On the special angle of surface cracks propagation in the railway rail heads

Abstract

Investigation of crack-like surface defects on running surfaces of railway rails was carried out using the Keer-Bryant model scheme. For this purpose by singular integral equation method, the contact problem for an elastic half-plane with an edge crack was solved, taking into account the general conditions of crack faces interaction (slip, stick, opening). Dependence of the range of stress intensity factors KII in contact cycle on crack orientation angle for different service parameters, namely friction between the wheel and the rail, length of the crack and friction between its faces was investigated in detail. As a result, it has been shown that surface cracks on running surfaces of rails grow in the direction of the rolling stock traffic at shallow characteristic angle by transverse shear mechanism. This angle is a basis for formation of typical surface contact fatigue damages, such as pitting, squat, checks. The conditions for finding it have been put down. Characteristic angle values found theoretically agree with engineering data well.