Research On Design And Dynamics Performance Of High-speed Gauge Changeable Bogie

With the increase of cooperation between China and Eurasian countries,the connectivity of the Belt and Road infrastructure has become a focus of attention.The 400 km/h High-speed Gauge Changeable EMU project was officially launched as a national R&D program in October 2016.The gauge changeable bogie has a lateral locking mechanism.During the operation period,the wear of clearance surface between wheel and axle will causes more intensified vibrations,which affect the safety vehicles with changeable gaugie.This investigation focuses on the design of high-speed gauge changeable bogie and the automatic gauge changeover facility,strength check of key mechanism and dynamic performance of the vehicle.The main researches are as follows:(1)Based on the design of locking mechanism and the follow-up foundation brake system,the design schemes for high-speed gauge changeable bogie and gauge changeover facility are proposed.The strength of the wheels,axles and splines are checked.When wheel is in curve condition,the maximum stress of wheel web is 141 MPa.When axle is in braking condition or motor short-circuit condition,the safety coefficient of 44 dangerous sections are larger than 1.The maximum stress is 4.3 MPa when the maximum acceleration input torque of motor is 1550 N·m.(2)Based on design parameters and considering the clearance and friction factors,this investigation establishes the lateral dynamic differential equation model with 6-dof wheelset and 9-dof semi-vehicle.The maximum lateral acceleration of wheel is 1.2 m/s2 and the change of the distance between backs of wheel flanges is less than 3 mm.According to the analysis of transverse limit of wheel in five steps,displacement response and acceleration response of wheel and axle are investigated when train passes through the gauge changeover facility at different speed level,and the passing speed is determined to be less than 15 km/h.(3)Considering non-linear factors such as clearance contact stiffness and air spring,the SIMPACK dynamics simulation model for the gauge changeable vehicle is established.The vibration transfer of three radial contact models and two rotational contact models are compared.The Hertz model and Bushing model are selected for radial contact and rotational contact respectively.Based on different track boundary conditions,the dynamic calculation results of four tread types and three rail types are calculated,and the LMB10 N tread is selected as the design wheel tread.Using LMB10 N tread,the critical speed of the vehicle is higher than 600 km/h.When the velocity is less than 400 km/h,the model can provide good dynamic performance.(4)The influence of environment lubrication on the stress distribution of contact surface is analyzed,with the change of clearance contact parameters.Based on the standard gauge railway in China,the influence of clearance parameters on the dynamic performance is investigated using the LMB10 N tread and the CN60 rail.The influence of rotational clearance on stability,radial clearance on vertical force and derailment safety is significant.Comparing three wheelset conditions with no clearance,with initial clearance and with larger clearance,the difference in vehicle vibration transfer characteristics are analyzed.After adding initial clearance,the vibration of axle and frame becomes worse,and the wheel rotation rate appears in vibration acceleration of the radial contact in wheel.When the clearance increases to a certain value,the vibration of each structure increases sharply.