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1
Content available remote Numerical analysis of vibration in a brake system for high speed train
100%
Konowrocki R. , Bogacz R.
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tom Vol. 25
235--240
EN
The paper is devoted to a computer simulation of brake pad/brake disc dynamic interaction. The main purpose of the studies is a numerical analysis of friction pair dynamics, aiming at describe generation of vibration related to the process of transition phenomena associated with braking. To investigation will be used environment of Automatic Dynamic Analysis of Mechanical Systems. In the analysis is used two-dimensional friction model. The results show the slip-stick and creep phenomenon.
2
Content available remote On Evaluation of the Wheelsets-Track Interaction Quality in Railway Engineering
100%
Konop J. , Konowrocki R.
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2013
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tom Vol. 37, No. 4
61-70
EN
The paper is devoted to the evaluation of wheel-rail interaction quality and possibility of utilize of acceleration measurement for the determination of quality of tracks. After review of methods used for this purpose in Germany, Austria and othercountries, the proposal used for experimental investigation by PESA S.A. will be reported and some theoretical analysis for the track quality evaluation will be given.
3
Content available remote Influence of Correctness of Running Gear Assembly on Freight Wagon Wheels’ Wear
100%
Konowrocki R. , Zbieć A.
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tom Vol. 42, No. 1
139--151
EN
The paper presents an analysis of a newly diagnosed cause of wheel thread wear in a freight wagon and also possible other causes of abnormal wear of wheels in freight wagon wheelsets are mentioned. Newly diagnosed cause for excessive wear of the railway wheel thread is an incorrect position of wheelsets in relation to the bogie frame. The paper presents results of measurements carried out on a real freight wagon to get identification of wheels’ wear and geometry of vehicle components. In order to analyze the influence of incorrectly positioned wheelset axles on the degree of wheel wear a numerical model of a freight wagon was developed. Numerical calculations at various speeds of wagon and several versions of wheelsets skew position were carried out. The results obtained from numerical tests i.e. a significant influence of non-parallel axles of wheelsets on abnormal wear of wheel threads are shown. Conclusions drawn from the computation results can be very useful at a running gear repairs as well as helpful in a regular maintenance process. It will also reduce the costs of repairs of wheelsets and extend their service life.
4
Content available remote Vibrations due to the passage of a railway vehicle on straight and curved tracks
100%
Konowrocki R. , Bajer C.
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2008
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tom Vol. 23
199--204
EN
The paper presents the results of vibration measurements on line of railway during passages of a train at a constant speed. The measurements have been performed on a railway track at straight and curve sections as well as and inside the train on the floor. The experimental results exhibited higher amplitudes of vibrations on the curve of the track than on its straight segments. The lateral slip in rail/wheel contact zone is considered as a possible reason of such a phenomenon.
5
Content available remote Influence of Flexibility Parameters of Wheels and Wheelset on the Railway Bogie Dynamics : Experimental and Theoretical Investigations
100%
Konowrocki R. , Walczak S.
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2017
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tom Vol. 41, No. 1
128--142
EN
The paper is devoted to the experimental and theoretical analysis of wheelset elastic properties on the railway vehicle-track interaction. Results of experimental measurements of stiffness components of wheelsets obtained by a new measurement method are shown. Some types of wheelsets are considered with different wheel-disk design. For the theoretical analysis of bending and torsional flexibility of the wheel and wheelset are used. To numerical modeling of the considered wheels and wheelsets models the Finite Element Method (FEM) are applied. Simulation of dynamic interaction between a railway bogie and a curved sector of track in the rigid multibody systems method (VI-Rail software) is modeled. Exemplary simulations results obtained from the bogie-track system model using flexible and rigid model of the wheel and wheelset are presented.
6
Content available remote Semi-active control of track subjected to an inertial moving load
80%
Dyniewicz B. , Pisarski D. , Konowrocki R.
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tom Vol. 25
147--152
EN
The paper deals with the problem of stabilization of vibrations of the load carrying structure via adaptive damping performed with a smart material. The properties of such a material must ensure reduction of vibrations, especially accelerations and displacements of selected stationary or follower points in a higher range than in the case of the material with homogeneous bilateral characteristics. Analytical calculations and numerical simulations proved the efficiency of the approach. Results obtained with the testing system equipped with magnetorheological controlled dampers will allow us to prove experimentally assumed control strategies and rheological properties of the filling material.
7
Content available Semi-active vibration control using a rotary magnetorheological damper - experimental verification
80%
Pręgowska A. , Konowrocki R. , Szolc T.
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2013
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tom R. 17, nr 2
487-491
EN
From all kinds of vibrations, torsional ones are very important as naturally associated with fundamental rotational drive system motion. The aim of this paper is to present semiactive control of torsional vibrations of the working machine drive systems, which is performed using a rotary damper with the magnetorheological fluid. The main purpose of this research is minimization of vibration amplitudes in order to increase fatigue durability of the most responsible machine elements. The special control strategies are proposed for steady-state torsional vibrations suppression. The semi-active control method is based on a principle of on-line selection of optimum damping coefficient values, which is realized by application of the magnetorheological fluid. The analysis performed in the paper combines experimental verification using the laboratory test rig with theoretical computations. This experiment was designed in the form of the laboratory drive system co-operating with two asynchronous motors generating properly programmed driving and retarding electromagnetic torques.
PL
Drgania skrętne są jednym z najważniejszych rodzajów drgań, ponieważ są naturalnie związane z podstawowym ruchem roboczym wielu maszyn i urządzeń. Prezentowany artykuł jest poświęcony półaktywnemu sterowaniu drganiami skrętnymi napędu maszyny roboczej przy wykorzystaniu obrotowych tłumików z cieczą magnetoreologiczną o zmiennych właściwościach dyssypacyjnych. Głównym celem prezentowanych badań jest zmniejszenie poziomu amplitudy drgań skrętnych w celu zwiększenia trwałości zmęczeniowej najbardziej odpowiedzialnych elementów maszyny roboczej. Półaktywne sterowanie sprowadza się do wyznaczenia optymalnej wartości współczynnika tłumienia, który jest realizowany przy wykorzystaniu właściwości filmu z cieczy magnetoreologicznej. Teoretyczna koncepcja sterowania została doświadczalnie zweryfikowana za pomocą stanowiska doświadczalnego w postaci laboratoryjnego układu napędowego, na którym zmienne napędowe i oporowe momenty wymuszające są generowane odpowiednio przez silnik i hamownicę asynchroniczną.
8
Content available remote Dynamiczna współpraca wstawki hamulcowej oczyszczającej w pociągach dużej prędkości - badania eksperymentalne
80%
Konowrocki R. , Kukulski J. , Walczak S. , Groll W.
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2013
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tom z. 98
279--289
PL
Artykuł poświęcony jest badaniom eksperymentalnym współpracy wstawki oczyszczającej z powierzchnią toczną koła kolejowego, stosowanego w pojazdach kolejowych dużych prędkości. W takich układach stosuje się pojedynczą wstawkę hamulcową, która przez kontakt z powierzchnią toczną koła kolejowego zapewnia usuwanie wszelkich elementów, które mogą w czasie eksploatacji w wyniku adhezji przykleić się do koła. Elementy pozostając w kontakcie z powierzchnią toczną koła wpłynęłyby na przyspieszone zużycie zestawów kołowych oraz wzrost nadwyżek dynamicznych w strefie kontaktu koło szyna, skutkujące degradowaniem powierzchni tocznej kół i szyn. W pracy zaprezentowane zostały badania eksperymentalne przeprowadzone na rzeczywistym układzie hamulcowym z zastosowaniem wstawki oczyszczającej z jednostronnym naciskiem przy hamowaniu z dużej prędkości. Na podstawie badań określono parametry jakie występują w takich układach.
EN
Paper is devoted experimental studies of the dynamics of cleansing brake insert. The test system is used in high-speed railway vehicles. In this case, the single brake insert during contact with the surface of the wheel tread removes any elements that as a result adhesion stick to the rolling surface of wheels. Foreign objects glued to the wheel tread affected the accelerated wear of wheel sets, as well as be able to damage the rail track. As a result of installing such a system during the braking process, which is a temporary phenomenon, there are variables vibrations induced by friction interaction of brake insert with railway wheel. In the paper presented results of experimental studies carried out on a real high-speed brake system.
9
Content available A semi-active control of lateral vibrations of the overhung rotor using dampers with the magneto-rheological fluid
80%
Michajłow M. , Konowrocki R. , Szolc T.
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tom Vol. 27
273--280
EN
In the paper there is proposed an algorithm of an efficient semi-active control of steady-state periodic lateral vibrations of the overhung rotor-shaft system. This algorithm has been developed using fundamentals of the Optimal Control Theory. In the considered system the control is realized by means of the linear dampers with the magneto-rheological fluid built in the bearing housing. The computational example demonstrates possibilities of the applied approach resulting in an additional reduction of out-of-resonance and near-resonance harmonic oscillation amplitudes in comparison with an analogous passive control.
10
Content available Walking the Line. Traveling Forces vs Moving Masses
80%
Bogacz R. , Frischmuth K. , Konowrocki R.
Symulacja w Badaniach i Rozwoju
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2015
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tom Vol. 6, nr 3
165--173
EN
In railway mechanics, and more general, in civil engineering and vehicle dynamics, the problem of simultaneous modeling of a track and a vehicle has been the subject of many papers. Often one of the coupled subsystems is highly simplified in order to be able to obtain results on the other. For example, when the propagation of waves in the track is the main concern, vehicles such as a train or a taxiing airplane, are treated as an external force, travelling at a certain speed along a given path. In that case, the force is assumed as independent of the motion in the track, which results from the load. On the other hand, dynamical simulations of vehicles typically run on a defined ground, which is given and invariant, whatever the motion of the vehicle. In order to make a track model more realistic, the vehicle model may be improved, without going as far as to couple a full-fledged vehicle model with a realistic model of a track consisting of rails on sleepers, supported via some subgrade on the ground. A first simple step is to attach an additional mass in the contact point, i.e. the position, where the external force is applied.
PL
W inżynierii kolejowej lub ogólniej - w budownictwie i dynamice pojazdów zagadnienie równoczesnego modelowania toru i pojazdu było przedmiotem wielu badań. Często jeden ze sprzężonych układów był nadmiernie upraszczany, aby uzyskać rozwiązanie problemu. Zagadnienie struny najczęściej rozpatruje się w zakresie małych przesunięć i kątów, poszukiwana jest wówczas funkcja skalarna jednej zmiennej. Gdy konfiguracja aktualna odbiega znacznie od konfiguracji materialnej, wyniki uzyskane mogą być fizycznie nieakceptowalne. W pracy do rozwiązywania tego typu zadań zaleca się podejście parametryczne. Zalety takiego podejścia demonstrowane są na podanych przykładach z zakresu modelowania współpracy pojazdu z trakcją oraz popularnych sportów rekreacyjnych.
11
Content available remote Vibration control of the rotating machine geared drive system using linear actuators with the magneto-rheological fluid
80%
Michajłowicz M. , Konowrocki R. , Szolc T.
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tom Vol. 25
279--284
EN
In this paper there is proposed a semi-active control technique based on the linear actuators with the magnetorheological fluid (MRF) connecting the drive system planetary gear housing with the immovable rigid support. Here, control damping torques are generated by means of the magneto-rheological fluid of adjustable viscosity. Such actuators can effectively suppress amplitudes of severe transient and steady-state rotational fluctuations of the gear housing position and in this way they are able to minimize dangerous oscillations of dynamic torques transmitted by successive shaft segments in the entire drive system. The general purpose of the considerations is to control torsional vibrations of the real power-station coal-pulverizer geared drive system driven by means of the asynchronous motor. The investigations have been carried out using the experimental test rig based on the real object, where the measurement results were compared with analogous theoretical ones obtained by the use of computer simulations.
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