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Wyszukujesz frazę "self-excited" wg kryterium: Temat


Tytuł:
Application of self-excited acoustical system for stress changes measurement in sandstone bar
Zastosowanie samowzbudnego akustycznego systemu do pomiaru zmian naprężeń
Autorzy:
Kwaśniewski, J.
Dominik, I.
Konieczny, J.
Lalik, K.
Sakeb, A.
Powiązania:
https://bibliotekanauki.pl/articles/279363.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
self-excited system
stress monitoring
Opis:
A self-excited acoustical system is suggested for monitoring of the change of stress in a sandstone bar. Stress changes manifest themselves in small but detectable variations of frequency in the self-excited system. The suggested system can be applied for the continuous stress changes monitoring in elastic constructions and rock masses. Tests on a single sample of sandstone were performed. They examined the impact on the stress measurement such parameters as: position of sensors and the actuator as well as the influence of geometrical shape and dimensions of the sample. A theoretical model whose parameters have been confirmed by performed experiments is also developed.
W artykule przedstawiono koncepcję i wyniki badań nad samowzbudnym akustycznym systemem, który jest proponowany jako nowy sposób monitorowania zmian naprężeń w belce z piaskowca. W badanym rozwiązaniu zmiana naprężeń objawiała się małymi, aczkolwiek mierzalnymi, zmianami częstotliwości. Proponowany system pomiarowy może znaleźć zastosowanie do ciągłego monitorowania zmian naprężeń w konstrukcjach sprężystych oraz masach skalnych. W artykule opisano przeprowadzone badania doświadczalne z zastosowaniem próbki wykonanej z piaskowca. Podczas badań sprawdzono wpływ umiejscowienia nadajnika i odbiornika oraz wymiary geometryczne i kształt próbki na uzyskiwane wyniki. Dodatkowo został zbudowany model teoretyczny, którego parametry zostały pozyskane i potwierdzone na drodze eksperymentalnej.
Źródło:
Journal of Theoretical and Applied Mechanics; 2011, 49, 4; 1049-1058
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Simulation of Self-Excited Vibrations Under Variable Cutting Conditions
Autorzy:
Bąk, P. A.
Jemielniak, K.
Powiązania:
https://bibliotekanauki.pl/articles/99477.pdf
Data publikacji:
2015
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
self-excited vibration
numerical simulation
virtual machining
Opis:
A self-excited vibrations are one of the most important constraints to the performance and quality of machining part and it is affecting its dimensions and geometrical accuracy. Machining stability can be evaluated by different analytical and numerical methods. The paper presents utilization of numerical simulation of non-linear chatter in the time domain in stability analysis of machining process. Vibrations and cutting forces are an output from numerical simulation. In order to perform chatter recognition during excessive vibrations an automatic chatter detection is implemented in machining simulation. By combining all the above in one and enabling G-code reading, a tool for numerical simulation and validation of entire machining operation was created which is a subject of this paper.
Źródło:
Journal of Machine Engineering; 2015, 15, 1; 36-45
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis and simulation of nonlinear self-excited vibrations in turning
Autorzy:
Zeleny, J.
Repak, T.
Fojtu, P.
Powiązania:
https://bibliotekanauki.pl/articles/1429152.pdf
Data publikacji:
2008
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
machine tool
machining
machining process
self-excited vibrations
Opis:
Commonly applied theories of self-excited vibrations in machine tools are prevailingly based on frequency domain analysis of linear models and are devoted in most cases only to evaluation of stability limits of strictly linear systems. In this way, the behaviour of more stable or more unstable systems cannot be studied and analyzed. Certain important nonlinear effects cannot be studied as well for limitations connected with classical representation of systems only in the frequency domain. Evaluation of stability by analysis of nonlinear systems in time domain has not been applied until now. The paper shows a new approach based on interpretation of the self-excited vibration systems as nonlinear servo-systems. With this approach, linear and nonlinear systems of any degree of stability can be studied by combination of frequency and time-domain methods. This can considerably contribute to better understanding of complex phenomena in various regimes and special situations.
Źródło:
Journal of Machine Engineering; 2008, 8, 4; 68-79
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling and simulation of adhesion of the rail vehicle
Autorzy:
Lewandowski, Mirosław
Grzesikiewicz, Wiesław
Makowski, Michał
Rutczyńska-Wdowiak, Katarzyna
Powiązania:
https://bibliotekanauki.pl/articles/2200273.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Technologiczno-Humanistyczny im. Kazimierza Pułaskiego w Radomiu
Tematy:
modelling
self-excited vibrations
simulation
wheel adhesion
unstable friction
Opis:
In the paper we consider the issue related to the phenomenon of wheel-to-rail adhesion. This issue concerns self-excited vibrations in the area of wheel-rail contact, caused by unstable friction. Such friction is characterized by decreasing values of the friction coefficient with increasing slipping velocity. The paper includes mathematical formulation of the problem and presents the method for solving it. In addition, a simulation of elementary vehicle driving was performed. During the simulation, self-excited vibrations arose during wheel slip caused by high driving torque. The paper presents graphs illustrating the tangential force and the slipping velocity during these vibrations.
Źródło:
Journal of Automation, Electronics and Electrical Engineering; 2022, 4, 2; 17--21
2658-2058
2719-2954
Pojawia się w:
Journal of Automation, Electronics and Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic parameter identification in nonlinear machining systems
Autorzy:
Nicolescu, M.
Archenti, A.
Powiązania:
https://bibliotekanauki.pl/articles/100167.pdf
Data publikacji:
2013
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
machining system
dynamic parameters
white noise excitation
self-excited vibration
Opis:
The demand for enhanced performance of production systems in terms of quality, cost and reliability is ever increasing while, at the same time, there is a demand for shorter design cycles, longer operating life, minimisation of inspection and maintenance needs. Experimental testing and system identification in operational conditions still represent an important technique for monitoring, control and optimization. The term identification refers in the present paper to the extraction of information from experimental data and is used to estimate operational dynamic parameters for machining systems. Such an approach opens up the possibility of monitoring the dynamics of machining systems during operational conditions, and can also be used for control and/or predictive purposes The machining system is considered nonlinear and excited by random loads. Parametric and nonparametric techniques are developed for the identification of the nonlinear machining system and their application is demonstrated both by numerical simulations and in actual machining operations. Discrimination between forced and self-excited vibrations is also presented. The ability of the developed methods to estimate operational dynamic parameters ODPs is presented in practical machining operations.
Źródło:
Journal of Machine Engineering; 2013, 13, 3; 91-116
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of self-excited synchronous generator with inverter as DC grid voltage source
Autorzy:
Kozak, M.
Powiązania:
https://bibliotekanauki.pl/articles/378011.pdf
Data publikacji:
2018
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
self-excited generator
FOC control
DC grid
controlled voltage source
Opis:
Self-excited generators are the most popular voltage sources installed onboard of modern ships. Because of fuel savings on some specialized vessels (PSV, cable layers etc.) varying revolutions drives are used and this trend seems to increase. Very interesting issue is use of such type of alternator working with inverter acting as rectifier in DC grid system. As the control method most suitable to use is modified field oriented control known from induction machines. This control method involves decoupling of currents and control voltages to flux and torque components and keeping them in optimal (orthogonal) condition. Theoretical background of inverter and synchronous generator adopted FOC control method along with experimental results obtained in laboratory of such system were presented.
Źródło:
Poznan University of Technology Academic Journals. Electrical Engineering; 2018, 95; 209-220
1897-0737
Pojawia się w:
Poznan University of Technology Academic Journals. Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Geometric Simulation for Determination of Dynamic Undeformed Chip Thickness in Milling
Autorzy:
Bombiński, Sebastian
Jemielniak, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/2201898.pdf
Data publikacji:
2023
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
self-excited vibration
numerical simulation
computer graphics
5-axis milling
Opis:
Self-excited vibration is a significant constraint on productivity and production quality, which makes various forms of virtual machining widely used to find stable conditions before starting the actual machining operation. Numerical simulation of self-excited vibration, although much slower than analytical solutions, makes it possible to consider the nonlinearity of the process and its continuous variation. In 5-axis milling, predicting the instantaneous cross-sections of the uncut chip is very difficult, so geometric simulation is readily used to check the correctness of the NC program and the obtained shape of the workpiece. However, the known solutions take into consideration only programmed movements of the tool relative to the workpiece without considering vibrations, and those in which attempts have been made to consider vibrations have significant limitations. This paper uses a Geometric Simulator that determines the nominal positions of the tool relative to the workpiece, to which the displacements due to vibration, determined by the Dynamic Simulator, are added, making it possible to effectively determine the dynamic thickness of the cut layer and the trace on the workpiece material left by the vibrating tool. The use of geometric simulation, in which the material is represented by discrete voxels, introduces signal quantization, that is, the limited resolution of undeformed chip thickness and trace left on the machined surface. The paper presents the effect of voxel dimension on the accuracy of the simulation of self-excited vibrations.
Źródło:
Advances in Science and Technology. Research Journal; 2023, 17, 1; 173--181
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Regular and chaotic vibrations of van der Pol-Mathieu oscillator with non-ideal energy source
Drgania regularne i chaotyczne oscylatora van der Pola-Mathieu z nieidealnym źródłem energii
Autorzy:
Warmiński, J.
Powiązania:
https://bibliotekanauki.pl/articles/281469.pdf
Data publikacji:
2002
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
non-ideal systems
chaos
parametric and self-excited vibrations
synchronisation
Opis:
Vibrations of a parametrically and self-excited system with a non-ideal source of energy have been analysed in this paper. The model has consisted of the van der Pol-Mathieu oscillator and non-ideal energy source, which characteristic has been assumed as a straight line. Regular motion of the complete system, energy source - vibrating model, near the main parametric resonance, has been solved analytically by the applying Krilov-Bogolubov-Mitropolski method. Possible types of motion and transition from regular to chaotic motion have been investigated by using the Lyapunov's exponent criterion and attractor topological structure analysis.
W pracy przeprowadzono analizę drgań układu parametryczno-samowzbudnego z nieidealnym źródłem energii. Model składa się z oscylatora van der Pola-Mathieu oraz nieidealnego źródła energii, którego charakterystykę założono w postaci linii prostej. Drgania regularne całego systemu, źródło drgań - model drgający, zostały określone w otoczeniu głównego rezonansu parametrycznego na drodze badań analitycznych z zastosowaniem metody Krilova-Bogolubova-Mitropolskiego. Możliwe typy ruchów oraz przejście układu do ruchu chaotycznego prześledzono poprzez zastosowanie kryterium wykładnika Lapunowa oraz analizę struktury topologicznej atraktorów.
Źródło:
Journal of Theoretical and Applied Mechanics; 2002, 40, 2; 415-433
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A single-phase induction motor operating as a self-excited induction generator
Autorzy:
Leicht, A.
Makowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/141000.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
induction generator
single-phase
circuit modelling
self-excited
induction motor
Opis:
The purpose of the paper is the investigation of possibility of utilization of a single-phase induction machine, designed and normally operating as a single-phase capacitor induction motor, as a self-excited single-phase induction generator, which can be used to generate electrical energy from non-conventional energy sources. The paper presents dq model of the self-excited single-phase induction generator for dynamic characteristics simulation and steady-state model based on double revolving field theory with two phase symmetrical components – a forward and backward revolving field for performance of the generator under resistive load. Excitation and load characteristics obtained by simulation showed considerable influence of method of capacitor configuration in the load stator winding on terminal voltage, current and output power of the generator under load. An specific construction of the stator windings together with capacitor requirements to obtain nominal output power at desired self-regulating terminal voltage over the operating range will be the aim of further research.
Źródło:
Archives of Electrical Engineering; 2013, 62, 3; 361-373
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Remarks on aerodynamic forces in seals of turbine stages
Autorzy:
Stępień, R.
Kosowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/259359.pdf
Data publikacji:
2009
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
rotor dynamics
self-excited vibrations
aerodynamic forces
blade seals
turbine shrouds
Opis:
This paper presents results of numerical examination of flow through over-shroud seals of turbine stages. Various labyrinth seals of different configurations and number of sealing teeth were considered. It was demonstrated that results of investigations of isolated seals cannot be directly used for analyzing turbine stage operation. Such approach may lead to relatively large errors in determining value of aerodynamic force and direction of its action.
Źródło:
Polish Maritime Research; 2009, S 1; 58-63
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Self excited vibrations in four-high rolling mills caused by stochastic disturbance of friction conditions on the roll-roll contact surface
Samowzbudne drgania walcarek kwarto powstające w wyniku stochastycznego charakteru zaburzeń sił tarcia na powierzchni kontaktu walców roboczych i oporowych
Autorzy:
Świątoniowski, A.
Gregorczyk, R.
Powiązania:
https://bibliotekanauki.pl/articles/369053.pdf
Data publikacji:
2010
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
walcarki
drgania
drgania samowzbudne
rolling mill
friction phenomena
self-excited vibrations
Opis:
In this paper an probabilistic model of the friction phenomena on the work- back up rolls contact surface has been presented. It has been shown that such character of the disturbance in distribution of zones with static and kinetic friction. can be regarded as one of the sources of self-excited vibrations appearing in the system consisting of a rolling mill and a strip.
Przedmiotem pracy jest probabilistyczny model opisujący zaburzenia rozkładu sił tarcia na powierzchni kontaktu walców roboczych i oporowych walcarki kwarto. Analiza tego modelu wskazuje, iż taki charakter tarciowego sprzężenia obu walców może być przyczyną wzbudzania w układzie drgań o charakterze samowzbudnym.
Źródło:
Mechanics and Control; 2010, 29, 3; 158-162
2083-6759
2300-7079
Pojawia się w:
Mechanics and Control
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the modelling of aerodynamic force coefficients for over-shroud seals of turbine stages
Autorzy:
Włodarski, W.
Kosowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/259389.pdf
Data publikacji:
2009
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
rotor dynamics
self-excited vibrations
aerodynamic forces
blade seals
turbine shrouds
Opis:
This paper presents experimental investigations which made it possible to determine dynamic coefficients of labyrinth over-shroud seal of a model air turbine. The coefficients associate pressure forces with turbine rotor displacement, velocity and acceleration respective to turbine casing (linear model) and play important role in analyzing turbine-set dynamics. The obtained results indicated that involving serious errors can be expected in the case of application of the simplification consisting in neglecting inertia coefficients, proposed in the literature. It was simultaneously demonstrated that seals can be also met of weak damping qualities, for which to neglect damping coeffcients is allowable.
Źródło:
Polish Maritime Research; 2009, S 1; 71-74
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The use of self-excited vibrations for dynamic strain measurements carried out by vibrating wire tensometers
Wykorzystanie drgań samowzbudnych do dynamicznych pomiarów odkształceń realizowanych za pomocą tensometrów z drgającą struną
Autorzy:
Cieplok, G.
Bednarski, Ł.
Sieńko, R.
Powiązania:
https://bibliotekanauki.pl/articles/368879.pdf
Data publikacji:
2015
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
vibrating wire transducers
self-excited vibrations
tensometers
czujniki strunowe
drgania samowzbudne
tensometry
Opis:
This study examines a set of vibrating wire extensometers in which a van der Pol generator has been used to maintain the natural vibrations of the wire. Excited in this way, self-exited vibrations allow for uninterrupted strain measurements over time, including fast-changing strains as well as chaotic nature strains. For the two typical vibrating wire gauges used in the industry, the impact of the wire extension speed on its metrological characteristics and applicability has been analyzed.
W pracy poddano analizie układ ekstensometru strunowego, w którym w celu utrzymania niegasnących drgań własnych struny zastosowano generator van der Pola. Wzbudzone w ten sposób drgania samowzbudne pozwalają na nieprzerwany w czasie pomiar odkształceń, w tym również odkształceń szybkozmiennych i o charakterze chaotycznym. Dla dwóch typowych czujników strunowych stosowanych w przemyśle przeanalizowano wpływ szybkości rozciągania struny na jej właściwości metrologiczne i możliwości zastosowania.
Źródło:
Mechanics and Control; 2015, 34, 1; 1-8
2083-6759
2300-7079
Pojawia się w:
Mechanics and Control
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cause investigation of metro corrugation in vehicle braking section of track
Autorzy:
Wang, Zhiqiang
Lei, Zhenyu
Powiązania:
https://bibliotekanauki.pl/articles/2055056.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
metro
braking section
rail corrugation
transient rolling contact model
friction self-excited vibration
Opis:
In order to study the cause of rail corrugation in the tangential braking section near the metro entrance, a transient rolling contact model of three-dimensional solid wheelset-track was established by using the finite element software ABAQUS, and the corrugation phenomenon was analyzed in the time-domain and frequency-domain based on the field measurement. The results show that the unstable friction self-excited vibration of the wheelset-track system is the fundamental cause of rail corrugation in the measured section, and it is precisely because of the “saturated-unsaturated” periodic characteristic of the wheel-rail creep force that ultimately promotes the formation of rail corrugation.
Źródło:
Journal of Theoretical and Applied Mechanics; 2021, 59, 4; 637--647
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The impact of primary suspension stiffness of 2-axle bogie of MKIII passenger car on its dynamical behaviour
Autorzy:
Zboiński, K.
Golofit-Stawińska, M.
Powiązania:
https://bibliotekanauki.pl/articles/961421.pdf
Data publikacji:
2018
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
numerical simulation
non-linear dynamics
self-excited vibration
symulacja numeryczna
dynamika nieliniowa
samowzbudne wibracje
Opis:
This article presents results of the study on the impact of stiffness in vehicle primary suspension for lateral direction kzy and longitudinal direction kzx. The study was carried out for 2-axle bogie of MKIII passenger car. The problem was solved by numerical tests performed with the simulation software for dynamics of vehicle-track system. Performed study consisted in varying both stiffness types through change of their values from 0.001 to 1000 times as compared to nominal value.
Źródło:
Transport Problems; 2018, 13, 1; 135-146
1896-0596
2300-861X
Pojawia się w:
Transport Problems
Dostawca treści:
Biblioteka Nauki
Artykuł

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