Wyniki wyszukiwania - BazTech

1

Determination of a torsional vibration viscous damper’s operating temperature using a new thermohydrodynamic model

Homik Wojciech, Mazurkow Aleksander, Chmielowiec Andrzej

Transport Problems

|

2023

|

T. 18, z. 4

161--174

EN

This article presents an innovative algorithm and mathematical model of a torsional vibration viscous damper. The problem of torsional vibrations damping in a multicylinder internal combustion engine is extremely important for the reliable operation of a drive unit. The effective reduction of the vibration amplitude extends the service life and prevents failures that generate logistic and transport problems. One of the key parameters used to assess the quality of vibration damper operation is the temperature. This criterion is so important that it is the main indicator for the possible replacement of dampers installed in trucks, locomotives, and ships. Despite the importance of this parameter, the literature lacks mathematical models that describe the thermodynamics of damper operation. Therefore, the authors of this paper developed and presented an innovative thermohydrodynamic model of a torsional vibrations viscous damper, which was used to determine the operating parameters.

2

Transfer function for a controllable pitch propeller with added water mass

Leshchev Volodimir, Maslov Igor, Palagin Oleksandr, Naydyonov Andrii

Polish Maritime Research

|

2023

|

nr 4

74--80

EN

The relevance of this study lies in the fact that it presents a mathematical model of the dynamics of the propulsion system of a ship that takes into consideration the mass of water added to it. The influence of this phenomenon on the resonant frequencies of the propeller shaft is examined, and a transfer function for a controllable-pitch propeller is obtained for various operating modes. The purpose of the study is to improve the calculation of the dynamic operating modes of a controllable-pitch propeller by examining the features of a visual models. The VisSim software package is used in the study. A visual model is developed that considers the influence of the rotational speed on the value of the rotational inertia attached to the variable-pitch screw of the mass of water, and a special transfer function is proposed. The study shows that a transfer function of this type has a loop enabling negative feedback. An analysis of the operation of the propeller shaft at its resonant frequency is conducted based on the application of frequency characteristics using the transfer functions obtained. We show that in the low-frequency region, a consideration of the added rotational inertia using the proposed transfer function leads to a significant difference compared to the result obtained with the existing calculation method.

3

Suppression of rotating machine shaft-line torsional vibrations by a driving asynchronous motor using two advanced control methods

Hańczur Paweł, Szolc Tomasz, Konowrocki Robert

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2023

|

Vol. 71, nr 6

art. no. e147925

EN

Many industrial rotating machines driven by asynchronous motors are often affected by detrimental torsional vibrations. In this paper, a method of attenuation of torsional vibrations in such objects is proposed. Here, an asynchronous motor under proper control can simultaneously operate as a source of drive and actuator. Namely, by means of the proper control of motor operation, it is possible to suppress torsional vibrations in the object under study. Using this approach, both transient and steady-state torsional vibrations of the rotating machine drive system can be effectively attenuated, and its precise operational motions can be assured. The theoretical investigations are conducted by means of a structural mechanical model of the drive system and an advanced circuit model of the asynchronous motor controlled using two methods: the direct torque control – space vector modulation (DTC-SVM) and the rotational velocity-controlled torque (RVCT) based on the momentary rotational velocity of the driven machine working tool. From the obtained results it follows that by means of the RVCT technique steady-state torsional vibrations induced harmonically and transient torsional vibrations excited by switching various types of control on and off can be suppressed as effectively as using the advanced vector method DTC-SVM.

4

Diagnostics of the internal combustion engines operation by measurement of crankshaft instantaneous angular speed

Dereszewski Mirosław, Sikora Grzegorz

Journal of KONBiN

|

2019

|

Vol. 49, iss. 4

281--295

EN

Diagnostics based on measuring of crankshaft instantaneous rotational speed allows precise location of damage to the injection system and detection of external disturbances. Active measurement of instantaneous rotational speed requires use of equipment with high sensitivity, permanent assembly at the ends of the crankshaft and the analysis of a very large amount of data. Presented method can be used for measurement of torsional vibration of crankshaft, indirectly through simultaneous measurement of the width of the pulses generated by the encoder disks. Momentary, relative displacement of both disks determines the angle of temporary crankshaft twisting. This paper presents first results of pulse width measurement, obtained by using described system.

PL

Diagnostyka metodą pomiarów chwilowej prędkości obrotowej wału korbowego umożliwia precyzyjną lokalizację uszkodzeń układu wtryskowego oraz wykrywanie zakłóceń zewnętrznych. Aktywny pomiar chwilowej prędkości obrotowej wymaga zastosowania aparatury o dużej czułości, trwałego montażu na końcach wału korbowego oraz analizy bardzo dużej ilości danych. Przedstawiona metoda może posłużyć do obliczania drgań skrętnych wału korbowego pośrednio poprzez symultaniczny pomiar szerokości pulsów generowanych przez tarcze enkoderów. Chwilowe, względne przemieszczenie obu tarcz określa kąt chwilowego skręcenia wału korbowego. W artykule przedstawiono wyniki pierwszych pomiarów szerokości impulsów, uzyskane na opisanym stanowisku badawczym.

5

Wpływ wzrostu dawki paliwa na zmiany amplitud składowych harmonicznych drgań skrętnych wału zespołu spalinowo-elektrycznego

Drewing S., Dereszewski M.

Zeszyty Naukowe Akademii Morskiej w Gdyni

|

2018

|

nr 108

34--42

PL

Artykuł przedstawia wyniki badań wpływu zmian dawki paliwa na składowe harmoniczne drgań skrętnych wału zespołu spalinowo-elektrycznego, ze szczególnym uwzględnieniem składowej harmonicznej odzwierciedlającej wtrysk paliwa. W badaniach wykorzystano metodę pomiaru drgań skrętnych wału za pomocą zmian chwilowych prędkości kątowych.

EN

The article presents the results of research on the impact of changes in the fuel dose on the harmonic components of torsional vibrations of the shaft of the combustion-electric unit, with particular emphasis on the harmonic component responsible for fuel injection. In the tests, the method of measuring torsional vibrations of the shaft was used by means of changes of instantaneous angular velocities.

6

Processing of long lasting signals of torsional vibrations measured using incremental encoders

Dereszewski M., Sikora G.

Journal of KONES

|

2018

|

Vol. 25, No. 4

59--65

EN

The article describes processing method of a signal, coming from torsional deflections of an internal combustion piston engine’s crankshaft, registered using two optical encoders ETNP-10. Standard measurement and recording set ETNP-10 enables recording of Instantaneous Angular Speed values encompassing 10 revolutions of the crankshaft, what is equal to 5 cycles of four-stroke engine. That time duration is sufficient for analysis of changes of angular speed caused by, for example, malfunction of fuel injection valve, but is insufficient in case of observation characterized by low frequency changes with period of fluctuations, lower than 0.8 sec. Short time for recording makes impossible following of instantaneous angular speed deviations caused by magnitude modulation of engine’s load value. In the article is presented an algorithm written in MATLAB environment, which allows processing of the data recorded using the recorder DAS 1600 Sefram. The recorded this way signals have around 26 seconds' duration of engine work. Data acquired from two encoders mounted at opposite sides of the shaft, in form of square magnitude signals are transformed into instantaneous speed and subsequently to instantaneous angular shift, what is basis for torsions calculation. In the article is also presented method of elimination of systematic error due to assumed method of averaging. Finally, some examples of results of torsional deflection measurement and analysis are presented.

7

Diagnostic aspects of a crankshaft torsional oscillations monitoring by IAS measurement

Dereszewski M.

Journal of KONES

|

2018

|

Vol. 25, No. 1

67--74

EN

Continuous monitoring of diesel engine performance under its operating is critical for prediction of malfunction development and subsequently functional failure detection. Analysis of Instantaneous Angular Speed (IAS) of the crankshaft is considered as one of non-intrusive and effective method of detection of combustion quality deterioration. The article contains presentation of attempt of monitoring of piston engine’s crankshaft torsional vibrations by measurement of Instantaneous Angular Speed at free, and power output ends of the engine’s crankshaft. The angular speed measurements was done using two optical sensors for reading the IAS, mounted at shaft line’s opposite ends, one at free end of the crankshaft and second at end of generator’s shaft. In the article is presented description of the measurement system and explanation of its mode of work. Experiments were based at two kinds of malfunction possible to be simulated at test bed. First one was simulation of a leak of fuel injection pump, the second one relayed on mounting of sets of injection valves with different nozzles characteristics (spraying nozzle angle), giving different parameters of fuel injection. Presented results of experiment derives from test cycle carried out using laboratory stand of Gdynia Maritime University equipped with 3- cylinder self − ignition engine, powering electric generator.

8

Decomposition of harmonic wavelets of torsional vibrations as basis for evaluation of combustion in compression-ignition engines

Dereszewski M., Drewing S.

Journal of KONES

|

2018

|

Vol. 25, No. 3

129--135

EN

The aim of analysis presented in the article is results of measurements of torsional deflections of a crankshaft of three-cylinder internal combustion diesel engine. The wavelets of the run of torsional twists were processed by decomposition to harmonics using FFT. In order to exactly recognize all dynamic aspects of gas forces acting during working stroke, decomposition was done in two ways: first one relaying on records encompassing one working cycle (two revolutions), the second one based at separated periods encompassing angular an interval from TDC (Top Dead Centre) of one cylinder to TDC of subsequent in firing order. For three-cylinder engine, width of the interval is 240 degrees of crank angle. In order to obtain reliable results, torsional deflection signals acquisitions were recorded numerous times including changes of outer conditions (temperature, atmospheric pressure) and different values of the engine loads. The main goal of conducted experiments was looking for an answer of a question if exist any differences between frequency spectrums of harmonics of run of full cycle ( two revolutions) and the same cycle divided by three separate intervals. Analysis was conducted in order to state any possibility of diagnostic signals acquisition caused by abnormalities of combustion process. Results were presented in form of comparison of frequency spectra taken from full cycle and divided intervals.

9

Test stand for monitoring of torsional vibration of engine’s crankshaft by instantaneous angular speed measurement

Dereszewski M.

Zeszyty Naukowe Akademii Morskiej w Gdyni

|

2016

|

nr 96

15--23

EN

Continuous monitoring of diesel engine performance under its operating is critical for prediction of malfunction development and subsequently functional failure detection. Analysis of Instantaneous angular Speed (IAS) of the crankshaft is considered as one of non intrusive, and effective method of detection of combustion quality deterioration.The paper contains presentation of attempt of monitoring of piston engine’s crankshaft torsional vibrations by measurement of Instantaneous Angular Speed at free and power output ends of the engine’s crankshaft. It is assumed that calculation of differentia value between both ends shall give the picture of torsion angle magnitudes and phases of the peak values. The angular speed measurements is to be done utilising two optical sensors for reading and two perforated discs mounted at shaft’s ends playing the role of speed signal emitters. In the paper is presented description of the measurement system and explanation of its mode of work. It is also shown analysis of measurement accuracy, way errors elimination and method of signals runs filtration. Presented results of experiment derives from test cycle carried out using laboratory stand of Gdynia Maritime University equipped with 3-cylinder self – ignition engine, powering electric generator.

10

An analysis of the self-excited torsional vibrations of the electromechanical drive system

Konowrocki R., Szolc T.

Vibrations in Physical Systems

|

2016

|

Vol. 27

187--194

EN

This paper presents a dynamic analysis of torsional vibrations of the railway drive system. A dynamic electromechanical drive model has been created and then integrated with the railway wheelset-rail system to simulate self-excited torsional vibrations of the considered system. Results of this analysis are used in order to investigate the drive system’s sensitivity to torsional oscillations. Here, the dynamic electromechanical interaction between the electric driving motor and the rotating wheelset is considered. This investigation has proved that the torsional stiffness and damping of drivetrain system strongly affect amplitudes of the selfexcited vibrations. A self-excited vibrations affecting on an energy consumption of the electric motor of the considered system are studied.

11

Monitoring of torsional vibration of a crankshaft by instantaneous angular speed observations

Dereszewski M.

Journal of KONES

|

2016

|

Vol. 23, No. 1

99--106

EN

Continuous monitoring of diesel engine performance under its operating is critical for prediction of malfunction development and subsequently functional failure detection. Analysis of Instantaneous angular Speed (IAS) of the crankshaft is considered as one of non-intrusive and effective method of detection of combustion quality deterioration. The paper contains presentation of attempt of monitoring of piston engine’s crankshaft torsional vibrations by measurement of Instantaneous Angular Speed at free and power output ends of the engine. It is assumed that calculation of differential value of angular distance run between both ends in the same time shall give the picture of torsion angle magnitudes and phases of the peak values. Fir carrying out such measurements, high frequency of sampling was required. The angular speed measurements is to be done utilising two optical sensors for reading and two perforated discs mounted at shaft’s ends playing the role of speed signal emitters. In the paper is presented description of the measurement system and explanation of its mode of work. It is also shown analysis of measurement accuracy, way errors elimination and method of signals runs filtration. Presented results of experiment derives from test cycle carried out using laboratory stand of Gdynia Maritime University equipped with 3- cylinder self - ignition engine, powering electric generator.

12

Analysis of bending-torsional vibrations for diagnostics of the crank system

Burdzik R., Pankiewicz J., Wądołowski M.

Diagnostyka

|

2016

|

Vol. 17, No. 4

79--84

EN

The article presents the model of the crankshaft taking into account the coupling of bending and torsional vibrations. In engineering practice the simplification which is omitting this phenomenon is commonly used. Authors using more complicated model show the influence of bending torsional coupling on the frequency structure of the crank system.At the beginning of the article the problem of vibrations in combustion engine is generally discussed. Then there is presented the analysis of forces distribution in a crank system with the assumption that there is no friction in bearing nodes. Further chapters present two approaches to modeling torsional and bending vibrations in crank systems and indicate the application area of the proposed methodology. In the last but one chapter there were discussed the results of numerical simulations of the proposed model of the crank system. The whole was summarized with synthetic conclusions and plans regarding further research.

PL

Artykuł przedstawia model wału korbowego uwzględniający sprzężenie drgań giętnych i skrętnych. W praktyce inżynierskiej powszechnie stosuje się uproszczenie polegające na pominięciu tego zjawiska. Autorzy wykorzystując bardziej rozbudowany model, pokazują wpływ sprzężenia giętno-skrętnego na strukturę częstotliwościową układu korbowego. Na wstępie artykułu ogólnie omówiono zagadnienie drgań w silnikach spalinowych. Następnie przedstawiono analizę rozkładu sił w układzie korbowym przy założeniu braku tarcia w węzłach łożyskowych. Dalsze rozdziały prezentują dwa podejścia do modelowania drgań skrętnych i giętnych w układach korbowych oraz wskazują na obszar zastosowań proponowanej metodyki. W przedostatnim rozdziałe omówiono wyniki symulacji numerycznych zaproponowanego modelu układu korbowego. Całość podsumowano syntetycznymi wnioskami oraz planami odnośnie dalszych badań.

13

Infulence of Geometry Imperfections on Flexural-Torsional Vibrations in Rotating Systems

Łazarz B., Matyja T.

Machine Dynamics Research

|

2015

|

Vol. 39, No. 2

97-110

EN

In paper we investigated the influence of geometry imperfections on coupled flexural-torsional vibrations in the transient states, at start-up, in rotating systems. Consideration was given to two types of errors: the permanent deflection of a shaft in place of rotors installation (shaft bow) and inclination of a rotor plane with respect to the designed axis of rotation of the machine (angular misalignment). Used was the specialist Simulink library developed by the authors.

14

Analiza drgań skrętnych wału śmigłowego silnika lotniczego PZL-200 podczas pracy z zapłonem awaryjnym

Ostapski W., Aromiński A.

Logistyka

|

2015

|

nr 3

3636--3645, CD 1

PL

W pracy przedstawiono wyniki badań drgań wału śmigłowego prototypowego silnika lotniczego PZL200, oraz wybranych parametrów w warunkach pracy z awaryjnym układem zapłonowym.

EN

This paper briefly presents results of torsional shaft vibration bench tests for a prototype PZL-200 aircraft engine utilizing secondary ignition system. Some additional parameters while running on secondary ignition system were also presented.

15

Analytical solution of excited torsional vibrations of prismatic thin-walled beams

Augustyn E., Kozień M. S.

Journal of Theoretical and Applied Mechanics

|

2015

|

Vol. 53 nr 4

991--1004

EN

In the paper, the analytical solution of excited torsional vibrations of prismatic thin-walled beams for different types of boundary conditions and different types of external excitation of torsional moment are formulated. The presented solution can be applied, among others, to preliminary analysis of the optimal position of the actuators and the value of the applied voltage to the elements for minimization of the vibrations of the beams.

16

Possibility of existence of torsional vibrations of beams in low frequency range

Augustyn E., Kozień M. S.

Czasopismo Techniczne. Mechanika

|

2015

|

Y. 112, iss. 3-M

3--11

EN

This paper discusses the problem of the existence of torsional natural modes in the low frequency range for a beam with a rectangular cross-section with different ratios between width and height and different lengths. The rectangular type of cross-section is chosen because of practical applications to describe the vibrations of some turbine blades. The analyses were conducted by applying an analytical model, but were verified using the finite element method.

PL

W artykule rozważono zagadnienie możliwości wystąpienia form własnych drgań skrętnych w zakresie niskoczęstotliwościowym belek o prostokątnym kształcie przekroju. Rozważono wpływ stosunku wysokości do szerokości przekroju oraz długości belki. Prostokątny kształt przekroju został wybrany ze względu na zastosowania praktyczne analiz do opisu drgań łopatek turbin niektórych wirników. Rozważania opierają się na modelu analitycznym, ale były również weryfikowane poprzez analizy metodą elementów skończonych.

17

Analysis of rotating systems using actuators with magnetorheological fluid to vibrations minimization - theoretical and experimental investigation

Pręgowska A., Konowrocki R., Szolc T.

Symulacja w Badaniach i Rozwoju

|

2014

|

Vol. 5, nr 3

191--198

EN

The analysis of damped rotating systems using actuators with magnetorheological fluid is the subject of interest. The main purpose of this research is minimization of vibration amplitudes in order to increase fatigue durability of the most responsible machine elements. Here, control damping torques are generated by magnetorheological fluid of adjustable viscosity. The theoretical investigations are based on a hybrid and finite element structural model (FEM) of the mechanical structure as well as on sensitivity analysis of the response with respect to the actuators damping characteristics. The analysis performed in the paper combines experimental verification using the laboratory test rig with theoretical computations.

PL

Prezentowany materiał poświęcony jest analizie układów wirujących z wykorzystaniem aktuatorów z cieczą magnetoreologiczną o zmiennych właściwościach dyssypacyjnych. Głównym celem realizowanych badań jest zmniejszenie poziomu amplitudy drgań skrętnych, aby zwiększyć trwałość zmęczeniową najbardziej odpowiedzialnych elementów maszyny roboczej. W praktyce sprowadza się to do wyznaczenia optymalnej wartości współczynnika tłumienia, który jest realizowany przez film z cieczy MRF. W pracy przedstawione są wyniki analiz otrzymanych z modeli teoretycznych, poparte badaniami symulacyjnymi. Potwierdzają one rezultaty badań przeprowadzonych na zbudowanym w tym celu stanowisku eksperymentalnym. Dalsze analizy związane z tą tematyką będą dotyczyły identyfikacji defektów w układach wirujących.

18

Małowymiarowe gumowe tłumiki drgań skrętnych

Homik W.

Przegląd Mechaniczny

|

2014

|

nr 12

41--46

PL

Artykuł zawiera informacje dotyczące historii, budowy i zastosowania gumowych tłumików drgań skrętnych walów korbowych wielocylindrowych silników spalinowych. Autor artykułu koncentruje się głównie nad metodami modelowania małowymiarowych gumowych tłumików drgań. Prezentuje także wyniki numerycznych analiz dynamicznych układu, w którym zastosowano gumowy małogabarytowy tłumik. W artykule zamieszczone są również niektóre wytyczne, które powinny być uwzględniane na etapie projektowania tłumika.

EN

The article presents information on the history, construction and use of rubber torsional vibration dampers of internal crankshafts in multi-cylinder combustion engines. The author concentrates on the methods of modeling rubber torsional vibration dampers. The author also provides the results of dynamic numerical analysis of the unit, where small rubber damper is used. The article also provides some guidelines which should be considered when designing the damper.

19

Simulation research on hybrid electromechanical device - BLDC motor, torsion torque generator - for torsional vibration spectrum identification of drive systems

Kochan A., Trawiński T.

Przegląd Elektrotechniczny

|

2014

|

R. 90, nr 7

58--64

PL

W artykule przedstawiono koncepcję hybrydowego przetwornika elektromechanicznego służącego do wytwarzania drgań skrętnych. Przedstawiono podstawowe własności przetwornika takie jak, np.: zależności generowanych częstotliwości momentów skrętnych od prędkości obrotowej wału generatora. Na drodze obliczeń symulacyjnych sprawdzono efektywność wyznaczenia charakterystyki modalnej układu napędowego na przykładzie zespołu prądotwórczego, złożonego z turbiny gazowej oraz generatora energii elektrycznej.

EN

In this article the general concept of hybrid electromechanical converter for torsion torque generation is presented. Fundamental properties of proposed electromechanical device, including dependence of frequencies of generated torsion torque on generator's rotor angular speed has been shown. Based on computer calculations the usefulness of proposed method for determination of modal characteristics of drive system is shown. As an exemplary drive system the set of gas turbine and electric energy generator were chosen.

20

Analiza porównawcza drgań skrętnych wału korbowego z drganiami poprzecznymi korpusu silnika

Dąbrowski Z., Dziurdź J.

Logistyka

|

2014

|

nr 6

2965--2972

PL

W artykule zaproponowano wykorzystanie informacji zawartej w sygnałach drgań poprzecznych silnika spalinowego do określenia stanu technicznego tłumika drgań skrętnych wału korbowego. Przyjmując tezę zakładającą istnienie sprzężenia drgań giętych i skrętnych wału, w sygnałach drgań poprzecznych powinny pojawić się symptomy związane ze zmianami zachodzącymi w drganiach skrętnych. W celu udowodnienia tej tezy przeprowadzono czynny eksperyment badawczy na hamowni podwoziowej. Wykonano pomiary w trakcie rozpędzania silnika samochodu od prędkości obrotowej biegu jałowego do prędkości maksymalnej. Przedstawiono przykładowe wyniki pomiarów drgań skrętnych wału korbowego i drgań poprzecznych korpusu silnika. Analizując zmiany wartości amplitud kilku pierwszych składowych harmonicznych częstotliwości obrotowej zarejestrowanych sygnałów drgań skrętnych i poprzecznych zauważono analogię odpowiedzi dynamicznej 3 harmonicznej drgań skrętnych z 4 harmoniczną drgań poprzecznych. Dodatkowym potwierdzeniem tezy są wyniki badań z zablokowanym tłumikiem drgań skrętnych.

EN

The article proposes the use of information contained in signals of transverse vibration of internal combustion engine to determine the condition of torsional vibration damper mounted on crankshaft. Accepting the argument assuming the existence of feedback between bending vibrations and torsional vibrations of the shaft, in the transverse vibration signals should appear symptoms associated with changes in the torsional vibrations. In order to prove this thesis active research experiment was conducted on a chassis dynamometer. Measurements were made during the acceleration of the car's engine from idle speed to maximum speed. Exemplary results of measurements of the crankshaft torsional vibration and the transverse vibration of the engine body are presented. Analyzing changes in the amplitudes of the first few harmonics of rotational frequency of the recorded signals of torsional vibrations and transverse vibrations, the analogy has been noted in the dynamic response of 3rd harmonic torsional vibrations and 4th harmonic transverse vibrations. An additional confirmation of the thesis is a study of locked torsional vibration damper.