Academic literature on the topic 'Train/track dynamic interaction'
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Journal articles on the topic "Train/track dynamic interaction"
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Vu, Linh, Dong-Doo Jang, and Yun-Suk Kang. "Assessment of Structural Dynamic Response and Vehicle-Track Interaction of Precast Slab Track Systems." Applied Sciences 11, no. 8 (April 15, 2021): 3558. http://dx.doi.org/10.3390/app11083558.
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Recently, precast slab tracks have been used widely in railway applications, especially in conventional urban railway lines. These types of tracks are rapidly constructed and limit interruptions to train operation. However, the problems of dynamic stability when the trains run on the discontinuous type of tracks must be seriously considered. This paper focuses on analyzing the train-track interaction in two types of tracks under the dynamic load by using the numerical analysis program (APATSI) to evaluate the structural response as well as the running safety to precisely understand the load transfer efficiency of precast slab track systems.
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Lau, Albert, and Inge Hoff. "Simulation of Train-Turnout Coupled Dynamics Using a Multibody Simulation Software." Modelling and Simulation in Engineering 2018 (July 22, 2018): 1–10. http://dx.doi.org/10.1155/2018/8578272.
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With the advancements of computing power, multibody simulation (MBS) tool is used to study not only train dynamics but also more realistic phenomena such as train-track coupled dynamics. However, train-turnout coupled dynamics within MBS is still hard to be found. In this paper, a train-turnout coupled model methodology using a MBS tool GENSYS is presented. Dynamic track properties of a railway track are identified through numerical receptance test on a simple straight track model. After that, the identified dynamic track properties are adopted in a switch and crossing (turnout) to simulate train-turnout coupled dynamic interaction including parameters such as rail bending stiffness and sleeper mass variation along the turnout. The train-turnout coupled dynamic interaction is compared to the dynamic interaction simulated from a widely accepted moving mass train-turnout model. It is observed that the vertical and lateral normal forces for the new train-turnout coupled model and the conventional moving mass train-turnout model are in good agreement. In addition, the new train-turnout coupled model can provide additional track dynamics results. It is concluded that the train-turnout coupled model can provide a more realistic train-turnout dynamic interaction compared to the moving mass train-turnout model.
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Bhatti, M. H., V. K. Garg, and K. H. Chu. "Dynamic Interaction Between Freight Train and Steel Bridge." Journal of Dynamic Systems, Measurement, and Control 107, no. 1 (March 1, 1985): 60–66. http://dx.doi.org/10.1115/1.3140708.
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The dynamic responses of a railway steel bridge due to vehicle-track-bridge interaction were investigated for the effects of vertical and lateral track irregularities, approach track quality, vehicle weight and type, and train speed. It was found that (1) greater approach irregularities produce higher impact factors and dynamic forces in bridge members; (2) light weight and empty cars produce higher impact factors but small dynamic forces; and (3) impact factors depend on such parameters as axle spacing, suspension system stiffness, truck center distances, etc.
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Chang, Chao, Liang Ling, Zhaoling Han, Kaiyun Wang, and Wanming Zhai. "High-Speed Train-Track-Bridge Dynamic Interaction considering Wheel-Rail Contact Nonlinearity due to Wheel Hollow Wear." Shock and Vibration 2019 (October 31, 2019): 1–18. http://dx.doi.org/10.1155/2019/5874678.
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Wheel hollow wear is a common form of wheel-surface damage in high-speed trains, which is of great concern and a potential threat to the service performance and safety of the high-speed railway system. At the same time, rail corridors in high-speed railways are extensively straightened through the addition of bridges. However, only few studies paid attention to the influence of wheel-profile wear on the train-track-bridge dynamic interaction. This paper reports a study of the high-speed train-track-bridge dynamic interactions under new and hollow worn wheel profiles. A nonlinear rigid-flexible coupled model of a Chinese high-speed train travelling on nonballasted tracks supported by a long-span continuous girder bridge is formulated. This modelling is based on the train-track-bridge interaction theory, the wheel-rail nonelliptical multipoint contact theory, and the modified Craig–Bampton modal synthesis method. The effects of wheel-rail nonlinearity caused by the wheel hollow wear are fully considered. The proposed model is applied to predict the vertical and lateral dynamic responses of the high-speed train-track-bridge system under new and worn wheel profiles, in which a high-speed train passing through a long-span continuous girder bridge at a speed of 350 km/h is considered. The numerical results show that the wheel hollow wear changes the geometric parameters of the wheel-rail contact and then deteriorates the train-track-bridge interactions. The worn wheels can increase the vibration response of the high-speed railway bridges.
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Shkurnikov, Sergey, and Olga Morozova. "On interaction of a rolling stock and geometrical parametres of high-speed networks’ route." Bulletin of scientific research results, no. 3 (October 17, 2017): 96–104. http://dx.doi.org/10.20295/2223-9987-2017-3-96-104.
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Objective: Due to the lack of global experience of holding on one track high-speed passenger trains (moving at a speed up to 400 km/h), high-speed passenger trains (moving at a speed up to 250 km/h) and special freight trains (accelerating to a speed of more than 200 km/h), the only possible way of studying the influence of a train on a track is computer simulation modeling. The analysis of the existing computer programs was carried out and the most effective programme for the solution of combined train movement was selected. Methods: Simulation modeling was applied. On the basis of the obtained model the possibility of “Universal mechanism” software practical application was considered. Results: A test simulation model of a high-speed train carriage was developed in “Universal mechanism” software application. Preliminary results showed the possibility of its usage for the study of a high-speed train and track interaction. Practical importance: Modern computer technologies make it possible to solve the tasks of dynamic interaction with a high degree of accuracy. Among the variety of software used for the study of dynamic behavior of a railway vehicle in Russia, “Universal mechanism” software application is of wide popularity and may be used for the study of dynamic behavior of different types of trains on railway tracks of different plans and profiles.
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Chen, Zhaowei, Wanming Zhai, and Qiang Yin. "Analysis of structural stresses of tracks and vehicle dynamic responses in train–track–bridge system with pier settlement." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 232, no. 2 (October 28, 2016): 421–34. http://dx.doi.org/10.1177/0954409716675001.
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Pier settlement causes deformation of bridge structures, and further distorts the track structures placed on bridge decks, which may greatly affect the service life of the tracks and safe operation of trains. This study analyzes track stresses and vehicle dynamic responses in train–track–bridge system with pier settlement and determines the pier settlement safe value for high-speed railways with China Railway Track System (CRTS) II slab tracks. First, a detailed train–track–bridge dynamic model is established based on the train–track–bridge dynamic interaction theory. Verified with field experimental results, the model is utilized to calculate the dynamic responses of the vehicle–track–bridge system with different pier settlement values. Finally, the safe value of the pier settlement in the CRTS II slab track railway line is determined according to the limit of the vehicle dynamic indicators and the structural stresses of tracks. The results show that the vertical acceleration of the car body is more sensitive to pier settlement among all the vehicle dynamic indicators. Structural stresses of tracks caused by pier settlement appear at the positions of the pier with settlement and its two adjacent piers. The effect of train loads on the track stresses is much smaller than that of the pier settlement. It is important to adopt the structural stresses of tracks as the evaluation criteria of the pier settlement safe value than the vehicle dynamic indicators. Taking the effects of the bridge pier settlement, the vehicle load, the prestress effect, and the self-weight into consideration, the pier settlement safe value for the high-speed railway lines with the CRTS II slab track is 11.5 mm.
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Chen, Zhaowei, and Hui Fang. "An Alternative Solution of Train-Track Dynamic Interaction." Shock and Vibration 2019 (September 11, 2019): 1–14. http://dx.doi.org/10.1155/2019/1859261.
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Train-track interaction (TTI) is a classic research topic in railway engineering, which consists of three main parts, namely, train model, track model, and wheel-rail interaction. To improve the computational accuracy and broaden the application range, an alternative calculation method to investigate TTI based on secondary development technology of the commercial software ANSYS through APDL language is introduced in this article. Primarily, the train-track interaction theory is briefly presented. On this basis, TTI is programmed and implemented on the computing platform of ANSYS by fully taking the nonlinear wheel-rail interaction into consideration. In this calculation method, the train model, which is established based on multibody dynamics theory and solved by an advanced explicit integration method, is programmed into ANSYS through APDL language, while the track part is simulated according to finite element theory. Then, the proposed calculation method is validated with field test results to verify the validity. Finally, a numerical demonstration is conducted employing the present method. Results show that the introduced method is effective and able to investigate TTI. Different complicated track systems can be accurately simulated employing this method. Moreover, this method is also adoptable to explore train-bridge interaction and train-track-bridge interaction.
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Zhu, Shengyang, Jun Luo, Mingze Wang, and Chengbiao Cai. "Mechanical characteristic variation of ballastless track in high-speed railway: effect of train–track interaction and environment loads." Railway Engineering Science 28, no. 4 (November 30, 2020): 408–23. http://dx.doi.org/10.1007/s40534-020-00227-6.
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AbstractDue to the fact that ballastless tracks in high-speed railways are not only subjected to repeated train–track dynamic interaction loads, but also suffer from complex environmental loads, the fundamental understanding of mechanical performance of ballastless tracks under sophisticated service conditions is an increasingly demanding and challenging issue in high-speed railway networks. This work aims to reveal the effect of train–track interaction and environment loads on the mechanical characteristic variation of ballastless tracks in high-speed railways, particularly focusing on the typical interface damage evolution between track layers. To this end, a finite element model of a double-block ballastless track involving the cohesive zone model for the track interface is first established to analyze the mechanical properties of the track interface under the loading–unloading processes of the negative temperature gradient load (TGL) followed by the same cycle of the positive TGL. Subsequently, the effect of wheel–rail longitudinal interactions on the nonlinear dynamic characteristics of the track interface is investigated by using a vehicle-slab track vertical-longitudinal coupled dynamics model. Finally, the influence of dynamic water pressure induced by vehicle dynamic load on the mechanical characteristics and damage evolution of the track interface is elucidated using a fluid–solid coupling method. Results show that the loading history of the positive and negative TGLs has a great impact on the nonlinear development and distribution of the track interface stress and damage; the interface damage could be induced by the wheel–rail longitudinal vibrations at a high vehicle running speed owing to the dynamic amplification effect caused by short wave irregularities; the vehicle dynamic load could produce considerable water pressure that presents nonlinear spatial–temporal characteristics at the track interface, which would lead to the interface failure under a certain condition due to the coupled dynamic effect of vehicle load and water pressure.
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Li, Su, and Kaewunruen. "Saturated Ground Vibration Analysis Based on a Three-Dimensional Coupled Train-Track-Soil Interaction Model." Applied Sciences 9, no. 23 (November 20, 2019): 4991. http://dx.doi.org/10.3390/app9234991.
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A novel three-dimensional (3D) coupled train-track-soil interaction model is developed based on the multi-body simulation (MBS) principle and finite element modeling (FEM) theory using LS-DYNA. The novel model is capable of determining the highspeed effects of trains on track and foundation. The soils in this model are treated as saturated media. The wheel-rail dynamic interactions under the track irregularity are developed based on the Hertz contact theory. This model was validated by comparing its numerical results with experimental results obtained from field measurements and a good agreement was established. The one-layered saturated soil model is firstly developed to investigate the vibration responses of pore water pressures, effective and total stresses, and displacements of soils under different train speeds and soil moduli. The multi-layered soils with and without piles are then developed to highlight the influences of multi-layered soils and piles on the ground vibration responses. The effects of water on the train-track dynamic interactions are also presented. The original insight from this study provides a new and better understanding into saturated ground vibration responses in high-speed railway systems using slab tracks in practice. This insight will help track engineers to inspect, maintain, and improve soil conditions effectively, resulting in a seamless railway operation.
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Oscarsson, Johan. "Dynamic Train-Track-Ballast Interaction with Unevenly Distributed Track Properties." Vehicle System Dynamics 37, sup1 (January 2002): 385–96. http://dx.doi.org/10.1080/00423114.2002.11666248.
Full textDissertations / Theses on the topic "Train/track dynamic interaction"
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Elm, Dahlman Rasmus, and Emil Lundberg. "Parametric Studies of Train-Track-Bridge Interaction : An evaluation of the dynamic amplification due to track irregularities for freight transport." Thesis, KTH, Bro- och stålbyggnad, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-301309.
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In this thesis a train-track-bridge interaction (TTBI) model is developed in order to study the dynamic amplification from track irregularities on railway bridges traversed by freight trains. These simulations are of great importance since rail freight transport is expected to increase in order to meet the climate goals. The shift of the freight industry is however not accomplished without complications, because of the heavier and more frequent transportation higher demand is put on the infrastructure supporting the railways. In order to adequately assess the bearing capacity of the railway bridges, more detailed models assessing the dynamic behavior of the bridges are needed. The research underlying the current model in Eurocode were made during the 1970s (ORE, 1976) and the 1990s (ERRI, 1999) which were based on very simplified relations of the interaction and irregularities. Two research questions are therefore established in this thesis. The first one is if the current dynamic amplification factor in Eurocode which accounts for track irregularities is over conservative and secondly if the same factor is suitable to utilize for both section forces and deflections. The model developed in order to answer the stated research questions is a 2D model (considering only vertical excitation) with a linearized Hertz contact spring coupling the vehicle subsystem to the track-bridge system. The bridges examined in the thesis are limited to simply supported bridges with a span length between 4-20 m carrying a ballasted track. The studied train speeds vary between 60 - 120 km/h in order to replicate the speed range utilized by freight trains. The quality of the track (irregularities) is varied between a standard variation of 0.5-5 mm and is generated based on the German power spectral density (PSD) function. Research have previously been carried out in the field of TTBI system but have mostly been focusing on high-speed railway engineering and few studies have been performed on heavy transportation. One of the pioneers in the field of TTBI modelling is Wanming Zhai and the model developed in this thesis is validated against one of his 2D models. Based on the simulations performed in this thesis it is evident that the current model in Eurocode EN 1991-2 is over conservative and in great need of a revision. The model presented in this thesis is for the case with the largest dynamic amplification (120 km/h and a 4 m span length) significantly lower than the model presented in Eurocode. From the sensitivity analysis it is possible to conclude that many of the parameters in the system have low influence on the dynamic amplification while others have considerable influence. The parameters that have a considerable influence might be more suitable with a probabilistic approach instead of a deterministic which was utilized in this thesis.I denna avhandling upprättas en tåg-spår-bro interaktionsmodell i syfte att studera den dynamiska förstorningsfaktorn som uppkommer av ojämnheter från spåret för järnvägsbroar trafikerade av godståg. Dessa typer av simuleringar är viktiga då järnvägstransporter förväntas öka för att klara av att möta de klimatmål som fastställts. Denna ökning av järnvägstransporter genomförs dock inte utan problem. Ökningen medför fler och tyngre transporter vilket skapar problem för järnvägsinfrastrukturen (främst broarna). För att med säkerhet kunna fastställa bärförmågan hos broarna, behövs mer avancerade modeller än de som idag finns i Eurokod. Modellerna som finns angivna i Eurokod bygger på forskning genomförd under 70- (ORE, 1976) och 90-talet (ERRI, 1999), där det användes väldigt förenklade interaktions- och ojämnhets-modeller. På grund av detta har två frågeställningar upprättats. Den första är om den dynamiska förstoringsfaktorn som används i Eurokod för att ta hänsyn till ojämnheterna i spåret är överdrivet konservativ och den andra är om samma faktor är lämplig att använda för både snittkrafter och nedböjning. Modellen som upprättats för att besvara dessa forskningsfrågor är en 2D modell (vertikalt led) med en linjäriserad Hertz kontaktfjäder för att koppla samman fordonet med spår-bro systemet. Broarna som har studerats i denna avhandling är endast fritt upplagda broar med en spannlängd mellan 4-20 m med ballasterat spår. Tåg-hastigheten har varierats mellan 60-120 km/h i syfte att simulera relevanta hastigheter för godståg. Spårkvalitén (ojämnheterna) har beskrivits m.h.a. standardavvikelsen från det perfekta spårläget och har varierats mellan 0.5-5 mm. Dessa ojämnheter har genererats baserat på den tyska power spectral density (PSD) funktionen. Tidigare forskning har utförts inom ämnet tåg-spår-bro interaktion men med huvudsaklig fokus på höghastighetståg/resonans-beteenden och få studier har genomförts på godståg. En av föregångsmännen inom ämnet är Wanming Zhai, och modellen som upprättas i denna avhandling har därav validerats mot hans 2D modell. Baserat på simuleringarna i denna avhandling är det tydligt att den nuvarande modellen som används i Eurokod EN 1991-2 är överdrivet konservativ och i stort behov av en uppdatering. Det fall med stört dynamisk förstoringsfaktor (120 km/h och en spannlängd på 4 m) som behandlas i denna rapport är avsevärt lägre än det som återfinns i Eurokod. Från känslighetsanalysen som genomfördes kunde det fastställas att många av parametrarna i systemet har en låg inverkan på förstoringsfaktorn. För parametrarna som dock hade inflytande skulle ett probabilistiskt angreppssätt kunna vara mer passande än det deterministiska som använts i denna avhandling.
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Martino, Davide. "Train-Bridge Interaction on Freight Railway Lines." Thesis, KTH, Bro- och stålbyggnad, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-99386.
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This study investigates the dynamic response of a railway bridge under train passage. Three load models designed around the Swedish Steel Arrow freight train are tested and compared. A series of Concentrated Forces, a succession of single degree of freedom Sprung-Masses, and a sequence of complex multi-degree of freedom Train Wagons. The increase in accuracy of the representation corresponds to taking into account the inertial properties of the wagons. The track-bed layer is substitute by a sequence of regularly spaced couple of springs and dampers at the sleeper distance. Under the assumption of this work, a portion of the ballast vibrates with the sleeper during train passage. Both bridge and rail are modelled under Bernoulli-Euler beam theory. The dynamic behavior of the bridge is investigated in presence or absence of vertical track irregularities. The main conclusions of the report can be summarized as: • the dynamic amplification attains its maximum value, for every train model, at the critical train speeds of 120 km/h. Proper resonance has also been detected at the speed of 60 km/h in all the simulations; • the Concentrated Forces model provided an upper boundary of the acceleration response of the bridge while the Sprung-Mass systems a lower boundary. The response of the two models is in very good agreement at non resonance speeds. The simulation with Train Wagons loading does not fit completely this trend, it adds two peaks on the diagram; Besides that, the bridge response lies between the two limits; • the presence of track irregularities determines a variation of the bridge dynamics only if combined with Train Wagon load model. The Concentrated Force pattern couldn’t detect the modification of the profile while the Sprung-Masses case provided a diagram of maximum acceleration similar to the one over flat rail simply shifted upwards; • the position of the track irregularities along the bridge influence its dynamics.
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Giner, Navarro Juan. "Advances Techniques for Time-Domain Modelling of High-Frequency Train/Track Interaction." Doctoral thesis, Universitat Politècnica de València, 2017. http://hdl.handle.net/10251/90637.
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[EN] The aim of the present Thesis is to develop models for the study of very high-frequency phenomena associated with the coupling dynamics of a railway vehicle with the track. Through these models, this Thesis intends to address squeal noise as a particular case of rolling noise when the train negotiates a small radius curve.
Wheel/rail interaction is the predominant source of noise emission in railway operations. Rolling contact couples the wheel and the rail through a very small area, characterised by strongly non-linear and non-steady state dynamics that differentiates rolling noise from any other noise problem. Wheel/rail contact problem is studied based on Kalker's variational theory and the local falling behaviour of the coefficient of friction is introduced by means of a regularisation of Coulomb's law. Its implementation shows that the influence of the falling friction on the creep curves can be assumed negligible, thus rolling contact is finally modelled using a constant coefficient of friction.
Flexibility is introduced in railway substructures through the Finite Element (FE) method in order to cover the high-frequency range. This work adopts a rotatory wheelset model that takes computational advantage of its rotational symmetry. It also develops a cyclic flexible rail model that fixes the translational contact force in a spatial point of the mesh through a technique called Moving Element (ME) method. A modal approach is used to reduce significantly the number of degrees of freedom of the global problem and a diagonalisation technique permits to decouple the resulting modal equations of motion in order to increase the computational velocity of the time integrator.
Simulations in curving conditions in the time domain are carried out for constant friction conditions in order to study if the proposed interaction model can reproduce squeal characteristics for different curve radii and coefficients of friction.[ES] El objetivo de la presente Tesis es desarrollar modelos para el estudio de fenómenos de muy alta frecuencia asociados a la dinámica acoplada de un vehículo ferroviario con la vía. A través de estos modelos, esta Tesis pretende abordar el fenómeno de los chirridos como un caso particular de ruido de rodadura en condiciones de curva cerrada. La interacción rueda/carril es la fuente predominante de ruido en las operaciones ferroviarias. El contacto es el responsable del acoplamiento entre la rueda y el carril a través de un área muy pequeña caracterizada por una dinámica fuertemente no lineal y no estacionaria. El problema de contacto rueda/carril se estudia mediante la teoría variacional de Kalker y la caída local del coeficiente de fricción se introduce por medio de una regularización de la ley de Coulomb, que muestra que su influencia sobre las curvas de fluencia se puede despreciar. Como consecuencia, el coeficiente de fricción se considera constante. La flexibilidad se introduce en las subestructuras ferroviarias a través del método de los Elementos Finitos (EF) para cubrir el rango de las altas frecuencias. La Tesis adopta un modelo de eje montado rotatorio que toma ventaja computacional de su simetría rotacional. También desarrolla un modelo de carril flexible y cíclico que fija la fuerza de contacto en un punto espacial de la malla mediante el método de los Elementos Móviles (EM). Se utiliza un enfoque modal para reducir significativamente el número de grados de libertad del problema global; las ecuaciones de movimiento resultantes en coordenadas modales se desacoplan mendiante una técnica de diagonalización para aumentar la velocidad computacional del integrador temporal. Las simulaciones en condiciones de curva en el dominio del tiempo se llevan a cabo en condiciones de fricción constante con el objetivo de estudiar si el modelo de interacción propuesto puede reproducir las características del chirrido en curva para diferentes radios de curva y coeficientes de fricción.
[CAT] L'objectiu de la present Tesi és desenvolupar models per a l'estudi de fenòmens de molt alta freqüència associats amb la dinàmica acoblada d'un vehicle ferroviari amb la via. Aquests models permeten simular el soroll de rodament encara que, en particular, aquest treball es proposa abordar el fenomen del soroll grinyolant produït quan el tren negocia un radi de curvatura estret. La interacció roda/carril és la font predominant de l'emissió de soroll en les operacions ferroviàries. El contacte acobla la roda i el carril a través d'una àrea molt reduïda que es caracteritza per una dinàmica fortament no lineal i no estacionària. El problema de contacte roda/carril s'estudia mitjançant la teoria variacional de Kalker i el descens local del coeficient de fricció s'introdueix per mitjà d'una regularització de la llei de Coulomb, què demostra que la seua influència en les corbes de fluència es pot suposar insignificant. Per tant, s'utilitza un coeficient de fricció constant per a modelar el contacte. La flexibilitat s'introdueix en les subestructures de ferrocarril a través del mètode d'Elements Finits (EF) per tal de cobrir el rang d'alta freqüència. La present tesi adopta un model d'eix muntat rotatori que s'aprofita de la seua la simetria rotacional per a augmentar la eficiència computacional. També desenvolupa un model de carril flexible i cíclic que fixa la força de contacte en un punt espacial de la malla a través del mètode dels Elements Mòbils (EM). S'empra un enfocament modal per reduir significativament el nombre de graus de llibertat del problema global, al temps que s'implementa una tècnica diagonalització que permet desacoblar les equacions modals de moviment per a augmentar la velocitat computacional de l'integrador temporal. Les simulacions en les condicions de corba en el domini del temps es duen a terme per a condicions de fricció constant per tal d'estudiar si el model d'interacció proposat pot reproduir les característiques del soroll grinyolant per a diferents radis de corba i coeficients de fricció.
Giner Navarro, J. (2017). Advances Techniques for Time-Domain Modelling of High-Frequency Train/Track Interaction [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/90637
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Pecile, Bérénice. "Modèle dynamique d'interaction véhicule-voie ferroviaire en présence de défauts géométriques sur les surfaces en contact." Thesis, Valenciennes, 2017. http://www.theses.fr/2017VALE0004/document.
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Les phénomènes dynamiques observés lors de la circulation des trains provoquent des nuisances, notamment sonores et vibratoires, qui sont amplifiées par la présence de défauts sur la roue et sur le rail. Pour les analyser, il est nécessaire de prédire avec robustesse le comportement dynamique des composants impliqués dans l’interaction véhicule-voie et donc de simuler les efforts de contact générés pour des interfaces non idéalisées.L’objectif de cette thèse est donc de proposer un modèle semi-analytique global compatible avec l’intégration de multiples défauts géométriques sur les surfaces en contact. Afin de simuler l’interaction véhicule-voie dans le domaine temporel et garantir une applicabilité en phase de dimensionnement, une attention particulière est portée sur le compromis entre la précision des résultats et les temps de calcul associés.Le modèle ainsi proposé est composé d’un demi-bogie, dont le comportement vertical est représenté par un ensemble de masses-ressorts-amortisseurs, circulant sur une voie ballastée. Cette dernière est assimilée à une poutre bi-appuyée, supportée périodiquement à l’emplacement des traverses. Ces deux systèmes sont couplés en contact grâce à une procédure Distributed Point Reacting Spring (DPRS) sous forme discrétisée.Une validation du modèle est, d’une part, proposée en considérant des travaux antérieurs dans le cas de géométries parfaites. D’autre part, de multiples combinaisons de défauts, localisés comme le méplat ou répartis comme l’usure ondulatoire, sont introduites dans la simulation. La variabilité spatiale, particulière au cas de l’écaillage, est modélisée par des champs aléatoiresThe appearance of dynamic phenomena during the running of train on track leads to issues such as noise and vibration pollution, which can be further amplified by the presence of defects on the treads. In order to analyze them, it is necessary to predict with reliability the dynamic behavior of the vehicle-track interaction components, in particular the contact forces produced by non perfect treads.The aim of this PhD thesis is to provide a semi-analytical vehicle-track interaction model able to take into account multiple defects on the surfaces in contact. In order to conduct simulations in the time-domain and ensure applicability in the sizing phase, a special attention is given on the compromise between the accuracy of the results and the simulation times.The proposed model is therefore composed of half a bogie running on a ballasted track. This latter is modeled by a pinned-pinned beam with periodic supports located at the sleepers while the vertical behavior of the bogie is given by masses, springs and dampers. These two models are coupled in contact by a discretized Distributed Point Reacting Spring (DPRS) procedure.A validation of the model, based on previous work, is firstly proposed for perfect treads. Then, multiple combinations of defects, either localised as wheelflat or spread as corrugation, are introduced in the simulation. The spatial variability, specific to shelling, is modeled by random fields
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Chaar, Nizar. "Wheelset Structural Flexibility and Track Flexibility in Vehicle-Track Dynamic Interaction." Doctoral thesis, Stockholm : Farkost och flyg, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4345.
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Hunt, Geoffrey A. "Dynamic analysis of railway vehicle/track interaction forces." Thesis, Loughborough University, 1986. https://dspace.lboro.ac.uk/2134/7492.
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Methods of predicting the dynamic forces are developed for the cases of vehicles negotiating vertical and lateral track irregularities. The bounds of validity of various models of the track are evaluated, from single degree of freedom, lumped parameter models to the case of a two layered beam on elastic foundation with a moving dynamic load. For the case of the lateral response of a vehicle negotiating a track switch, a finite element model of the track is also developed. The vehicle model developed for-the vertical case contains all the rigid body modes of a four axle vehicle for which primary and secondary suspension can be included with viscous or friction suspension damping. Solution of the vehicle/track interaction problem for these non-linear models is obtained by numerical integration, vehicle and track being connected by the non-linear wheel/rail contact stiffness. The most significant forces are shown to arise from the interaction of the unsprung mass and track resilience, with the vehicle modes also making a significant contribution, particularly in friction damped cases. For the lateral case use is made of an existing model of transient vehicle behaviour containing the wheel/rail contact non-linearities, to which track resilience is added in order to predict the track forces. The model is used to predict the forces which would be anticipated at discrete lateral irregularities such as those to be found at track switches. Once again the interaction with the track introduces modes of vibration which are significant in terms of wheel/rail forces. Comparison is made with experimental results obtained from full scale tests in the field. In one experiment the vertical track forces due to a range of vehicles negotiating a series of dipped welds in the track were measured, and in a second the lateral forces were recorded at the site of an artificially introduced lateral kink. A particular application of the results is in the prediction of the rate of deterioration of vertical and lateral geometry due to dynamic forces. This is to offer an improved understanding of the deterioration mechanism in order to influence the future design of vehicles and track to reduce maintenance costs.
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Hawari, Haitham M. "Minimising track degradation through managing vehicle/track interaction." Queensland University of Technology, 2007. http://eprints.qut.edu.au/16366/.
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The rate at which a railway track deteriorates depends on the response of the track under different static and repeated dynamic forces. These wheel/rail forces lead to imperfections in the rail surface and deviation in track geometry alignment. The wheel/rail forces are dependent upon the quality of maintenance of the characteristics of both train and track. If train components such as wheelsets and suspensions are maintained to a high standard, less dynamic forces are generated at the wheel/rail interface and less damage is caused over time. Therefore, the amount and cost of maintenance of track are reduced. However, there is little known about how the characteristics of train components affect time-dependent track degradation. Track degradation through deviation of track from its ideal position has the most effect on maintenance costs. Therefore, the present research aims to investigate this track degradation and improve understanding of the effects of train characteristics (such as train mass and speed, suspension stiffness and damping) on railway tracks. The research is conducted by looking into the relationship between wheel/rail forces and track degradation on one hand and between wheel/rail forces and train characteristics on the other hand, with the objective of assisting in managing vehicle/track interaction in order to minimise track degradation. This aim is achieved by investigating the above two relationships to attain the desired relationship between track degradation and train characteristics. The research focuses on wheel/rail vertical forces (both amplitudes and frequencies), vertical track alignment (longitudinal vertical profile), and rail head defects. The study started by collecting wheel/rail vertical forces data in addition to data on vertical track degradation under sustained traffic loads on a heavy haul railway section of track in Central Queensland. Also, five years of degradation and maintenance history data were collected on three other test sections of railway track under variety of traffic conditions and loads in Central Queensland. There were four main analyses of this data employed to probe the study. The first analysis was performed by examining the track degradation history data. The standard deviation method was used in this first analysis to acquire the rate of deterioration in terms of its relationship to track profile (roughness). The second analysis was accomplished by correlating the vertical wheel/rail forces to both vertical track profile and rail roughness using signal processing principles and a function know as coherence. The third analysis was carried out by using the computer simulation software NUCARS to obtain the link between wheel/rail forces and the deterioration of the vertical track profile. The fourth analysis was achieved by combining the results obtained from the above three analyses to acquire the rate of track deterioration in terms of its relationship to varying train characteristics. The first analysis mentioned above quantified the relationship between the level of roughness of the track and rate at which that roughness deteriorated. An important outcome of this relationship is that there is a threshold of roughness below which track deterioration is minimal. The track maintenance planners can now use that threshold for cost effective targeting of tamping activities. The correlation study between track roughness and wheel/rail forces using the coherence function found, surprisingly, that the overall deterioration of the track roughness, in the absence of frequencies of forces above 30 Hz, is due to the so-called quasi-static lower frequency oscillations of dynamic forces. This conclusion together with the relationship between vehicle characteristics and track forces, established in the analyses above, has significant implications for the design of wagon bogies and for charges track owners might levy on trains using their tracks. This research is part of a larger Rail CRC project 11/4 called 'Enhancing the Optimisation of Maintenance/Renewal' being carried out in the School of Urban Development in Queensland University of Technology.
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OLIVEIRA, ADENILSON COSTA DE. "A DYNAMIC INTERACTION MODEL OF TRACK RAILWAY STRUCTURAL ELEMENTS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2006. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=9498@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOREm uma ferrovia, o veículo interage dinamicamente com a superestrutura (trilhos, palmilha e dormentes) e a subestrutura (lastro, sublastro e sub- base). O conforto dos passageiros, a vibração no solo e a freqüência dos trabalhos, de manutenção tanto dos veículos como também dos trilhos são determinadas considerando-se que todos os elementos estruturais interagem entre si. A resposta de cada componente estrutural é sensível µa pressão do eixo da roda no trilho, µas irregularidades na superfície do trilho e µa velo- cidade do trem, que está relacionada com à velocidade crítica na ferrovia (velocidade da fase mínima com que as ondas se propagam no trilho e no dormente). No projeto de uma nova ferrovia, como também na própria ava- liação das condições de trabalho de ferrovias existentes, todos os aspectos brevemente mencionados acima têm que ser levados em conta em um modelo matemático. A interação trilho-palmilha-dormente-lastro é representada por um modelo unidimensional em que os trilhos são representados por vigas de Timoshenko, assim como os dormentes; o lastro é representado por uma fundação elástica com amortecimento viscoso. A interação local entre tri- lho e dormente é simulada utilizando um elemento de treliça com rigidez e amortecimento. As propriedades mecânicas de cada componente da ferro- via são na maioria dos casos desconhecidas, principalmente as propriedades do lastro. Para cada elemento, são desenvolvidas as equações de equilíbrio entre esforços e deslocamentos. As equações de equilíbrio global são dadas por um desenvolvimento em série das matrizes de massa, rigidez e amorte- cimento em função de uma freqüência circular de vibração. O interesse final é a resposta transiente no domínio do tempo, obtida utilizando técnicas de superposição modal. Por fim, são propostos três modelos globais para a ferrovia, obtidos considerando algumas modificações no dormente.
In a railway, the vehicle interacts dynamically with a track superstructure (rails, rail pad and sleepers) and sub-structure (ballast, sub-ballast, sub- grade). Passengers' comfort, environmental loading (ground vibration) and frequency of maintenance works of vehicles as well as of the track are deter- mined by the way all the structural elements interact. The response of each single structural component is sensitive to the wheel-axle pressure on the track, the effects of joint in un welded rails, the unevenness of wheel and rail, and the train speed as referred to the track critical velocity (minimum phase velocity of bending waves propagating in the track rails, supported by the ballast). An important issue is for example how the ballast will be affected when old, soft, timber sleepers and replaced by much, stiffer, pres- tressed concrete elements, and how newly introduced irregularities propa- gate along the track, among uncountable mathematical model possibilities, the presents a rail-pad-sleeper-ballast model mainly based on an assemble of Timoshenko beam elements (for the rail) including, in case of the sle- epers, elastic foundation (for the ballast) and viscous damping. The local interaction of the rail-pad-sleeper set is simulated with a bar element that includes damping. The dissertation reports on the numerical model, which relies on exact, dynamic beam and truss elements derived on a variational basis for the frequency-domain analysis. The model enable the assessment of the vibration characteristics of a rail track, the inverse evaluation of se- veral mechanical properties of the structural components and eventually, if everything goes well, the assessment of a dynamic behavior of the rail track actual service load. Theoretical basis for transient analysis is the advanced mode superposition technique. Finally, are proposed three global models for the railway, obtained considering some modifications in the sleeper.
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Shan, Yao [Verfasser]. "Numerical Investigation of Dynamic Railway Vehicle-Track-Subgrade Interaction / Yao Shan." Aachen : Shaker, 2013. http://d-nb.info/1050342585/34.
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Frohling, Robert Desmond. "Deterioration of railway track due to dynamic vehicle loading and spatially varying track stiffness." Thesis, Pretoria : [s.n.], 1997. http://upetd.up.ac.za/thesis/available/etd-01122009-160350.
Full textBooks on the topic "Train/track dynamic interaction"
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Xia, He, Nan Zhang, and Weiwei Guo. Dynamic Interaction of Train-Bridge Systems in High-Speed Railways. Berlin, Heidelberg: Springer Berlin Heidelberg, 2018. http://dx.doi.org/10.1007/978-3-662-54871-4.
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Zhang, Nan, He Xia, and Weiwei Guo. Dynamic Interaction of Train-Bridge Systems in High-Speed Railways: Theory and Applications. Springer, 2018.
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Zhang, Nan, He Xia, and Weiwei Guo. Dynamic Interaction of Train-Bridge Systems in High-Speed Railways: Theory and Applications. Springer, 2017.
Find full textBook chapters on the topic "Train/track dynamic interaction"
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Kassa, Elias, and Xiaopei Cai. "Modelling of the Dynamic Train-Track-Substructure Interaction for Track Monitoring." In Springer Series in Reliability Engineering, 3–17. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-62472-9_1.
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Andersson, Clas, and Johan Oscarsson. "Dynamic Train/Track Interaction Including State–Dependent Track Properties and Flexible Vehicle Components." In The Dynamics of Vehicles on Roads and on Tracks, 47–58. London: CRC Press, 2021. http://dx.doi.org/10.1201/9781003210924-4.
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Sun, Yanquan, Qing Wu, Wubin Cai, and Maksym Spiryagin. "Innovative Methodology for Heavy Haul Train-Track Interaction Dynamics Issues." In Lecture Notes in Mechanical Engineering, 899–907. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-38077-9_104.
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Collina, Andrea, Roberto Corradi, Egidio Di Gialleonardo, and Qianqian Li. "Nonlinear Model of an Embedded Rail System for the Simulation of Train-Track Dynamic Interaction and the Analysis of Vibration Transmission." In Notes on Numerical Fluid Mechanics and Multidisciplinary Design, 251–58. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-70289-2_25.
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Popović, Zdenka, Luka Lazarević, Milica Vilotijević, and Nikola Mirković. "Interaction Phenomenon Between Train, Track and Bridge." In International Scientific Conference Energy Management of Municipal Transportation Facilities and Transport EMMFT 2017, 3–11. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-70987-1_1.
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Chang, Chao, Liang Ling, Wanming Zhai, and Kaiyun Wang. "Influences of Infrastructure Property on the Train-Track Interaction Due to Track Irregularities." In Lecture Notes in Mechanical Engineering, 269–77. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-38077-9_32.
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Lei, Xiaoyan. "Analysis of Dynamic Behavior of the Train, Ballast Track, and Subgrade Coupling System." In High Speed Railway Track Dynamics, 323–40. Singapore: Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-10-2039-1_12.
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Lei, Xiaoyan. "Analysis of Dynamic Behavior of the Train, Slab Track, and Subgrade Coupling System." In High Speed Railway Track Dynamics, 341–64. Singapore: Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-10-2039-1_13.
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Guo, W. W., H. Xia, and N. Zhang. "Resonance analysis of train-bridge dynamic interaction system." In Environmental Vibrations: Prediction, Monitoring, Mitigation and Evaluation (ISEV 2005), 181–87. London: CRC Press, 2021. http://dx.doi.org/10.1201/9781003209379-28.
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Xia, He, Nan Zhang, and Weiwei Guo. "Dynamic Analysis of Train-Bridge Coupling System." In Dynamic Interaction of Train-Bridge Systems in High-Speed Railways, 227–89. Berlin, Heidelberg: Springer Berlin Heidelberg, 2017. http://dx.doi.org/10.1007/978-3-662-54871-4_5.
Full textConference papers on the topic "Train/track dynamic interaction"
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Datta, Arya, Dimitris Rizos, Yu Qian, and Robert Mullen. "A Computationally Efficient Algorithm for Simulating the Dynamic Train-Track Interaction." In 2020 Joint Rail Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/jrc2020-8117.
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Abstract A new method to determine the dynamic interaction between the train and track has been presented. The train and the track are considered as different subsystems. The subsystems are solved independently assuming no contact force exists, and the overall solution of the system is obtained enforcing displacement compatibility and dynamic force equilibrium equations. The proposed method solves the interface contact forces and the displacements of the contact points explicitly. The method proposed avoids iterative methods to enforce compatibility and equilibrium conditions as devised by other authors. The proposed method is also computationally efficient to the methods devised by different authors when the system is solved as one system since smaller systems are solved at a time and there is no need to update structural matrices at every time step. The numerical examples presented show the accuracy and efficiency of the proposed algorithm.
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Durali, Mohammad, and Mohammad Mahdi Jalili. "Investigation on Dynamic Interaction Between Wagon and Randomly Irregular Rail Track." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-80206.
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Rail profile irregularities are one of the main vibration sources to vehicle and track. In this article a dynamic model of wagon, rail track and its substrate is developed to examine the vertical interaction of the rail track and the wagon system due to random irregularities of track vertical profile. The model consists of a wagon with body, two bogies and four wheels having 21 degrees of freedom. The rail system is treated as a Timoshenko beam supported by sleepers, ballast, subballast, and subgrade. The rail irregularities are assumed to be stationary random and ergodic processes in space, with Gaussian amplitude probability densities and zero mean values. To determine rail-wheel contact forces, Hertzian nonlinear contact theory has been used. The interaction forces between the vehicle and the rail and the vertical acceleration generated in the wagon body due to random irregularities of the track vertical profile with different track grades for different train speeds have been simulated by this model. The results are compared to previous works in the literature.
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Shi, Hongmei, and Zujun Yu. "Estimation of Track Irregularity Based on Genetic Algorithm and Unscented Kalman Filtering." In 2012 Joint Rail Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/jrc2012-74021.
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Track irregularity is the main excitation source of wheel-track interaction. Due to the difference of speed, axle load and suspension parameters between track inspection train and the operating trains, the data acquired from the inspection car cannot completely reflect the real status of track irregularity when the operating trains go through the rail. In this paper, an estimation method of track irregularity is proposed using genetic algorithm and Unscented Kalman Filtering. Firstly, a vehicle-track vertical coupling model is established, in which the high-speed vehicle is assumed as a rigid body with two layers of spring and damping system and the track is viewed as an elastic system with three layers. Then, the static track irregularity is estimated by genetic algorithm using the vibration data of vehicle and dynamic track irregularity which are acquired from the inspection car. And the dynamic responses of vehicle and track can be solved if the static track irregularity is known. So combining with vehicle track coupling model of different operating train, the potential dynamic track irregularity is solved by simulation, which the operating train could goes through. To get a better estimation result, Unscented Kalman Filtering (UKF) algorithm is employed to optimize the dynamic responses of rail using measurement data of vehicle vibration. The simulation results show that the estimated static track irregularity and the vibration responses of vehicle track system can go well with the true value. It can be realized to estimate the real rail status when different trains go through the rail by this method.
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Leon, L., and D. C. Rizos. "On the Development and Implementation of Scalable Models of Long Tracks for the Rapid Computation of Transient Response and Dynamic Interaction of Train-Track Systems due to High Speed and Freight Train Traffic." In 2014 Joint Rail Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/jrc2014-3868.
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In continuation of the authors’ previous published work, this paper presents improved models of relatively long railway tracks and discusses the new studies on their development and implementation. The proposed models address the through-the-soil interaction of ties in a long track segment and capture the traveling wave effects on ties located long distances from a loaded tie. These models are very computationally efficient, since they are expressed in a closed solution form. They are also very accurate and capture all the dynamic characteristics of the physical problem (e.g. frequency content), since they represent scaled characteristics responses of a reference response that is computed through rigorous analytical procedures. It is noted that the proposed models are developed for all vibration modes of ties due to wave propagation in linear, isotropic and homogeneous media. The models are verified through comparisons with other BEM solutions, and the accuracy and efficiency are established. Implementation of the proposed modes is demonstrated through a study on the critical train velocity and the effects on the system’s vibration response are quantified and discussed.
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Lee, Kyoung-Chan, Seung Yup Jang, Dong-Ki Jung, Hyung-Kyoon Byun, Hyo-Ki Park, and Tae-Sock Yang. "Rail-Structure Interaction Analysis of Sliding Slab Track on Bridge." In 2015 Joint Rail Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/jrc2015-5661.
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Continuous welded rail (CWR) on a bridge structure typically experiences a large amount of additional longitudinal axial forces due to longitudinal rail-structure (or track-bridge) interaction under temperature change and train vertical and traction/braking load effect. In order to reduce the additional axial forces, a special type of fastener, such as zero longitudinal restraint (ZLR) and reduced longitudinal restraint (RLR) or rail expansion joint (REJ) should be applied. Sliding slab track system is developed to reduce the effect of rail-structure interaction through the application of a low-frictional sliding layer between slab track and bridge structure. This study presents a track-bridge interaction analysis of the sliding slab track and compares them with conventional fixed slab track on bridges. Various types of span length and longitudinal profiles of bridges are considered in the analysis, which also include multiple continuous spans and extra-dosed bridges. The analysis found that the sliding slab track can reduce the additional axial forces of the continuous welded rail from 80% to 90%, and the difference is more significant for long and continuous span bridge. By the application of the sliding slab track, the use of any other special type of rail fasteners or REJ can be avoided. In addition, span length will not be restricted by the rail-structure interaction effect in planning the railway bridge layout. Continuous span bridge has been usually avoided for railway bridges, but it is preferred for the application of the sliding slab track because the interaction effect can mostly be removed. A continuous span bridge usually has an economical cross-section for the bridge girder, pier and foundation and better dynamic characteristics compared to simple span bridge, and its application eventually will reduce the construction cost of the railway infrastructure.
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Nour, Said I., and Mohsen A. Issa. "High Speed Rail Short Bridge-Track-Train Interaction Based on the Decoupled Equations of Motion in the Finite Element Domain." In 2016 Joint Rail Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/jrc2016-5785.
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The interaction between the train, track, and bridge was considered as an interaction between two decoupled subsystems. A first subsystem consisted of the train vehicle simulated as a four-wheelset mass-spring-damper system having two layers of suspensions and ten degrees of freedom. A second subsystem consisted of the track-bridge system assumed to be a top rail beam and a bottom bridge beam coupled by continuous springs and dampers representing the elastic properties of the trackbed smeared over the spacing of the railway ties. The bridge supports were assumed to be rigid or flexible. The equations of motion of a finite element form were derived for each subsystem independently by means of the Newton’s second law. The dynamic interaction between the moving vehicle of the first subsystem and the stationary underlying track-bridge structure of the second subsystem was established by means of a no-separation constraint equation in the contact points between the wheels and the rails. The proposed two-dimensional analysis was intended to accurately describe the vertical behavior of short span bridges subjected to high-frequency excitations due to the passage of high speed trains; therefore, shear deformations, rotational inertia effects, and consistent mass matrices were adopted in the mathematical model. Numerical solutions of the decoupled equations of motion for both subsystems were obtained with the step-by-step direct integration in the time domain using HHT alpha method with a special scheme in the contact interface. The solution accuracy of the proposed method was validated against responses obtained from a semi-analytical method of a train car travelling over a simply supported bridge. The practical engineering application was demonstrated with a case study investigating effects of key parameters in the behavior of a ballasted short span railway bridge. Compared with the moving force model, results showed that for bridges with rigid supports both the vehicle interaction and trackbed produce lower peak responses at resonance speeds with the latter being more significant. However an increase in support flexibility had a greater impact across all speeds in increasing the bridge responses.
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Ballew, B., B. J. Chan, and C. Sandu. "Three-Piece Half-Truck Multibody Dynamics Models for Freight Train Suspensions." In IEEE/ASME/ASCE 2008 Joint Rail Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/jrc2008-63055.
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A three-piece bogie acts as a support for the freight train car bodies so that they can run on straight and curved tracks. It also absorbs the vibrational energy generated by the track. The three main parts of a traditional three-piece bogie are two side frames and a bolster. The side frames run parallel to the rails and are connected to each other by the bolster, which runs perpendicular to the rail. The side frames are connected to the axles, which are directly connected to the wheels that run on the track through the primary suspension. The primary suspension includes the bearing adapter and pedestal roof. The secondary suspension, which includes the friction wedge and load coils, connects and provides damping on each end of the bolster at its intersection with the side frame. Moreover, the friction wedge aids in warp resistance of the bogie. Because of the wedge’s non-linear frictional characteristics and load sensitive behavior, accurately capturing its dynamics in a computational model proves difficult. Previous work at the Railway Technology Laboratory (RTL) at Virginia Tech focused on better capturing the dynamics of the friction wedge modeled as a 3D rigid body. The current study extends that work to a half-truck model treated as an application of multibody dynamics with unilateral contact to model the friction wedge interactions with the bolster and the side frame. The half-truck model created in MATLAB is a 3D, dynamic, stand-alone model comprised of four rigid bodies: a bolster, two friction wedges, and a side frame assembly. The model allows each wedge four degrees of freedom: vertical displacement, longitudinal displacement (between the bolster and side frame), pitch (rotation around the lateral axis), and yaw (rotation around the vertical axis). The bolster and the side frame have only a vertical translation degree of freedom. The geometry of these bodies can be adjusted for various simulation scenarios. The bolster can be initialized with a pre-defined static yaw (rotation around the vertical axis) and the side frame may be initialized with a predefined pitch/toe geometry (rotation around the lateral axis). The model simulation results have been compared with results from NUCARS®, an industrially used train modeling software developed by the Transportation Technology Center, Inc., for similar inputs.
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Gao, Yin, Hai Huang, Shushu Liu, and Shelley M. Stoffels. "The Movement of Railroad Ties: Simulation and Field Validation." In 2016 Joint Rail Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/jrc2016-5770.
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The railroad tie is an important component in track structure which provides lateral resistance, continuous support for rail and transfers the train load to ballast. The movement of the tie subject to train loading is usually considered as a vertical motion. However, it is believed that the real-world tie movement is not only translational but rotational due to moving load. In order to investigate the real movement of railroad ties, a train-track interaction computer program was used. The computer program includes a vehicle dynamics model and 3-D Finite Element (FE) track model. The wheel-rail contact forces were obtained from the vehicle dynamics model, and then input to FE track model to simulate the tie movement. Furthermore, the field validation was conducted at Northeast Corridor (NEC) in United States. The measuring units were mounted on the edge of ties to record the angle and acceleration change of the tie in three orthogonal directions. The data analysis showed that the field-measured translational and rotational movement of ties have good agreement with the simulation results. It is concluded that the tie movement is not only up-and-down motion under moving train load, but also comprises rotation and lateral movements.
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Aboubakr, Ahmed K., and Ahmed A. Shabana. "Numerical Study on the Delay Effect of Air Brake Mass Flow on Train Coupler Forces." In 2020 Joint Rail Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/jrc2020-8013.
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Abstract In existing freight-train braking systems, braking is applied on individual cars sequentially at the speed of the air pressure. In the case of long trains that consist of hundreds of rail cars, there is a time delay that results in large and impulsive compressive and tensile coupler forces. These coupler forces compromise the train safe operation and stability, make train handling difficult, cause track damage, raise significantly the maintenance cost, and increase the stopping distances which can lead to serious accidents. The objective of this investigation is to investigate the effect of the brake-delay time on the train longitudinal dynamics (LTD) coupler forces by integrating for the first time detailed three-dimensional coupler and air-brake force models. A spatial non-linear coupler model that takes into account the geometric nonlinearities is employed in order to allow for capturing arbitrary three-dimensional rail-car motion and coupler kinematic degrees of freedom that cannot be captured using existing simpler models. This coupler model is integrated with a detailed air brake model that consists of the locomotive automatic brake valve, air brake pipe, and car control unit (CCU) in order to evaluate conventional air brake force models that account for the air-flow effect in long train pipes as well as the effect of leakage and branch pipe flows. The coupling between the air brake, locomotive automatic brake valve, car control units, and train equations is established and used in the nonlinear LTD simulations, which are performed using the computer software ATTIF (Analysis of Train/Track Interaction Forces). Different LTD braking scenarios are considered and the effect of brake signal time delay on the coupler forces is examined. The results obtained in this study demonstrate the importance of applying all brake forces simultaneously in order to ensure train stability and safety.
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Yin, Huabing, Jingling Fan, Lichen Hu, and Xiaofneg Ma. "Automatic Gearshift Algorithm and Its Dynamic Performance Simulation of Tracked Vehicle With Integrated Power Train System." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-15842.
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The automatic gearshift algorithm and its dynamic control is an important research area in tracked vehicle design. In the paper the models of power train system such as engine, transfer gearbox, hydraulic torque converter, planetary gearbox, running gear propulsion system and virtual terrain are built. The program for gearshift algorithm design is developed. The model of designed gearshift algorithm is developed with MATLAB/simulink and finite state machine theory. The hydraulic control system is modeled with MATLAB/simulink and the oil pressures can be applied on the clutches and brakes of power train system. The planetary gearbox and other transmission parts are modeled through EASY5 power train library models and the gear contact stiffness, torsional stiffness of links between planetary gear sets and shafts are taken into consideration. The running gear system model are built with ADAMS, and the terrain loads from the interaction between terrain and tracks are applied on the sprocket extended to the power train, which considers the dynamic contacts among road wheel, track and terrain. Many terrain models including the slope, obstacle and road model with A, B, C, D etc. levels at different vehicle speeds can be built and integrated with the virtual prototyping models These different disciplinary models are integrated with MATLAB, ADAMS and EASY5 development environment and the virtual test can be done in various operation conditions. The integrated method is through the interfaces provided by these simulation software. It realizes the time synchronization between two different models of EASY5 and MATLAB/simulink with the digital electric circuit theory. The virtual test is been made in the integrated MATLAB/simulink development environment. The tracked vehicle's acceleration performance is simulated. The acceleration time from second gear to 32 km/h is about 14.5 seconds. Many other performances such as the virtual dynamic torque loads of rotating parts, the clutch torque capacity and the jerks of any parts in the power train can be obtained from simulation and can be verified with the physical tests later. There are some innovations in modeling method in this paper. Firstly, it builds many subsystem models with the virtual prototyping technology. Secondly, it builds the integration environment and interfaces. Many models of different areas are integrated to simulate transmission gearshift process. Thirdly, it provides a modeling method and environment for power train modeling and simulation. Fourthly, the acceleration performance of a tracked vehicle is simulated and the two results of virtual and physical tests are close.
Reports on the topic "Train/track dynamic interaction"
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Karafiath, Leslie L. Dynamic Track-Terrain Interaction Model. Fort Belvoir, VA: Defense Technical Information Center, April 1988. http://dx.doi.org/10.21236/ada196031.
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