On the Effective Speed Control Characteristics of a Truck Escape Ramp Based on the Discrete Element Method

This paper presented a numerical analysis of the damping characteristics of truck escape ramps. To explore the procedure of out-of-control trucks running into arrester beds, the discrete element method (DEM) models of both the tire and the truck escape ramp were built. Tire compression tests were conducted on a homemade tire test system, and the results were used to calibrate the parameters of the tire DEM model. A compression machine was used to conduct dynamic compression tests on pebbles obtained from escape ramps, and the results were used to calibrate the parameters of the pebble DEM model. Road tests were then conducted to further validate the simulation method. An adaptive master-slave simulation procedure analysis was utilized in the simulation process. The error of the travel distance between the simulation and test results was 2.95%. The built tire-pebble DEM model was used to perform the simulations of trucks running into truck escape ramps with different truckloads and laying depths. The results of different truckloads indicated that the truck speed was mainly determined by the laying depth at the entrance of the truck escape ramp. With an increase in time, the truckload started to take effect. The results of different laying depths indicated that the truck speed results were approximately constant at the entrance of the truck escape ramp. As the laying depth increased, the truck speed decreased. When the laying depth exceeded approximately 60 cm, the damping properties of the different laying depths were approximately constant.