Qin Pinpin, Wu Fengmin, Wu Da, Zhang Shunfeng, Huang Daming
Guangxi Key Laboratory of Manufacturing System & Advanced Manufacturing Technology, School of Mechanical Engineering, Guangxi University, Nanning, China.
Transportation College, Nanning University, Nanning, China.
Sci Prog. 2020 Jul-Sep;103(3):36850420940890. doi: 10.1177/0036850420940890.
Due to imperfect design norms and guidelines for China's truck escape ramp, previous studies have not been able to reflect the effect of wheel subsidence process on the deceleration of runaway vehicles. A discrete element method was used to establish an aggregate discrete element and a wheel discrete element. The three-dimensional discrete element model for an aggregate-wheel combination was established based on a particle flow code in three dimensions on a software platform using the "FISH" language. The microscopic parameters of the aggregate discrete element particles and wheel discrete element particles were calibrated using a simulated static triaxial compression test and real vehicle test data, respectively. Four sets of numerical simulation tests were designed for analyzing the influence of the aggregate diameter, grade of the arrester bed, truckload, and entry speed on the wheel subsidence depth and stopping distance of runaway vehicles. The results indicate that the smaller the aggregate diameter and entry speed and the greater the truckload and grade of the arrester bed, the more easily the wheel falls into the gravel aggregate, the better the deceleration effect, and the smaller the stopping distance. As the wheel subsidence depth increases, the speed at the unit stopping distance decreases more quickly. The maximum subsidence depth mainly depends on the truckload. The research results can provide a theoretical basis for the design of the arrester bed length and the thickness of the aggregate pavement in a truck escape ramp.
由于我国避险车道设计规范和指南尚不完善，以往的研究未能反映车轮沉陷过程对失控车辆减速的影响。采用离散元方法建立集料离散元和车轮离散元。基于三维颗粒流程序，利用“FISH”语言在软件平台上建立了集料 - 车轮组合的三维离散元模型。分别利用模拟静态三轴压缩试验和实车试验数据对集料离散元颗粒和车轮离散元颗粒的细观参数进行了标定。设计了四组数值模拟试验，分析集料粒径、避险车道坡度、车辆荷载和驶入速度对失控车辆车轮沉陷深度和停车距离的影响。结果表明，集料粒径和驶入速度越小，车辆荷载和避险车道坡度越大，车轮越容易陷入碎石集料中，减速效果越好，停车距离越小。随着车轮沉陷深度的增加，单位停车距离处的速度下降越快。最大沉陷深度主要取决于车辆荷载。研究结果可为避险车道避险床长度和集料路面厚度的设计提供理论依据。
