Experimental and Numerical Analysis on Mechanical Behaviour of Steel Turnout Sleeper

Abstract

Due to the mechanical structure of railway turnouts, the drive arm of point machines at the switch point is exposed and can be easily damaged during the tamping maintenance. As a result, the tamping maintenance at the switch point has to either be performed after removing drive arms or to be skipped. As a solution, the steel turnout sleeper (STS) has been invented, which has a hollow structure to protect the drive arm and thus increase the integrity of the switch. However, the user experience shows shortcomings of the STS including ballast void and low lateral resistance. In order to find reasons for the shortcomings and further improve the design, a series of full-scale tests of the STS has been conducted, including the modal analysis and the lateral resistance test. After that, the mechanical behaviour of the STS has been analysed in detail using both the Finite element method (FEM) and the Discrete element method (DEM). The main characteristic frequencies and mode shape of the STS in the free and in-situ constrain conditions are analysed. Besides, the lateral resistance of the STS, concrete sleeper, and STS with USP are tested. The proportion of various parts of the STS to the lateral resistance is discussed. At last, design improvements for the STS are provided.

Keywords: Steel turnout sleeper, Modal analysis, Railway track, Lateral resistance