Squat formation and rolling contact fatigue in curved rail track

June 18, 2015 in

Journal Paper

Michaël Steenbergen

ISSN Engineering Fracture Mechanics 143 (2015) 80–96


Engineering Fracture Mechanics

Publisher: elsevier
Publishing date: June 18, 2015

Curve negotiation, Head-hardened rail, Rail crack, rolling contact fatigue (RCF), squat, Tangential stress

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A new theory is presented for predicting squat morphology on high and low rails of curves, based on tangential contact stress directivity for running bogies and local loading history. Notably, squats on high and low rails are predicted as distinct, with generally no branching on the latter. Field data confirm predictions, and illustrate three other aspects of squat growth: repetitive and transient tangential contact stress redistribution at the leading RCF-crack may explain branching; white etching material is found unrelated to crack initiation on head-hardened rails, and high-frequency dynamic wheel–rail interaction is shown incapable of explaining basic features of squat growth.