10.36336/akustika202141173
A. Chukarin, B. Meskhi, David Shoniya
The acoustic characteristics of the planing machines, which are the most widespread and the most noisy metalworking equipment, are considered. The article presents the theoretical models of the process of noise generation of planing, slotting and planing-milling machines. Regularities of sound pressure levels and sound power are obtained for brittle materials (cast iron blanks) mounted on the machine table. The regularities of the vibration velocities of the cutting tool and the workpiece are derived. The system of second-order differential equations is obtained for the version of the cantilever fixing of the planing cutter, using the developed approaches to the calculating vibrations and noise of machine equipment.
{"title":"THEORETICAL ANALYSIS ON REGULARITIES OF THE PROCESS OF NOISE GENERATION OF PLANING, SLOTTING AND PLANING-MILLING MACHINES","authors":"A. Chukarin, B. Meskhi, David Shoniya","doi":"10.36336/akustika202141173","DOIUrl":"https://doi.org/10.36336/akustika202141173","url":null,"abstract":"The acoustic characteristics of the planing machines, which are the most widespread and the most noisy metalworking equipment, are considered. The article presents the theoretical models of the process of noise generation of planing, slotting and planing-milling machines. Regularities of sound pressure levels and sound power are obtained for brittle materials (cast iron blanks) mounted on the machine table. The regularities of the vibration velocities of the cutting tool and the workpiece are derived. The system of second-order differential equations is obtained for the version of the cantilever fixing of the planing cutter, using the developed approaches to the calculating vibrations and noise of machine equipment.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70175810","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 : 2021-01-01DOI: 10.36336/akustika202141178
Natalya Yaitskova, M. Tchavychalov, Ivan Yaistskov
The article describes the features of the occurrence of vibroacoustic activity of a promising type of electric motors – switched reluctance. Explanations of the mechanism of occurrence of an increased level of vibrations and noise from the action of unbalanced radial forces of interaction between the stator and the rotor are given. The calculation of radial forces for a valve-inductor motor is given, on the basis of which recommendations are given to reduce the impact of vibrations and noise from a running motor on a human.
{"title":"THEORETICAL RESEARCH OF THE SWITCHED RELUCTANCE MOTOR VIBROACOUSTIC ACTIVITY","authors":"Natalya Yaitskova, M. Tchavychalov, Ivan Yaistskov","doi":"10.36336/akustika202141178","DOIUrl":"https://doi.org/10.36336/akustika202141178","url":null,"abstract":"The article describes the features of the occurrence of vibroacoustic activity of a promising type of electric motors – switched reluctance. Explanations of the mechanism of occurrence of an increased level of vibrations and noise from the action of unbalanced radial forces of interaction between the stator and the rotor are given. The calculation of radial forces for a valve-inductor motor is given, on the basis of which recommendations are given to reduce the impact of vibrations and noise from a running motor on a human.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70175824","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 : 2021-01-01DOI: 10.36336/akustika20214140
L. Drozdova, V. Manokhin, E. Golovina, Alexander Kudaev
The main goal of the work is a comprehensive assessment of the impact of noise and dust in the foundry. Based on the results of the analysis, the main disadvantage areas with exceeding the permissible noise and dust level are presented – areas of knockout grates and casting cleaning areas. Recommendations are proposed for the selection of technical measures, including the rational placement of equipment, their mode of operation, the installation of acoustic screens and sound-insulating partitions near unprotected workplaces, as well as a rational selection of the equivalent sound absorption area of the workshop premises, which will create safe production conditions. Ways of improving the working conditions of operators of sand and shot blasting installations by reducing noise at their workplaces are considered: increasing sound absorption in the body of the shot blasting chamber and installing noise-protective shielding structures to fence off areas with the most intense noise.
{"title":"COMPREHENSIVE ASSESSMENT OF THE IMPACT OF AIR NOISE AND DUST ON FOUNDRY OPERATORS","authors":"L. Drozdova, V. Manokhin, E. Golovina, Alexander Kudaev","doi":"10.36336/akustika20214140","DOIUrl":"https://doi.org/10.36336/akustika20214140","url":null,"abstract":"The main goal of the work is a comprehensive assessment of the impact of noise and dust in the foundry. Based on the results of the analysis, the main disadvantage areas with exceeding the permissible noise and dust level are presented – areas of knockout grates and casting cleaning areas. Recommendations are proposed for the selection of technical measures, including the rational placement of equipment, their mode of operation, the installation of acoustic screens and sound-insulating partitions near unprotected workplaces, as well as a rational selection of the equivalent sound absorption area of the workshop premises, which will create safe production conditions. Ways of improving the working conditions of operators of sand and shot blasting installations by reducing noise at their workplaces are considered: increasing sound absorption in the body of the shot blasting chamber and installing noise-protective shielding structures to fence off areas with the most intense noise.","PeriodicalId":42295,"journal":{"name":"Akustika","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70176747","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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