Abstract
Flange bearing frogs are designed to provide continuous rolling surfaces for trains traveling on the through line, but the interaction between wheel and rail in a diverging line is more complex than that for a common crossing, especially including flange bearing mode and multipoint contact during the transition. The wheel load will be transited from tread to flange and back to tread, which will intensify the wheel-rail interaction. In this paper, a numerical procedure is presented for the analysis of wheel-rail rolling contact behavior and damage prediction for the flange bearing frog. The three-dimensional explicit finite element (FE) model of a wheel passing the flange bearing frog is established to obtain the dynamic wheel-rail interaction in both the facing and the trailing move. The evolution of contact forces, the distribution of adhesion-slip regions, and shear surface stress and microslip at the contact patch are revealed. Then, the competition relationship between RCF (rolling contact fatigue) and wear of a flange bearing frog is analyzed. The results of numerical simulations can contribute to an understanding of the mechanism of the transient rolling contact behavior and provide guidance in design optimization for flange bearing frogs.
Highlights
Turnouts are essential components of railway infrastructure, providing flexibility in traffic operation
To enable a vehicle to change between tracks, the profiles of switch and frog rail are designed to vary in turnout. e variation of rail profiles will change the wheel-rail contact parameters, and the combination of point rail and wing rail carrying the wheel loads together leads to more complicated multipoint contact in railway turnouts [1, 2]. e normal wheel-rail contact relationship is altered when wheel load is transferred from the point rail to the wing rail in the crossing panel, sometimes resulting in severe impact between wheel and rail
According to the area of slip regions shown above, under the effect of wheel-rail impact induced by frog structural irregularities, the adhesion coefficient between wheel and rail is decreased, which leads to larger slip regions as shown in Figures 9(d) and 9(f ); when the wheel load is transformed from tread to flange, the area of the slip region in contact patch increases from 32% to 43% during transition, which may lead to quicker wear development rate
Summary
Turnouts are essential components of railway infrastructure, providing flexibility in traffic operation. Ren et al [8] calculated the wheel-rail force transfer/distribution characteristics of turnout areas based on the vehicle-turnout space coupling vibration model, and a method for reducing dynamic wheel-rail response through optimization of the sectional geometric profile of frog crossing is introduced. Wiest et al [12] established a simplified finite element model for elastoplastic wheel-rail contact frogs based on Abaqus and presented the change of stress-strain fields at crossing when wheels passed through the frog several times; the evolution characteristics of the geometric profile of frog sections along spaces were not taken into account. The competition between wear and RCF at different regions in flange bearing frog is evaluated based on the damage coefficient functions of wear numbers. e results of the study can provide a theoretical basis for optimization, damage control, and maintenance of flange bearing frog
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
