Thin film coatings for lubricated slip-rolling contacts under high initial Hertzian contact pressure [Couches minces pour les contacts lubrifiés en slip-rolling (glissement-roulement) sous haute pression hertzienne initiale]
Manier C.-A.,BAM Institute Federal Pour la Recherche et lEssai des Materiaux |
Theiler G.,BAM Institute Federal Pour la Recherche et lEssai des Materiaux |
Spaltmann D.,BAM Institute Federal Pour la Recherche et lEssai des Materiaux |
Woydt M.,BAM Institute Federal Pour la Recherche et lEssai des Materiaux |
And 2 more authors.
Materiaux et Techniques | Year: 2010
The light-weight approach and fuel economy targets in today's automotive engineering require tribosystems, which can withstand higher contact pressures associated with low coefficients of friction. The application of surface coatings represents one approach among others. This paper presents thin film coatings performances in a bench mark test procedure exerting slip-rolling conditions in the presence of liquid lubricants. After a first selection at room temperature, the most resistant coatings were evaluated at 120 °C. These are newly developed DLC coatings (a-C:H & ta-C) as well as a novel coating-substrate system. Some of the newly developed DLC-coatings are slip-rolling resistant for at least up to 10 million cycles at 120 °C oil temperature) under Hertzian contact pressures of P0max = 2600 / 2940 MPa. Furthermore, this novel Zr-based thin film coating can withstand at least 1 million cycles under initial Hertzian contact pressures of up to P 0max = 3500 MPa and oil temperatures of at least 120 °C associated with low coefficients of friction under mixed/boundary conditions. © EDP Sciences.
Vehicle-track-soil interaction and train-induced ground vibration. Complex modelling and experimental verifications [Interaction véhicule-voie-sol et vibrations dues aux trains, Modélisations et vérifications expérimentales]
Auersch L.,BAM Institute Federal Pour la Recherche et lEssai des Materiaux |
Maldonado M.,Gem Laboratoire Of Genie Civil Et Mecanique
European Journal of Computational Mechanics | Year: 2011
This contribution presents models that are necessary to calculate the vibrations due to the passage of a train. The models allow to calculate the propagation of the waves and the receptances of the soil and the track. The layered soil and the coupling with the track are treated by a (double) integration in wavenumber domain. The dynamic stiffnesses of the track and vehicle are combined and the excitation forces due to the irregularities of the track and the wheel are calculated. Finally, these excitation forces are used to simulate the ground vibration of a passing train. All these models are validated by a number of different measurements at two sites in France and Germany. © 2011 Lavoisier, Paris.