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EN
The study is devoted to the explanation of the influence of hot plastic deformation on the properties of railway wheels. The shape of individual elements of the wheel provides for a different degree of hot compression, which determines the mechanism for the development of the recrystallization at austenite. With a decrease in the degree of the hot deformation, a certain proportion of grains with a low energy of linear stretching are formed in austenite. As a result, of the low mobility of such boundaries, the likelihood of preservation of part of the substructural state of the austenite increases, which should affect the formation of a colony of perlite during the cooling of the carbon steel. Against background preservation and a dependence of strength properties on the dispersion of the pearlite colony, the appearance in austenite of grain boundaries with a low energy of linear tension leads to a qualitative change in the plastic properties of railway wheel steel. The increase in plasticity of carbon steel with an increase in dispersion of the pearlite colony is due to a decrease in the effect of solid solution hardening and an increase in the role of the ferrite-cementite interface in the development processes of strain hardening carbon steel. The results obtained can be useful for improving the technology of manufacturing all-rolled railway wheels.
EN
On a fragment of the rim of a railway wheel removed from service, the volume of the metal with non-metallic inclusions located near the tread surface was investigated. The use of the microhardness measurement technique made it possible to establish the nature of strain hardening of carbon steel near non-metallic inclusions. It showed that with a normal orientation of the plastic flow relative to the inclusion surface, the metal volumes undergo hardening. In proportion to the appearance of a fraction of the tangential component of the deformation near the nonmetallic inclusion, a decrease in the degree of hardening of the metal was observed.
EN
The systematization results of microstructure studies of carbon steel has made it possible to explain the mechanism of formation of certain damages to the rolling surface of railway wheels during operation. The evaluation ability of metal to strain hardening was used to explain the nature of the influence compactly located non-deformable dispersed particles on the strength properties steel during cold plastic deformation. In the process of the interaction of a railway wheel with a rail, successively occurring heterogeneities in the distribution of the plastic flow metal are one of the main reasons for the formation of defects on the rolling surface of the wheel.
EN
The formation of grain structures with boundaries similar to substructures is one of the factors contributing to grain refinement in hot-reduction carbon steel. At the forming of a rim, the slight cooling-down (100-150°С) of the surface volumes is sufficient to increase their strength characteristics. After that, an increase in the magnitude of the hot-hardening of metal in the central rim volumes will lead to the formation of a more uniform fine-grain austenite structure over the rim section.
5
Content available remote Research of derailed wheelset impact marks on the concrete sleepers
EN
The process of destruction of reinforced concrete sleepers under the railway wheel impact loading is being studied. The article proposes the impact test method of sleepers using a pendulum impact machine. It was developed a device to measure the parameters of impact marks. Using the proposed device it was analyzed the form of the impact marks left by the railway wheel.
PL
W artykule przeanalizowano charakter uszkodzenia żelbetowych podkładów kolejowych poddanych działaniu dynamicznego obciążenia udarowego od kół taboru kolejowego (na bazie badań z użyciem kafara wahadłowego). Przeprowadzono badania laboratoryjne żelbetowych podkładów kolejowych aż do zniszczenia. Opracowano urządzenie do pomiaru geometrycznych parametrów śladu uderzeń koła pociągu.
EN
A person is forced to travel constantly throughout its entire life. The more modern the society, the greater the pace of life, and the greater the need to be present in many places that are distant from each other. Rail transport occupies second place in this regard, after air transport. This means of transportation has many advantages, however the time of travel requires continuous improvement, in particular, to match the competition. One factor limiting the speed of travel is inter-operation between the wheels – rail kinematic pair. When rolling on a rail, a wheel is subject to wear, which unavoidably leads to its degradation. Frequent damage to both the wheel and the rail necessitates consideration of this problem. Because any changes to the rail are very expensive and time-consuming, this paper focuses on possible changes to the wheel. This paper is of an analytical nature and is based on sources in the literature, as well as on own simulations. The objective of the paper is to indicate the advantages of using ADI (Austempered Ductile Iron) as a material for the wheel of a railway rolling stock through analysis of available scientific materials and analysis based on a conducted simulation. The application of ADI on a large scale would certainly make a large impact on the development of railway engineering, significantly reducing the costs of manufacturing the product and its future exploitation.
7
Content available Kryteria decyzyjne odnowy zarysu kół kolejowych
PL
Artykuł dotyczy zagadnienia stosowania kryteriów, na podstawie których podejmowane są decyzje o odnowie zarysu kół kolejowych. Zwrócono uwagę na to, że dominującym rodzajem zużycia kół kolejowych jest zużycie ścierne obrzeża oraz zewnętrznej części powierzchni tocznej kół. Analiza dokumentów dotyczących wymagań, jakie muszą spełniać zestawy kołowe, pozwala na wyodrębnienie nieprzekraczalnych wartości cech diagnostycznych stanowiących podstawę dopuszczenia pojazdów kolejowych do ruchu. W praktyce decyzje o odnowie zarysu kół podejmuje się nieco wcześniej, przed osiągnięciem wartości granicznych przez cechy diagnostyczne, ze względu na możliwość pojawienia się innych symptomów świadczących o niezdatności kół zestawu kołowego. W pracy przedstawiono wykresy zmian takich cech diagnostycznych, jak grubość obręczy, grubość, wysokość i stromość obrzeża (mierzone podczas przeglądów okresowych czteroosiowych lokomotyw elektrycznych). Na wykresach zaznaczono przypadki podjęcia decyzji o odnowie zarysu kół oraz powody ich podjęcia.
EN
The paper concerns the question of the criteria on which decisions are made about the renovation of railway wheel profile. Attention is drawn to the fact that the dominant railway wheel wear is abrasive wear of wheel flange and running surface of the wheel. Analysis of the documents relating to the requirements to be met by wheel-sets allows to extract value of diagnostic features which could not be exceeding for the admission of vehicles to move. In practice, decisions about the renovation of the wheel profile are taken a little earlier, before reaching the limits of diagnostic feature values, because there is a possibility of the other wheel-set unfitness appearance. This paper presents the curves of diagnostic feature changes such as the thickness of the rim, thickness, height and steepness of the wheel flange which were measured during periodic inspections of electric locomotives. The graphs marked by instances of a decision on the renovation of wheel rim and the symbol of reason for their decision were a/so added.
EN
The work presents research of defective railway wheel and rail dynamics and mathematical model of system “Railway vehicle wheel – track”. An assumption was made that the Rail R–65 and railway wheel with flats are with unevenness. The aim of this investigation is to identify the contact forces resulting from the wheel/rail contact at the various defects. Rail track dynamics is described by finite element method, while soil and wagon dynamics is described by the discrete elements. The mathematical model is to assess physical and mechanical properties, roughness of wheel and rail surface, and their geometry. In the mathematical model of the rail is evaluated: the impact of axial force, the initial deformation of rail, the foundation of soil, the gap between sleeper and rail. Profile of railway wheel is defined as a function of radius variable depending on the polar angle and described by Fourier series. In this mathematical model of railway wheel and rail contact area is divided into small sections, where the force is set in contact using the Hertz theory. Total system of non-linear equations of motion is solved by applying the Newton-Raphson method. The speed of the train is 100 km/h and static load on the rail is 100 kN. The flat of the wagon wheel is L=100 mm. Numerical results of contact problem are obtained. Duration of contact is nearly equal to period during which the wheel set passes a half of the flat length. The contact force operating the wheelset is equal to approximately 1.0 MN. Maximum value of the sleeper acceleration is equal 410 g.
PL
W artykule przedstawiono przykład wykorzystania algorytmu ewolucyjnego, który w połączeniu z autorskim oprogramowaniem oraz programem wykorzystującym metodę elementów skończonych pozwala na w pełni automatyczne i niezależne od człowieka projektowanie i optymalizację konstrukcji kół kolejowych.
EN
The article presents an example of using an evolutionary algorithm, which in combination with authorship software and software using the FEM allows for a automatic and independent of human designing and construction optimization of railway wheels.
10
Content available remote Rozwój głowic piezoelektrycznych do pomiarów dwójłomności akustycznej
PL
W artykule opisano rozwój głowic ultradźwiękowych do pomiarów dwójłomności akustycznej, budowanych od początku lat 70. ub.w. w Pracowni Badań Ultradźwiękowych prof. Juliana Deputata, a obecnie w Pracowni Badań Nieniszczących Zakładu Wytrzymałości Materiałów IPPT PAN. W pracy omówiono różne zastosowania pomiarów dwójłomności akustycznej, a także przedstawiono historię rozwoju głowic wyposażonych w przetworniki piezoelektryczne. Opisane głowice budowane były głównie z myślą o pomiarach naprężeń własnych w wieńcach monoblokowych kół kolejowych. Przedstawiono różne układy przetworników, w jakie wyposażano kolejno głowice, oraz zalety i wady zbudowanych głowic.
EN
The paper describes the development of ultrasonic probeheads, built since 70-ties in Ultrasonic Testing Division lead by prof. Julian Deputat and than in Nondestructive Testing Division IPPT PAN. Presented are applications of acoustic birefringence measurements and the history of development of probeheads equipped with piezoelectric transducers. Described are probeheads with various piezoelements configurations, designed mainly for residua stress evaluation in monoblock railroad wheels. Presented are advantages and disadvantages of various probeheads.
11
Content available remote On Evaluation of the Wheelsets-Track Interaction Quality in Railway Engineering
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.
EN
Causes of wear particles formation on railway wheels tread were investigated. Structural factors connecting with plastic deformation, formation of "white layer", and also with non-metallic inclusions and corrosive products of wheel steel, defining wear of railway wheels tread during operation were fixed.
EN
It was shown possibility and necessity of local laser strengthening of cove zone of railway wheels tread by coming out of bainite structure.
14
Content available remote Badania dopuszczeniowe i eksploatacyjne układu koło - klocek hamulcowy
PL
W artykule przedstawiono wyniki prac Katedry Transportu Szynowego w zakresie badań eksploatacyjnych, stanowiskowych i numerycznych elementów układu koło kolejowe - szyna oraz koło - klocek hamulcowy (KSK) czyli elementów, które mają szczególnie istotne znaczenie dla bezpieczeństwa w transporcie szynowym. Ze względu na znaczną ilość badań związanych z dopuszczeniem układu KSK artykuł ten poświęcono głównie zjawiskom termicznym.
EN
In this paper present the results of works made by Department of Railway Engineering in the field of exploitation and numerical research of railway wheel - rail and wheel - brake shoe subsystem which are main influence on railway safety. This paper is devote of thermal phenomena conducting in this subsystems during braking.
PL
W artykule przedstawiono podstawy aerodynamiki pojazdów szynowych w uproszczonym, autorskim ujęciu, które w sposób ilościowy obrazuje układ obciążeń działających na skład pociągu w trakcie ruchu. W artykule wskazano na zakresy prac prowadzonych w ramach aerodynamiki pojazdów szynowych oraz omówiono jej specyficzne wykorzystanie dla określenia intensywności oddawania ciepła generowanego w trakcie hamowania do otoczenia z układu koło kolejowe - klocek hamulcowy (KKH). Uzyskany w ten sposób rozkład współczynnika konwekcji jest podstawową wielkością niezbędną do wykorzystania w trakcie modelowania wszelkich zjawisk termicznych w układzie KKH. W ramach publikacji przedstawiono również wyniku rozkładu prędkości strugi powietrza dla hamowania lokomotywą EU07 z prędkości 100 km/h.
EN
In this paper present the basic of railway vehicle aerodynamics with authorship and simplified way. This presentation shows in quantitative way the system of loads acting on train during moving. In this paper present also methodology for determination convection coefficient for railway wheel and brake shoe modelling with thermal phenomena taking into account. Additionally, shown also result of aerodynamically research of EU07 locomotive during moving up to 100 km/h.
EN
In the paper the dynamical processes are presented which lead to damage of rolling surfaces of rails and railway wheels. Due to dynamic interaction of rail vehicles with track on the rolling surfaces appear permanent deformations and structural changes inducing generation of surface deformations and fatigue cracks. As the main reason of cracking one approve thermal strokes during braking changing residual stresses in wheel rims and compressible stress in rails. But the principle influence have dynamical phenomena.
EN
In this paper, we will describe new methods and technology in production of railway wheels and axles. The aim of these new methods and technology is to increase fatigue strength of railway wheels and axles, and, by this, to also increase their reliability in railway service. In this paper, we will again describe new methods for the evaluation and certification of production quality during serial manufacture, including a description of verification tests and a reliability of these new methods within the scope of qualification tests.
PL
W artykule opisano nowoczesne metody i technologie w produkcji kół i osi kolejowych zestawów kołowych. Celem prezentowanych metod i technologii jest zwiększenie wytrzymałości zmęczeniowej zestawów kołowych oraz ich niezawodności. W referacie opisano nowoczesne metody oceny i certyfikacji jakości produkcji w seryjnym wytwarzaniu wyrobów.
18
Content available remote On the Critical Speed of Wheel/Rail Systems
EN
The presentation considers the term "critical speed of wheel/rail-systems". The equations of motion are written down and its solutions are compared with the experimental findings. Great attention is given to stable limit cycles and to nonlinear and linearized behaviour. Finally a more complex vehicle like a steam locomotive is studied for investigation of its critical speed.
PL
W artykule przedstawiono przebieg oraz wyniki badań prowadzonych w Katedrze Transportu Szynowego Politechniki Śląskiej w zakresie analizy wpływu własności aerodynamicznych układu koło kolejowe - klocek hamulcowy (KKH) na obciążenia termiczne tych elementów. Przedstawiono wyniki badań, z których wynika, że w lokomotywie EU07 prędkość strugi powietrza w otoczeniu układu KKH stanowi niespełna 10% prędkości pojazdu. Dowiedziono, że wiodącym sposobem oddawania ciepła podczas hamowania jest konwekcja, której intensywność zależy głównie od prędkości strugi powietrza.
EN
This article presents course and results of research conducted in Department of Railway Engineering within the range of railway wheel-brake shoe system (KKH) aerodynamic property and influence on thermal loads. Presented also results, which come from that air stream velocity in KKH environment is less than 10% of vehicle velocity. Proved also, that leading way of heat exchange during braking is convection, which intensity depends strongly on air stream velocity.
20
Content available remote On the Dynamics of Beams under Moving Oscillating Load
EN
The paper is devoted to the study of several cases of stationary dynamical problems, whe the motion is driven by a concentrated oscillating load applied acting on a beam on ; elastic foundation at a moving position. The velocity of motion is assumed as constant, particular, we studied cases of the harmonically varying load described by the del function (or superposition of such a forces). Some problems studied by authors of previo studies are revisited.
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