失控车辆在避险车道制动床上减速过程的 三维离散元模拟

由于中国避险车道设计规范或指南不完善,存在设计缺陷的避险车道易诱发失控车辆冲出避险车道末端或在制动床上侧翻等事故,严重威胁驾驶员生命。以往研究还不能体现车轮沉陷变形对失控车辆减速作用的影响。为此,从颗粒层面入手采用离散元方法,分别构建集料离散元和车轮离散元,在PFC^3D软件平台建立集料－车轮三维离散元模型;采用模拟静力三轴压缩试验标定集料离散元颗粒微观参数;采用实车足尺试验数据标定车轮离散元颗粒微观参数。利用标定后模型对失控车辆在避险车道制动床上的减速过程进行数值模拟,设计4组数值模拟试验分析失控车辆车轮沉陷深度、停车距离的变化规律。研究成果为避险车道制动床长度设计和集料铺筑厚度设计提供了理论依据,对避险车道设计规范或指南的完善具有指导意义。

Three-dimensional Discrete Element Simulation of Deceleration Process of Runaway Vehicle on Arrester Bed of Truck Escape Ramp

: Due to imperfect design norms or guidelines for China"s truck escape ramp, the ramp with design flaws can easily induce accidents in which the runaway vehicle rushes out of the end of the truck escape ramp or roll over on the arrester bed, seriously threatening the driver"s life. Previous studies have not been able to reflect the effect of wheel subsidence deformation on the deceleration of runaway vehicles. Therefore, this paper starts from the particle level and uses the discrete element method to establish the gravel discrete element and the wheel discrete element, establishing a three-dimensional discrete element model of aggregate-wheel on the PFC^3D software platform; The simulated static triaxial compression test is used to calibrate the microscopic parameters of the aggregate discrete element particles; The microscopic parameters of the wheel discrete element particles were calibrated using real vehicle full-scale test data. The deceleration process of the runaway vehicle on the arrester bed of the ramp is simulated by the calibrated model. Four sets of numerical simulation tests were designed to analyze the variation law of wheel subsidence depth and stopping distance of runaway vehicles. The research results provide a theoretical basis for the design of the arrester bed length and the thickness of the aggregate pavement in the truck escape ramp, which is of guiding significance for the improvement of design norms or guidelines for the ramp.