| With the accelerating process of the well-off society in an all-round way, it requires the speed of railway system constantly improving, train load increasing. At the same time the wheel-track force increases sharply, running stability and safety decline, and even parts of locomotive track could be fatigue failure, serious deformation, wear. In order to solve these problems, the vehicle/track coupling dynamics develop rapidly in recent year. But as a big system, containing many degrees of freedom, in order to give prominence to the analysis of some problems, it needs the necessary simplification. At present, the locomotive car-body structure in the vehicle/track coupling dynamics is analyzed less, used simplified mass in large systems. In order to analyze the vibration of locomotive more comprehensive and accurately, it is necessary to establish a more detailed locomotive/track coupling model.This paper first reviews the development and current status of the vehicle/track coupling dynamics, and then a special locomotive/track vertical coupling model is established. In this model the locomotive body’s space internal structure can be considered, the added mass of the equipment can also be contained. This paper focuses on the comparison of the accuracy of calculations by using different beam element, compares the chassis load-bearing with the whole load-bearing to the strength of the locomotive, and computes the function and simplification of the locomotive skin. By using the contact spring instead of the wheel/rail vertical relationship, wheel/rail contact model is established, and the wheel/rail vertical spring stiffness is calculated. Some factors which effect on the contact zone, as rail bending, friction and ballast bed, can be analyzed. In this model the cycled sleeper can also be considered which effect on the wheel/rail vertical stiffness. On the basis of the locomotive/track coupling model, the dynamic response of the locomotive/line coupling system which works at ideal cosine irregularity or cycled irregularity can be discussed. This paper systematically sums up the influence of cosine irregularity parameters on the wheel/rail vertical forces, such as cosine irregularity wavelength, wave depth, the locomotive running speed, etc. Some of the situation that on both sides of the rail has different cosine irregularity which effect wheel/rail vertical force should be discussed carefully. This paper also analyses the influence of cycled irregularity parameters on the locomotive vibration, such as eccentricity and eccentric phase difference. Finally, the influence of the rigid and elastic rail on locomotive vibration can be contrasted.The simulation shows that if the locomotive model is established with the second order interpolation Timoshenko beam or the third order Euler beam the calculation is not affected by the grid size. However, using first-order interpolation Timoshenko beam, calculation precision is influenced by the grid size seriously. Locomotive integral bearing strength is greatly superior to chassis bearing strength from the simulation. Locomotive’s skin structures have played an important role to strengthen, which should not be completely ignored. In order to reduce the degree of freedom model, the method of simplified skin is effective.Friction and material of the plastic deformation are taken into account, the influence of cycled sleeper also is considered. So the spring stiffness which is calculated by Wheel/rail contact is more reasonable than the spring stiffness calculated by Hertz nonlinear theory.When both sides of the rail has different cosine irregularity, wheel load will be reallocation and the dynamic response of the coaxial wheels will mutual influence that lead to surge the wheel/rail vertical force and locomotive torsion. Periodic force caused by eccentric wheel has little impact on the wheel/rail vertical force; Eccentricity and eccentric phase difference are able to slightly increase the vertical wheel/rail force. Contrasting rigid with elastic rail, the vibration of locomotive bogie is different no matter form or peak. However, this effect can be ignored to locomotive body. |
