Dissertations / Theses on the topic 'Wheel / rail contact'
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Smith, Lindsey. "Rolling contact fatigue in wheel-rail contact." Thesis, University of Newcastle Upon Tyne, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438385.
Full textZhu, Yi. "Adhesion in the wheel-rail contact." Doctoral thesis, KTH, Tribologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-133342.
Full textQC 20131031
Galas, Radovan. "Friction Modification within Wheel-Rail Contact." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-367508.
Full textPang, Tao, and tony_pang@hotmail com. "Studies on Wheel/Rail Contact Impact Forces at Insulated Rail Joints." Central Queensland University. Centre for Railway Engineering, 2008. http://library-resources.cqu.edu.au./thesis/adt-QCQU/public/adt-QCQU20080410.154708.
Full textJon, Sundh. "On wear transitions in the wheel-rail contact." Doctoral thesis, KTH, Maskinkonstruktion (Avd.), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-11563.
Full textQC 20100721
Samba 6
Shahzamanian, Sichani Matin. "Wheel-rail contact modelling in vehicle dynamics simulation." Licentiate thesis, KTH, Spårfordon, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-127949.
Full textQC 20130911
Martin, Michael. "The Effect of Geometrical Contact Input to Wheel-Rail Contact Model." Thesis, KTH, Spårfordon, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-239735.
Full textWickramasinghe, Munidasa Widhana Pathiranage Isuru Udara. "Investigation of surface ratchetting due to rail/wheel contact." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/67800/1/Munidasa%20Widhana%20Pathiranage%20Isuru%20Udara_Wickramasinghe_Thesis.pdf.
Full textZhu, Yi. "Adhesion in the wheel-rail contact under contaminated conditions." Licentiate thesis, KTH, Tribologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-48441.
Full textQC 20111123
Zhou, Yongji. "System-on-chip accelerator of wheel-rail contact laws." Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531591.
Full textYao, C. W. "Experimental methods for measurement of wheel and rail contact." Thesis, University of Sheffield, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.500083.
Full textHosseini, SayedMohammad. "A Statistical Approach to Modeling Wheel-Rail Contact Dynamics." Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/101864.
Full textMaster of Science
The interaction between the wheel and rail plays an important role in the dynamic behavior of railway vehicles. The wheel-rail contact has been extensively studied through analytical models, and measuring the contact forces is among the most important outcomes of such models. However, these models typically fall short when it comes to addressing the practical problems at hand. With the development of a high-precision test rig—called the VT-FRA Roller Rig, at the Center for Vehicle Systems and Safety (CVeSS)—there is an increased opportunity to tackle the same problems from an entirely different perspective, i.e. through statistical modeling of experimental data. Various experiments are conducted in different settings that represent railroad operating conditions on the VT-FRA Roller Rig, in order to study the relationship between wheel-rail traction and the variables affecting such forces. The experimental data is used to develop parametric and non-parametric statistical models that efficiently capture this relationship. The study starts with single regression models and investigates the main effects of wheel load, creepage, and the angle of attack on the longitudinal and lateral traction forces. The analysis is then extended to multiple models, and the existence of interactions among the explanatory variables is examined using model selection approaches. The developed models are then compared with their non-parametric counterparts, such as support vector regression, in terms of "goodness of fit," out-of-sample performance, and the distribution of the predictions. The study develops regression models that are able to accurately explain the relationship between traction forces, wheel load, creepage, and the angle of attack.
Spangenberg, Ulrich. "Reduction of rolling contact fatigue through the control of the wheel wear shape." Thesis, University of Pretoria, 2017. http://hdl.handle.net/2263/62796.
Full textThesis (PhD)--University of Pretoria, 2017.
Mechanical and Aeronautical Engineering
PhD
Unrestricted
Duan, FangFang. "Numerical tribology of the wheel-rail contact : Application to corrugation defect." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0019/document.
Full textFor more than a century, rail corrugation has been exposed as one of the most serious problems experienced in railway networks. It also comes with a series of problems for maintenance, such as rolling noises and structural vibrations that can reduce lifetime of both train and track. This periodical phenomenon on rail surface is closely linked to wheel-rail contact dynamic, which depends on friction, train dynamics… To better understand corrugation birth conditions, a numerical model is suggested to complement the experimental limitations and to instrument a wheel-rail contact both locally and dynamically. At first, an appropriate tool was chosen to create the dynamic wheel-rail contact model to reproduce straight-track corrugation, also called “short-pitch” corrugation. The implicit dynamic finite element code Abaqus was chosen to investigate the dynamic local contact conditions. Both the origin and the evolution of straight-track corrugation under transient conditions (acceleration / deceleration) are studied. The parametrical sensibility of corrugation is thus investigated both with single/multiple wheel passing(s) and with geometric defect. A stick-slip phenomenon, linked to both wheel and rail dynamics coupled through the contact, is identified as the root of straight-track corrugation under transient conditions. Secondly, results obtained with the previous model have highlighted a quick decrease of corrugation amplitude with the increase of wheel passings over the rail. This last result seems to be in contradiction with reality. This problem comes from the difficulty to reliably manage contact dynamics, and particularly with local impacts, with the use of classical finite element models such as the one implemented in Abaqus. To compensate for this lack, a mass redistribution method is implemented in Abaqus and used with the previous case. The results show a more realistic corrugation growth according to the number of wheel passings
Shakleton, Philip Andrew. "An optimised wheel-rail contact model for vehicle dynamics simulation." Thesis, Manchester Metropolitan University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.515184.
Full textGallardo, Hernandez Ezequiel Alberto. "Wheel and rail contact simulation using a twin disc tester." Thesis, University of Sheffield, 2009. http://etheses.whiterose.ac.uk/14924/.
Full textLai, Van-Vuong. "Dynamic model of wheel/rail contact for curve squeal simulation." Thesis, Lille 1, 2018. http://www.theses.fr/2018LIL1I088/document.
Full textSqueal noise of railbound vehicles emitted in tight curves (radius lower than 200m) is characterized by high sound pressure levels at pure medium and high frequencies. State-of-the-art abounds with models trying to simulate curve squeal. However the instability mechanisms are still controversial. In addition, existing curve squeal models are often simplified (analytical frictional contact laws or elastic half-space assumption). The first aim of the thesis is to contribute to a clarification of the possible generation mechanisms. For this purpose, a stability analysis of wheel/rail rolling contact in the case of lateral full sliding is performed by using a point-contact model and wheel/rail modal bases. It is found that, even with a constant Coulomb friction coefficient, the rail vertical flexibility is notably found to play an important role on the instability occurrence without "falling friction" nor without "mode-coupling". The second aim of the thesis is to develop a full Finite Element model of wheel/rail contact in order to compute reference solutions and especially to verify the effects of the simplifications carried out in the point-contact model. Appropriate numerical techniques are used in order to solve the nonlinear discrete equations. In order to reduce the computational effort, reduction strategies are proposed for both domains. The methods are then applied in a realistic wheel/rail model in curve. It is found that the discretization of the contact zone does not substantially modify the instability mechanisms but the divergence rates of the unstable modes due to a stronger coupling between the normal contact degrees of freedom
ZANI, NICOLA. "Numerical and analytical models applied to wheel-rail contact problems." Doctoral thesis, Università degli studi di Brescia, 2021. http://hdl.handle.net/11379/544084.
Full textShahzamanian, Sichani Matin. "On Efficient Modelling of Wheel-Rail Contact in Vehicle Dynamics Simulation." Doctoral thesis, KTH, Spårfordon, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-181691.
Full textQC 20160202
Sundh, Jon. "An experimental study on wear transitions in the wheel-rail contact /." Stockholm : Institutionen för maskinkonstruktion, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4389.
Full textHussain, I. "Multiple model based real time estimation of wheel-rail contact conditions." Thesis, University of Salford, 2012. http://usir.salford.ac.uk/38094/.
Full textBuckley-Johnstone, Luke. "Wheel/rail contact tribology : characterising low adhesion mechanisms and friction management products." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/17291/.
Full textBOZZONE, MICHELANGELO. "Dynamic analysis of railway systems using computationally efficient wheel-rail contact models." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2010. http://hdl.handle.net/2108/1332.
Full textThe present thesis describes an investigation on the railway system motion like a wheel-set, a bogie or a wagon. Through the search of equilibrium configurations, the positions of contact points between rails and wheels are first located. The detection methods allow also the definition of the normal vectors to rail and wheel surfaces and the principal curvatures at contact points. To reduce computing time the results are stored in a lookup table that can be used for dynamic analysis of wheel-sets, bogie or wagon. A dynamic analysis has been performed on a bogie composed of two wheel-sets and a frame. The bogie frame is joined to the wheel-sets by means of a primary suspension system, acting on the three principal directions, i.e. longitudinal, transverse and vertical. The bogie moves along rails following its variable path. In particular, the dynamic analysis investigates the bogie behaviour in both straight and curved paths, with or without an initial perturbation and a super-elevation angle. Imposing an initial transverse disturbance, the hunting motion is observed and the critical speed value estimated. The contact characteristics have been determined by means of the lookup table. In order to minimize cpu-time, a new method for the interpolation of the lookup table entries has been developed. Finally, two different methods for the integration of the differential equations have been tested and comparisons with the results obtained by Simpack-rail multibody software are discussed. The railway systems have been analyzed in proximity of their critical conditions both in straight and curved tracks. The critical speed is estimated through the rise up of hunting motion. The critical speed, the contact forces in the critical conditions and the derailment limits are determined under different load conditions and track paths; two methods are used for its determination. The influence of the longitudinal suspension stiffness of the primary and secondary suspension systems on the critical conditions of the bogie and wagon are deduced for straight and curved track type.
Enblom, Roger. "On Simulation of Uniform Wear and Profile Evolution in the Wheel - Rail Contact." Doctoral thesis, Stockholm : Dept. of aeronautics and vehicle engineering, Royal Institute of Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4184.
Full textRinaldi, Elisa. "3D Finite Element Analysis of Wheel/Rail normal contact problem using ANSYS software." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
Find full textWhite, Ben. "Using tribo-chemistry analysis to understand low adhesion in the wheel-rail contact." Thesis, University of Sheffield, 2018. http://etheses.whiterose.ac.uk/21007/.
Full textLewis, Stephen Robert. "Measurement, control and enhancement of friction/traction in a simulated wheel/rail contact." Thesis, University of Sheffield, 2011. http://etheses.whiterose.ac.uk/12868/.
Full textKothari, Karan. "Accurate Wheel-rail Dynamic Measurement using a Scaled Roller Rig." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/96633.
Full textMS
Keylin, Alexander. "Analytical Evaluation of the Accuracy of Roller Rig Data for Studying Creepage in Rail Vehicles." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/49607.
Full textFor Kalker\'s theory, it is shown that the correction factor for creep coefficients is strictly a function of wheel and rail geometry, primarily the wheel and roller diameter ratio. For Johnson and Vermeulen\'s theory, the effects of creepage, scale, and load on the creep force correction factor are demonstrated. �It is shown that INRETS\' scaling strategy causes the normalized creep curve to be identical for both a full-size and a scaled roller rig. �It is also shown that the creep force correction factors for Johnson and Vermeulen\'s model increase linearly with creepage, starting with the values predicted by Kalker\'s theory. �Therefore, Kalker\'s theory provides a conservative estimate for creep force correction factors. �A case study is presented to demonstrate the creep curves, as well as the correction and transformation factors, for a typical wheel-rail configuration. �Additionally, two studies by other authors that calculate the correction factor for Kalker\'s creep coefficients for specific wheel-rail geometries are reviewed and show full agreement with the results that are predicted by the formulae derived in this study. �Based on a review of existing and past roller rigs, as well as the findings of this thesis, a number of recommendations are given for the design of a roller rig for the purpose of assessing the wheel-rail contact mechanics. �A scaling strategy (INRETS\') is suggested, and equations for power consumption of a roller rig are derived. Recommendations for sensors and actuators necessary for such a rig are also given. Special attention is given to the resolution and accuracy of velocity sensors, which are required to properly measure and plot the creep curves.
Master of Science
Moas, Eduardo. "Investigation of the finite element method for computing wheel/rail contact forces in steady curving." Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/50064.
Full textMaster of Science
incomplete_metadata
Enblom, Roger. "Simulation of Wheel and Rail Profile Evolution : Wear Modelling and Validation." Licentiate thesis, KTH, Aeronautical and Vehicle Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1754.
Full textNumerical procedures for reliable wheel and rail wearprediction are rare. Recent development of simulationtechniques and computer power together with tribologicalknowledge do however suggest computer aided wear prediction.The objective of the related research field at the RoyalInstitute of Technology (KTH) is to arrive at a numericalprocedure able to simulate profile evolution due to uniformwear to a degree of accuracy sufficient for application tovehicle dynamics simulation. Such a tool would be useful formaintenance planning as well as optimisation of the transportsystem and its components.
The research contribution accounted for in this thesisincludes, in addition to a literature review, refinement ofmethods applied to uniform wheel wear simulation by inclusionof braking and improvement of the contact model. Further atentative application to uniform rail wheel simulation has beenproposed and tested.
The first part addresses issues related to braking andwheel-rail contact conditions in the context of wheel wearsimulation. The KTH approach includes Archards wear modelwith associated wear maps, vehicle dynamics simulation andrailway network definition. In previous work at KTH certainvariations in operating conditions have been accounted forthrough empirically estimated average scaling factors. Theobjective of the current research is to be able to include suchvariations in the set of simulations. In particular theinfluence of disc braking and varying friction and lubricationconditions are investigated. Both environmental factors likemoist and contamination and deliberate lubrication need to beconsidered. As part of the associated contact analysis theinfluence of tangential elastic deformation of the contactingsurfaces on the sliding velocity has been separatelyinvestigated and found to be essential in case of partial slipcontact conditions.
In the second part validation of the improvements related towheel wear simulation is addressed. Disc braking has beenincluded in the simulation set and a wear map for moist contactconditions based on recent tribometer tests has been draftedand tested. It has been shown that the previously used brakingfactor accounts for the combination of the contributions fromsurface elasticity and braking. Good agreement withmeasurements from the Stockholm commuter service is achieved.It is concluded that the model improvements accounted for aresufficient for adequate simulation of tread wear but thatfurther development of the flange / gauge corner contactmodelling may be needed.
In the final part a procedure for simulation of rail wearand corresponding profile evolution has been formulated. Asimulation set is selected defining the vehicles running on thetrack to be investigated, their operating conditions, andcontact parameters. Several variations of input data may beincluded together with the corresponding occurrenceprobability. Trial calculations of four non-lubricated curveswith radii from 303 m to 802 m show qualitatively reasonableresults in terms of profile shape development and difference inwear mechanisms between gauge corner and rail head. The wearrates related to traffic tonnage are however overestimated. Itis believed that model refinements in terms of environmentalinfluence and contact stress calculation are useful to improvethe quantitative results.
QC 20100531
Meymand, Sajjad Zeinoddini. "State of the Art Roller Rig for Precise Evaluation of Wheel-Rail Contact Mechanics and Dynamics." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/64920.
Full textPh. D.
Lee, Hyunwook. "A Polynomial Chaos Approach for Stochastic Modeling of Dynamic Wheel-Rail Friction." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/77195.
Full textPh. D.
Inglot, Agnieszka, and Oskar Franzén. "PREVENTION OF WHEEL WEAR, A CASE STUDY : Developing a functioning wheel profile for rail-mounted transportation trolley." Thesis, Högskolan i Skövde, Institutionen för ingenjörsvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-17695.
Full textLundberg, Oskar Erik. "Vibrations induced by surface roughness in nonlinear rolling contacts." Licentiate thesis, KTH, MWL Marcus Wallenberg Laboratoriet, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-155049.
Full textQC 20141103
ECO2 Vehicle Design
Doulgerakis, Emmanouil. "Influence of Switches and Crossings on Wheel Wear of a Freight Vehicle." Thesis, KTH, Spårfordon, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-134704.
Full textHosseinipour, Milad. "Electromechanical Design and Development of the Virginia Tech Roller Rig Testing Facility for Wheel-rail Contact Mechanics and Dynamics." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/82542.
Full textPh. D.
Zong, Nannan. "Development of optimal designs of insulated rail joints." Thesis, Queensland University of Technology, 2013. https://eprints.qut.edu.au/61125/1/Nannan_Zong_Thesis.pdf.
Full textSimon, Samuel. "De la dynamique ferroviaire à l’accommodation microstructurale du rail : Contribution des TTS à la réponse tribologique des aciers : Cas du défaut de squat." Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0028/document.
Full textSquats have recently become recognised as one of the major rolling contact fatigue defects in modern railway networks for which there is currently no solution other than preventive grinding operations or costly rail renewal. To better understand the entire damage mechanism of squat, A tribological and metallurgical analysis of the rolling band and the near surface layer was performed close to an incipient squat. This characterization show a significant anisotropy of the rail surface layer associated with developments of Tribological Transformation of Surface. These results reflect some specific wheel/rail contact conditions in this squat area, including an unusual level of shear forces in a straight track. In order to validate this observations, two tests were performed. On the one hand, the contact conditions in a squat area were measured from an instrumented train. On the other hand, the tribological response of the rail steel was studied through regular monitoring of a test site subjected to railway traffic. These tests allow to identify a high imbalance of the traction forces and the presence of local slips at the wheel/rail interface. Several thermomechanical initiation mechanism of squats are then given in a overall diagram of the tribological response of rail steels
Fumes, Fabiano Gonzaga 1986. "Estudo comparativo entre critérios de fadiga multiaxial aplicados ao contato roda-trilho : A comparative study of multiaxial fatigue criteria applied to the wheel-rail contact." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265955.
Full textDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: Este trabalho apresenta a comparação entre os diversos critérios de fadiga multiaxial de alto ciclo aplicados ao problema de contato roda-trilho. Para isto, é utilizado um modelo elastoplástico tridimensional de elementos finitos capaz de permitir o cálculo tanto das tensões geradas pelo rolamento de uma roda livre de tensões residuais de fabricação como de uma roda que contenha as tensões residuais provenientes do processo de tratamento térmico, obtidas através de uma simulação térmico-estrutural. Estes dois cenários são avaliados segundo critérios de fadiga multiaxial baseados tanto em planos críticos, como Dang Van, Matake e McDiarmid, quanto nos baseados em invariantes do tensor de tensões, como Sines, Crossland e Kakuno Kawada. Pela natureza da fadiga de contato, que não possui condição de vida infinita, é estimado para cada critério um número de ciclos para o aparecimento das trincas. Como resultado, observa-se que para alguns critérios como Dang Van, Sines e Kakuno-Kawada, a vida em fadiga é beneficiada pelo processo de tratamento térmico, enquanto para os demais, as tensões residuais de fabricação provocam uma redução no número de ciclos para o aparecimento das trincas
Abstract: This work presents a comparison of different high cycle multiaxial fatigue criteria, applied to wheel- rail contact. For this, it is used a three-dimensional elastoplastic finite element model able to calculate stresses generated by the rolling of a wheel free of residual stresses from manufacturing process and also by a wheel containing the residual stresses from heat treatment process, generated by a thermal-structural simulation. These two scenarios are evaluated according to multiaxial fatigue criteria based on critical planes, as Dang Van, Matake and McDiarmid, and also based on the invariants of the stress tensor, as Sines, Crossland and Kakuno Kawada. Due to the nature of rolling contact fatigue, which has no condition of infinite life, a number of cycles for crack appearance are estimated for each criterion. It can be notice that for some criteria, such as Dang Van, Sines and Kakuno-Kawada, fatigue life is benefited by the heat treatment process, while for others the residual stresses from manufacturing promote a reduction in the number of cycles
Mestrado
Mecanica dos Sólidos e Projeto Mecanico
Mestre em Engenharia Mecânica
Knápek, Jiří. "Experimentální studium modifikátorů tření v kolejové dopravě." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318387.
Full textAlmeida, Fabio Cardoso. "Análise das forças de contato e comportamento dinâmico de rodeiro ferroviário." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/3/3152/tde-05092006-113355/.
Full textRailway dynamics systems are modeled regarding the creep forces between wheel-rail. The equations of movement are strongly influenced by these forces, what requests the knowledge of the theory in mechanical of contact, necessary tool to foresee the behavior of a railway vehicle. The wheelset is responsible by receiving the perturbations of irregularities and transfer them to the primary suspension. A railway vehicle is composed by primary and secondary suspensions. The proposal is based on performing simulations in the time domain, dynamic mresponse of a railway wheelset of two degrees of freedom. The mathematical model is developed. The stiffness of contact and conicity are linearized around an operation point, near to track center. The influence of speed is determined to linearized model and to a range of 0.1 to 1.0 in the conicity. The eigenvectors are presented. In the following, the non linear model of the wheelset is generated using a specialized package of multi body system, VAMPIRE. The package creates equations of movement after the generation of the topology. The non linear mathematical model are defined by the benchmark proposed by International Association of Vehicle System Dynamics (IAVSD). The wheelset is submitted to 20kN at the rail level. In a second case, the wheelset is submitted to a rate of 50kN/s of lateral force until derailing. The determined longitudinal and lateral forces on contact, yaw angle and displacement of the center of gravity of the wheelset, contact angle are compared with the benchmark results and other authors.
Campos, Paulo Roberto Refachinho de. "A rigid body and a master-master contact formulation for multibody railway applications." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/3/3144/tde-01112018-150928/.
Full textEm simulação computacional o termo \"sistema multicorpos\" é usualmente empregado para descrever um sistema de corpos interconectados. Diversos exemplos de sistemas multicorpos podem ser encontrados no campo da engenharia ferroviária. Um rodeiro interagindo com a via através de uma interface de contato é apenas um dos exemplos de interesse prático. A modelagem de sistemas mecânicos em um ambiente virtual contribui para o entendimento de assuntos como comportamento dinâmico, estabilidade, durabilidade, desgaste, fadiga, etc. No contexto de um sistema multicorpos rígido-flexível descrito matematicamente por uma forma fraca, o propósito do presente trabalho é avaliar as contribuições devido à presença de corpos rígidos considerando interações de contato. Contribuições inerciais devido à distribuição de massa do corpo rígido são desenvolvidas e apresentadas em totalidade, considerando um polo genérico associado a um único nó, representando o corpo rígido. Parâmetros de rotação de Rodrigues são usados para descrever rotações finitas em uma descrição Lagrangiana atualizada. A formulação de contato master-surface to master-surface é adaptada para ser usada em conjunto com o elemento de corpo rígido e corpos flexíveis, estabelecendo a interação entre esses corpos em um ambiente de simulação multicorpos. Novas parametrizações de superfícies de contato são desenvolvidas para estabelecer os pares de contato, assumindo-se interações pontuais, em um cenário de contato com atrito. A formulação proposta é usada para representar sistemas mecânicos em diferentes contextos, incluindo um exemplo numérico do caso de contato roda-trilho. Os resultados obtidos mostram a robustez e a aplicabilidade dos métodos.
Merino, Pierrick. "Reproduction expérimentale du contact roue-rail à échelle réduite : Voies de formation des sources de défauts." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI101.
Full textThe safety issue is still the main concern of railway network due to the development of railway transportation and the increase of the amount of passengers. The understanding of the origin of the rolling contact fatigue (RCF) defect, is one key to safety requirements. The White Etching Layer associated to the initiation of the squat defect is hardly recreated. The use of laboratory test bench enable the replication of the wheel-rail contact. Nevertheless, only a fraction of the characteristic parameters is taken into account and compromises are necessary. The test bench “Triboring” built at LaMCoS, fulfills a gap in the existing apparatus. The “roller on circular rail” design was chosen to fit the tribological behavior of wheel-rail contact, and replicate RCF defects. The production of a test bench required to relate and differentiate the measured data to the phenomena corresponding to the operating from the phenomena corresponding to wheel-rail contact. The bench was characterized with dynamic and cinematic analysis. The design of the sample was improved. The tribological behavior of the bench was optimized with the preparation of the initial surface of the samples and the production of a tribological “fuse”. This layer delays the speed accommodation by wear and benefit the shear of the first bodies and the formation a Tribological Transformation of Surface (TTS), as the White Etching Layer. The two different fuse layer created (Run-in and oxidized), induced a significant wear reduction. The tribological and metallurgical analysis of the surfaces and cuts of the sample, enabled to the explanation of the evolution of the microstructure of the rail close to the surface, submitted to various mechanical solicitations. The transformation of this microstructure led to the formation of white etching layer mechanically formed
Jandora, Radek. "Výpočtové modelování dynamických projevů v kontaktu kola a kolejnice s obecnou geometrií kontaktních povrchů." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-234020.
Full textPecile, 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.
Full textThe 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
Nepovím, Radovan. "Konstrukce experimentálního zařízení pro studium mazání okolků kolejových vozidel." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230331.
Full textLundberg, Oskar. "On the influence of surface roughness on rolling contact forces." Doctoral thesis, KTH, MWL Marcus Wallenberg Laboratoriet, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-193935.
Full textQC 20161013
Centre for Eco2 Vehicle Design
Toumi, Moncef. "Modélisation numérique du contact roue-rail pour l’étude des paramètres influençant les coefficients de Kalker : Application à la dynamique ferroviaire." Thesis, Paris Est, 2016. http://www.theses.fr/2016PESC1158/document.
Full textThe calculation of normal and tangential forces is important for the dynamic modeling of the railway vehicle-track interaction. To determine the tangential forces at the wheel-rail contact level, the Kalker’s coefficients of stiffness are used in most of computer codes for different contact models. These coefficients were measured on bench several times in the 80s. A survey of these works, conducted by Hobbs, shows a decrease of up to 50 % in value compared to Kalker’s theory. The aim of this thesis is first to identify the real causes of the dispersion observed between the various measurements, usually attributed to the surface contamination, then to develop a model taking into account some of them.The numerical modeling of the wheel-rail contact is presented in two parts. In the first part, a direct boundary element method based on Boussinesq-Cerruti solution is developed to study the normal and sliding contact between two elastic bodies, and then extended to the resolution of rolling contact problem. Successfully applied to the wheel-rail contact for non-Hertzian situation, this method is a promising tool for studying the parameters influencing Kalker’s coefficients which combines both precision and speed.In the second part, a finite element model for rolling contact between wheel and rail is developed to study the normal and the tangential contact problems using the explicit and the implicit integration schemes. The elastic solution is compared with the solution of the CONTACT software. The three-dimensional finite element model takes into account the elastoplastic behavior of the bodies in contact as well as the existence of a third body layer at the interface between the wheel and the rail. Finally, a correction of Kalker’s coefficients is estimated from the results of the numerical simulations.To study the impact of this correction on the critical speed of the vehicle, a stability analysis is performed using the multibody dynamics software VOCO in which the reduced factors of Kalker’s coefficients are considered
Candeloro, Lucas Pinotti. "Sistemas multicorpos avançados: modelamento da interação dinâmica entre veículo e via permanente de metrô." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/18/18149/tde-22062015-192405/.
Full textNowadays, the dynamic simulation of metro vehicles have been an important method of analysis and verification in design engineering as in maintenance engineering. The simulation packages available are highly developed and can be adapted for different scenarios. This paper aims to demonstrate the functionality of these programs, supporting the theory behind its computational algorithm, in order to expand the frontier of knowledge in the national design and maintenance engineerings. For this, two case studies are made of: modelling flexible permanent way; modelling AMVs and crossings; passing vehicle in a region with gauge opening on a constant radius curve; passing a vehicle sequence of reverse curves. Thus, this dissertation presents an overview of the state of the art in the simulation of the interaction vehicle and permanent way of metro.