Dynamic Behavior Modeling of Full-Scale High-Speed Ballasted Track Using Discrete Element Method

Abstract

Ballast layer dynamic behavior is critically important for railway track design and maintenance optimization. This paper presents findings on crosstie and ballast particle dynamic responses obtained from: (i) laboratory tests conducted at Zhejiang University innovative high-speed rail tester (ZJU-iHSRT) and (ii) discrete element method (DEM) simulations using algorithms with newly featured parallel computing capability developed at UIUC. Overall, more than 170,000 ballast particles and eight crossties were assembled in the DEM model. A proportional integral derivative (PID) controller was utilized to ensure realistic dynamic loads applied on crossties at three train speeds: (1) 108 km/h; (2) 252 km/h; (3) 300 km/h. Crosstie vibration velocities predicted using the DEM model matched closely with measurements from laboratory tests both in trends and in magnitudes. With Fourier transformation and Butterworth filter techniques implemented on ballast particle vibration velocities captured in the DEM model, inherent signal noise could be reduced, and as a result, the predicted ballast particle vibration trends matched closely with laboratory sensor measurements. However, individual ballast particle vibration magnitudes predicted by the DEM simulations revealed certain discrepancies with the measurements since velocity sensors used in the experiment only recorded vibration responses of an assembly of ballast particles. Further studies are necessary to reveal more detailed findings.