Optimization of superelevation runoff model for cycling tracks

To improve the possible superelevation runoff models for the cycling track design, at first, two existing representative superelevation runoff models used in China were investigated and fitted. Then, an optimization methodology was proposed, which was focused on the track geometry itself, without the consideration of the physical characteristic of the cyclist, assuming that less vertical curvature values correspond to less riding time. The riding performance formulae were obtained with the variables of riding time, riding velocity and vertical curvature of cycling track. Finally, with the refined adjustment on the vertical curvatures with the help of cycling track design software and considering the effect of horizontal alignments, the optimized models were finalized. It is clearly seen that these optimized models take the form of quartic parabola and are verified to achieve 0.005–0.021 s improvement in the event of 200 m time trial.     

平面设计中横向力系数与舒适度关系的探讨

道路路线设计规范在定义极限圆曲线半径时,把横向力系数作为衡量车辆稳定性的一个重要因素。通过车辆动态模型仿真车辆在同一圆曲线不同横坡上行驶,表明乘客的舒适度感受与横向力系数是不等同的,车辆轮胎与地面的横向力系数随着超高横坡的变化而变化。仿真结果发现比现行设计规范中所设超高极限圆半径值增加约10%才能满足车辆最不利轮胎处的横向力系数要求。