| With the increase of the demand for transportation,increasing the axle load of wagons has become an effective way for railway transportation organizations at home and abroad to increase traction weight.However,as the axle weight increases,the wheel-rail dynamic interaction will be intensified,and the traditional design system of heavy haul railway will not fully meet the safety and economic requirements of larger axle load transportation.At present,many countries are actively promoting the research work of large-axle load heavy haul railways,and a few countries such as Australia have taken the lead in the operation of 40 t axle load heavy haul trains.Rich experience in 30 t axle load heavy haul railway has been accumulated in our country,but we still lacks the design and technical reserves of 35 t to 40 t axle load heavy haul railway.In this thesis,the key parameters of plane and profile which are applied to the heavy haul railway of 40 t axle load are studied systematically from the perspective of improving running safety,mitigating wheel-rail wear and fatigue damage,and the reasonable value of each parameter is present,with the purpose of providing the technical support for the parameters design of plane and profile of 40 t axle load railway.According to domestic and foreign practical experience and relevant specifications,the design principles and value ranges of the plane and profile parameters are analyzed in this thesis,the structural characteristics of the 40 t axle load wagon and coupler and draft gear are described.A calculation model of the 40 t axle load four-wagon formation train is established based on the multi-body system dynamics software UM,and the wheel-rail dynamic performance indexes used to evaluate the running safety,wheel-rail wear and fatigue damage are selected.Using the established four-wagon formation train model,the change trend of the running safety,wheel-rail wear and fatigue damage of the 40 t axle load wagon on circle curve segment under different curve radius and unbalanced superelevation is studied.The dynamic response of 40 t axle load wagon on the transition curve segment of different lengths is investigated,especially the variation of the wear and damage performance at the beginning point and the ending point of circular curve.The effects of the length of the straight line between reverse curves and the slope section between vertical curves as well as the radius of the vertical curve are explored,and the reasonable values of the first two parameters are further analyzed by combining with the design requirements to avoid vibration superposition.In addition,the influence of different longitudinal press forces is also considered in the safety assessment of plane and profile parameters.The results show that as the radius of curve increases,the wheel-rail dynamic interaction decreases accordingly,and the same trend to all indexes of the running safety,wheel-rail wear and fatigue damage.Appropriate deficient superelevation can not only decrease the wheel-rail interaction force,improve the safety of train operation,but also enhance the ability of the wheelset guiding,and reduce the wheel and rail wear and fatigue damage.The vertical performance of wagon is mainly influenced by the radius of vertical curve,and the increment and reduction(for concave and convex vertical curve)amplitude of wheel-rail vertical load and the vertical acceleration of vehicle body decrease significantly during the process of increasing the radius of vertical curve from 1000 m to 3000 m.The suitable length of the straight line between reverse curves and the slope section between vertical curves could greatly damp the vibration response of wagon and effectively improve the running safety.The minimum circular curve radius,vertical curve radius,the shortest straight line between reverse curves,the slope section between vertical curves and the superelevation ramp rate are recommended to be 1200 m,10000 m,50 m,25 m,1.5‰～1.6‰. |
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