Research On Matching Relationship Between Axle Load&Running Speed Of Heavy Haul Freight Wagon

With its comprehensive advantages such as the large transport capacity, low energy consumption, light pollution, less occupation of the land and high safety, the heavy haul railway has been developed rapidly all over the world. To achieve heavy haul transportation mainly has two ways, one is to enlarge the number of the train, and extend the length of the train; the other is to increase the axle load, and develop heavy haul freight car. The model of Chinese railway freight transport is equally development of the running speed and heavy load, to fully improve the transport capacity of the railway lines. However, with the running speed or the axle load increasing, the wheel/rail interaction forces accordingly increase to damage the track structure and the railway line, and increase the costs of freight car manufacture and track maintenance, finally reduce the whole benefits of heavy haul transportation. Therefore, research on the wheel/rail dynamic interaction of the heavy haul freight cars to carry out the matching relationship between axle load and running speed is one of the basic research subjects to meet the need of achieving railway heavy haul transportation in China.On the basis of the theory of vehicle-track coupling dynamics, the thesis briefly reviews the domestic and abroad technical development of the heavy haul railway, the history and the current situation of the vehicle-track dynamics and the wheel/rail relationship. According to the structure specialties of the heavy haul freight car and track, and the wheel/rail dynamic interactions, regarding the heavy haul freight car and track as a whole coupling system, on the basis of the vehicle dynamics and track dynamics, considering wheel/rail contact geometry relationship, the numerical simulation method was applied to study the characteristic of wheel/rail dynamic interaction, and to work out the properly matching relationship between the running speed and the axle load of the heavy haul freight cars.The reliability of the simulation results relies on the validity of the model, and the validity of the model depends on the reality of the physical model. At first, considering the structure characteristics of the three-piece bogie, the cross-bracing bogie and the sub-frame radial bogie, the heavy haul freight vehicle-track coupling dynamic model was respectively set up in this thesis. The heavy haul freight car and the track was regarded as a multi-rigid body, the freedom degrees of the car body, the bolster, the side-frame and the wheel-set and various sorts of non-linear factors in vehicle suspension system were fully considered. The cross-bracing linkage bar and the sub-frame radial joint device were simulated separately by the three-dimensional rigidity values, and all the movement parts were analyzed in detail to set up the vibration equations. In the model, rails are modeled as infinite Euler beams laid on three-layer continuous and discrete elasticity supports, the vertical, lateral and torsional freedoms of rails were considered, sleepers, blocks and discrete ballast blocks were modeled as rigid bodies, the vertical, lateral and torsional freedoms of sleepers were also considered, but only vertical freedom was considered for discrete ballast blocks in the thesis.The wheel/rail contact geometry relationship is the linkage joint between vehicle and track. The principle of vehicle-track dynamic analysis on the wheel/rail spatial contact geometry relationship, the Hertz nonlinear elastic contact theory and the wheel/rail tangential creep theory was discussed in detail, the simulation programs were also compiled and debugged in this paper. The low dynamic interaction evaluation index domestic or aboard of the rolling stocks and track were summed up in this thesis such as the wheel/rail vertical force, wheel/rail horizontal force, wheel/rail contact stress, wheel/rail wear power, and acceleration of track structure etc.The dynamical wheel/rail interaction of the different axle load heavy haul freight cars under different running speed and different rail line conditions were simulated and evaluated with the simulation program, and based on the simulation results, the main methods to decrease wheel/rail dynamical interaction and the proper matching relationship between axle load and running speed were proposed, and the advice of running heavy haul freight cars on the extending railway line was also put forward in the thesis.Finally, the structure and dynamical parameters of the heavy haul freight cars were analyzed and optimized in this thesis, and the reasonable range of the values of the parameters was put forward, different types of heavy haul freight prototypes were manufactured and put into testing.