铁路重载货车轮对弹性振动及其动态影响

为研究轮对弹性振动特性及其对重载货车动力学性能的影响，以30 t轴重重载货车为研究对象，对轮对刚、柔建模时的整车运动稳定性、曲线通过性能等进行了对比研究. 首先，给出了多体动力学中弹性体的数学建模方法；其次，建立轮对柔性体有限元模型，分析了轮对的弹性振动模态，进一步将其集成于多刚体系统中，形成重载货车刚柔耦合动力学分析模型；最后，针对货车多刚体和刚柔耦合两类建模方法，以干线不平顺叠加短波不平顺作为系统激励源，对比分析了重载货车的轮对振动响应、蛇行运动稳定性以及动态曲线通过性能的差异. 研究结果表明:相对刚性轮对而言，柔性轮对的变形能够缓和轮轨刚性冲击，同时弱化轮轨间的刚性约束能力，导致其振动幅度降低，使得车辆非线性临界速度下降约9%，通过小半径曲线时，轮轨横向力也降低了约13.7%，轮对弹性振动对重载货车动态性能的影响同样不容忽视. 

Elastic Vibration of Wheelset and Its Dynamic Effect on Railway Heavy-Haul Freight Wagon

To study the characteristics of wheelset elastic vibration and their effect on the dynamic performance of heavy-haul freight wagon, a railway wagon with a 30 t axle load is considered as the research object in this work. The running stability and the curving performance of vehicle are investigated in a comparative manner. First, the mathematical modeling method of elastic body based on multi-body dynamics is presented. Then, a finite element model of wheelset’s flexible body is established, and the elastic vibration modes are analyzed. The flexible wheelset is integrated in to the multi-rigid-body system, which then forms the rigid-flexible coupling dynamic model of heavy-haul wagon. Finally, for the multi-rigid body and rigid-flexible coupling modeling methods used for the wagon, the differences in wheelset vibration responses, running stability, and curving performance characteristics determined by these methods for a heavy-haul wagon were compared when using the main-line track irregularity with short-wave irregularity as the excitation source. The research results indicate that the deformation of elastic wheelset can alleviate the wheel-rail impact and also weaken the wheel-rail rigid restraining effect when compared with rigid wheelset. Therefore, the vibration amplitude for the flexible wheelset is reduced and the vehicle’s nonlinear critical speed is decreases by 9%. In sharp curves, the wheel-rail lateral force of flexible wheelset is reduced by 13.7%. The influence of wheelset’s elastic vibration on the dynamic performance of the heavy-haul wagon thus can not be ignored.