Rack Vehicle-Track Coupled Dynamics Model And Dynamic Characteristics

In recent years,rack railway has been introduced into major tourist attraction in China for large slope and complex terrain in mountainous areas,and large-scale planning and construction have been made for it.Although the gear-rack transmission system greatly improves the climbing ability of rack vehicle,the meshing operation of the gear-rack will produce significant impacts and vibrations,seriously affecting the operational performance of the rack vehicle.In order to study the basic dynamic characteristics of rack vehicle,this paper establishes a rack vehicle-track coupled dynamic model of based on the theory of vehicle-track coupled dynamics and gear dynamics.The basic dynamic characteristics of rack vehicle are analyzed,and the effects of slope and irregularity of rack railway on the dynamic characteristics of rackvehicles are studied.Relevant optimization suggestions are made.The specific work is as follows:Firstly,based on the structure of the Strub system and the theory of vehicle-track coupled dynamics and gear dynamics,a rack vehicle-track coupled dynamic model is established.Among them,the vehicle model is considered as a 48 degree of freedom multi rigid body system.The Timoshenko beam model is used for both the steel rail and rack in the track model.In the contact model,the wheel-rail is a spatial dynamic coupled model,and the gear-rack system is a bending torsion coupled model that considers friction,elastic and viscous.And the effectiveness and accuracy of the coupled dynamic model are verified through the line test.Next,based on the different motor arrangement modes of rack vehicles,the basic dynamic characteristics of rack vehicle are studied based on the coupled dynamic model established in this paper.The results show that the main frequency of gear vertical acceleration vibration on the straight section is between 44.3 Hz and 52.2 Hz.The gear vertical vibration frequency on the climbing section is mainly the intermediate frequency vibration of 35.6 Hz,36.7 Hz,and 88.3 Hz.Then,based on the rack vehicle-track coupled dynamic model,a comparative analysis is conducted on the random vibration laws and reference frequencies of various important components of rack vehicle at a slope of 0 ‰-300 ‰.The influence of different line slopes on the dynamic characteristics of rack vehicle is studied.The results indicate that the slope has a small impact on the random vibration of the carbody,bogie and wheelsets,but a significant impact on the vibration and meshing characteristics of the gear system.Finally,the dynamic response mechanism of rack vehicle under random track irregularity excitation is studied.The adverse effects of track irregularity on the gear-rack system are analyzed in depth.The results indicate that the random irregularity of the track has a significant impact on the vibration characteristics of the rack vehicle and the gear-rack meshing system.The vibration and meshing characteristics of the gear-rack system are mainly affected by the irrgularity II(latral irregularity,gauge irregularity).It is recommended to improve the stability of the gear-rack system by reducing the irrgularity II.