Numerical analysis of train-track-subgrade dynamic performance with crumb rubber in ballast layer

Crumb rubber (CR) has been proposed to apply in the ballast or sub-ballast layer for degradation mitigation and vibration (noise) reduction. The CR can change stiffness, which affect train-track-subgrade dynamic performance cause travel comfort safety issues. Towards this, this study aims at confirming 1) how much application of train layer; 2) what extent CR-ballast distribute loadings reduce subgrade surface stress. To achieve aim, a whole system model was built by coupling multibody dynamics (MD), discrete element method (DEM) finite difference (FDM). MD used build train, including one vehicle body, two bogies four wheelsets. DEM ballasted track, rail, sleepers layer. FDM subgrade. Using coupled model, track were studied, body acceleration, wheel-rail force, rail dynamical bending moment, sleeper displacement acceleration. In addition, energy dissipation bed also presented. For subgrade, acceleration stress measured analysed. different size percentage considered. Results show that using increase accelerations sleeper, train. But it decrease degradation, helps consume loading energy, reducing be consumed friction. Small (8–22.4 mm) greater influence on than big (9.5–63 mm). summary, 10% mixture is recommended, difficult give recommendation. more CR, but small are better improving displacement,