Study On Shoulder Wear Mechanism And Control Method Of Straddle-type Monorail Trains' Running Wheel Tires

Due to the multi-wheel bogie of the straddle-type monorail train,the shoulder wear of running wheel tires is very severe under curve negotiating,which leads to the decrease of running wheel tires' service life and the huge cost of replacing tires.Besides,the shoulder wear could significantly reduce tires' adhesion performance,resulting in poorer curve negotiation performance,lower drive efficiency and longer braking distance.Therefore,it is necessary to study shoulder wear mechanism and control method of straddle-type monorail train's running wheel tires.A 3D finite element(FE)model of single running wheel tire is developed using ABAQUS software.In order to verify the accuracy of the present model,tire vertical stiffness test,lateral stiffness test and tire contour geometry measurement are designed.Then,tire static,steady-state and dynamic cleat tests are modeled.Finally,data like vertical stiffness and cornering stiffness are derived.Based on the data derived from FE simulations,FTire model parameters are identified and then validated by comparing the force responses of FTire simulation in ADAMS/Tire testrig and FE simulations.The results show that there is an acceptable agreement between them,reflecting that the method is feasible.A 3D FE model of two running wheel tires is developed for wear prediction,and the friction work and its skewness are chosen as evaluation indexes of tire wear and shoulder wear.Then using FE method to study running wheel tires' wear and shoulder wear properties under both straight line free-rolling and cornering conditions.Besides,the effect of tire load,speed and slip angle on wear and shoulder wear are studied.Also,the relationship of tire grounding characteristics and tire wear and shoulder properties as well as tire shoulder wear mechanism are investigated from the prospect of the contact properties between running wheel tires and track beam surface.It shows that the inside running wheel tire's wear and shoulder wear are a bit severer than those of the outside running wheel tire.Besides,the wear amount is proportional to tire load and speed.Compared with tire load,its speed and slip angle have more noticeable impact on the wear and shoulder wear properties.The last but not least,there is a strong correction between grounding characteristics and the wear and shoulder wear properties.In order to explore the control method of running wheel tire's shoulder wear,the contact pressure distribution and contact patches under pure slip angle and virtual camber angle are compared.Besides,the virtual camber method is put forward to reduce running wheel tires' wear and shoulder wear.According to the wear and shoulder wear properties under virtual camber conditions,the curved running surface method is proposed to optimize the virtual camber method.It shows that there is a strong reciprocal compensation between both the contact pressure distribution and contact patches under pure slip angle and virtual camber conditions.The virtual camber method is capable of reducing running wheel tires' total wear amount,but the shoulder wear of the outside running wheel tire is much severer.Compared with the virtual camber method,the curved running surface method could not only reducing the total wear amount,but also effectively relive the shoulder wear of both inside and outside running wheel tires.