准静态下轮对脱轨安全限值研究

Study on Safety Limit of Wheelset Derailment under Quasi-static Condition

基于准静态下的三维轮对脱轨分析模型,推导轮对脱轨临界状态下的力学平衡方程,建立同时考虑轮轴脱轨系数和轮重减载率的轮对稳态脱轨评价方法。采用Shen-Hedrick-Elkins非线性蠕滑理论充分考虑轮轨蠕滑力对轮对脱轨安全限值的影响。结果表明自旋蠕滑率对轮对脱轨安全限值与安全域影响明显,若忽略自旋蠕滑率的影响,计算得到的轮对脱轨安全限值则偏大,使脱轨安全性评价标准变宽松,对车辆脱轨的评价产生不利影响。研究摩擦系数对轮对脱轨安全限值的影响,结果表明降低轮轨间的摩擦系数对车辆脱轨安全性有利有弊,轮轨间过低的摩擦系数也可能引发车辆脱轨,在确定合理的轮轨摩擦系数时应注意权衡车轮爬轨脱轨与滑轨脱轨。

Based on the quasi-static wheelset derailment analysis model,the mechanical equilibrium equation under the derailment critical condition of the wheelset was deduced.A derailment evaluation method for wheelset was proposed considering the derailment coefficient and rate of wheel load reduction.In this paper,the influence of wheel-rail creep force on the safety limit of wheelset was considered using the nonlinear creep theory of Shen-Hedrick-Elkins.The results show that the spin creep rate has obvious impact on the safety limit value and safety domain of the wheelset.The safety limit for wheelset derailment would be higher if the spin creep rate is ignored,which can cause loose derailment safety evaluation standard and may have adverse impact on the evaluation of vehicle derailment.Reducing the friction coefficient between wheel and rail has advantages and disadvantages to vehicle derailment.The low wheel-rail friction coefficient can also cause the derailment of vehicles.The relationship between wheel climb derailment and wheel slide derailment should be considered during the determination of the reasonable friction coefficient.