PhD Research by Nico Burgelman
Rolf Dollevoet, Zili Li
09/01/2010 - 12/01/2015
vehicle simulations, wheel/rail contact mechanics,
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As turnouts are an maintenance intensive and so expensive component of a railway network, there is a lot of incentive to understand the mechanism behind the wear and damages that occur in turnouts. Therefore it is necessary to gain insight in the interaction between a train and a turnout, such insight can be obtained through numerical modelling. As a the train-turnout interaction is too complex to grasp in one model different models focus on different aspects. In this research the there are two focusses: one on the wheel rail contact in the turnout and one on the coupling of the wagons of the train that passes the turnout.
Many of the assumptions commonly made in wheel-rail contact calculation models do not hold for contact between a wheel and a turnout. The contact patches cannot be assumed planar, multiple contact points occurs, and very high creepages occur. One approach is to do a vehicle calculation in a turnout with a simple contact method and then apply a complex contact model (such as the model WEAR) in post-processing. This approach gives realistic results, but does not guaranty the force equilibrium. A second approach is to apply a medium advanced contact method online during the vehicle simulation. Results obtained with difference models were compared with each other and their influence on the simulated vehicle dynamics is studied in.
When a train passes through a turnout or a sharp curve the lateral forces can increase when the couplers between the wagons are loaded in compression. This is the case when a front locomotive starts braking or a rear locomotive starts pushing the train. This increase in lateral force is a function of the braking/traction efford, the number of vehicles, and the curve radius.