车轮谐波磨耗对轮轨蠕滑特性的影响分析

为探究车轮谐波磨耗对轮轨间蠕滑特性的影响,建立了4种不同轮轨关系下的车辆-轨道耦合动力学模型。基于多体动力学理论,以实测车轮谐波磨耗为依据,对比分析了4种模型的轮轨振动特性,得到最能反映真实情况的轮轨关系模型。基于柔性轮轨分析车轮谐波磨耗对轮轨蠕滑特性的影响,并进一步探究谐波磨耗下扣件刚度和速度对蠕滑特性的影响。结果表明:柔性轮下的振动响应要高于刚性轮,而刚性轨下的振动响应要大于柔性轨。其发生机理表现为柔性体的固有模态与谐波激励频率相近引发模态共振,使得柔性体的振动响应大于刚性体。对比分析结果表明多柔体更能反映轮轨真实接触状态;车轮谐波磨耗的阶次和幅值对柔性轮轨关系下的蠕滑特性影响显著,整体呈现出随阶次和幅值增大而增大的趋势,且高阶次下,幅值对蠕滑特性的影响更加显著。进一步发现扣件刚度对蠕滑特性的影响与速度呈现相关性,当速度低于250 km/h时,扣件刚度对蠕滑率/力的影响并不显著,但仍呈现出随刚度增大而减小的趋势;当速度高于300 km/h时,扣件刚度对蠕滑率/力的影响比较明显,呈现随刚度增大而增大的趋势。

Effects of harmonic wear of wheels on creep characteristics of a wheel-rail system

Four vehicle-track coupling dynamics models of different wheel-rail relations were established to study the influence of harmonic wear of wheels on the creep characteristics between wheels and rails.Based on the multi-body dynamics theory,the vibration characteristics of the four models were compared and analyzed on the basis of the measured harmonic wear of wheels,and the wheel/rail relationship model that could best reflect the real situation was obtained.Based on the analysis of the impact of harmonic wear on the wheel-rail contact characteristics,the impact of the fastener stiffness and velocity on the creep characteristics under the harmonic wear was further explored.The results show that the vibration response of the flexible wheel is higher than that of the rigid wheel,and that of the rigid rail is higher than that of the flexible rail;the mechanism is that the intrinsic mode of the flexible body is close to the harmonic excitation frequency,which causes the modal resonance and makes the vibration response of the flexible body greater than that of the rigid body;the analysis results show that the muti-flexible body can better reflect the real contact state of wheel-rail;the order and amplitude of harmonic wear of wheels have significant influence on the creep behavior of flexible wheel-rail relationship,and the overall trend increases with order and amplitude,and the effect of amplitude on the creep behavior is more significant in higher order.It is found that the influence of the fastener stiffness on the creep behavior is correlated with the velocity;when the speed is less than 250 km/h,the impact of the fastener stiffness on the creep rate/force is not significant,but still shows a trend of decreasing with the stiffness;when the speed is higher than 300 km/h,the impact of the fastener stiffness on the creep rate/force is obvious,which shows a trend of increasing with the stiffness.