Dissertations / Theses: 'Track dynamics'

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Lukes, Richard Angus. "Improving track cycling performance using computational fluid dynamics." Thesis, University of Sheffield, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.505805.

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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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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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Rabone, Jeremy Andrew Leslie. "Molecular dynamics of fission track annealing in apatite minerals." Thesis, Birkbeck (University of London), 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.499138.

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Bezin, Yann. "An Integrated Flexible Track System Modelfor Railway Vehicle Dynamics." Thesis, Manchester Metropolitan University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.502435.

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This thesis describes the development and validation of a versatile and Flexible Track System Model (FTSM) and its integration into a commercial railway vehicle dynamics software tool. The work was initiated to fill a gap in current disciplines and tools used to investigate problems relating to vehicle and railway track dynamics due to a lack of correlation between Finite Element (FE) and MuItibody System (MBS) based models. The. FTSM track model was validated against results from laboratory testing and compared with existing models. It was then used to study several aspects of the deterioration of ballasted track under the dynamic loading of passing vehicles at speeds, including consideration of the non-linear nature of the track support condition such as sleeper voiding and variable sleeper support stiffness. . The research contributes to the fundamental understanding of the vehicl~-track interaction forces and particularly to the relation that exists between wheel-rail contact forces and track forces. It shows that.in order to accurately predict track degradation forces, a detailed flexible track model is essential. The major differences in terms of wheel-rail contact condition and forces obtained from the conventional simplified track models and from the FTSM are also highlighted. The presence of higher frequency modes of vibration of the flexible track proves essential for those studies involving local and sudden track events. The model was also applied to the analysis and design development of innovative track structures that seem to offer several advantages with respect to conventional ballasted tracks, most importantly a more consistent or continuous support to the rail. This characteristic is shown to be essential for minimising the interactive cycle of dynamic interaction forces and track deformation leading to track settlement and deterioration.

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Witt, Stephen. "The Influence of Under Sleeper Pads on Railway Track Dynamics." Thesis, Linköping University, Department of Management and Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-12232.

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In this work the influence of Under Sleeper Pads on the dynamic forces on a railway track is investigated. A special interest is devoted to the effect of using Under Sleeper Pads in a railway track with changing vertical stiffness. The contact force between wheel and rail and the ballast contact forces are examined. For the investigation a finite element model with the length of thirty sleepers is created and calculations are performed with the software LS-DYNA. Three different cases of varying vertical track stiffness are studied: the transition from an embankment to a bridge, a randomly varying track stiffness along the railway track and hanging sleepers.

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Gong, Cencen. "The interaction between railway vehicle dynamics and track lateral alignment." Thesis, University of Huddersfield, 2013. http://eprints.hud.ac.uk/id/eprint/19755/.

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This thesis examines the effect of vehicle dynamics on lateral deterioration of the track alignment. As rail traffic runs along a route, the forces imposed upon the track cause the ballast to settle, and hence the track geometry deteriorates. At a specified value of deterioration the track geometry needs to be restored by tamping or other methods. As the deterioration is mainly in the vertical direction, this aspect has been more widely studied and models have been developed to predict vertical track geometry deterioration. On the other hand, lateral track deterioration is not as well understood, and this thesis aims to fill the gap in this knowledge. However, the understanding of the lateral deterioration mechanisms becomes more important as speed and capacity increase. This thesis describes statistical studies of track lateral deterioration, as well as the development and validation of a vehicle-track lateral dynamic interaction model. This work is undertaken to contribute to the fundamental understanding of the mechanisms of track lateral deterioration, therefore making the effective control and reduction of the lateral deterioration achievable. The statistical analysis provides a better understanding of three aspects of track lateral irregularities, namely: the relationship between vertical and lateral irregularities, the relationship between track curvature and track lateral irregularity and the change in track lateral deterioration over time. The vertical and lateral track irregularity magnitudes are clearly correlated. The track quality in the vertical direction is generally worse than in the lateral direction, however the number of track sections with lateral quality significantly worse than the vertical is non-negligible. The lateral irregularities tend to be larger on curves. It is notable that less than ten percent of the track studied has a constant lateral deterioration due to frequent maintenance activities and bidirectional lateral dynamic forces. Unlike vertical settlement, lateral deterioration develops exponentially in both magnitude and wavelength, and the major influences are found from the irregularities with wavelength longer than 10 m. The change in track lateral irregularity with different curve radii and the lateral deterioration rate are described in separate exponential power functions due to the limitation of the available track data. The parameters for these empirical equations do not remain constant due to the change in track conditions. Current track lateral models mainly focus on lateral failures such as buckling and lateral sliding. The development of lateral track irregularities tends to be studied using representative values of net lateral forces and net L/V (Lateral/Vertical) load ratios. Unlike other track lateral deterioration models, the model developed in this thesis focuses on the development of lateral irregularities based on the dynamic interactions between the vehicles and the track system. This model makes it possible to carry out more integrations and analysis of the track lateral deterioration in a realistic dynamic simulation, using vehicle models, contact conditions, track initial irregularities, and traffic mix more close to the reality. The vehicle-track lateral dynamic interaction model was validated against track geometry data measured on the West Coast Mainline (WCML) in England. It has been found that the model gives a reasonably accurate prediction of the development of lateral track irregularities. However, it also tends to predict a short wavelength deterioration that is not seen in the actual track deterioration. Improvements to the model are suggested by either adding more factors or simplifying the model depending on specific target application. Enhancing the model by including more details, such as longitudinal forces, temperature effect, more layered track systems, uneven track bed conditions and more representative wheel-rail contact conditions etc., may help understand the reason of the additional short wavelength. A sensitivity analysis was performed in order to identify the critical factors that influence lateral track deterioration. The track damage caused by specific vehicles can be controlled by understanding different vehicle dynamics behaviour on a particular track section or route. Vehicles with simple suspension design and heavy axle loads tend to cause more lateral track damage. Within a certain speed range, there will be a critical speed that generates the largest lateral deterioration. Vehicles with different dynamic behaviours can generate a potential offset of the lateral deterioration, so it is possible to design the traffic mix to cancel out the peak deterioration. However, it may not be very practical to redesign the traffic mix due to different traffic requirements. Subsequently, actions can be taken to effectively reduce track lateral deterioration, such as optimise the suspension design, vehicle weight, the selection of an optimal operation speed, and enhance the traffic mix design. As the most important interface between vehicle and track, the wheel-rail contact condition has an extremely large influence on lateral deterioration. Wheel and rail profiles with different wear conditions can cause altered vehicle-track lateral dynamic interaction. It is found that increasingly worn wheel/rail profiles within an acceptable tolerance can effectively reduce the lateral deterioration. Lateral deterioration can also be reduced by increasing all the track stiffness values, damping values and the mass of rails and sleepers, or alternatively, by decreasing the sleeper spacing. The sleeper-ballast interface is found to play the most important role in lateral deterioration. The interfaces between the sleeper and ballast shoulder, crib and base determines the non-linear characteristic such as hysteresis and sliding features. Improving the strength of the sleeper-ballast interface can improve the elastic limits and hysteresis characteristics, hence reducing the lateral deterioration. The findings of the investigation indicate that the model provides in-depth knowledge of the mechanisms influencing lateral deterioration and provides effective solutions with consideration of vehicles, wheel-rail contact and the track system. Further work would include track data with sufficient information in order to develop a more comprehensive empirical model that describes the lateral deterioration, inclusion of more potentially influential factors such as: temperature, ground condition, traffic etc. The model can be improved by taking into account additional factors such as the influence of longitudinal forces from the wheels to the rails, different weather and temperatures, subgrade and ground conditions, etc. The reason for the high frequency noise in the deterioration prediction is not understood yet and it should be discussed in terms of more accurate vehicle simulation results and more comprehensive rail and wheel worn profiles measured on the target track and vehicles. Furthermore, the sleeper-ballast lateral characteristics are not well understood and the previous research in this area is quite limited. To improve on the present work it would be useful to carry out laboratory tests in order to capture more accurately track lateral stiffness and damping values as well as the comprehensive non-linear characteristic of track lateral residual resistance behaviour.

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Leiviskä, Albin. "Load generation on a CV90 track system using multibody dynamics." Thesis, Umeå universitet, Institutionen för fysik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-187750.

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Feng, Huan. "3D-models of railway track for dynamic analysis." Thesis, KTH, Transportvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-52619.

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In recent decades, railway transport infrastructures have been regaining their importance due to their efficiency and environmentally friendly technologies. This has led to increasing train speeds, higher axle loads and more frequent train usage. These improved service provisions have however brought new challenges to traditional railway track engineering, especially to track geotechnical dynamics. These challenges demanded for a better understanding of the track dynamics. Due to the large cost and available load conditions limitation, experimental investigation is not always the best choice for the dynamic effect study of railway track structure. Comparatively speaking, an accurate mathematical modeling and numerical solution of the dynamic interaction of the track structural components reveals distinct advantage for understanding the response behavior of the track structure. The purpose of this thesis is to study the influence of design parameters on dynamic response of the railway track structure by implementing Finite Element Method (FEM). According to the complexity, different railway track systems have been simulated, including: Beam on discrete support model, Discretely support track including ballast mass model and Rail on sleeper on continuum model. The rail and sleeper have been modeled by Euler-Bernoulli beam element. Spring and dashpot has been used for the simulation of railpads and the connection between the sleeper and ballast ground. Track components have been studied separately and comparisons have been made between different models. The finite element analysis is divided into three categories: eigenvalue analysis, dynamic analysis and general static analysis. The eigenfrequencies and corresponding vibration modes were extracted from all the models. The main part of the finite element modeling involves the steady-state dynamic analysis, in which receptance functions were obtained and used as the criterion for evaluating the dynamic properties of track components. Dynamic explicit analysis has been used for the simulation of a moving load, and the train speed effect has been studied. The displacement of the trackbed has been evaluated and compared to the measurement taken in Sweden in the static analysis.

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Thellman, Jonas. "Vehicle Dynamics Testing in Advanced DrivingSimulators Using a Single Track Model." Thesis, Linköpings universitet, Fordonssystem, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-79397.

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The purpose of this work is to investigate if simple vehicle models are realisticand useful in simulator environment. These simple models have been parametrisedby the Department of Electrical Engineering at Linköping University and havebeen validated with good results. The models have been implemented in a simulatorenvironment and a simulator study was made with 24 participants. Eachtest person drove both slalom and double lane change manoeuvres with the simplemodels and with VTI’s advanced model. The test persons were able to successfullycomplete double lane changes for higher velocities with the linear tyre modelcompared to both the non-linear tyre model and the advanced model. The wholestudy shows that aggressive driving of a simple vehicle model with non-linear tyredynamics is perceived to be quite similar to an advanced model. It is noted significantdifferences between the simple models and the advanced model when drivingunder normal circumstances, e.g. lack of motion cueing in the simple model suchas pitch and roll.

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Shimatake, Masao. "A track maintenance model for high-speed rail : a systems dynamics approach." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/43385.

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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1997. Vita. Includes bibliographical references (leaves 174-175). by Masao Shimatake. M.S.

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Berggren, Eric. "Railway Track Stiffness : Dynamic Measurements and Evaluation for Efficient Maintenance." Doctoral thesis, KTH, Farkost och flyg, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10360.

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Railway track stiffness (vertical track load divided by track deflection) is a basic parameter oftrack design which influences the bearing capacity, the dynamic behaviour of passing vehiclesand, in particular, track geometry quality and the life of track components. Track stiffness is abroad topic and in this thesis some aspects are treated comprehensively. In the introductionpart of the thesis, track stiffness and track stiffness measurements are put in their propercontext of track maintenance and condition assessment. The first aspect is measurement of track stiffness. During the course of this project, Banverkethas developed a new device for measurement of dynamic track stiffness called RSMV(Rolling Stiffness Measurement Vehicle). The RSMV is capable of exciting the trackdynamically through two oscillating masses above one wheelset. The dynamic stiffness is acomplex-valued quantity where magnitude is the direct relation between applied load anddeflection (kN/mm) and phase is a measure of deflection-delay by comparison with force. Thephase has partial relationship with damping properties and ground vibration. The RSMVrepeatability is convincing and both overall measurements at higher speeds (up to 50 km/h)and detailed investigations (below 10 km/h) can be performed. The measurement systemdevelopment is described in Paper A and B. The second aspect is evaluation of track stiffness measurements along the track from a trackengineering perspective. Actual values of stiffness as well as variations along the track areimportant, but cannot always answer maintenance and design related questions alone. InPaper D track stiffness is studied in combination with measurements of track geometryquality (longitudinal level) and ground penetrating radar (GPR). The different measurementsare complementary and a more reliable condition assessment is possible by the combinedanalysis. The relation between soft soils and dynamic track stiffness measurements is studiedin Paper C. Soft soils are easily found and quantified by stiffness measurements, in particularif the soft layer is in the upper part of the substructure. There are also possibilities to directlyrelate substructure properties to track stiffness measurements. Environmental vibrations areoften related to soft soils and partly covered in Paper C. One explanation of the excitationmechanism of train induced environmental vibrations is short waved irregular supportconditions. This is described in Paper E, where track stiffness was evinced to have normalvariations of 2 – 10 % between adjacent sleepers and variations up to 30 % were found. Anindicative way of finding irregular support conditions is by means of filtering longitudinallevel, which is also described in the paper. Train-track interaction simulation is used in PaperH to study track stiffness influence on track performance. Various parameters of trackperformance are considered, e.g. rail sectional moment, rail displacement, forces at wheel-railinterface and on sleepers, and vehicle accelerations. Determining optimal track stiffness froman engineering perspective is an important task as it impacts all listed parameters. The third aspect, efficient maintenance, is only partially covered. As track stiffness relates toother condition data when studied from a maintenance perspective, vertical geometricaldefects (longitudinal level and corrugation/roughness) are studied in paper F. The generalmagnitude dependency of wavelength is revealed and ways of handling this in conditionassessment are proposed. Also a methodology for automated analysis of a large set ofcondition data is proposed in Paper G. A case study where dynamic track stiffness,longitudinal level and ground penetrating radar are considered manifests the importance oftrack stiffness measurements, particularly for soil/embankment related issues. QC 20100623

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Wiegand, Lars. "Equatorwards-breaking Rossby waves in the North Atlantic storm track : forecast quality, predictability and dynamics." Thesis, University of Leeds, 2011. http://etheses.whiterose.ac.uk/3359/.

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Upper-level disturbances (ULDs) penetrating from the extratropics into low lati- tudes are a frequent feature of the synoptic-scale circulation over the North Atlantic and can be involved in significant weather events such as heavy precipitation over the western and northern parts of Africa, or Saharan dust outbreaks. The present project is the first to systematically explore the huge dynamical information content of long-term data from the European Centre for Medium-Range Weather Forecasts operational ensemble prediction system (EPS) and from the recently established THORPEX Interactive Grand Global Ensemble (TIGGE) for that particular at- mospheric feature. It investigates the dynamics, forecast quality and predictability of this atmospheric phenomenon exploring a wide range of verification and analysis tools based on potential vorticity (PV). The main conclusions from this work are: (i) The EPSs shows a generally underdispersive behaviour in the ULD region. (ii) Forecast errors are reduced by about 50% if each TIGGE centre's own analysis is used instead of the ECMWF analysis, particularly in regions of large PV gradients. (iii) There is a tendency of too weak Rossby wave breaking and therefore a north- ward shift of the PV streamers in the forecasts. (iv) Ensemble-mean multi-model forecasts of a four-day accumulated precipitation event appear accurate enough for a successful severe-weather warning in contrast to some single-model EPSs. (v) Diabatic processes upstream early in the forecasts appear to be more impor- tant than blocking downstream for strengthening the PV streamers in the medium range. The results and the analysis tools developed in this project have improved the understanding of such ULDs and their impacts and has advanced the verifica- tion of EPSs, which can both contribute to an improvement of numerical weather forecasting in the long term.

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Kamuriwo, Dzidziso Samuel. "Fast track knowledge development in new firms : an investigation of knowledge building dynamics within firms." Thesis, City University London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.446453.

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Thomas, Jossian, and Barenys Assís Arañó. "Evaluation of 3D dynamic effects induced by high-speed trains on double-track slab bridges." Thesis, KTH, Bro- och stålbyggnad, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-188850.

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In addition to a static design, a dynamic analysis has to be performed for bridges for which the maximum permissible train speed exceeds 200 km/h. This analysis requires a lot of computing time, for this reason Svedholm and Andersson (2016) have developed a simple tool describing the relationship between the first eigenfrequency of the bridge, the span length and the minimum mass to fulfill the regulation specified in EN-1990. However, these diagrams are based on 2D beam models in which the 3D dynamic effects are not considered. An evaluation of the torsional modes has been performed by analyzing parametrized 3D bridge models, in order to obtain design diagrams including these effects. To do so, a frequency domain analysis has been implemented, based on a steadystate step previously performed in a FEM software. This approach provides a fast way to solve the equation of motion due to the Fourier transform properties, and allows applying several load configurations which are convenient for a parametric study. From this analysis it can be concluded that the thickness to fulfill the demands is larger for 3D models than for 2D. On one hand, contribution of torsional modes of vibration is more significant for the shortest span length, and on the other hand shear-lag effects lead to a reduction of the total resisting bending section.

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Lestoille, Nicolas. "Stochastic model of high-speed train dynamics for the prediction of long-time evolution of the track irregularities." Thesis, Paris Est, 2015. http://www.theses.fr/2015PEST1094/document.

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Les voies ferrées sont de plus en plus sollicitées: le nombre de trains à grande vitesse, leur vitesse et leur charge ne cessent d'augmenter, ce qui contribue à la formation de défauts de géométrie sur la voie. En retour, ces défauts de géométrie influencent la réponse dynamique du train et dégradent les conditions de confort. Pour garantir de bonnes conditions de confort, les entreprises ferroviaires réalisent des opérations de maintenance de la voie, qui sont très coûteuses. Ces entreprises ont donc intérêt à prévoir l'évolution temporelle des défauts de géométrie de la voie pour anticiper les opérations de maintenance, et ainsi réduire les coûts de maintenance et améliorer les conditions de transport. Dans cette thèse, on analyse l'évolution temporelle d'une portion de voie par un indicateur vectoriel sur la dynamique du train. Pour la portion de voie choisie, on construit un modèle stochastique local des défauts de géométrie de la voie à partir d'un modèle global des défauts de géométrie et de big data de défauts mesurés par un train de mesure. Ce modèle stochastique local prend en compte la variabilité des défauts de géométrie de la voie et permet de générer des réalisations des défauts pour chaque temps de mesure. Après avoir validé le modèle numérique de la dynamique du train, les réponses dynamiques du train sur la portion de voie mesurée sont simulées numériquement en utilisant le modèle stochastique local des défauts de géométrie. Un indicateur dynamique, vectoriel et aléatoire, est introduit pour caractériser la réponse dynamique du train sur la portion de voie. Cet indicateur dynamique est construit de manière à prendre en compte les incertitudes de modèle dans le modèle numérique de la dynamique du train. Pour identifier le modèle stochastique des défauts de géométrie et pour caractériser les incertitudes de modèle, des méthodes stochastiques avancées, comme par exemple la décomposition en chaos polynomial ou le maximum de vraisemblance multidimensionnel, sont appliquées à des champs aléatoires non gaussiens et non stationnaires. Enfin, un modèle stochastique de prédiction est proposé pour prédire les quantités statistiques de l'indicateur dynamique, ce qui permet d'anticiper le besoin en maintenance. Ce modèle est construit en utilisant les résultats de la simulation de la dynamique du train et consiste à utiliser un modèle non stationnaire de type filtre de Kalman avec une condition initiale non gaussienne Railways tracks are subjected to more and more constraints, because the number of high-speed trains using the high-speed lines, the trains speed, and the trains load keep increasing. These solicitations contribute to produce track irregularities. In return, track irregularities influence the train dynamic responses, inducing degradation of the comfort. To guarantee good conditions of comfort in the train, railways companies perform maintenance operations of the track, which are very costly. Consequently, there is a great interest for the railways companies to predict the long-time evolution of the track irregularities for a given track portion, in order to be able to anticipate the start off of the maintenance operations, and therefore to reduce the maintenance costs and to improve the running conditions. In this thesis, the long-time evolution of a given track portion is analyzed through a vector-valued indicator on the train dynamics. For this given track portion, a local stochastic model of the track irregularities is constructed using a global stochastic model of the track irregularities and using big data made up of experimental measurements of the track irregularities performed by a measuring train. This local stochastic model takes into account the variability of the track irregularities and allows for generating realizations of the track irregularities at each long time. After validating the computational model of the train dynamics, the train dynamic responses on the measured track portion are numerically simulated using the local stochastic model of the track irregularities. A vector-valued random dynamic indicator is defined to characterize the train dynamic responses on the given track portion. This dynamic indicator is constructed such that it takes into account the model uncertainties in the train dynamics computational model. For the identification of the track irregularities stochastic model and the characterization of the model uncertainties, advanced stochastic methods such as the polynomial chaos expansion and the multivariate maximum likelihood are applied to non-Gaussian and non-stationary random fields. Finally, a stochastic predictive model is proposed for predicting the statistical quantities of the random dynamic indicator, which allows for anticipating the need for track maintenance. This modeling is constructed using the results of the train dynamics simulation and consists in using a non-stationary Kalman-filter type model with a non-Gaussian initial condition. The proposed model is validated using experimental data for the French railways network for the high-speed trains

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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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Frydrýšek, Jan. "Simulační modely vozidel." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218012.

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This thesis deals with simulation vehicle models for lateral control. It surveys step by step to models of tire, truck and control. At the end are showed influences of model parameters to vehicles dynamics.

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Shahzamanian, 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.

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The wheel-rail contact is at the core of all research related to vehicletrackinteraction. This tiny interface governs the dynamic performanceof rail vehicles through the forces it transmits and, like any high stressconcentration zone, it is subjected to serious damage phenomena. Thus,a clear understanding of the rolling contact between wheel and rail is keyto realistic vehicle dynamics simulation and damage analysis. In a multi-body dynamics simulation, the demanding contact problemshould be evaluated at about every millisecond for several wheel-rail pairs.Hence, a rigorous treatment of the contact is highly time-consuming.Simplifying assumptions are therefore made to accelerate the simulationprocess. This gives rise to a trade-o between the accuracy and computationaleciency of the contact model in use. Conventionally, Hertz+FASTSIM is used for calculation of the contactforces thanks to its low computational cost. However, the elliptic patchand pressure distribution obtained by Hertz' theory is often not realisticin wheel-rail contact. Moreover, the use of parabolic traction bound inFASTSIM causes considerable error in the tangential stress estimation.This combination leads to inaccurate damage predictions. Fast non-elliptic contact models are proposed by others to tacklethis issue while avoiding the tedious numerical procedures. The studiesconducted in the present work show that the accuracy of these models iscase-dependent. To improve the accuracy of non-elliptic patch and pressure estimation,a new method is proposed. The method is implemented in an algorithmnamed ANALYN. Comparisons show improvements in patch and, particularly,pressure estimations using ANALYN. In addition, an alternative to the widely-used FASTSIM is developed, named FaStrip. Unlike FASTSIM, it employs an elliptic traction boundand is able to estimate the non-linear characteristic of tangential stressdistribution. Comparisons show more accurate estimation of tangentialstress and slip velocity distribution as well as creep forces with FaStrip. Ultimately, an ecient non-elliptic wheel-rail contact model consistingof ANALYN and FaStrip is proposed. The reasonable computationalcost of the model enables it to be used on-line in dynamics simulationand its accuracy can improve the damage predictions. QC 20160202

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McFarland, Andrew J. "Using Ostracode Dynamics to Track Ecosystem Response to Climatically and Tectonically Induced Lake-Level Fluctuations in Fossil Basin, Green River Basin, Wyoming, USA." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1348242706.

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Kehoe, Ryan M. "Characteristic errors in 120-H tropical cyclone track forecasts in the western North Pacific." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://handle.dtic.mil/100.2/ADA432822.

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Tabe, Arrey Sylvester. "Understanding the dynamics of pursuing reconcilitation and peacebuilding in intractable intergroup conflict situations using multi-track diplomacy: A case study of Somalia's diaspora in Denmark." Doctoral thesis, Universitat Jaume I, 2017. http://hdl.handle.net/10803/463329.

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The project sought to deepen current understanding on how to overcome intractable conflicts. It equips intervening parties with knowledge to boost their efforts for greater results. Intractable conflicts are conflicts that stay for long and refuse to go even when the best available techniques are applied. At times, they last for decades. Given that a lot of methods have been repeatedly tried on them without success, the need for new techniques has been a priority. This work investigated what happens when a society in conflict and another experiencing peace come together. Using Denmark and Somalia as research samples, it studied connections between Danes and Somalis residing in Denmark, noting how and in what ways, intractable conflicts are affected by such connections. To be brief, only one of our findings will be shared: the peace in one of the societies positively affected the conflict in the other through different flows. El objetivo del proyecto fue profundizar sobre el conocimiento actual a la hora de resolver conflictos intratables. El proyecto provee a las partes intermediarias el conocimiento para promover sus esfuerzos con la finalidad de conseguir grandes resultados. Los conflictos intratables son conflictos que permanecen por un largo período de tiempo y declinan salir incluso cuando se presentan los mejores procedimientos, durando en ocasiones décadas. Debido a que muchos métodos se han repetido reiteradas veces en ellos sin éxito, la necesidad por aplicar nuevas técnicas se ha convertido en una prioridad. Este trabajo investigó que sucede cuando una sociedad en conflicto y otra que está experimentando la paz se unen. Usando Dinamarca y Somalia como muestras de investigación, se han estudiado las conexiones entre daneses y somalís residentes en Dinamarca, mencionando como y de qué manera dichas conexiones afectan a los conflictos intratables. En resumen, se compartirá solamente uno de los resultados: la paz en una de las comunidades afectó positivamente el conflicto en la otra mediante diferentes corrientes.

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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.

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The wheel-rail contact is at the core of all research related to vehicle-track interaction. This tiny interface governs the dynamic performance of rail vehicles through the loads it transmits and, like any high stress concentration zone, it is subjected to serious damage phenomena. Thus, a clear understanding of the rolling contact between wheel and rail is key to realistic vehicle dynamic simulation and damage analyses. In a multi-body-system simulation package, the essentially demanding contact problem should be evaluated in about every millisecond. Hence, a rigorous treatment of the contact is highly time consuming. Simplifying assumptions are, therefore, made to accelerate the simulation process. This gives rise to a trade-off between accuracy and computational efficiency of the contact models in use. Historically, Hertz contact solution is used since it is of closed-form. However, some of its underlying assumptions may be violated quite often in wheel-rail contact. The assumption of constant relative curvature which leads to an elliptic contact patch is of this kind. Fast non-elliptic contact models are proposed by others to lift this assumption while avoiding the tedious numerical procedures. These models are accompanied by a simplified approach to treat tangential tractions arising from creepages and spin. In this thesis, in addition to a literature survey presented, three of these fast non-elliptic contact models are evaluated and compared to each other in terms of contact patch, pressure and traction distributions as well as the creep forces. Based on the conclusions drawn from this evaluation, a new method is proposed which results in more accurate contact patch and pressure distribution estimation while maintaining the same computational efficiency. The experience gained through this Licentiate work illuminates future research directions among which, improving tangential contact results and treating conformal contacts are given higher priority. QC 20130911

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Kim, Andrew Eundong. "Experimental Evaluation of the Dynamic Performance Benefits of Roll Stability Control Systems on A-train Doubles." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/102377.

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The ride stability of an A-train 28-foot double tractor trailer when outfitted with different Roll Stability Control (RSC) systems with the same payload and suspension configurations is studied experimentally for various dynamic maneuvers. The primary goal of the study is to determine the effect of different commercially-available RSC systems on the extent of improvements they offer for increasing roll stability of commercial vehicles with double trailers, when subjected to limit-steering maneuvers that can rise during highway driving. A semitruck and two 28-foot trailers are modified for enduring the forces and moments that can result during testing. A load structure is used for placing the ballast loads within the trailers at a suitable height for duplicating the CG height of the trailers during their commercial use. Outriggers and jackknifing arresting mechanisms are used to prevent vehicle damage and ensure safety during the tests. The test vehicle is equipped with multiple sensors and cameras for the necessary measurements and observations. The analog and video data are time-synced for correlating the measurements with visual observation of the test vehicle dynamics in post-processing. An extensive number of tests are conducted at the Michelin Laurens Proving Grounds (MLPG) in Laurens, SC. The tests include evaluating each RSC system with different maneuvers and speeds until a rollover occurs or the vehicle is deemed to be unstable. The maneuvers that are used for the tests include: double lane change, sine-with-dwell, J-turn, and ramp steer maneuver. Both a steering robot and subjective driver are used for the tests. The test data are analyzed and the results are used to compare the three RSC systems with each other, and with trailers without RSC. The test results indicate that all three RSC systems are able to improve the speed at which rollover occurs, with a varying degree. For two of the systems, the rollover speed gained, when compared with trailers without RSC, is marginal. For one of the systems, there are more significant speed gains. Since most RSC systems are tuned for a conventional tractor-trailer, additional testing with some of the systems would be necessary to enable the manufacturers to better fine-tune the RSC control scheme to the dynamics of double trailers. MS

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Dong, K., D. P. Connolly, O. Laghrouche, P. K. Woodward, and Costa P. Alves. "The stiffening of soft soils on railway lines." Elsevier, 2018. https://publish.fid-move.qucosa.de/id/qucosa%3A73234.

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Railway tracks experience elevated rail deflections when the supporting soil is soft and/or the train speed is greater than approximately 50% of the wave propagation velocity in the track-soil system (i.e. the critical velocity). Such vibrations are undesirable, so soil replacement or soil improvement of the natural soil (or alternatively mini-piles or lime-cement treatment) is often used to increase track-ground stiffness prior to line construction. Although areas of existing soft subgrade might be easily identified on a potential new rail route, it is challenging to determine the type and depth of ground remediation required. Therefore, major cost savings can be made by optimising ground replacement/improvement strategies. This paper presents a numerical railway model, designed for the dynamic analysis of track-ground vibrations induced by high speed rail lines. The model simulates the ground using a thin-layer finite element formulation capable of calculating 3D stresses and strains within the soil during train vehicle passage. The railroad track is modelled using a multi-layered formulation which permits wave propagation in the longitudinal direction, and is coupled with the soil model in the frequency-wavenumber domain. The model is validated using a combination of experimental railway field data, published numerical data and a commercial finite element package. It is shown to predict track and ground behaviour accurately for a range of train speeds. The railway simulation model is computationally efficient and able to quickly assess dynamic, multi-layered soil response in the presence of ballast and slab track structures. Therefore it is well-suited to analysing the effect of different soil replacement strategies on dynamic track behaviour, which is particularly important when close to critical speed. To show this, three soil-embankment examples are used to compare the effect of different combinations of stiffness improvement (stiffness magnitude and remediation depths up to 5 m) on track behaviour. It is found that improvement strategies must be carefully chosen depending upon the track type and existing subgrade layering configuration. Under certain circumstances, soil improvement can have a negligible effect, or possibly even result in elevated track vibration, which may increase long-term settlement. However, large benefits are possible, and if detailed analysis is performed, it is possible to minimise soil improvement depth with respect to construction cost.

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Sureka, Arihant. "Improvement of an existing Integrated Vehicle Dynamics Control System influencing an urban electric car." Thesis, KTH, Flygdynamik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-284446.

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The Integrated Vehicle Dynamics Control (IVDC) concept can influence the vehicle behaviour both longitudinally and laterally with just one upper level control concept and further lower level controllers. This demands for state estimation of the vehicle which also includes estimating parameters of interest for the vehicle dynamicist. The approach to this research is firstly in developing a robust unscented Kalman filter (UKF) estimator for the vehicle side slip tracking and also for cornering stiffness estimation which is then fed to the existing model predictive control allocation (MPCA) controller to enhance the lateral stability of the vehicle for the different manoeuvres studied. Based on these developments, two types of filters are created. One with adaption of distance between center of gravity (COG) and roll center height and another without adaption. The key factor in the estimator development is the time adaptive process covariance matrix for the cornering stiffnesses, with which only the initial values have to be parameterised. Combining this research encompasses effective and adaptive method for a better quality of estimation with a kinematic vehicle model which behaves like a real world vehicle, at least virtually.This study is carried out with the understanding of various optimal estimators, parametric sensitivity analysis and statistical inferences, facilitating a base for robust estimation. Keywords: kalametric, state estimation, design matrix, aliasing, kalman filter, projection algorithm, resolution Konceptet Integrated Vehicle Dynamics Control (IVDC) kan påverka fordonets beteende både longitudinellt och lateralt med bara ett regler koncept iett övre lager och ytterligare regulatorer på lägre nivåer. Detta kräver tillståndsuppskattning av fordonet som också inkluderar uppskattning av parametrar av intresse för en fordonsdynamiker. Tillvägagångssättet för denna studie är för det första att utveckla en robust tillståndsestimering med hjälp av ett Unscented Kalman Filter (UKF) för att uppskatta ett fordons avdriftsvinkel och även för uppskattning av ett däcks sidkraftskoefficient, vilket sedan används i den befintliga modell-prediktiva regleralgoritmen (MPCA) för att förbättra lateralstabiliteten hos fordonet för de olika studerade manövrarna. Baserat på denna utveckling skapades två typer av filter, ett med anpassning av avståndet mellan tyngdpunkten (COG) och krängcentrumhöjden och ett annat utan anpassning. Nyckelfaktorn i estimeringsutvecklingen är den tidsberoende adaptiva inställningenav processkovariansmatrisen för sidkraftskoefficienterna, med vilken endast de initiala värdena behöver parametriseras. Efter filterutvecklingen identifieras parametrar baserade på en förväntad kundanvändning och en statistisk variansanalys (ANOVA) utförs för att bestämma de mest inflytelserika faktorerna i gruppen. En parameteroptimering utförs för att förbättra uppskattningskvaliteten. Kombinationen av detta arbete omfattar en effektiv och anpassningsbar metod för en bättre uppskattningskvalitet med en kinematisk fordonsmodell som har en fordonsrespons som ett verkligt fordon, åtminstone praktiskt taget. Denna studie har genomförts med förståelse för olika optimala estimatorer, parametrisk känslighetsanalys och statistiska slutsatser, vilket underlättaren bas för robust uppskattning. Nyckelord: kalametric, tillståndsestimering, designmatris, vikningsdistorsion, kalmanfilter,projection algorithm, upplösning

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Perrin, Guillaume. "Random fields and associated statistical inverse problems for uncertainty quantification : application to railway track geometries for high-speed trains dynamical responses and risk assessment." Phd thesis, Université Paris-Est, 2013. http://pastel.archives-ouvertes.fr/pastel-01001045.

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Les nouvelles attentes vis-à-vis des nouveaux trains à grande vitesse sont nombreuses: on les voudrait plus rapides, plus confortables, plus stables, tout en étant moins consommateur d'énergie, moins agressif vis-à-vis des voies, moins bruyants... Afin d'optimiser la conception de ces trains du futur, il est alors nécessaire de pouvoir se baser sur une connaissance précise de l'ensemble des conditions de circulations qu'ils sont susceptibles de rencontrer au cours de leur cycle de vie. Afin de relever ces défis, la simulation a un très grand rôle à jouer. Pour que la simulation puisse être utilisée dans des perspectives de conception, de certification et d'optimisation de la maintenance, elle doit alors être tout à fait représentative de l'ensemble des comportements physiques mis en jeu. Le modèle du train, du contact entre les roues et le rail, doivent ainsi être validés avec attention, et les simulations doivent être lancées sur des ensembles d'excitations qui sont réalistes et représentatifs de ces défauts de géométrie. En ce qui concerne la dynamique, la géométrie de la voie, et plus particulièrement les défauts de géométrie, représentent une des principales sources d'excitation du train, qui est un système mécanique fortement non linéaire. A partir de mesures de la géométrie d'un réseau ferroviaire, un paramétrage complet de la géométrie de la voie et de sa variabilité semblent alors nécessaires, afin d'analyser au mieux le lien entre la réponse dynamique du train et les propriétés physiques et statistiques de la géométrie de la voie. Dans ce contexte, une approche pertinente pour modéliser cette géométrie de la voie, est de la considérer comme un champ aléatoire multivarié, dont les propriétés sont a priori inconnues. En raison des interactions spécifiques entre le train et la voie, il s'avère que ce champ aléatoire n'est ni Gaussien ni stationnaire. Ce travail de thèse s'est alors particulièrement concentré sur le développement de méthodes numériques permettant l'identification en inverse, à partir de mesures expérimentales, de champs aléatoires non Gaussiens et non stationnaires. Le comportement du train étant très non linéaire, ainsi que très sensible vis-à-vis de la géométrie de la voie, la caractérisation du champ aléatoire correspondant aux défauts de géométrie doit être extrêmement fine, tant du point de vue fréquentiel que statistique. La dimension des espaces statistiques considérés est alors très importante. De ce fait, une attention toute particulière a été portée dans ces travaux aux méthodes de réduction statistique, ainsi qu'aux méthodes pouvant être généralisées à la très grande dimension. Une fois la variabilité de la géométrie de la voie caractérisée à partir de données expérimentales, elle doit ensuite être propagée au sein du modèle numérique ferroviaire. A cette fin, les propriétés mécaniques d'un modèle numérique de train à grande vitesse ont été identifiées à partir de mesures expérimentales. La réponse dynamique stochastique de ce train, soumis à un très grand nombre de conditions de circulation réalistes et représentatives générées à partir du modèle stochastique de la voie ferrée, a été ainsi évaluée. Enfin, afin d'illustrer les possibilités apportées par un tel couplage entre la variabilité de la géométrie de la voie et la réponse dynamique du train, ce travail de thèse aborde trois applications

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Blanco, Blas. "Railway track dynamic modelling." Licentiate thesis, KTH, Farkost och flyg, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-207180.

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The railway vehicles are an increasing mean of transportation due to, its reduced impact on environment and high level of comfort provided. These reasons have contributed to settle a positive perception of railway traffic into the European society. In this upward context, the railway industrial sector tackles some important challenges; maintaining low operational costs and controlling the nuisance by-products of trains operation, the most important being railway noise. Track dynamic plays a main role for both issues, since a significant part of the operational costs are associated with the track maintenance tasks and, the noise generated by the track can be dominant in many operational situations. This explains why prediction tools are highly valued by railway companies. The work presented in this licentiate thesis proposes methodologies for accurate and efficient modelling of railway track dynamics. Two core axes have led the development of this task, on one hand, the rail modelling and, on the other hand, the characterisation of the finite length nature of track supports. Firstly, concerning the rail modelling technique, it has evolved under two major premises. On one hand, regarding the frequency domain, it should describe high frequency behaviour of the rail. In order to accomplish with this first premise, a model based on Timoshenko beam theory is used, which can accurately account for the vertical rail behaviour up to 2500 Hz. On the other hand, with respect to the time domain, the response should be smooth and free of discontinuities. This last condition is fulfilled by implementation of the Timoshenko local deformation. Secondly, a model of support that considers its finite length nature is sought. For this purpose, a Timoshenko element over elastic foundation is formulated. Thus, the common model of support, which is based on a concentrated connection, is substituted by a distributed model of support. In this way, several enhancements are achieved; the temporal contact force response is smoothed and a more realistic shape is obtained, the amplitude of the displacement due to the parametric excitation is reduced and the magnitude associated to the ‘pin-pin’ frequency is not overestimated. QC 20170522

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Elsayed, Abdel Hameed Amer Shaltout Ramy. "MULTIBODY APPROACH FOR RAILWAY DYNAMIC ANALYSIS." Doctoral thesis, Universitat Politècnica de València, 2013. http://hdl.handle.net/10251/27622.

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En este trabajo se ha llevado a cabo el desarrollo de una herramienta computacional para la simulación dinámica de vehículos ferroviarios. El modelo está basado en técnicas multicuerpo debidas a Shabana. Con respecto a otras metodologías existentes, la propuesta hace uso de un conjunto de sistemas de referencia que permite el empleo de coordenadas independientes sin la posibilidad de configuraciones singulares debidas a grandes giros. El conjunto de sistemas de referencia sirve de base para formular de manera precisa el problema de contacto rueda-carril. El programa está diseñado para considerar de forma flexible distintas configuraciones de vehículo así como diversas geometrías de trazado. La estructura del programa está abierta a cambios orientados a la mejora del modelo de contacto rueda-carril o a la implementación de la dinámica estructural de la vía. Se ha implementado un modelo eficiente que permite detectar con precisión las coordenadas de los puntos en contacto localizados en la interfase entre la rueda y el carril. La herramienta de simulación desarrollada en esta tesis se ha aplicado para diferentes casos-estudio con el objetivo de validar la idoneidad de la metodología propuesta en el análisis del sistema ferroviario. Se ha realizado una comparación entre los resultados obtenidos por la herramienta de simulación presentada y los resultados ofrecidos por varios programas comerciales de simulación dinámica en el análisis del vehículo de Manchester Benchmark. Además, la herramienta se ha empleado para desarrollar un análisis dinámico del vehículo de la locomotora TGV y los resultados obtenidos se han comparado con los ofrecidos por el programa comercial SIMPACK para el mismos modelo de vehículo, bajo las mismas condiciones de operación. Finalmente, sobre la base de la calidad de los resultados, se puede concluir que la herramienta de simulación es fiable y eficiente para emplearse en el análisis dinámico de los diferentes sistemas ferroviarios. Elsayed Abdel Hameed Amer Shaltout, R. (2013). MULTIBODY APPROACH FOR RAILWAY DYNAMIC ANALYSIS [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/27622 TESIS

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Ma, Zongqiang. "Spontaneous speech recognition using statistical dynamic models for the vocal-tract-resonance dynamics." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0020/NQ53993.pdf.

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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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Feng, Chih-Liang. "Heavy truck dynamics modeling using multi-body dynamics." The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1295551522.

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Berggren, Eric. "Dynamic track stiffness measurement : a new tool for condition monitoring of track substructure /." Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-341.

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Melo, Ladislao Roger Ticona. "Estudo de efeitos dinâmicos de pontes ferroviárias considerando interação veículo-estrutura." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/3/3144/tde-02122016-100030/.

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Este trabalho apresenta o estudo dos efeitos dinâmicos de duas pontes ferroviárias para trens de carga pesada e trens de alta velocidade considerando a interação veículo-estrutura. O estudo centrou-se principalmente no desenvolvimento de uma metodologia iterativa para a simulação do fenômeno de interação. Em seguida, a metodologia desenvolvida foi utilizada para analisar a ponte Suaçuí (Brasil) e a ponte Antuã (Portugal), e para realizar um estudo paramétrico para avaliar o comportamento não linear da interface via-estrutura de algumas tipologias de pontes ferroviárias. A fim de entender os princípios básicos que governam a resposta dinâmica do sistema veículo-estrutura, foi realizada uma revisão das formulações analíticas e os conceitos básicos de interação veículo-estrutura. A partir das formulações analíticas desenvolveu-se uma metodologia para a resolução de problemas dinâmicos de interação, aproveitando as ferramentas de modelagem do programa ABAQUS por meio do programa MATLAB. A validação do aplicativo foi realizada comparando as respostas de exemplos simples analisados com programas de referência. A principal vantagem desta metodologia é a flexibilidade na seleção dos métodos de resolução do problema dinâmico, permitindo inclusive a incorporação de não linearidades tanto no modelo do veículo quanto da ponte. Utilizando a capacidade de simulação do aplicativo para problemas não lineares foi realizado um estudo paramétrico para verificar os parâmetros que mais influenciam no comportamento não linear da interface via-estrutura e uma aplicação prática para avaliar o desempenho de algumas tipologias de pontes ferroviárias. Para a análise dinâmica da ponte Suaçuí e Antuã desenvolveram-se modelos numéricos tridimensionais de elementos finitos no programa ABAQUS. As propriedades dos materiais das pontes, assim como as propriedades dinâmicas dos veículos foram determinadas a partir de técnicas de calibração numéricas, experimentais e da literatura. A calibração dos modelos numéricos foi realizada utilizando metodologias iterativas baseadas em técnicas de otimização, tais como os algoritmos genéticos. Na falta de dados experimentais das irregularidades, estas foram geradas a partir de funções de densidade espectral de potência. A validação dos modelos numéricos da ponte envolveu a comparação dos resultados numéricos, obtidos da análise de interação, e os resultados experimentais, encontrados nos ensaios dinâmicos sob ação de tráfego. Os resultados da comparação mostraram que os modelos numéricos conseguem reproduzir com boa aproximação as respostas medidas experimentalmente. Finalmente, são realizadas simulações das pontes sob ação de tráfego para diferentes velocidades de circulação dos veículos, a fim de verificar a segurança estrutural da ponte e da via, além do conforto dos passageiros. This research presents the study of the dynamic effects of two railway bridges for heavy axle load trains and high speed trains considering the vehicle-structure interaction. The study was mainly focused on the development of an iterative method for simulating the interaction phenomenon. The developed methodology was used to investigate the Suaçuí railway bridge (Brazil) and the Antuã railway bridge (Portugal), and to carry out a parametric study to evaluate the non-linear behavior of the trackstructure interface of some typologies of railway bridges. In order to understand the basic principles that govern the dynamic response of the vehicle-structure system, a review of the analytical formulations and the basics of the vehicle-structure interaction were performed. Based on the analytical formulations a methodology for solving dynamic interaction problems was developed, taking advantage of modeling tools of the ABAQUS software managed from MATLAB. The validation of the methodology was carried out by comparing responses of simple examples analyzed with reference programs. The main advantage of this methodology is the flexibility in the selection of the methods for solving the dynamic problem, even allowing the incorporation of nonlinearities in the vehicle and bridge model. Using the capability of the developed program for modeling nonlinear problems it was carried out a parametric study to determine the parameters that influence in the non-linear behavior of the track-structure interface and a practical application to evaluate the performance of some typologies of railway bridges. For dynamic analysis of the Suaçuí and Antuã railway bridge threedimensional numerical finite element models in ABAQUS program were developed. Material properties of the bridges, as well as the dynamic properties of the vehicles were determined through numerical and experimental calibration techniques and from the literature. The calibration of numerical models was performed using iterative methodologies based on optimization techniques, such as genetic algorithms. In absence of experimental data irregularities of the Suaçuí bridge, these were generated using spectral density functions. The validation of numerical models of the bridges involved the comparison of numerical results obtained from the interaction analysis with experimental results obtained from dynamic tests under traffic loads. The results of comparison showed that the numerical models were capable to reproduce with good accuracy the responses experimentally measured. Finally simulations of the bridges under traffic loads were performed for different vehicle speeds in order to evaluate the structural and track safety and passenger comfort.

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Abrahamsson, Felix. "Microscopic Models for Trac Dynamics." Thesis, KTH, Skolan för teknikvetenskap (SCI), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-193629.

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As the volume of vehicular trac has been increasing ever since its advent in the early 20th century, trac dynamics has become a popu- lar topic of study amongst physicists and mathematicians. This paper aims to explain di erent ways of modeling and simulating trac and trac dynamics. In general, modeling of trac can be divided into two types of models, microscopic and macroscopic. In this paper, pri- mary focus is on microscopic models. Examples are shown on how to implement simulations of so called car-following models as well as models based on cellular automata. Certain problems and scenarios regarding trac are studied as well. These include how to eciently distribute a roadblock, how to set the green/red time periods of a traf- c light in order to achieve a high trac ow or a low vehicle density, and how trac ow can be maximized with respect to density or other parameters. Results show that simulations using cellular automata models generally compute faster than simulations using car-following models. However, the results obtained from cellular automata models tend to be more dicult to interpret and apply to real-world sce- narios. A high level of stochasticity in the cellular automata models was also found to be necessary for the models to give applicable re- sults. Car-following models, on the other hand, were found to have the advantage of being more deterministic.

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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.

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Berndl, Marc. "Dynamic profiling and trace creation." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80226.

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Effective dynamic virtual-machine optimization depends on quickly finding and optimizing frequently-executed code regions. Such regions are naturally represented with a trace-cache, a collection of long, frequently-executed sequences of instructions. An ideal trace-cache is small and captures the majority of the program's execution stream, yet consists of traces large enough to allow for useful inter-bytecode optimizations and improve instruction-fetch performance. This thesis describes an efficient dynamic technique for finding and constructing such traces. Our trace caching algorithm relies on three innovative techniques: profiling data is managed with the Branch Implication Graph(BI-Graph) data structure, decomposing the program into small, independent, tree-like components using our hot subgraph filters the BI-Graph for relevant data, and traces are constructed from components using a minimum-bounded expected completion rate. We evaluated the runtime performance of our generated traces using a trace cache simulator implemented on top of the Java Virtual Machine, SableVM. Tested against Java benchmarks, our primary data structure, the BI-Graph, scales linearly with the loaded program size and is no larger than a control flow graph. On our benchmarks set, our traces capture 98.5% of the executed instructions, average 34 bytecodes instructions in length, and execute to completion 98.5% of the time. Further, the total size of all traces created scales linearly at 83% of the program's size, averaging only 50000 bytecodes. The entire algorithm, including context-sensitive, branch bias profiling and trace creation, has a projected overhead of only 4.5%. Thus, our algorithm efficiently constructs a small trace cache consisting of long traces that both tend to execute to completion and capture the majority of the execution stream.

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Liu, Yang Ping. "Modelling estuarine chemical dynamics of trace metals." Thesis, University of Plymouth, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360359.

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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 SUPERIOR Em 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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Fesharaki, Mohammad. "3-D Dynamic Analysis of High-Speed Railroad Track." FIU Digital Commons, 2017. http://digitalcommons.fiu.edu/etd/3366.

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High-Speed Rail (HSR) as a fast, reliable and environmentally friendly mode of transportation has received a lot of attention in recent decades. The International Union of Railways reported that there are more than 18600 miles of HSR in operation and about 1.6 billion passengers per year are carried by them. Although there are plans for HSR in many states including Florida, the United States, however, is still hesitant to develop its own HSR network. One of the main barriers to developing high-speed rail is excessive vibration propagation to the media which may cause annoyance to people who live in the track neighborhood. Train induced vibration also contributes to track settlement, developing track flaws, and increasing life cycle cost of track and supporting structures. The aim of this research is to address this problem by conducting a comprehensive investigation into track dynamics. For this purpose, three-dimensional mass-spring-damper models of vehicle, track and supporting structures were developed and matrices of mass, stiffness, and damping of each subsystem were formed. The response of the whole system was, then, determined by coupling the subsystems using Hertz contact theory. The differential equations of the coupled system were solved by the Newmark integration method and the results including vertical and lateral displacements and forces were presented in the time domain. Since the purpose of this dissertation is to quantify the effect of track and vehicle condition on vibration level, rail defects were also taken into account and rail random irregularities for the vertical profile, Gauge, alignment and cross level (super elevation) were incorporated into a numerical solution. The results of the study show the effect of track and vehicle parameters on the response of the vehicle, track, and substructures. Since Florida and some other states in the United States are very prone to hurricanes, an investigation was conducted into the effect of wind speed on vehicle stability. For this purpose, a curved beam was modeled to consider the influence of track curvature, cant deficiency, wind speed and train speed simultaneously. The results from the study show the maximum allowable values of train speed and axle load for different wind speeds. The findings can be used to decide under what circumstances there is a risk of vehicle overturning and how to avoid it.

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Allen, P. "Models for the Dynamic Simulation of Tank Track Components." Thesis, Cranfield University, 2006. http://hdl.handle.net/1826/1106.

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This project has been sponsored by QinetiQ Limited (QinetiQ); whose aim it is to model the dynamics of a prototype high-speed military tracked vehicle. Specifically their objective is to describe the mechanism by which force inputs are transmitted from the ground to the vehicle’s hull. Many track running gear components are steel and can be modelled as simple lumped masses or as linear springs without internal damping. These present no difficulty to the modeller. However tracked vehicle running gear also has nonlinear components that require more detailed descriptions. Models for two rubber components, the road wheel tyre and track link bush, and a model for the suspensions rotary damper, are developed here. These three components all have highly nonlinear dynamic responses. Rubber component nonlinearities are caused by the materials nonlinear elastic and viscoelastic characteristics. Stiffness is amplitude dependent and the material exhibits a significant amount of internal damping, which is predominantly Coulombic in nature but also relaxes overtime. In this work, a novel method for measuring the elastic and viscoelastic response of Carbon Black Filled Natural Rubber components has been devised and a ‘general purpose’ mathematical model developed that describes the materials response and is suited to use in multibody dynamic analysis software. The vehicle’s suspension rotary damper model describes three viscous flow regimes (laminar, turbulent and pressure relief), as a continuous curved response that relates angular velocity to damping torque. Hysteresis due to the compression of entrapped gas, compliance of the dampers structure and compression of damper oil is described by a single non-parametric equation. Friction is considered negligible and is omitted from the model. All components are modelled using MSC.ADAMS TM multibody dynamic analysis software. The models are shown to be easily implemented and computationally robust. QinetiQ’s requirement for ‘practical’ track running gear component models has been met.

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Allen, Paul. "Models for the dynamic simulation of tank track components." Thesis, Cranfield University, 2006. http://dspace.lib.cranfield.ac.uk/handle/1826/1106.

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This project has been sponsored by QinetiQ Limited (QinetiQ); whose aim it is to model the dynamics of a prototype high-speed military tracked vehicle. Specifically their objective is to describe the mechanism by which force inputs are transmitted from the ground to the vehicle’s hull. Many track running gear components are steel and can be modelled as simple lumped masses or as linear springs without internal damping. These present no difficulty to the modeller. However tracked vehicle running gear also has nonlinear components that require more detailed descriptions. Models for two rubber components, the road wheel tyre and track link bush, and a model for the suspensions rotary damper, are developed here. These three components all have highly nonlinear dynamic responses. Rubber component nonlinearities are caused by the materials nonlinear elastic and viscoelastic characteristics. Stiffness is amplitude dependent and the material exhibits a significant amount of internal damping, which is predominantly Coulombic in nature but also relaxes overtime. In this work, a novel method for measuring the elastic and viscoelastic response of Carbon Black Filled Natural Rubber components has been devised and a ‘general purpose’ mathematical model developed that describes the materials response and is suited to use in multibody dynamic analysis software. The vehicle’s suspension rotary damper model describes three viscous flow regimes (laminar, turbulent and pressure relief), as a continuous curved response that relates angular velocity to damping torque. Hysteresis due to the compression of entrapped gas, compliance of the dampers structure and compression of damper oil is described by a single non-parametric equation. Friction is considered negligible and is omitted from the model. All components are modelled using MSC.ADAMS TM multibody dynamic analysis software. The models are shown to be easily implemented and computationally robust. QinetiQ’s requirement for ‘practical’ track running gear component models has been met.

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Morfett, K. D. "Trace metal dynamics in a seasonally anoxic lake." Thesis, Lancaster University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235236.

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Lucic, Ivana. "Truck Modeling Along Grade Sections." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/32842.

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This research effort first characterizes the trucks traveling along US highways by analyzing data from Interstate 81. It is hypothesized that I-81 is typical of US highways and thus can provide some insight into typical truck characteristics. These truck characteristics are important for the development of an exhaustive vehicle performance procedure. Analysis was done based on data collected at the Troutville weigh station. The characterization involves an analysis of vehicle class distribution, GVW (Gross Vehicle Weight) distribution, vehicle volume distribution, Average Weight on Tractive Axle (AWTA), and typical weight-to-power ratios. The thesis then assembles a database of systematic field data that can be utilized for the validation of vehicle performance models. This database is unique because it was conducted in a controlled field environment where the vehicle is only constrained by its dynamics. Using the assembled field database, a simple constant power vehicle dynamics model for estimating maximum vehicle acceleration levels based on a vehicle's tractive effort and aerodynamic, rolling, and grade resistance forces was tested and validated. In addition, typical model input parameters for different vehicle, pavement, and tire characteristics are included in the thesis. The model was found to predict vehicle speeds at the conclusion of the travel along the section to within 5 km/h (3.1 mi/h) of field measurements, thus demonstrating the validity and applicability of the model. Finally, the research effort introduces the concept of variable power in order to enhance current state-of-the-art vehicle dynamics models and capture the build-up of power as a vehicle engages in gearshifts at low travel speeds. The proposed enhancement to the current state-of-practice vehicle dynamics model allows the model to reflect typical vehicle acceleration behavior more accurately. Subsequently, the model parameters are calibrated using field measurements along a test roadway facility. Master of Science

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Gibson, Alexander O. "Modeling of heavy truck dynamics for computing pavement loads." Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/15137.

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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1985. MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING Bibliography: leaves 82-83. by Alexander O. Gibson. M.S.

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Jones, Ashley. "Trace metal dynamics in mine-impacted, circum-neutral streams." Thesis, University of Hull, 2014. http://hydra.hull.ac.uk/resources/hull:11405.

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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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Steffens, David Martyn. "Identification and Development of a Model of Railway Track Dynamic Behaviour." Queensland University of Technology, 2005. http://eprints.qut.edu.au/16029/.

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The research presented in this thesis has identified and developed a sophisticated computer model for the analysis of railway track dynamic behaviour to be used by the Rail Cooperative Research Centre for Railway Engineering and Technologies (Rail CRC) in Australia. To be competitive railway track owners need to extract as much performance as possible from their asset without serviceability or catastrophic failure. Railway track designers therefore need to develop more knowledge of the static and dynamic loadings that track may be subjected to in its lifetime. This would be best undertaken using computer modelling capable of quantifying the effects of train speed, traffic mix, wheel impact loading and distribution of vehicle loads into the track. A comprehensive set of criteria for the selection of a model of track dynamic behaviour was developed. An international review of state-of-the-art models which represented the railway track structure under the loading of a passing train was undertaken. The models' capabilities were assessed and a number of potential models identified. A benchmark test was initiated to compare current models available throughout the international railway research community. This unique benchmark test engaged six researchers to compare their railway track models using a set of theoretical vehicle and track data. The benchmark results showed that significantly different results may be obtained by models, depending on the assumptions of the user in representing a particular track scenario. Differing complexities and modelling methods, the number of different input parameters required and the representation of the irregularities in the wheel and rail all have effect on the results produced. As a result of these initiatives, the DARTS (Dynamic Analysis of Rail Track Structures) computer model was chosen for use by the Rail CRC. A user-friendly interface was created for DARTS by the writer, which was readily interpretable by railway design engineers. At the time of writing, DARTS was found to be suitable for detailed investigations planned by the Rail CRC for future research and was provided for use through an Intellectual Property agreement with its author.

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Man, Amnon Pieter de. "Dynatrack a survey of dynamic railway track properties and their quality /." Delft, the Netherlands : Delft University Press, 2002. http://books.google.com/books?id=UydSAAAAMAAJ.

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Young, Melinda. "The foraminiferal and sedimentological dynamics of a Portuguese submarine canyon system." Thesis, University of Southampton, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295866.

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Dissertations / Theses on the topic 'Track dynamics'

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