A passive damping strategy of driven wheel set is discussed as a solution against rail corrugation (rutting corrugation). In order to study this phenomenon, a multi-body model of the vehicle-track system has been developed in the software SIMPACK, a program where calculations are based in the time domain. The vehicle is constituted of two bogies, fixed on a car-body through the secondary suspensions. On each bogie, two wheel sets are fixed through the primary suspensions. Wheel set flexibility, resonance frequencies and mode shapes of the wheel set, as well as track model (including rail pads and ballast) are calculated during a pre-processing stage. The validation of the model was carried out with numerical data from a track section of the STIB network. Rail corrugation was discussed in terms of frictional power dissipated in the wheel-rail contact patch. After the integration, the short time Fourier transform (STFT) of the frictional power was used to point out modes excited during the motion of the vehicle. In order to damp this second torsional mode a passive dynamic absorber (DVA) is introduced, that consists of a simple ring fixed on the wheel set axle through a thin layer of viscoelastic material, represented with a simple Kelvin model. Parameters of this model are tuned in order the damper to have a natural torsional frequency equals to the frequency of the second torsional mode of the wheel set. To test the efficiency of the damper in working conditions, the same test case has been considered when the DVA is mounted on the driving wheel sets of the vehicle. After the integration, STFT of the model are again calculated, showing a reduction of about 15 % of the total amount of energy dissipated in the contact, which is related to the damping of the second torsional mode of the wheel set. Preliminary experiments suggest that a DVA can actually damp more than one mode of the wheel set (torsional and bending mode).
Passive damping of driven wheel set as a solution against rail corrugation
2005
4 Seiten, 2 Bilder, 1 Quelle
Conference paper
English
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