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1
Spirin, Anatoly, Dmytro Borysiuk, Oleksandr Tsurkan e Igor Tverdokhlib. "NFLUENCE OF VIBRATION ON THE ERGONOMIC INDICATORS OF THE PRODUCTION PROCESS". Vibrations in engineering and technology, n. 1 (108) (1 maggio 2023): 45–56. http://dx.doi.org/10.37128/2306-8744-2023-1-5.
Abstract (sommario):
Features of the impact of industrial vibration, the nature, depth and direction of physiological changes of various body systems depend on the level, frequency composition of vibrations and physiological properties of the human body. Vibration is one of the main causes of occupational diseases. The study of the sources of production vibration, the ways of its propagation, the specifics of the impact on the human body and protection against harmful effects is currently an urgent issue. The analysis of the latest sources shows that the majority of works consider individual elements of a complex system of ergonomic provision of safe working conditions in case of vibrational impact on workers. Therefore, there is a need to deepen the study of this issue, comprehensive consideration of the causes of vibration, its characteristics and specific effects on the worker's body, planning measures and means to minimize the consequences of its negative effects. There are two types of vibration: local, which primarily affects those organs of the human body that are in direct contact with vibrating elements, and general vibration, which causes the body to move in space and affects the entire body. The main parameters of vibration are amplitude and frequency of oscillations, speed and vibration acceleration. The effect of general vibration on the central nervous system leads to a disturbance in the balance between excitation and inhibition. Under the influence of vibration, workers become irritable, get tired quickly, feel drowsy (and sometimes, on the contrary, insomnia), work capacity decreases, the time it takes to complete production tasks increases, and the time of simple and complex reactions increases. The fight against the harmful effects of mechanical vibrations in most cases boils down to compliance with existing norms and rules. Also, a special role is played by means of protecting workers from the harmful effects of vibration. First of all, this is the improvement of the design of vehicles, machines, mechanisms and tools.
2
Ryazancev, V., M. Gerasimov e Y. Brazhnik. "REDUCTION OF DIFFERENTLY DIRECTIONAL VIBRATIONS TO ASYMMETRICAL BY CHANGING THE RATIO OF VALUES COMPOSING THE DRIVING FORCE". Bulletin of Belgorod State Technological University named after. V. G. Shukhov 6, n. 5 (18 maggio 2021): 87–94. http://dx.doi.org/10.34031/2071-7318-2021-6-5-87-94.
Abstract (sommario):
Vibrating machines play a primary role in the implementation of programs in the construction and road construction kit. The improvement of vibration machines allows to significantly increase the speed of construction and road construction work. The main working unit of a vibrating machine is a vibrating device or vibrator. Currently, in the industry, vibration devices are used with circular or directional, along a certain straight line of vibrations. Further improvement of vibrating machines is carried out in the direction of creating vibration devices with asymmetric vibrations. At present, there are practically no vibrating machines with asymmetric vibrations. These machines allow to distinguish between the "working" process phase and the "idle" phase within each oscillation period. Moreover, the value of the driving force in the phase of performing useful work is several times higher than the value of the driving force in the direction of idling. Therefore, much less work is spent on idling. This allows to get rid of massive elements - overloads that extinguish the magnitude of the driving force in the direction of idling. Therefore, the urgency is to develop a method for converting existing machines with directional vibrations into asymmetric ones, with a given coefficient of asymmetry of the driving force. This makes it possible to reduce the specific indicators of the metal consumption of vibrating machines and the energy consumption of the work performed.
3
Bespalov, A. L., e I. G. Svidrak. "Universalization of the elastic system of vibration feeders with vertical electromagnetic vibration drive". Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies 24, n. 97 (28 giugno 2022): 41–45. http://dx.doi.org/10.32718/nvlvet-f9707.
Abstract (sommario):
Vibrating feed bins with electromagnetic drive are widely used in the automation of production processes in mechanical engineering and instrument engineering. They are used for feeding miniature, small, or medium-sized parts to automated production equipment. This equipment is used in automatic lines, automated complexes, or any other flexible automated production facilities. These devices are most widely used for loading parts to assembly positions in automated assembly complexes. In this case, the parts fed to these positions must be located in a certain stable position. Various orientation tools are used for this purpose. They are located directly on the transport trays in the bins of these devices. Therefore, for reliable operation of orientation devices, the movement of parts on the trays should be smooth without sensitive tossing. The designs of vibrating hopper feeders with a hopper connected to a reactive plate by a directional elastic system in the form of a lattice torsion bar are considered. An electromagnetic vibration exciter is placed between the torsion flanges. The disadvantage of such vibration feeders is low productivity in operating modes, especially when there are increased requirements for the smooth movement of transported parts. An increase in the productivity of such feeders is carried out by increasing the amplitude of hopper vibrations in the direction of movement of parts, that is, the horizontal component of vibrations. However, this also leads to an increase in the vertical component, since vibrations are carried out at an angle to the feeder transport tray. When the vertical component of vibrations increases, the transportation of parts switches to the intensive tossing mode. A further increase in the oscillation amplitude leads to a violation of the normal mode of vibrational transport. Modern production involves the modernization of existing structures, as well as the creation of new models of machines with high technical and economic indicators Therefore, the universalization of existing equipment and the development of new machine schemes is an important task for developers and manufacturers of technological equipment, since even a minimal improvement in its technological or operational indicators can lead to a significant economic effect. The paper considers a complex of additional elements used that make it possible to universalize the design of vibrating hopper feeders with electromagnetic drives having a directional elastic system. These changes make it possible to adjust the horizontal component of the device hopper vibrations at a constant vertical one. Additional structural elements are proposed that increase the range of application of such feeders.
4
Kiyko, V. N., N. M. Naumovich, M. V. Davydov e V. I. Zhuravliov. "Use of Cable Vibration Isolators for Vibration Protection of Quartz Generators". Doklady BGUIR 21, n. 4 (29 agosto 2023): 63–70. http://dx.doi.org/10.35596/1729-7648-2023-21-4-63-70.
Abstract (sommario):
Vibration isolators with damping properties of steel multiwire cables for vibration protection of quartz oscillators have been studied. Modeling of vibration characteristics of structural elements was carried out using numerical methods. The elastic characteristics and design parameters of the cable for the vibration isolator are calculated. A harmonic analysis was carried out with given values of mass and stiffness under the influence of external vibrations. A sample of a cable vibration isolator has been developed and manufactured. To verify the calculated results obtained, the structure of the test bench is proposed, which allows determining the values of na tural re sonant frequencies. The study of the dependence of vibration acceleration on the frequency of oscillations with a disturbing effect according to the sinusoidal and random laws with a variable frequency in the range of 10–2000 Hz was carried out. Tests of the cable vibration isolator have shown the effectiveness of vibration suppression for frequencies above 120 Hz. In the lower range of random vibrations, various resonances have a significant effect on each other. The experiments confirmed the simulation results and the effectiveness of the solution used: the difference in indicators in determining the resonant frequencies was less than 10 % with a decrease in the vibration level to a given indicator.
5
Dzhabborov, N., A. Dobrinov e A. Sergeev. "Vibration parameters and indicators of a dynamic tillage tool". IOP Conference Series: Earth and Environmental Science 937, n. 3 (1 dicembre 2021): 032048. http://dx.doi.org/10.1088/1755-1315/937/3/032048.
Abstract (sommario):
Abstract According to domestic and foreign research on the efficiency of active and passive vibrating tillage tools, the created vibration allows reducing the traction resistance of tillage implements compared to conventional tools, while improving the tillage quality. The study aimed to determine several vibration parameters and indicators of a dynamic tillage tool supplied with an energy storing and transmitting device: frequency and amplitude of oscillations, absolute velocity, vibration velocity, acceleration of vibration, a force of inertia, and oscillation energy. The study applied the energy assessment methods of tillage tools with the measuring and information system designed at IEEP – branch of FSAC VIM; analysis and generalisation of experimental data. Vibration variables were determined by the strain-gauge method. The study revealed a significant effect of oscillation frequency and amplitude of the tillage tool, depending on the machine travel speed and characteristics of elastic elements, on its vibration velocity and acceleration, the force of inertia and the energy of oscillations.The total increase in these forces owing to a high-frequency dynamic impact may affect the soil layer considerably as an additional loosening. The accumulated impact energy can provide a decrease in the traction resistance of the tillage tool.
6
Sánchez, Réne-Vinicio, Pablo Lucero, Jean-Carlo Macancela, Higinio Rubio Alonso, Mariela Cerrada, Diego Cabrera e Cristina Castejón. "Evaluation of Time and Frequency Condition Indicators from Vibration Signals for Crack Detection in Railway Axles". Applied Sciences 10, n. 12 (25 giugno 2020): 4367. http://dx.doi.org/10.3390/app10124367.
Abstract (sommario):
Railway safety is a matter of importance as a single failure can involve risks associated with economic and human losses. The early fault detection in railway axles and other railway parts represents a broad field of research that is currently under study. In the present work, the problem of the early crack detection in railway axles is addressed through condition-based monitoring, with the evaluation of several condition indicators of vibration signals on time and frequency domains. To achieve this goal, we applied two different approaches: in the first approach, we evaluate only the vibrations signals captured by accelerometers placed along the longitudinal direction and, in the second approach, a data fusion technique at the condition indicator level was conducted, evaluating six accelerometers by merging the indicator conditions according to the sensor placement. In both cases, a total of 54 condition indicators per vibration signal was calculated and selecting the best features by applying the Mean Decrease Accuracy method of Random Forest. Finally, we test the best indicators with a K-Nearest Neighbor classifier. For the data collection, a real bogie test bench has been used to simulate crack faults on the railway axles, and vibration signals from both the left and right sides of the axle were measured. The results not only show the performance of condition indicators in different domains, but also show that the fusion of condition indicators works well together to detect a crack fault in railway axles.
7
Tian, Kunpeng, Jicheng Huang, Bin Zhang, Aimin Ji e Zhonghua Xu. "Study on the Impact of Cutting Platform Vibration on Stalk Cutting Quality in Industrial Hemp". Agriculture 14, n. 2 (18 febbraio 2024): 321. http://dx.doi.org/10.3390/agriculture14020321.
Abstract (sommario):
In response to the unclear impact of header vibration on cutting performance (stalk cutting quality and cutting energy consumption) during field operations of industrial hemp harvesters, this study utilized a vibration recorder to collect information on header vibration during the operation of industrial hemp harvesters. Through data processing, the dominant range for the resonant frequency and amplitude of the cutting platform is primarily concentrated between 5–45 Hz and 0–35 mm, respectively. Using numerical simulation techniques, a quadratic orthogonal rotation combination experiment was conducted with vibration frequency and amplitude as experimental factors and stalk cutting quality and cutting energy consumption as indicators. Regression equations were established to reveal the relationships between indicators and factors, elucidating the influence of each factor and its interactions on the indicators. Specifically, for the crack length indicator, the amplitude has a highly significant influence on the model, and there is a significant interaction effect between vibration frequency and amplitude on the model. As for the cutting energy consumption indicator, frequency and the interaction between frequency and amplitude significantly affect the model, while amplitude has an extremely significant impact on the model. Through comprehensive fuzzy evaluation, the optimal vibration parameter combination satisfying comprehensive cutting performance indicators was determined as a vibration frequency of 37.86 Hz and an amplitude of 5.34 mm. Furthermore, the reliability of the model has been further validated. This research can provide a reference for improving the field performance of industrial hemp harvesters.
8
Shpachuk, V. P., M. A. Zasiadko, T. O. Suprun e V. V. Dudko. "Variation coefficient of torsional vibrations of the connection nodes of vibrating machines". Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu, n. 6 (2021): 85–89. http://dx.doi.org/10.33271/nvngu/2021-6/085.
Abstract (sommario):
Purpose. To formalize the dependence of the eigenfrequencies of translational and torsional vibrations of the structural elements of the vibrating machine articulated by the connection node on their design parameters and mechanical characteristics, as well as regulatory requirements for vibration activity, strength and accuracy. To develop a method for selecting the design parameters of the elastic band element of the package, taking into account the specified values of the amplitude and frequency characteristics of the dynamic loads reproduced by the supporting structure and the coefficient of variation of the natural frequencies of translational and torsional vibrations. Methodology. The research is based on fundamental approaches of applied mechanics, machine dynamics and vibration reliability. Findings. The dependences of the eigenfrequencies of torsional vibrations of the body parts of the vibrating machine connected by the connection node on their design parameters and mechanical characteristics are obtained and analyzed. Vibrations around an axis orthogonal to the working direction of the node are considered. A comparative analysis of the natural frequencies of the node in the direction of the transmitted vibration and its circular vibrations from the design parameters and mechanical characteristics of the elastic band elements, their number in the package and the number of packages in the connection node is performed. Originality. It is in the fact that for the first time the dependences describing the natural frequencies of translational and torsional vibrations of the body parts of a vibrating machine, articulated by a package of elastic band elements, are obtained. Also the paradigm for the choice of design parameters and mechanical characteristics of the elastic band element of the package, which is based on the results of a comparative analysis of the eigenfrequencies of vibrations in the working and connected directions through their coefficient of variation is innovative. This made it possible to include the criterion of vibration reproduction accuracy, which is formalized through the coefficient of frequency variation, together with the criteria of strength and rigidity, in the methodology of synthesis of the structural scheme of the vibrating machine. Practical value. The proposed methodological solutions for the calculation and selection of design parameters and mechanical characteristics of tape elastic elements ensure the achievement of vibration activity indicators of articulated parts, as well as the ratio of natural vibration frequencies in the working and related directions at the level of the requirements of normative documents when upgrading existing machines and creating new modern equipment. As a result, the reliability, durability, safety, productivity and load-bearing capacity of machines, equipment and mechanisms of mining engineering, aviation, transport and space technology are increased.
9
Zedgenizov, V. G., e S. Kh Faizov. "Research results of resonant vibration equipment for compaction of concrete mixtures on a physical model". Russian Automobile and Highway Industry Journal 21, n. 3 (18 giugno 2024): 366–75. http://dx.doi.org/10.26518/2071-7296-2024-21-3-366-375.
Abstract (sommario):
Introduction. The purpose of this article is to confirm the results of research on resonant vibration equipment for compacting concrete mixtures obtained using a mathematical model. The object of research is an oscillatory system of resonant vibration equipment consisting of two masses interconnected by elastic and dissipative elements. In addition, the first mass is connected to a fixed base through elastic and dissipative elements.Materials and methods. The main provisions of the theory of similarity and statistical processing of experimental data are used in the research. The required number of repeated experiments was determined statistically, and the reproducibility of the experiment was verified by the Cochran criterion. Results. The criteria and indicators of similarity of processes occurring in the system of resonant vibration equipment have been developed, formulas for the transition from the parameters of nature to the parameters of the physical model have been proposed. The technical characteristics of the physical model are presented.During the experiment, oscillograms of the movements of the vibrator and the working body which are shifted relative to each other by an angle of π/2 were obtained. At the same time, the amplitude of vibrations of the vibrator significantly exceeds the amplitude of vibrations of the working body.Discussions and conclusions. The presented dependences of the amplitudes obtained on mathematical and physical models qualitatively repeat each other. In the studied frequency range of the driving force, the maximum error is 12%. This confirms the results obtained on the mathematical model of resonant vibration equipment.
10
Bespalov, A. L., I. G. Svidrak e O. O. Boiko. "Improving the performance of vibration feeders with an electromagnetic vibration drive and a combined vibration system". Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies 22, n. 93 (13 maggio 2020): 26–30. http://dx.doi.org/10.32718/nvlvet-f9305.
Abstract (sommario):
Vibration loading devices are widely used in various branches of mechanical engineering to load piece blanks of automatic machines and automatic lines as well as robotic systems, automated systems and flexible automated production. Vibration devices for transportation and loading of miniature, small and medium-sized products are the most widely used. Modern designs of vibratory feeders, made according to the classical dynamic scheme and having a two-mass oscillating system, do not fully use the energy of the vibratory exciter to perform useful work. In addition, due to the presence of a heavy reactive mass, they have a fairly large weight. When the vibrating feeder is operating, the energy of the vibration exciter is spent on pumping both the hopper, which performs useful work, and the reactive plate, which performs idle vibrations. Thus, part of the energy of the vibration exciter is not used for performing useful work, but is spent idly. To increase the efficiency of the device, increase its performance and reduce its weight and metal consumption, it is necessary to change the design of the vibratory feeder and some of its elements, which affect the redistribution of the oscillation amplitudes of the working (hopper) and reactive mass of the vibratory feeder. Modern production involves the creation of new models of machines with high technical and economic indicators, therefore, improving the efficiency of existing equipment and the development of new schemes of machines is an important task for designers and manufacturers of technological equipment, as the minimum improvement of its technological and operational performance can lead to a tangible economic effect. To solve this problem we developed a new design vibrating hopper feeder, in which the increase of the horizontal component of the oscillation amplitude of the working element (hopper) is not at the expense of increased power of the vibratory exciter, but due to internal redistribution of energy between the elements of the oscillating system that makes better use of the energy of the vibratory exciter to perform useful work, i.e. to increase the coefficient of useful action. In addition, the weight and metal content of the vibrating feeder structure are simultaneously reduced.
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Sladkova, L. A., e A. N. Neklyudov. "Dynamics of the Rolling Stock and the Choice of Parameters of Vibration Dampers". World of Transport and Transportation 19, n. 4 (12 gennaio 2022): 13–20. http://dx.doi.org/10.30932/1992-3252-2021-19-4-2.
Abstract (sommario):
Modern railway rolling stock should meet requirements regarding comfort (maximum travel speed with minimum vibrations of wagons, noiselessness of movement, etc.).To eliminate the influence of dynamic loads, rolling stock is equipped with vibration dampers. The objective of the work is to select the parameters of the vibration dampers of rolling stock, depending on its characteristics, to ensure the due indicators of comfort and safety of transportation of passengers and goods by rail. To achieve this objective, applied methods of mathematical modelling were based on numerical programming of operation of dynamic systems. The indicators of vibration dampers are evaluated according to the results of studies of the dynamics of the rolling stock (in particular, of vibration protection rates).Assessment of dynamic state of the rolling stock implies application of methods of mathematical and physical modelling, which include the development of a physical and mathematical model, a calculation algorithm, and computer programming. The study of the mathematical model by numerical methods makes it possible to carry out a multifactorial experiment using a large number of input parameters (factors) and to select the characteristics of vibration dampers that are optimal for the conditions under consideration.To solve dynamic problems, the harmonic perturbation model, which is the most widespread, was specified in the form of a sinusoid with a period corresponding to the rail length.A quantitative assessment of the vibration process (frequency, amplitude) makes it possible to identify the main processes occurring in the system under consideration under various types of external load. The introduced assumptions related to rigidity, mobility and geometric immutability of the system allow determining the methods for obtaining a mathematical model and considering the vibrations as flat ones.The equations were solved in MathCad Prime 4.0 package using the Runge–Kutta method with automatic step selection. The subsequent study of the properties of the dynamic system was carried out by changing the resistance parameter of dampers of the first stage of spring suspension, while recording the values of the amplitude of the vibrations of the system and the period.The analysis of the results has shown that the vibration period of the body and bogies under any changes in the resistance parameter of the damper remains unchanged, while rational parameters of resistance of axle box dampers have been revealed for specified indicators. Hydraulic vibration dampers with the revealed parameters used on rolling stock help to reduce wear and damageability of running gears, improve ride comfort and traffic safety, as well as to reduce repair and maintenance costs.
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Kundu, Pradeep, Ashish K. Darpe e Makarand S. Kulkarni. "An ensemble decision tree methodology for remaining useful life prediction of spur gears under natural pitting progression". Structural Health Monitoring 19, n. 3 (6 agosto 2019): 854–72. http://dx.doi.org/10.1177/1475921719865718.
Abstract (sommario):
This article presents an ensemble decision tree–based random forest regression methodology for remaining useful life prediction of spur gears subjected to pitting failure mode. The random forest regression methodology does not require an elaborate statistics background knowledge and has an inbuilt health indicator selection capability compared to other existing data-driven remaining useful life prediction approaches. A correlation coefficient parameter based on the residual vibration signal is used for monitoring and detecting the pitting progression in spur gears. The effectiveness of the correlation coefficient of the residual vibration signal is assessed over the other existing health indicators for pitting fault progression. To show the inbuilt best health indicator selection capability of the random forest regression model, initially, eight indicators (existing seven and the correlation coefficient of the residual vibration signal) were used for model training. In addition, the effect of fusing the vibration sensor data from multiple positions on the gearbox on prediction accuracy of the random forest regression model is also evaluated. The accuracy in the remaining useful life prediction is found to increase after fusing the correlation coefficient of the residual vibration signal based health indicator derived from the accelerometers located at multiple positions on the gearbox in comparison to data from a single accelerometer. Furthermore, the accuracy of the proposed methodology is tested and proven using five accelerated run-to-failure experimental data collected from the specially built test rig.
13
Susanto, Agus, Chia-Hung Liu, Keiji Yamada, Yean-Ren Hwang, Ryutaro Tanaka e Katsuhiko Sekiya. "Milling Process Monitoring Based on Vibration Analysis Using Hilbert-Huang Transform". International Journal of Automation Technology 12, n. 5 (5 settembre 2018): 688–98. http://dx.doi.org/10.20965/ijat.2018.p0688.
Abstract (sommario):
Vibration analysis is one method of machining process monitoring. The vibration obtained in machining is often nonlinear and of a nonstationary nature. Therefore, an appropriate signal analysis is needed for signal processing and feature extraction. In this research, vibrations obtained in the milling of thin-walled workpieces were analyzed using the Hilbert-Huang transform (HHT). The features obtained by the HHT served as machining-state indicators for machining process monitoring. Experimental results showed the effectiveness of the HHT method for detecting chatter and tool damage.
14
Elbek M. Mirjuraev, Askar U. Sadikov, Shokhrukh Sh Fatkhullaev, Mukaddaskhon A. Hamrakulova,. "Multiple Influence of Vibration on Biochemical Brain Indicators". Tuijin Jishu/Journal of Propulsion Technology 44, n. 4 (16 ottobre 2023): 6212–17. http://dx.doi.org/10.52783/tjjpt.v44.i4.2119.
Abstract (sommario):
Dysfunction of the nervous system is one of the main manifestations caused by vibration. With repeated exposure to vibration, significant changes in the activity of enzymes and the content of the studied substrates in the brain tissue of experimental animals are observed. The observed changes in the activity of enzymes and the content of the studied substrates of brain tissue and the associated disturbances in the basic biochemical metabolic processes may be the direct cause of serious disorders of the functions of the nervous system. According to research results, it was revealed that exposure to general vibration leads to disturbances in the process of transamination of alanine-, aspartic-amino acids, cholinesterase, the activity of enzymes of the tricarboxylic acid cycle (GDH, SDH and MDH), alkaline phosphatase, ribonuclease and lactate dehydrogenase, as well as the content of total protein, serotonin, histamine and acetylcholine in the brain of experimental animals.
15
Konieczny, Jarosław, Waldemar Rączka, Marek Sibielak e Janusz Kowal. "Energy Consumption of an Active Vehicle Suspension with an Optimal Controller in the Presence of Sinusoidal Excitations". Shock and Vibration 2020 (12 febbraio 2020): 1–11. http://dx.doi.org/10.1155/2020/6414352.
Abstract (sommario):
Control of vibration is a significant problem in the design and construction of vehicle suspensions. The usage of controlled suspensions is important due to ride comfort, driving safety, and vehicle road holding. The control law for such systems is usually determined as a solution of an optimisation problem with a quality indicator. The effectiveness of vibration reduction is possible to be improved in the entire useful frequency range of a system operation, but usually increasing external energy consumption is observed. An additional problem in the case of vehicle suspensions includes the necessity for increased vibration reduction at selected frequencies. This is related to the natural frequencies of the driver’s internal organs or to other reasons. The goal of this work is to find a compromise between efficiency of the suspension in terms of the aforementioned indicators and energy consumption in the presence of sinusoidal excitations. This paper presents a synthesis of a weighted multitone optimal controller (WMOC) for an active vibration reduction system. Energy limitation is taken into account by selection coefficients of the weighting matrix associated with the control signal vector. The control signal in this case is determined on the basis of the parameter estimation of the sinusoidal disturbances vector (PESDV). The vibration transmissibility function and the energetic indicators for the active suspension were determined while taking note of nonlinearities occurring in the actual vehicle. The analysis of energy indicators is presented, depending on the level of vibration reduction efficiency. The results were compared with referencing to LQR control strategy.
16
Lv, Saige, e Xiong Hu. "Research on Performance Degradation Assessment and Abnormal Health Status Detection of Quayside Crane Lifting Gearbox Based on Information Fusion". Journal of Marine Science and Engineering 11, n. 7 (18 luglio 2023): 1434. http://dx.doi.org/10.3390/jmse11071434.
Abstract (sommario):
In order to solve the problems of subjectivity in the extraction of traditional degradation features and incomplete degradation information contained in a single sensor signal, a performance degradation assessment and abnormal health status detection method based on information fusion for the quayside crane lifting gearbox is proposed. Firstly, the correlation between the vibration and temperature of the gearbox is analyzed; secondly, the Convolutional Neural Network (CNN) and entropy degradation features from the full fault cycle vibration and temperature data of the lifting gearbox are extracted respectively; then, the final degradation indicators of the vibration and temperature data are obtained, respectively, through feature optimization, and the fusion degradation indicator is obtained by combining the two indicators; finally, the performance degradation assessment and abnormal health status detection of the gearbox are carried out. The effectiveness and superiority of the proposed method in the performance degradation evaluation of the gearbox are verified by comparison, and the proposed method can identify the initial degradation point of the gearbox earlier than the method based on the single vibration degradation index and the method based on the fusion of the traditional vibration degradation feature and the temperature entropy degradation feature.
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Kryuchkov, A. N., S. M. Plotnikov, E. V. Sundukov e A. E. Sundukov. "Simulation model of oscillations of the “sun gear – satellites” pair of turboprop engine planetary reduction gearbox in the presence of defects of tooth flanks". VESTNIK of Samara University. Aerospace and Mechanical Engineering 18, n. 4 (21 gennaio 2020): 87–95. http://dx.doi.org/10.18287/2541-7533-2019-18-4-87-95.
Abstract (sommario):
Defects of planetary reduction gearboxes of turboprop engines often cause excitation of high-frequency oscillations that bring about failures of compressor structural elements. The vibration behavior of these reduction grarboxes is a broadband process with the presence of a large quantity of vibration components, which significantly complicates the search for informative diagnostic indicators of defects. In order to simplify the procedure of identifying the vibrations caused by defects of toothed gearing a simulation model of the vibration behavior of a turboprop engine differential gear unit is proposed. The model takes into account kinematics and design of the gearbox, determines the structure of its vibration behavior in the presence of defects on the tooth flanks. Using the example of a commonly occurring defect in the form of wear of the teeth of the “solar gear – satellites” pair the adequacy of the model to the actual vibration behavior of the mechanism is shown.
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Erduran, Emrah, Frida Kristin Ulla e Lone Næss. "A Framework for Long-Term Vibration-Based Monitoring of Bridges". Sensors 21, n. 14 (11 luglio 2021): 4739. http://dx.doi.org/10.3390/s21144739.
Abstract (sommario):
A new framework for long-term monitoring of bridges is proposed in order to negate (i) the impact of measurement uncertainties on damage detection in vibration-based structural health monitoring and (ii) the low sensitivity of damage indicators to low levels of damage. The framework is developed using three vibration-based damage indicators that have an intuitive physical correlation with damage: modal curvature, modal strain energy and modal flexibility. The article first quantifies the efficacy of these damage indicators when based on two observations, one from the undamaged state and one from the monitored state, in detecting and locating damage for different damage levels that are simulated on an 84-m long railway bridge. A long-term monitoring framework based on a new parameter defined as the frequency of the damage indicator exceeding the threshold value within a population of observations is developed. Impact of several factors including the damage location, damage indicator used in the framework, and the noise level on the success of the developed framework was investigated through numerical analysis. The new parameter, when used together with modal strain energy, was shown to provide a very clear picture of damage initiation and development over time starting from very low damage levels. Furthermore, the location of the simulated damage can be identified successfully at all damage levels and even for very high noise levels using the proposed framework.
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Minnivaleev, T. N., L. S. Kuleshova, I. G. Arslanov, A. A. Gizzatullina e A. N. Minnivaleev. "Influence of shock-vibration loads of drilling equipment on the drilling indicators of oil and gas wells". Journal of Physics: Conference Series 2176, n. 1 (1 giugno 2022): 012025. http://dx.doi.org/10.1088/1742-6596/2176/1/012025.
Abstract (sommario):
Abstract When drilling oil and gas wells, downhole and drilling wellhead equipment is subject to the influence of significant vibration processes of different directions with different amplitude-frequency characteristics. The paper describes the main sources of vibration of drilling equipment, which have a downhole origin. In this paper an amplitude-frequency characteristic of oscillatory processes of a drill string and their influence on drilling performance are given. In addition to the sources of fluctuations of the bottomhole nature of origin, sources of the wellhead nature can also be distinguished. Thus drilling mud pump is a generator of pulsations and beats of the pressure of drilling fluid, which in turn leads to the increase in the dynamics of the drilling tool, the appearance of torsional vibrations of downhole motors and bits. We established the negative influence of vibrations of the bottomhole assembly and drilling mud on the stability of the operation of hydraulic downhole motors, penetration on the bit, durability of the elements of the string and energy indicators of drilling. The proposed device allows reducing the amplitude of pressure fluctuations of the drilling fluid and drilling tool.
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Migal, Vasiliy, Shchasiana Arhun e Andrii Hnatov. "Vibration characteristics of tractor gearboxes". Vehicle and electronics. Innovative technologies, n. 21 (29 giugno 2022): 87–96. http://dx.doi.org/10.30977/veit.2022.21.0.07.
Abstract (sommario):
Problem. Improving the efficiency, quality, reliability and economy of tractor equipment is one of the most important tasks of modern society. This is due to the fact that in agriculture, tractors can perform up to 80% of various operations. The cost of production, product quality, compliance with the conditions of technological operations, etc. depend on the properties and reliability of tractors. The main factor limiting the effective use of tractors in agriculture is the problem of insufficient reliability of tractors, namely, the reliability of its individual components. One of the most important units is its gearbox. The existing methods for diagnosing tractor gearboxes are designed to detect damage, but they are not able to determine the quality of the gearbox at the design and manufacturing stage. Such an opportunity would greatly simplify the process of diagnosing tractor boxes. Goal. The purpose of the research is to assess the quality of design and manufacture of tractor boxes according to their vibration characteristics by identifying design and manufacturing defects, which will allow developing the ways to improve them. Methodology. Methods for detecting statistical data on the boundary values of structural vibrational parameters and their connection with the technical condition of tractors were used. Experimental research methods and mathematical methods for processing and modulating the results obtained were used as well as the methods of statistical calculation and comparison of vibration characteristics with permissible vibrations that do not affect the acceleration of the process of tractor parts wear. Results. Experimental studies of vibro-diagnostic characteristics of tractors were carried out. Studies were made to measure vibration diagnostic indicators; a spectral analysis of gearbox vibration was carried out. An assessment of the quality of manufacturing parts and assembly of tractor gearboxes was made. Such an assessment was carried out by analyzing the spread of the maximum and minimum vibration levels for a sample of gearboxes. Originality. An assessment was made of the possibilities of reducing vibration levels by observing the technology for the production of tractor boxes. This assessment was based on the analysis of minimum vibration levels of tractor boxes. Statistical processing of the results of experimental studies was carried out with the determination of the arithmetic mean, minimum and maximum vibrations, and the standard deviations of the vibration of gearboxes when the fourth gear of the third (transport) range is engaged. Practical value. Vibro-diagnostic characteristics of tractor boxes make it possible to evaluate the quality of design and manufacture by vibration levels. It was established that the vibration levels of boxes at the manufacturing stage reach 85-113 dB and exceed the permissible vibrations by 10-25 dB. The main sources of gearbox vibration are: defects in the quality of gears and bearing assemblies; their assembly, the use of low-quality bearings, large clearances of bearing fit in the housing, and the problem of gearbox assembly technology.
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Medina Santiago, Alejandro, Jorge Antonio Orozco Torres, Carlos Arturo Hernández Gracidas, Salvador Hernández Garduza e Javier Duarte Franco. "Diagnosis and Study of Mechanical Vibrations in Cargo Vehicles Using ISO 2631-1:1997". Sensors 23, n. 24 (7 dicembre 2023): 9677. http://dx.doi.org/10.3390/s23249677.
Abstract (sommario):
This study presents the design and implementation of an electronic system aimed at capturing vibrations produced during truck operation. The system employs a graphical interface to display vibration levels, ensuring the necessary comfort and offering indicators as a solution to mitigate the damage caused by these vibrations. Additionally, the system alerts the driver when a mechanical vibration that could potentially impact their health is detected. The field of health is rigorously regulated by various international standards and guidelines. The case of mechanical vibrations, particularly those transmitted to the entire body of a seated individual, is no exception. Internationally, ISO 2631-1:1997/Amd 1:2010 oversees this study. The system was designed and implemented using a blend of hardware and software. The hardware components comprise a vibration sensor, a data acquisition card, and a graphical user interface (GUI). The software components consist of a data acquisition and processing library, along with a GUI development framework. The system underwent testing in a controlled environment and demonstrated stability and robustness. The GUI proved to be intuitive and could be integrated into modern vehicles with built-in displays. The findings of this study suggest that the proposed system is a viable and effective method for capturing vibrations in trucks and informing drivers about vibration levels. This system has the potential to enhance the comfort and safety of truck drivers.
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Liferenko, Vladimir Yuryevich. "On separate reasons of vibration occurrence in passenger cars". Transport of the Urals, n. 1 (2020): 48–53. http://dx.doi.org/10.20291/1815-9400-2020-1-48-53.
Abstract (sommario):
One of most important ecological tasks for carriage engineering is the abatement of vibrations in passenger cars. Nowadays before forwarding to the consumer all produced and modernized car models pass a mandatory certification procedure. During the procedure all characteristics of cars are thoroughly investigated including vibroacoustic characteristics because the values of these indicators significantly affect health of passengers and staff. Nevertheless, data from medical examination of guards show that the number of illnesses caused by the influence of excessive vibration levels doesn’t decrease. The paper proposes a variant of the problem solution that allows decreasing levels of vibration in passenger cars at frequencies above 16 Hz.
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Buzzoni, M., E. Mucchi, G. D’Elia e G. Dalpiaz. "Diagnosis of Localized Faults in Multistage Gearboxes: A Vibrational Approach by Means of Automatic EMD-Based Algorithm". Shock and Vibration 2017 (2017): 1–22. http://dx.doi.org/10.1155/2017/8345704.
Abstract (sommario):
The gear fault diagnosis on multistage gearboxes by vibration analysis is a challenging task due to the complexity of the vibration signal. The localization of the gear fault occurring in a wheel located in the intermediate shaft can be particularly complex due to the superposition of the vibration signature of the synchronous wheels. Indeed, the gear fault detection is commonly restricted to the identification of the stage containing the faulty gear rather than the faulty gear itself. In this context, the paper advances a methodology which combines the Empirical Mode Decomposition and the Time Synchronous Average in order to separate the vibration signals of the synchronous gears mounted on the same shaft. The physical meaningful modes are selected by means of a criterion based on Pearson’s coefficients and the fault detection is performed by dedicated condition indicators. The proposed method is validated taking into account simulated vibrations signals and real ones.
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Zhang, Xun, Linghui Ruan, Yu Zhao, Xiaogang Zhou e Xiaozhen Li. "A frequency domain model for analysing vibrations in large-scale integrated building–bridge structures induced by running trains". Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 234, n. 2 (8 aprile 2019): 226–41. http://dx.doi.org/10.1177/0954409719841793.
Abstract (sommario):
Integrated building–bridge structures are increasingly common in high-speed railway stations, where the elevated track floor is directly subjected to train–track dynamic forces that result in excessive vibrations. The common methods of predicting the train-induced vibrations in large-scale IBBS are implemented in the time domain and can have prohibitively long computation times. This paper presents a frequency domain model for the vibration analysis of large-scale IBBS, with the aim of reducing the computation time while retaining sufficient accuracy. The model consists of three coupled subsystems: train, track, and IBBS. The train and track subsystems are investigated analytically, and the IBBS subsystem is solved numerically using a finite element method. The receptance technique is introduced to obtain the wheel/rail force. The force transmitted to the floor slab is treated as the vibration source of the IBBS subsystem. The simulated vibration levels in the IBBS subsystem are compared with those obtained from in situ measurements, and a good agreement is observed in terms of both magnitude and frequency dependence. The vibration responses of the IBBS subsystem at different locations of the track floor and the waiting floor are compared, and the influence of the track position is investigated. Finally, a parametric analysis is conducted with the aim of formulating anti-vibration measures, in which the carbody acceleration, rail displacement, and ballast acceleration are considered as key indicators. The force transmission, vibration transmission and IBBS vibrations are also investigated. The results indicate that using a ballast mat and enlarging the column cross-section are the two most promising measures for reducing the vibration levels.
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Ma, Li, Jianguo Zhang, Chen Xu, Xingping Lai, Qiang Luo, Chendong Liu e Kemin Li. "Comprehensive Evaluation of Blast Casting Results Based on Unascertained Measurement and Intuitionistic Fuzzy Set". Shock and Vibration 2021 (28 gennaio 2021): 1–14. http://dx.doi.org/10.1155/2021/8864618.
Abstract (sommario):
In order to make a scientific and accurate evaluation of blast casting results, according to the characteristics of blast casting-dragline stripping system, effective casting rate, looseness coefficient, limit vibration velocity, powder factor, fragmentation distribution, muck pile shape, boulder generation, damage degree of coal seam step, and dust pollution are selected as the evaluation indicators of blast casting results, and a classification standard is established. The unascertained measure theory was adopted to determine the membership degree of influencing factor indicator, which expanded the expression method of fuzzy information of evaluation indicators. The Analytic Hierarchy Process was used to determine the subjective weight of indicators, the entropy weight method was used to determine the objective weight of indicators, and the intuitionistic fuzzy set was used to express the range of the comprehensive weights of indicators. An evaluation model of blast casting results was constructed based on unascertained measurement and intuitionistic fuzzy set. The measured and processed data of blast casting in Heidaigou Open-Pit Coal Mine were calculated by the evaluation model. Besides, the sensitivity of indicator weights to the evaluation result of blast casting results was also analyzed. The results show that the blast casting results are level III (well). The effective casting rate ranks first in terms of the influence on the evaluation result, followed by damage degree of coal seam step, muck pile shape, looseness coefficient, powder factor, dust pollution, limit vibration velocity, and boulder generation/fragmentation distribution, and it was proved that the weight fluctuation of the evaluation indicator has no obvious correlation with weight.
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Kuprina, Nadezhda I., Ekaterina V. Ulanovskaya e Olga A. Kochetova. "Ultrasound features of peripheral angiodistonic syndrome of the upper extremities in vibration disease". Russian Journal of Occupational Health and Industrial Ecology 60, n. 11 (3 dicembre 2020): 815–17. http://dx.doi.org/10.31089/1026-9428-2020-60-11-815-817.
Abstract (sommario):
Introduction. Vibration disease (VD) is an example of the most common pathology due to the systematic exposure of the worker to intense vibration with sufficient work experience, the main manifestation of which is peripheral angiodystonic syndrome. The aim of study was to learn the features of peripheral blood flow in the arteries of the forearm in vibration disease using the ultrasound method. Materials and methods. The radial and ulnar arteries in patients with vibration disease were examined by ultrasound in B- and PW-mode. These materials present the results of an ultrasound assessment of the speed indicators of the main arteries of the forearm in vibration disease stages 1 and 2. The selection criteria for patients in the study ware the presence of pronounced clinical manifestations of angiodystonic syndrome in vibration disease, confirmed by instrumental research methods and data on the sanitary and hygienic characteristics of working conditions, the absence of cardiovascular chronic diseases (ischemic heart disease, heart defects, rhythm and conduction disturbances), rheumatic, oncological, infectious diseases, osteo-traumatic changes in the upper extremities. Results. The groups of patients with the established diagnosis of vibration disease of 1 and 2 degrees were studied. With vibration disease stage 1 a decrease in the pulse velocity of blood flow was observed in isolation on the ulnar artery and an increase in peripheral resistance (pulsation index and resistance index) in the radial and ulnar arteries symmetrically on both upper extremities. The second stage of vibration disease differed from the first by a more significant decrease in speed indicators both on the ulnar and radial arteries on both sides, symmetrically in combination with a more pronounced increase in peripheral resistance indicators on both main arteries of the forearm (pulsation index and resistance index). The revealed changes were determined with the same frequency in men and women. Conclusions. A significant decrease in speed indicators on the ulnar artery and an increase in peripheral resistance indicators are detected already at the initial stages of vibration disease. Thus, the method of ultrasound examination of the main arteries of the middle caliber of the upper extremities is currently the only available and objective method for examining the vascular system in vibration disease.
27
Wang, Yan Yan, Jian Guo Yang e Zhou Ying Ji. "Study on Gasoline Engine Knock Indicators Based on Wavelet Transform and Rough Set". Advanced Materials Research 651 (gennaio 2013): 625–30. http://dx.doi.org/10.4028/www.scientific.net/amr.651.625.
Abstract (sommario):
In order to improve the knock diagnosis accuracy, knock tests were carried out on a gasoline engine, and the slight knock characteristics from vibration signals of the gasoline engine were extracted by wavelet transform method. Making use of sub-band signals which were generated by wavelet transform of vibration signals as the style signals, 23 time-domain parameters were studied by using rough set theory, and the redundant relationship of the various parameters for describing the knock characteristic was revealed. Finally, the best parameters combination of peak-to-peak value, mean amplitude and mean value was put forward as the knock indicators. The result shows that the indicators obtained by rough set theory can diagnose slight knock combustion, and the diagnostic accuracy is better than single indicator determination knock method.
28
Huang, Wei, Ahmed Farahat e Chetan Gupta. "Similarity-based Feature Extraction from Vibration Data for Prognostics". Annual Conference of the PHM Society 12, n. 1 (3 novembre 2020): 10. http://dx.doi.org/10.36001/phmconf.2020.v12i1.1298.
Abstract (sommario):
Many techniques for prognostics depend on estimating then forecasting health indicators that reflect the overall health or performance of an asset. For vibration data, health indicators are typically calculated by combining various vibration measurements along with derived features extracted from time, frequency or time-frequency domain analysis. However, selecting or handcrafting good features is a labor-intensive task. On the other hand, deep learning models might be able to learn health indicators automatically from vibration data but require large amount of training data, which are typically hard to obtain from real assets. In this paper, we propose an innovative similarity-based feature extraction method for vibration data which can then be used to learn health indicators and estimate remaining useful life of equipment. The method learns a set of representative templates of frequency spectra for both normal and failure states, and then calculates similarity-based features between new vibration data and the set of learned templates. These features are used to estimate health indicators which are then extrapolated to estimate the future health condition of the asset and its remaining useful life. The proposed method has been tested on the PRONOSTIA bearing dataset provided by FEMTO-ST Institute and achieved a higher accuracy in estimating the remaining useful life of bearings compared to other studies. The results demonstrate the effectiveness of the proposed method for assets with limited training data.
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Liu, Hao, Chengzhao Liu, Jiake Fu, Chenzhe Ma, Ye Zhang e Yumeng Lei. "Intelligent Analysis of Hydraulic Concrete Vibration Time Based on Convolutional Neural Network". Advances in Civil Engineering 2023 (7 ottobre 2023): 1–11. http://dx.doi.org/10.1155/2023/5530102.
Abstract (sommario):
The vibrating of concrete is one of the most important procedures that directly determines the quality of construction projects. The concrete vibration quality in field construction is mainly judged by the experience of workers, lacking quantitative indicators, and necessary supervision. However, the lack of research about concrete vibration quality led to these problems are still existing. There are some methods are proposed that are too difficult, or too expensive to use in field construction. Combined with the pouring project of Jianquan Pumped Storage Power Station in Yunyang, China, this research developed an intelligent detection system for concrete vibration time. The system took the convolutional neural network as the basic framework, and divided the concrete vibration process into three different states: vibrating, not vibrating, and no vibration tube, realized the concrete vibration time through the analysis of concrete vibration video data. The detection of concrete vibration process video with multiple stages in the actual project shows that the detection error of the system for each state is kept within 1 s, the accuracy is high, which can meet the quality management requirements of the construction process. The system can be quickly deployed to the construction site by using mobile phones, cameras, and other common equipment. It has the advantages of simple frame structure, low hardware requirements, and accurate detection results. In addition, the current system training process is only for the concrete pouring process of Jianquan Power Station, and the training sample can be further expanded in the future to enhance the applicability and accuracy of the system in other engineering applications in order to play a better role.
30
Buyalsky, V. I. "The Dynamic Analysis of Optimizing Function Within the Limits of Vibration Rotor Systems of Wind Electric Installation". Intellekt. Sist. Proizv. 20, n. 2 (26 giugno 2022): 50–60. http://dx.doi.org/10.22213/2410-9304-2022-2-50-60.
Abstract (sommario):
The problem of construction of basic and optimizing function within the limits of dynamic analysis of rotor systems wind-power installation vibrating fields, as one of subtasks of the mathematical algorithms of system dynamic behavior to modify wind-electric installation automatic control is solved that provides reduction of vibrations of all rotor system elements at different modes of operation power-unit of drive loading that promotes improvement of reliability indicators modern wind- installation components. Optimizing function has essential advantage with respeсt to the basic one as a result of minimization of portions with visible and peak vibrations within the frequence range of 190 - 310 rad/sec that is characteristic for negative cases of wind speed increase and reduction of electric power under different operation modes of wind-power installation. Measurement of vibration signal levels with obviously expressed peaks for the whole frequency range irrespectable to amplitude level is made, and calculation of longitudinal, bending and torsion fluctuations of own frequencies rotor-systems is executed. The dynamic analysis of frequency interactions of structural elements and power interactions of blade-elements on the basis of calculated data of dynamic factor for basic function vibrating portion at frequency 310 rad/sec with maximum vibration amplitude was carried out. The mimimum dynamic force transmitted makes 20.1 % from the total and it acts on longitudinal fluctuations of the rotor-system «wind wheel-control gear wheel», 100 % of maximum transferred dynamic force corresponds the second rotational frequency of 314 rad/sec which is resonant. The specified phenomena are not shown in the optimizing model as a result of vibrating portion absence for the investigated own frequencies and rotational fluctuations.
31
Bakinowski, Łukasz, e Bartosz Firlik. "Influence of the type of place occupied by a tram passenger on the ride comfort". Archives of Transport 62, n. 2 (30 giugno 2022): 49–58. http://dx.doi.org/10.5604/01.3001.0015.9176.
Abstract (sommario):
In cities with developed transport infrastructure, many people use public transport in their everyday lives. In order for the passenger's journey to be comfortable and for the passenger to travel more willingly by tram than by car, many conditions must be met. A passenger must feel comfortable in a public transport vehicle, which includes, among others: appropriate temperature in the vehicle, no crowding, the possibility to seat, the possibility of a quick vehicle-change, short travel time, no noise and many others. A very important criterion from the point of view of travel comfort is also the level of vibrations in the tram. A tendency can be noticed that vehicles with a low vibration level are rated much higher by public transport passengers and citizens. Vibration itself can also be an indirect cause of noise. The greater the noise, the greater the dissatisfaction of the passenger which indicates the high role of vibrations as a factor of passenger satisfaction or dissatisfaction. The aim of the work is to test and evaluate the vibration level in the partially low-floor Moderus Beta MF 02 AC tram manufactured by the company Modertrans Poznań in Poland. Assessed was be the vibration comfort in selected points of the vehicle, including the floor and passenger seat. The level of vibrations in trams of the same type were compared. Due to the lack of specific Polish regulations regarding the permissible level of vibration in trams, an attempt was made to compare the obtained results with railway standards requirements or for-eign countries requirements. The study proved that the level of vibrations differs in trams belonging to the same type. Significant damping of vibrations in the vertical direction by the passenger seat was observed. Maximum level of vibrations in the passenger area of the vehicle was observed on the floor above the bogie. It was found when compar-ing the values of vibration accelerations and comfort indicators with railway standards - that the Moderus Beta tram on the reference section of the track could be considered as a very comfortable vehicle.
32
Sandoval, Diego, Urko Leturiondo, Yolanda Vidal e Francesc Pozo. "Entropy Indicators: An Approach for Low-Speed Bearing Diagnosis". Sensors 21, n. 3 (27 gennaio 2021): 849. http://dx.doi.org/10.3390/s21030849.
Abstract (sommario):
To increase the competitiveness of wind energy, the maintenance costs of offshore floating and fixed wind turbines need to be reduced. One strategy is the enhancement of the condition monitoring techniques for pitch bearings, because their low operational speed and the high loads applied to them make their monitoring challenging. Vibration analysis has been widely used for monitoring the bearing condition with good results obtained for regular bearings, but with difficulties when the operational speed decreases. Therefore, new techniques are required to enhance the capabilities of vibration analysis for bearings under such operational conditions. This study proposes the use of indicators based on entropy for monitoring a low-speed bearing condition. The indicators used are approximate, dispersion, singular value decomposition, and spectral entropy of the permutation entropy. This approach has been tested with vibration signals acquired in a test rig with bearings under different health conditions. The results show that entropy indicators (EIs) can discriminate with higher-accuracy damaged bearings for low-speed bearings compared with the regular indicators. Furthermore, it is shown that the combination of regular and entropy-based indicators can also contribute to a more reliable diagnosis.
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Yamanin, A. I. "On Vibrational and Dynamic Characteristics of Engines with Deactivated Cylinders". Proceedings of Higher Educational Institutions. Маchine Building, n. 02 (719) (febbraio 2020): 26–34. http://dx.doi.org/10.18698/0536-1044-2020-2-26-34.
Abstract (sommario):
The article examines some features of dynamics of engines with shut-off cylinders. This technology can promote reduction of fuel consumption and emission of toxic substances with exhaust fumes at partial speed and loading modes. However, the dynamics of such engines have hardly been considered in previous works. Using calculations (solid state modeling, simulation of motion using software for studying dynamics of mechanisms, as well as the finite element method), the indicators of uniformity of stroke and torque, vibration displacement and vibration velocity of various points of the structure at low- and high-frequency vibration are determined. It is shown that when deactivating a different number of cylinders, the uniformity of the engine torque worsens (to a varying degree) and the load on the crankshaft bearings increases. The average quadratic values of vibration velocity of the bearings at low-frequency vibration and the vibration velocity of the lateral walls of the housing parts at high-frequency vibration increases as well. While engines with deactivated cylinders definitely have advantages in efficiency and environmental performance, they do not improve vibrational and dynamic characteristics, which is particularly evident at low rotational speeds of the shaft and at small loads.
34
Benrahmoune, Mohamed, Hafaifa Ahmed, Guemana Mouloud e Chen XiaoQi. "Detection and Modeling Vibrational Behavior of a Gas Turbine Based on Dynamic Neural Networks Approach". Strojnícky casopis – Journal of Mechanical Engineering 68, n. 3 (1 novembre 2018): 143–66. http://dx.doi.org/10.2478/scjme-2018-0032.
Abstract (sommario):
AbstractDuring the gas turbine exploitation the presence of small defects can cause very high vibration amplifications, localized on the components of this rotating machine. For this, a diagnostic process is necessary for decision-making during the monitoring of failures caused by vibration phenomena, which consists in observing the system by comparing its current data with the data coming from a normal operation. These indicators help engineer to determine the symptoms for the failing components of the system. This work deals with problems related to these vibrations, with the aim of developing a system of detection of failures using dynamic neural networks approach. The originality of this contribution is to calculate the various alarms based on this system which used the determined vibration models in order to ensure a reliable and safe operation of the gas compression installation using the examined gas turbine.
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Wu, Xi, e Jim Meagher. "A Two-Disk Extended Jeffcott Rotor Model Distinguishing a Shaft Crack from Other Rotating Asymmetries". International Journal of Rotating Machinery 2008 (2008): 1–11. http://dx.doi.org/10.1155/2008/846365.
Abstract (sommario):
A mathematical model of a cracked rotor and an asymmetric rotor with two disks representing a turbine and a generator is utilized to study the vibrations due to imbalance and side load. Nonlinearities typically related with a “breathing” crack are included using a Mayes steering function. Numerical simulations demonstrate how the variations of rotor parameters affect the vibration response and the effect of coupling between torsional and lateral modes. Bode, spectrum, and orbit plots are used to show the differences between the vibration signatures associated with cracked shafts versus asymmetric shafts. Results show how nonlinear lateral-torsional coupling shifts the resonance peaks in the torsional vibration response for cracked shafts and asymmetric rotors. The resonance peaks shift depending on the ratio of the lateral-to-torsional natural frequencies with the peak responses occurring at noninteger values of the lateral natural frequency. When the general nonlinear models used in this study are constrained to reduce to linear torsional vibration, the peak responses occur at commonly reported integer ratios. Full spectrum analyses of theXandYvibrations reveal distinct vibration characteristics of both cracked and asymmetric rotors including reverse vibration components. Critical speeds and vibration orders predicted using the models presented herein include and extend diagnostic indicators commonly reported.
36
Zhao, H., F. K. Choy e M. J. Braun. "Transient and Steady State Vibration Analysis of a Wavy Thrust Bearing". Journal of Tribology 128, n. 1 (22 giugno 2005): 139–45. http://dx.doi.org/10.1115/1.2033900.
Abstract (sommario):
This paper describes a numerical procedure for analyzing the dynamics of transient and steady state vibrations in a wavy thrust bearing. The major effects of the wavy geometry and the operating parameters on the dynamic characteristics of the bearing had been discussed in a previous paper; the present paper thus concentrates on examining the relationships between the development of the transient and steady state vibrations when operating conditions are parametrically varied. Special attention is given to the development of steady state vibrations from initial transients with comparisons and consequences to the overall system stability. Numerical based vibration signature analysis procedures are then used to identify and quantify the transient vibrations. The conclusions provide general indicators for designing wavy thrust bearings that are less susceptible to transients induced by external perturbations.
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Melentev, Andrey V., e Oleg A. Oshkoderov. "Assessment of the diagnostic significance of modern biomarkers and hemodynamic alterations in workers of vibration-hazardous occupations". HEALTH CARE OF THE RUSSIAN FEDERATION 65, n. 4 (7 settembre 2021): 379–83. http://dx.doi.org/10.47470/0044-197x-2021-65-4-379-383.
Abstract (sommario):
Introduction. One of the most significant tasks in modern labor medicine is to reduce the indicators of early disability in persons in contact with harmful and dangerous factors of the production environment. The issue of finding markers of early preclinical manifestations of vibrational disease and establishing comorbid conditions that are prognostically unfavorable for the course of the underlying occupational disease remains relevant. The purpose of the study is assessment of diagnostic significance of current neurospecific biomarkers and hemodynamic changes in workers of the profession related to vibration. Material and methods. The results of two studies were the basis for this work. The first, aimed at determining the concentration of neurospecific markers in the blood of miners, includes 154 working vibration hazardous professions. At the same time, groups were identified depending on the type of exposure to vibration: total (69 workers), local (24 workers) and combined general and local (61 miners) and control group of workers not in contact with vibration (49 people). The second study was performed to assess the change in hemodynamic parameters among 216 industrial workers, of which 114 people were in contact with vibration generating equipment, and 102 workers were included in the control group. Results. Data from the first study showed an increase in the titer of neuron-specific indicators, mainly protein S100B, depending on the type of exposure vibration and its seniority dose. The second study results indicated an increase in systolic blood pressure and total peripheral vascular resistance in miners under exposure to vibration factor. Conclusion. The results of both studies suggest that hemodynamic disorders and changes in the performance of neuro specific proteins may be interconnected. It seems advisable to continue the study in workers in vibrant occupations with comorbid pathology.
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Nanda, Bharadwaj, Aditi Majumdar, Damodar Maity e Dipak K. Maiti. "Performance Comparison among Vibration Based Indicators in Damage Identification of Structures". Applied Mechanics and Materials 592-594 (luglio 2014): 2081–85. http://dx.doi.org/10.4028/www.scientific.net/amm.592-594.2081.
Abstract (sommario):
A simple and robust methodology is presented to identify damages in a structure using changes in vibration data. A comparison is made among damage indicators such as natural frequencies, mode shape data, curvature damage factors and flexibility matrices to study their efficacy in damage assessment. Continuous ant colony optimization (ACOR) technique is used to solve the inverse problem related to damage identification. The outcome of the simulated results demonstrates that the flexibility matrix as a damage indicator provides better damage identification.
39
Bajric, Rusmir, Ninoslav Zuber, Georgios Alexandros Skrimpas e Nenad Mijatovic. "Feature Extraction Using Discrete Wavelet Transform for Gear Fault Diagnosis of Wind Turbine Gearbox". Shock and Vibration 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/6748469.
Abstract (sommario):
Vibration diagnosis is one of the most common techniques in condition evaluation of wind turbine equipped with gearbox. On the other side, gearbox is one of the key components of wind turbine drivetrain. Due to the stochastic operation of wind turbines, the gearbox shaft rotating speed changes with high percentage, which limits the application of traditional vibration signal processing techniques, such as fast Fourier transform. This paper investigates a new approach for wind turbine high speed shaft gear fault diagnosis using discrete wavelet transform and time synchronous averaging. First, the vibration signals are decomposed into a series of subbands signals with the use of a multiresolution analytical property of the discrete wavelet transform. Then, 22 condition indicators are extracted from the TSA signal, residual signal, and difference signal. Through the case study analysis, a new approach reveals the most relevant condition indicators based on vibrations that can be used for high speed shaft gear spalling fault diagnosis and their tracking abilities for fault degradation progression. It is also shown that the proposed approach enhances the gearbox fault diagnosis ability in wind turbines. The approach presented in this paper was programmed in Matlab environment using data acquired on a 2 MW wind turbine.
40
Tian, Zhi Gang, e Ming J. Zuo. "Spur Gear Crack Propagation Assessment Using Model-Based Analysis and Simulation". Key Engineering Materials 413-414 (giugno 2009): 299–304. http://dx.doi.org/10.4028/www.scientific.net/kem.413-414.299.
Abstract (sommario):
Model-based gear dynamic analysis and simulation has been a promising way for developing e®ective gearbox vibration monitoring approaches. In this paper, based on the dynamic model of a one-stage gearbox with spur gears and one tooth crack, we investigate statistical indicators and the discrete wavelet transform (DWT) technique to identify e®ective and sensitive health indicators for re°ecting the crack propagation level. Our results suggest that the root mean square (RMS) indicator is a good statistical indicator to re°ect the crack propagation in the early stage; DWT can improve the sensitivity of the RMS indicator and the RMS indicator becomes more sensitive with the increase of the DWT level.
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Yakimova, Natalya L., Vladimir A. Pankov, Aleksandr V. Lizarev, Viktor S. Rukavishnikov, Marina V. Kuleshova, Elena V. Katamanova, Evgeny A. Titov e Dina V. Rusanova. "Neurophysiological and morphological effects in the post-exposure vibration period during experimental modeling". Russian Journal of Occupational Health and Industrial Ecology, n. 5 (31 maggio 2019): 284–90. http://dx.doi.org/10.31089/1026-9428-2019-59-5-284-290.
Abstract (sommario):
Introduction. Vibration disease continues to occupy one of the leading places in the structure of professional pathology. In workers after the termination of contact with vibration generalization and progression of violations in an organism is noted. The pathogenetic mechanisms of the progredient course of disturbances in the nervous system in the post-contact period of vibration exposure remain insufficiently studied.The aim of the study was to test an experimental model of vibration exposure to assess the neurophysiological and morphological effects of vibration in rats in the dynamics of the post-contact period.Materials and methods. The work was performed on 168 white male outbred rats aged 3 months weighing 180–260 g. The vibration effect was carried out on a 40 Hz vibrating table for 60 days 5 times a week for 4 hours a day. Examination of animals was performed after the end of the physical factor, on the 30th, 60th and 120th day of the post-contact period. To assess the long-term neurophysiological and morphofunctional effects of vibration in rats, we used indicators of behavioral reactions, bioelectric activity of the somatosensory zone of the cerebral cortex, somatosensory and visual evoked potentials, parameters of muscle response, morphological parameters of nervous tissue.Results. In the dynamics of the post-contact period observed the preservation of violations of tentatively research, motor and emotional components of behavior. In the Central nervous system instability of activity of rhythms of an electroencephalogram, decrease in amplitude of visual evoked potentials, lengthening of latency of somatosensory evoked potentials, decrease in total number of normal neurons and astroglia is established. In the peripheral nervous system remained changes in indicators: increasing duration and latency, reducing the amplitude of the neuromuscular response.Conclusions: The experimental model allows us to study the long-term neurophysiological and morphological effects of vibration on the body. The formation and preservation of changes in behavioral activity, neurophysiological and morphological effects of vibration from the 30th to the 120th day of the post-contact period were confirmed.
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Delembovskyi, Maksym, e Oleksandr Diachenko. "METHODS FOR DETERMINING THE RELIABILITY INDICATORS OF VIBRATION SITES". ГРААЛЬ НАУКИ, n. 2-3 (8 aprile 2021): 263–70. http://dx.doi.org/10.36074/grail-of-science.02.04.2021.053.
Abstract (sommario):
The work is devoted to the issues of experimental research in order to ensure further effective improvement of the reliability of vibration sites. Today the problem is to determine the optimal margin of safety when calculating the strength depending on the predicted reliability criteria.
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Evans, Jack B., e Chad N. Himmel. "Lab vibration complaints due to secondary or questionable indicators". Journal of the Acoustical Society of America 130, n. 4 (ottobre 2011): 2345. http://dx.doi.org/10.1121/1.3654383.
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Múčka, Peter. "Correlation among Road Unevenness Indicators and Vehicle Vibration Response". Journal of Transportation Engineering 139, n. 8 (agosto 2013): 771–86. http://dx.doi.org/10.1061/(asce)te.1943-5436.0000558.
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Qiu, Lemiao, Ci He, Guodong Yi, Shuyou Zhang, Yang Wang, Yong Rao e Lichun Zhang. "Energy-Based Vibration Modeling and Solution of High-Speed Elevators Considering the Multi-Direction Coupling Property". Energies 13, n. 18 (15 settembre 2020): 4821. http://dx.doi.org/10.3390/en13184821.
Abstract (sommario):
Vibration of a high-speed elevator is one of the major factors contributing to a safe, stable and comfortable ride. Vibration control and systematic optimization rely on the establishment of an accurate and reliable model. An energy-based vibration model (EVM) is proposed in this paper to describe the multi-directional coupling properties of high-speed elevators. After analyzing the structural and kinematic characteristics, a combination of the kinematic energy, elastic potential energy and virtual works is implemented to describe the vibrational characteristics. The Gaussian precise integration method is implemented to obtain accurate solutions because of the infinite degrees of freedom and the time-varying parameters. An example study is conducted using the KLK2 high-speed elevator. EVM is established to obtain the Max(Pk)/Pk and A95 indices of the X, Y, Z axis vibrational acceleration through simulations. A comparison is proposed between the proposed EVM method, conventional methods based on differential-equation vibration model (DVM) and real prototype experimental data. Results show that the proposed EVM method could achieve more accurate results than the conventional DVM method. Deviations of these indicators are less than 5%, which suggest the efficiency, precision and reliability of the proposed EVM.
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Chkhaidze, Тengiz, Gabriel Merabishvili e Alexander Metreveli. "The Impact of Vibration Operational Reliability of Turning Mechanism of Gantry and Tower Cranes". Works of Georgian Technical University, n. 3(521) (29 settembre 2021): 92–101. http://dx.doi.org/10.36073/1512-0996-2021-3-92-101.
Abstract (sommario):
Impacts of vibration on operational reliability of turning mechanisms of gantry and rower cranes are considered. Besides that, the structural features of kinematic chain of drive, including gear transmission with internal large module teeth, roller bearing without retaining ring, excitement of torsional, bending low-frequency vibrations at operation in nominal mode of cargo lifting that causes the origination of of increasing friction moment and stop of turning mechanism are researched in this article. Moreover, the technological and structural solutions aimed on decreasing of excited vibrations are proposed, and the supporting-rotating rolling bearings without retaining ring with improved technical-economic indicators are considered.
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Zhang, Shiming, Ruifu Zhang e Zhipeng Zhao. "Demand-Based Optimal Design of Storage Tank with Inerter System". Shock and Vibration 2017 (2017): 1–14. http://dx.doi.org/10.1155/2017/2956153.
Abstract (sommario):
A parameter optimal design method for a tank with an inerter system is proposed in this study based on the requirements of tank vibration control to improve the effectiveness and efficiency of vibration control. Moreover, a response indicator and a cost control indicator are selected based on the control targets for liquid storage tanks for simultaneously minimizing the dynamic response and controlling costs. These indicators are reformulated through a random vibration analysis under virtual excitation. The problem is then transformed from a multiobjective optimization problem to a single-objective nonlinear problem using the ε-constraint method, which is consistent with the demand-based method. White noise excitation can be used to design the tank with the inerter system under seismic excitation to simplify the calculation. Subsequently, a MATLAB-based calculation program is compiled, and several optimization cases are examined under different excitation conditions. The effectiveness of the demand-based method is proven through a time history analysis. The results show that specific vibration control requirements can be met at the lowest cost with a simultaneous reduction in base shears and overturning base moments.
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Guo, Jiang, Peidong Zhao e Pingfeng Li. "Prediction and Optimization of Blasting-Induced Ground Vibration in Open-Pit Mines Using Intelligent Algorithms". Applied Sciences 13, n. 12 (15 giugno 2023): 7166. http://dx.doi.org/10.3390/app13127166.
Abstract (sommario):
Prediction and parameter optimization are effective methods for mine personnel to control blast-induced ground vibration. However, the challenge of effective prediction and optimization lies in the multi-factor and multi-effect nature of open-pit blasting. This study proposes a hybrid intelligent model to predict ground vibrations using a least-squares support vector machine (LSSVM) optimized by a particle swarm algorithm (PSO). Meanwhile, multi-objective particle swarm optimization (MOPSO) was used to optimize the blast design parameters by considering the vibration of particular areas and the bulk rate of blast fragmentation. To compare the prediction performance of PSO-LSSVM, a genetic-algorithm-optimized BP neural network (GA-BP), unoptimized LSSVM, and BP were used, by applying the same database. In addition, the root-mean-squared error (RMSE), the mean absolute error (MAE), and the correlation coefficient (r) were regarded as the evaluation indicators. Furthermore, the optimization results of the blasting parameters were obtained by quoting the established vibration prediction model and bulk rate proxy model in MOPSO and verified by field tests. The results indicated that the PSO-LSSVM model provided the highest efficiency in predicting vibrations with an RMSE of 1.954, MAE of 1.717, and r of 0.965. Furthermore, the blasting vibration can be controlled by using the two-objective optimization model to obtain the best blasting parameters. Consequently, this study can provide more specific recommendations for vibration hazard control.
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Jotautienė, Eglė, Antanas Juostas e Shankar Bhandari. "Proper Technical Maintenance of Combine Harvester Rolling Bearings for Smooth and Continuous Performance for Grain Crop Agrotechnical Requirements". Applied Sciences 11, n. 18 (16 settembre 2021): 8605. http://dx.doi.org/10.3390/app11188605.
Abstract (sommario):
The threshing mechanism is the main component of the combine harvester on which the grain separation and cleaning qualitative work indicators depend. It is important to ensure that all threshing mechanism components, including the threshing drum bearings and all other bearings of the combine, are working properly and reliably. There are many places in the combine where it is not possible to measure bearing vibrations directly without dismounting them, since there is no suitable spot to mount a sensor. The paper investigates the threshing drum rolling bearing condition of combines, which are difficult to access, by using a vibration diagnostics technique utilizing a newly manufactured steel bracket. The vibration measurements and analysis were conducted by the Adash A4900 Vibrio M analyzer (Adash spol. s.r.o., Ostrava, Czech Republic). The vibration source measurement was based on the fast Fourier transform (FFT) spectrum analysis. Analysis of the experimental results showed that average squared velocity values (in the frequency interval of 10–1000 Hz), together with other measured vibration parameters, can be used for the combine threshing drum‘s bearing condition evaluation.
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Babanov, S. A., A. V. Melentyev, T. M. Kiryushina, T. A. Azovskova, N. E. Lavrentieva, N. V. Vakurova, V. S. Lotkov, A. S. Agarkova e D. G. Boguslavsky. "Quality of life in vibration disease from the effects of local vibration and its combination with osteoarthritis". Terapevt (General Physician), n. 12 (18 dicembre 2023): 58–66. http://dx.doi.org/10.33920/med-12-2312-06.
Abstract (sommario):
The article describes the features of the quality of life in vibration disease from exposure to local vibration and its combination with osteoarthritis. It has been proven that when exposed to industrial vibration, there is a change in all indicators characterizing the quality of life, which is most pronounced in second-degree vibration disease from exposure to local vibration and its combination with osteoarthritis.