Numerical Investigation of Rail Bending Behaviour Focusing on the Effect of Track Modulus

Thorough understanding of steel rail response to wheel load is a key step towards design and evaluation of the railwaytrack structure. In current practice, maximum vertical deflection and bending moment are calculated using the theoryof infinite beam on continuous elastic foundation (Winkler model), in which the foundation stiffness is assumed asconstant. However, variation of track modulus along the rail is an inherent feature of the railway track structure. Inevitablevariation in local geology, layer properties, layer thickness and track construction procedure along the trackdisturb track support uniformity. Track modulus can also rapidly change over a short length of the track at transitionzones or at the locations of local problems, such as hanging or broken ties. This study aims to investigate the effect oftrack modulus variation on rail bending response using finite element method. In the proposed dynamic track model,various track modulus distributions are considered and track response to a moving wheel load set is calculated usingdirect integration time history analysis. The envelope profile of the rail maximum vertical deflection and bending momentderived from finite element models are then compared with the corresponding Winkler model results.

Keywords:

Railway track structure , rail bending behavior , track modulus variation