Wheel Rail Adhesion and Film Formation – The Influence of Friction Modifier Composition

různé

angličtina

In order to better understand wheel-rail interface problem, several papers focusing on adhesion phenomenon in wheel-rail contact were published in the last few decades. Recently, friction modifiers were developed and subsequently their performance was experimentally tested under different operating and environmental conditions. Application of these friction modifiers can lead to reduction of the adhesion coefficient to intermediate level of friction which is optimal in meaning of wear, traction and braking performance. Moreover, application of friction modifiers enables to achieve a positive traction curve. By providing positive friction, roll-slip oscillation is suppressed. This roll-slip oscillation can lead to formation of short pitch corrugation. In addition, this oscillation is accompanied by high pitched noise due to resonant frequency in the wheel. The previously published papers dealt with the influence of friction modifiers on adhesion particularly under different contact conditions. However, little is known about the effect of individual friction modifier components on adhesion and film formation. This paper provides an initial insight into film formation with respect to the composition of friction modifiers. In this study oil-based friction modifiers with metal particles were used in order to clarify friction behaviour of friction modifiers in an EHL contacts at fully flooded or starved regimes. Experiments were performed using a ball-on-disc tribometer with high-speed camera.

Wheel-rail contact, adhesion, adhesion coefficient, friction modifier, EHL contact, film formation.

GALAS, R.; OMASTA, M.; KŘUPKA, I.; HARTL, M.

14. 6. 2016

Finnish Society for Tribology

Hämeenlinna, Finland

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