钢弹簧故障状态的车辆动力学性能

考虑了车辆导向轮对一侧轴箱钢簧出现失效的四种工况: 钢簧内外圈均断裂、外圈断裂、内圈断裂和钢簧“冻死”, 建立了钢簧失效工况下的车辆系统动力学模型, 分析了钢簧失效对车辆动力学性能的影响。仿真结果表明: 钢簧失效后, 轮对的平衡位置偏离轨道中心线, 全断裂工况下偏离最大, 约为3mm; 车辆的临界速度降低, 全断裂工况下降低最大, 约为30km·h^-1;失效弹簧所在轮对的轮载差变化较大, 全断裂工况下轮载差最大, 约为50kN; 转向架断裂弹簧处及其斜对角轴箱悬挂垂向力将减小, 另一对角处的轴箱悬挂垂向力将增大, 从而使转向架承受较大的扭曲载荷; 钢簧失效很容易使脱轨系数和轮重减载率等安全性指标超过限定值, 增加了车辆运行安全的隐患, 在直线上200~300km·h^-1速度范围内和曲线(半径为7 000m)上100~300km·h^-1速度范围内, 全断裂工况下的减载率都超过0.8;钢簧失效对车辆横向平稳性影响不大, 但钢簧“冻死”会使垂向平稳性变差, 相对于正常工况, 在300km·h^-1时增加约0.1。

Vehicle dynamic performance under steel spring failure conditions

Four failure cases of axlebox steel spring for one side of leading wheelset were considered, namely: the inner and outer rings of steel spring both fractured; just the outer ring fractured; just the inner ring fractured; the whole spring frozen.Then vehicle dynamics model considering the failure cases was set up, and the influence of spring failure on vehicle dynamics performance was analyzed.Simulation result indicates that when the spring is in failure conditions, the equilibrium positions of wheelsets deviate from track center line, the critical speeds of vehicle reduce, the deviation and decrease are largest when the inner and outer rings of steel spring both fracture, and their largest values are about 3mm and 30km·h-1 respectively.The wheelset with failure spring has larger wheel unloading, the value is largest in the both fractured case and is about 50 kN.For the bogie, the vertical suspension forces decrease at the positions of failure spring and its diagonal axle box, while the vertical suspension forces increase at the positions of another diagonal axle boxes, which results in large torsion force acting on the bogie.Spring fracture more easily brings the safety indexes(such as derailment coefficient and wheel unloading rate)to exceed their limit values, which greatly increases the safety risk of vehicle operation.When the ranges of speed are 200-300km·h-1 on straight track and 100-300km·h-1 oncurved track with radius 7 000 m, wheel unloading rates in both fractured case are greater than 0.8.The spring failure has little influence on the lateral riding performance of vehicle, but spring frozen failure will worsen the vertical riding performance of vehicle, and it increases by 0.1when vehicle speed is 300km·h-1 compared with normal vehicle.