Thermal fatigue of steel tyres on urban railway systems

Sie sind hier: Homepage > Suche

Thermal fatigue of steel tyres on urban railway systems

Pistorius, P.G.H. / Marais, J.J.

A conceptually simple experimental apparatus, similar to that used in the original work by Coffin on thermal fatigue, could be used to elucidate important aspects of the initiation of thermal fatigue cracks in the running surface of pearlitic steel tyres fitted to vehicles operating in an urban railway system. With this apparatus, compressive straining occurs at high temperature. Subsequent cooling to low temperatures results in the development of a tensile stress, approaching the room temperature yield strength in the specimens. This probably mimics the conditions in the running surface of the tyre. The sign, and probably the magnitude of the initial stress in the specimen has very little influence on the development of this tensile stress. The residual stress in the running surface of a new wheel would therefore not influence the initiation of thermal fatigue cracks. Exposure to higher temperatures increases the strain range to which the specimen is subjected, and decreases the thermal fatigue life significantly.