一系螺旋弹簧动刚度对车辆-轨道耦合振动影响分析

建立准确表征一系悬挂轴箱螺旋弹簧波动特性的力学模型，运用动刚度矩阵法求解，研究其对悬挂系统隔振性能影响。结合基于格林函数法的车辆-轨道耦合动力学模型，引入弹簧刚度频变特性，对比分析考虑一系螺旋弹簧频变刚度前后车辆动力学性能之间的差异。结果表明，动刚度矩阵法可以精确求解螺旋弹簧随频率变化的动刚度特性，在一阶模态振动频率后弹簧刚度值呈现103等级的剧烈变化，该结果与有限元模型结果一致；一系螺旋弹簧的动态频率特性导致轮轨激励由车轮至构架的振动位移传递率提高到接近于1，而对车体的振动传递率提高到了10-3左右；在整车车辆-轨道动力学计算中，其对轮轨振动影响较小，但车体与构架出现了较高的高频振动能量峰值。包含一系悬挂动刚度的车辆模型更接近实际，为了降低车辆振动，应尽量提高一系螺旋弹簧自振频率并降低动刚度变化幅值。  

Analysis on Influence of Dynamic Stiffness of Primary Suspension on Vehicle-track Coupled Vibration

The dynamic model of helical spring in axle box of primary suspension, which is solved with dynamic stiffness matrix method, is established to get its dynamic stiffness for studying the effect of waves propagating in helical spring on vibration isolation performance of primary suspension. Then, the dynamic stiffness characteristics are introduced into the vehicle-track coupled dynamic model solving with Green’s function method for comparing the dynamic performance difference between constant stiffness and dynamic stiffness models. Results show that the frequency-dependent stiffness could be calculated efficiently by dynamic stiffness matrix method and the spring stiffness shows dramatic changes in the thousand fold after the first modal vibration frequency. This result is verified with finite element method. This change results in high vibration displacement transmission rate of both car body and bogie from wheel at high frequencies, which are about 1 and 10-3 respectively. There are lots of vibration peaks at high frequencies for car body and bogie during vehicle-track coupled dynamic simulation, which are much stronger than wheel or rail. Vehicle model including dynamic stiffness of primary suspension spring is more realistic. Therefore, as for reducing vehicle vibration, the modal frequency of spring should be improved and the change of dynamic stiffness amplitude should be lower.