The carbody plays an important role in rail vehicle dynamics.This thesis aims atdeveloping validated modelling methods tostudy its dynamics, how it is excited on trackand how itinteracts with the passengers. The primary interest is ridecomfort,considering vibrations up to 20 Hz. In this frequencyrange, the structural flexibility ofthe carbody is of majorconcern. The models are intended for use intime-domainsimulation, calling for small-sized models to reducecomputational time and costs. Keyparameters are proposed toselect carbody eigenmodes for inclusion in a flexiblemultibodymodel, and to quantify the interaction between passengers andcarbody. Extensive comparisons between measurements and correspondingsimulations arecarried out in a case study. On-track measurementsare performed to obtain operatingdeflection shapes and powerspectral densities of the accelerations in the carbody.Thecomplete vehicle is modelled using the pieces of softwareGENSYS (flexible multibodymodel) and ANSYS (finite element modelof the carbody). Actual, measured trackirregularities are used asinput. In order to investigate the influence of passengerload,experimental modal analysis of the carbody is performed withand without passengers.Also, amplitude dependence is examined.Simple models, based on human-body modelsfrom literature, of thepassenger-carbody system are proposed and validated.Verticalseating dynamics is considered. The models areimplemented and tested in the casestudy. Finally, ideas on modelreduction and approximation are presented and applied. The main conclusions drawn from the study are that     the structural flexibility of the carbody must be takeninto account when predictingvertical vibration comfort. It ispossible to predict which carbody modes that willcontributemost to the vibrations.     the carbody dynamical properties depend on the excitationamplitude.     passengers and carbody interact significantly.- theproposed models describe the interaction quite well. Theproposed passenger-carbodymodel gives an upper boundary on theinteraction.     the proposed passenger-seat-carbody model can be used tostudy the influence of theseat parameters on the interaction.This merits to be investigated further, however. <b>Keywords</b>: Carbody, Experimental modal analysis, Human-bodydynamics, Modelreduction, Multibody dynamics, Operatingdeflection shapes, Rail-vehicle dynamics,Ride comfort, Seatingdynamics, Structural dynamics.

<p>The carbody plays an important role in rail vehicle dynamics.This thesis aims atdeveloping validated modelling methods tostudy its dynamics, how it is excited on trackand how itinteracts with the passengers. The primary interest is ridecomfort,considering vibrations up to 20 Hz. In this frequencyrange, the structural flexibility ofthe carbody is of majorconcern. The models are intended for use intime-domainsimulation, calling for small-sized models to reducecomputational time and costs. Keyparameters are proposed toselect carbody eigenmodes for inclusion in a flexiblemultibodymodel, and to quantify the interaction between passengers andcarbody.</p><p>Extensive comparisons between measurements and correspondingsimulations arecarried out in a case study. On-track measurementsare performed to obtain operatingdeflection shapes and powerspectral densities of the accelerations in the carbody.Thecomplete vehicle is modelled using the pieces of softwareGENSYS (flexible multibodymodel) and ANSYS (finite element modelof the carbody). Actual, measured trackirregularities are used asinput. In order to investigate the influence of passengerload,experimental modal analysis of the carbody is performed withand without passengers.Also, amplitude dependence is examined.Simple models, based on human-body modelsfrom literature, of thepassenger-carbody system are proposed and validated.Verticalseating dynamics is considered. The models areimplemented and tested in the casestudy. Finally, ideas on modelreduction and approximation are presented and applied.</p><p>The main conclusions drawn from the study are that</p><p>    the structural flexibility of the carbody must be takeninto account when predictingvertical vibration comfort. It ispossible to predict which carbody modes that willcontributemost to the vibrations.</p><p>    the carbody dynamical properties depend on the excitationamplitude.</p><p>    passengers and carbody interact significantly.- theproposed models describe the interaction quite well. Theproposed passenger-carbodymodel gives an upper boundary on theinteraction.</p><p>    the proposed passenger-seat-carbody model can be used tostudy the influence of theseat parameters on the interaction.This merits to be investigated further, however.</p><p><b>Keywords</b>: Carbody, Experimental modal analysis, Human-bodydynamics, Modelreduction, Multibody dynamics, Operatingdeflection shapes, Rail-vehicle dynamics,Ride comfort, Seatingdynamics, Structural dynamics.</p>

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. / <p>QC 20160202</p>

No description available.

This diploma thesis deals with the design of door frame curvature, meant for rail vehicle. Flat glass is adhesively bonded onto the curved door frame and due to the elastic deformation the door frame bends backwards. Hence the door frame must be bend with reserve so that the elastic deformation is covered. Finite element analysis of currently manufactured door with constant curvatere has been carried out, with this analysis it has been checked that the chosen problem approach is suitable. Design of door frame curvature is then made for door frame with combined curvature (different for lower and upper part of door frame). The aim of this thesis was to design the curvature so that after glass is bonded onto it, the door frame will have the right dimensions.

The content of this diploma thesis is design of a low-floor tram, primarily intended for inner-city use. The thesis includes a brief summary of the historical development, analysis of current trends in tram design and analysis of currently used technical solutions. The main part is devoted to the design process, resulting in shape and graphical solution of the exterior and interior arrangement while respecting the structural and ergonomic requirements in respect of passengers and the driver of the vehicle.

The topic of this master’s thesis is design of electric locomotive, more specifically universal independent machine made for pull of personal trains and industrial trains as well. The main aim of this design is to create compact design which follows current estetical trends and fulfill technical and ergonomic needs.

Wheel-rail contact is an important aspect of railway, the forces transferred between the wheel and rail are the one that guide, brake, or accelerate the train, and that is why the understanding of the contact between wheel and rail is an interesting research topic. In this master thesis wheel-rail contact model named ANALYN is used to see the effect of the different geometrical input, like undeformed distance, relative longitudinal curvature, and relative lateral curvature calculation affect the contact patch estimation formed at the wheel-rail contact.  In the process, a geometrical contact search code is made to find the contact point between wheel and rail for certain lateral displacement, yaw angle, and roll angle of the wheelset. The codes used to calculate the three geometrical inputs are also prepared, with two methods are prepared for each input. The results that generated from combination of the geometrical contact search and geometrical input preparation are used as the input to ANALYN. The results showed that different geometrical input calculations do affect the shape of the contact patch, with the calculation of lateral curvature being the most important since it affects the shape of the contact patch greater than other geometrical inputs. It is also shown that taking yaw angle into account in the contact search will affect the shape of the contact patch.

This thesis aims at systematically studying the possibilities of minimising devastatingconsequences of high-speed derailments by appropriate measures and features in thetrain design, including the running gear. The course of events immediately afterderailments is studied with respect to whether the train stays upright and close to thetrack centre line or deviates laterally with probably serious consequences. There is abelief in the railway community that some trains can better cope with derailment thenothers, although this superiority is apparently hard to quantify.Firstly, an empirical database has been established containing as much relevantinformation as possible of past incidents and accidents occurred at higher speeds due tomechanical failure close to the interface between the running gear and the track, as wellas other causes that ultimately brought the train into a derailed condition. Although nevertwo derailments are the same, certain patterns appeared to crystallise after analysing thecourse of events immediately after the failure based on the descriptions available in eachincident or accident report. Ultimately, this led to that several critical vehicle parameterscould be distinguished as capable to influence the outcome of a derailment.Secondly, two of the critical vehicle features found in the first stage have been subject todetailed analysis by means of multi-body system (MBS) simulations. The first phase ofthe computer simulation program focused on studying the tendency of a wheelset toderail as a result of an axle journal failure on the outside of the wheel. The prederailmentcomputer simulation model has been validated with good results for twoauthentic Swedish events of axle journal failure.Thereafter, one of the newly found critical vehicle feature, the wheelset mechanicalrestrictions relative to the bogie frame, have been extensively studied on an X 2000power unit and trailer car model. The results show that a vertical mechanical restrictionof the wheelset relative to the bogie frame of approximately 50 to 60 mm is capable ofkeeping the wheelsets on the rails after an axle journal failure, for the studied conditions.An axle mounted brake disc constitutes the second critical vehicle feature that has thepotential to favourably influence the sequence of events in cases of wheel flangeclimbing. A minimal range of geometrical parameters for which the rail would safely fillthe gap between the brake disc and the wheel has been calculated.The third and last part of the thesis establishes the prerequisites necessary in order tostudy the remaining of the critical vehicle parameters found in the first part, whichrequires complete MBS simulations of derailed vehicles rolling on track structures, i.e.concrete sleepers. To accomplish this task, hysteresis data for the force as function ofconcrete material indentation, are aimed to be acquired by means of finite element (FE)simulations. Therefore, the intended FE model of wheel-concrete sleeper impact issubjected to a tentative validation procedure. A good agreement is observed whencomparing the FE model results with an authentic accident in terms of concrete sleeperindentation. Furthermore, preliminary results in terms of a wheelset tendency to reboundafter concrete sleeper impact are presented. / QC 20101125

The aim of this project is to design and implement a drive system and a driving strategy for a lightweight, battery-driven rail vehicle partaking in the Delsbo Electric student competition. The goal of the competition is to create a vehicle which consumes as little energy as possible.  A simulation model of the vehicle is developed in Simulink, based on existing hybrid car models. Different drive cycles are written in MATLAB and tested in the vehicle simulation, which calculates energy consumption, power and torque usage and other important data. This data is used to select an optimal driving strategy and dimension the drive system components.  The final drive system design consists of a permanent-magnet synchronous motor powered by lead acid batteries and controlled by a microcontroller and motor driver through a user interface consisting of a control board with buttons and switches.  The chosen driving strategy combines slow acceleration and constant speed in slopes with the pulse and glide strategy on flat parts of the track. The simulation shows a total energy consumption of 0.67 Wh/person and km, which is in the same order of magnitude as results from previous years, which is promising for the competition. However, the actual energy consumption can not be known until the vehicle has been built and tested. There is a lot of uncertainty around its parameters at this stage, which affects the reliability of the simulations. / Syftet med det här projektet är att designa och implementera ett drivsystem och en körstrategi för ett lättviktigt, batteridrivet rälsfordon. Fordonet ska användas i studenttävlingen Delsbo Electric. Målet med tävlingen är att bygga ett fordon som förbrukar så lite energi som möjligt.  För att göra detta utvecklas en simuleringsmodell av fordonet i Simulink, baserat på redan existerande modeller av hybridbilar. Olika körprogram skrivs i MATLAB och testkörs i modellen, som beräknar energiåtgång, använd effekt och vridmoment och annan viktig data. Dessa värden används sedan för att optimera körstrategin och dimensionera drivsystemets komponenter.  Det färdigdesignade drivsystemet består av en permanentmagnetiserad synkronmotor som matas från blyackumulatorer och styrs av en mikrokontroller och en driver via en kontrollpanel med knappar och switchar. Den valda körstrategin kombinerar låg acceleration och konstant hastighet i backarna med pulse-and-glide-strategin på de platta delarna av banan. Enligt simuleringarna ger den en total energiåtgång på 0.67 Wh/person-km, vilket är i samma storleksordning som tävlingsresultat från tidigare år. Detta bådar gott inför tävlingen, men det går inte att veta hur stor den faktiska energiförbrukningen kommer bli förrän fordonet är byggt och testat. Än så länge är många av dess parametrar osäkra, vilket påverkar tillförlitligheten hos simuleringarna. / Kandidatexjobb i elektroteknik 2022, KTH, Stockholm