摘要
车轮多边形磨耗和钢轨焊缝是轮轨界面重要的激振源,会加剧轮轨动力相互作用,严重时将威胁行车安全.既有研究主要关注单一激励作用下的轮轨动力响应,而多边形车轮通过钢轨焊接区普遍存在,对于两种激励叠加作用下的轮轨动力特性的研究尚不充分.基于此,本文采用高速车辆-板式轨道垂向耦合动力学模型,研究多边形车轮通过钢轨焊接区的轮轨动力响应特征,分析高速行车条件下车轮多边形阶数和波深对钢轨焊接区轮轨动力响应的影响规律.分析结果表明:车轮多边形不平顺变化率最大点与叠合型焊缝不平顺变化率最大点重合时,引起的轮轨动力响应波动幅值最大.多边形车轮通过钢轨焊接区时,在车轮多边形和焊缝不平顺的叠加作用下,产生了更明显的轮轨冲击效应,轮轨垂向力、轮重减载率、轮对垂向振动加速度、扣件力以及钢轨垂向振动加速度均显著增大,而对车体垂向加速度影响较小.高速行车条件下,轮轨垂向动力响应最大值整体上随着车轮多边形阶数和波深的增加而增大,在钢轨焊接区易出现轮轨瞬时脱离现象.
Wheel polygonal wear and rail weld irregularity are important excitation sources of wheel-rail interface,which will intensify the wheel-rail dynamic interaction,posing threats to running safety.Most of the previous research is focused on wheel rail dynamic responses under a single excitation,while the research on the wheel rail dynamic characteristics caused by the superposition of two excitations is not sufficient considering polygonal wheels generally exist in rail weld zones.On the basis of this,a high-speed vehicle-slab track vertical coupled dynamic model was employed,in order to study the effect of polygonal wheels passing through the rail weld zone on the wheel-rail dynamic characteristics.The vehicle-track coupled dynamic model is divided into two subsystems based on the vehicle-track coupled dynamics theory,that is,vehicle subsystem and track subsystem.Originating from the multi-rigid-body dynamics theory,the vehicle is treated as a four-axle mass-spring-damper multi-rigid-body system by taking one car body,two bogies and four wheelsets into account.As a result,the total degrees of freedom of the vehicle are 10.The rail is simplified as a Bernoulli-Euler beam supported by rail pads.The interactions between the vehicle and rail are characterized by the wheel-rail contact.The dynamic equations of motion for the whole system are described by differential equations.In this dynamics simulation,the measured wheel polygonal wear and rail weld irregularity were used to reflect the real running conditions.It should be noted that the complex-wave rail weld irregularity occurring extensively in the rail weld zones was used.The basic feature of the complex-wave rail weld irregularity is that a main 1 m wavelength cosine wave is superposed with a secondary short-wavelengthen wave.Moreover,the influences of the polygonal order and amplitude on wheel-rail dynamic responses were analyzed under the high-speed operation.In this matter,the simple harmonic model was applied to describe the wheel polygon of the single order.In addition,the superposition relationship of the wheel polygonal wear and rail weld irregularity was investigated.The results show that the maximum response occurs at the coincident point where the variation rates of the wheel polygon and the rail weld irregularity are both the maximum.When polygonal wheel passes through the rail weld zone,under the superposition of the wheel polygon and the rail weld irregularity,more obvious wheelrail impact effect is induced,and the high-frequency vibration caused by the measured polygonal wheel is generated.In the rail weld zone,due to the wheel polygonal wear,the wheel-rail vertical force,wheel load rate,wheelset vertical acceleration,fastener force and rail vertical acceleration increase significantly,while the car body vertical acceleration is hardly affected.Under the high-speed operation,the maximum values of the wheel-rail dynamic responses are significantly exacerbated by the increased polygon order and amplitude.In the low orders,the maximum values of the dynamic responses varies slightly with the increase of wave depth,while in the high orders,the maximum values of the dynamic responses increase dramatically with the increased wave depth,which may easily cause instantaneous wheel rail separation.
作者
陈美
翟婉明
閤鑫
孙宇
Mei Chen;Wanming Zhai;Xin Ge;Yu Sun(State Key Laboratory of Traction Power,Southwest Jiaotong University,Chengdu 610031,China)
出处
《科学通报》
EI
CAS
CSCD
北大核心
2019年第25期2573-2582,共10页
Chinese Science Bulletin
基金
国家自然科学基金(51735012)
国家重点研发计划(2016YFB1200401-102C)资助
关键词
高速铁路
车轮多边形
钢轨焊缝
车辆-轨道耦合动力学
轮轨相互作用
high-speed railway
wheel polygon
rail weld irregularity
vehicle-track coupled dynamics
wheel-rail interaction
