国家自然科学基金重点项目 高速、.ppt

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1、(一）轮轨型面和材料优化匹配（车辆稳定性） (二）轮轨滚动接触疲劳和磨损(波磨) (三）轮轨粘着和材料强度 (四）脱轨 (五）轮轨滚动接触噪声 (六）滚动接触基本理论,轮轨关系问题的研究,蛇形运行条件下轨枕间距对直线钢轨波磨形成的影响,金学松 大连交通大学 交通运输工程学院西南交通大学 牵引动力国家重点实验室2007. 1. 17,1. Introduction,R. A. Clark (British, 1980s),R. A. Clark P. A. Dean J. A. Elkins S. G. Newton,Journal of Mechanics Engineering Scienc

2、e 24(1982),Rail,Sleeper,直线压痕波磨,电车直线轨道波磨,欧洲高速线上短波波磨,广深高速线长波长波磨,S. L. Grassie J. Kalousek,Proc. Institution of Mechanical Engineers 207 (Part F), 1993,Such a type of corrugations was referred to as roaring rail corrugation, and attributed to wear mechanism and the concerned factors including vertical

3、dynamical loads, the creepages between wheel and rail. Usually, the misalignment and rolling-slip of wheelsets occur when the wheelsets hunting a tangent track, the lateral and longitudinal creepages between the wheels and rails become larger. It can be predicted that the larger conformity and conta

4、ct angle between wheel and rail leads to the larger spin creepage and the severe wear between them.,D. K. Ahlbeck L. E. Daniels,Proc. 1990 ASME Joint Railroad Conference,Transit/Passenger corrugations show characteristic grouping in their development. These short wavelength corrugations mainly group

5、ed in the second half sleeper bay and near the peak of wheelset kinematical hunting.,Normal Load Fluctuating,Creepage Fluctuating,Constant Normal Load,Constant Creepage,Corrugationdue to Plastic Deformation,Basic Factors AffectingRail Corrugation Initiation,Corrugationdue to Material Wear,2. Corruga

6、tion Model,2.1 Model of Passenger Car and Track (Before),(b) Elevation,(a) Side Elevation,Model of Passenger Car and Track (Now),(a) Side Elevation,(b) Elevation,Improvement 1: Vertical Bending Restricted by Fastening Systems,Improvement 2: Backward Moving of Fastening System,The two ends hinged,Ind

7、ependent Second Partial Equations for Beam in Vertical, Lateral and Torsional Directions,Backward MovingCoordinates of Sleepers,Equivalent Loads on Rail,Fastening System,Force Diagram of Rail,基本思想,2.2 Model of Rolling Contact,Mesh Size: 0.80.8 mm2,2.3 Model of Rail Material Wear,2.4 Contact Model of

8、 Wheel and Rail,Model for Normal Load:,CH =1.131011 N/m (Hertzian Contact Spring Coefficient),Zwnk, Zrnk The Normal Distance of Wheel and Rail,0 The Normal Approach of Wheel and Rail,Uw The Depth of Undulatory Wear,Model for Tangent Load: Creep Force Model by Shen et al,2.5 Contact Geometry of Wheel

9、 and Rail,Boundary Conditions: (1) At Beam Ends:,3. Results and Discussions,Initial Conditions: (1) (2),(2) For Ballasts:,3.1 Initial and Boundary Conditions of System,3.2 Values of Parameters of Model,Number of Sleeper Spans: 120Number of Mode Functions: 120Track Gauge: 1435 mmRail Cant: 1/40Sleepe

10、r Pitch: 600 mmRail Type: 60 kg/m,The Other Parameters Shown inX. S. Jin et al. Journal of Sound and Vibration. 293(2006): 830-855 X. S. Jin et al. Wear. 260(2006):619-633,3.3 Dynamics Characters of System,For the first initial condition and v=40240 km/h,Linear Damping System of A Single-Degree-of-F

11、reedom:,n: Resonant Frequency of System : Excitation Frequency,(a),(b),(c),(d),When n , the amplitude increases,When n , 0,Vertical Dent Excitation:,dp=0.1 mm, ld=30 mm,Linear Spectrums of Fluctuating Normal Loads,447 Hz,800 Hz,1222 Hz,1430 Hz,increases,increases,varies in a limited range,Wavelength

12、-fixing Mechanism,Corrugation Wavelength:,Enlargement of Local Area B,(1) For 40 km/h, f s=19 Hz ( 0, The peaks after the sleepers and the large amplitude.(2) For 80 km/h, the very small peak at f s=37 Hz, f s less than and far away from f c and f d 0, the peaks after the sleepers and the small ampl

13、itude.(3) For 120-240 km/h, f s increases with the speed increasing. f s less than and far away from f c , f d , f c and f d 0, the peaks after the sleepers and the amplitude increasing with the speed increasing.,3.4 Rail Corrugation,For the second initial condition and v=40240 km/h,Lateral Displace

14、ments of Wheelsets,Right Side,Left Side,Yaw Angles of Wheelsets,Longitudinal Creepages of Wheelsets,Lateral Creepages of Wheelsets,Enlargement of Local Area near Peak B,Maximum Depth of Corrugation Caused by Wheel 2,Enlargement of Local Area C,Pattern of Corrugation Caused by Wheel 2,The track model

15、 was further improvedThe discrete support by sleepers causes the normal load vibration with small amplitude; The different speeds leads to the different amplitudes and the different phase.The speed increasing excites the larger resonant frequencies of the system, therefore, the corrugation wavelengt

16、h varies in limited range. Such a situation explains the wavelength-fixing mechanism of corrugation.The severe vehicle hunting cause the lateral creepage vibrating at the sleeper passing frequency and the higher resonant frequency of the track when the wheelsets pass the center of the track laterally. Namely, at the peaks of the yaw angle, the corrugation initiates and develops, and also extends along the tangent track. The wear grows fast over sleepers.,4 Conclusions,Thanks,Thanks,Thanks,Thanks,Thanks,