Train Dynamic Response And Riding Comfort Evaluation Considering Non-circular Wheel Sets

With the increasing speed of trains such as bullet trains and high-speed rail,the dynamic effect between wheel sets and tracks of trains is increasing,and the wear rate of wheel sets is accelerating.The non-circular wheel sets will reduce the service life of the vehicle and track components,and seriously affect the comfort and safety of the train.In addition,the rapid development of social economy also makes people more and more strict for comfort.In this study,the vibration response and occupant comfort of equivalent occupant train track system under the excitation of non-circular wheel sets are studied as follows:(1)Trace back to the causes of wear wheel sets and some common wear forms and the polygonal non-circular wheel sets are analyzed emphatically.At the same time,some comfort research,especially the existing simple and complex occupant model are introduced.Based on the traditional 10-degree-of-freedom(DOF)train model,considering the impact of the occupants by using the equivalent human body 7DOF complex model,a time-varying calculation model of 31 DOF human-vehicle-line-bridge was finally established.The vibration equation of the system is derived,and the iterative solution process of the nonlinear contact problem of wheel rail under the action of worn wheel set and the adaptive solution algorithm of dynamic element are described.(2)Based on Visual Studio 2018 interactive software development platform and FORTRAN language,the 31 DOF equivalent human-vehicle-line-bridge system dynamic analysis program version 2.0(Vehicle Structure Dynamic Analysis Program 2.0 VSDAP2.0)with independent intellectual property rights was developed.Compared with the existing 13 DOF model,the 31 DOF model is verified to be effective,and compared with the field data,the correctness of the independent program is verified.(3)The vibration response and comfort of wheel-rail contact force,equivalent human body,vehicle body and line under the excitation of wheel sets wear studied and the influences of the order,the amplitude and the speed of the train on the vibration response of the system are analyzed by using VSDAP.The results show that increasing one single factor will not cause the constant increase of the vibration response of the train and human body.Through a large number of simulation data and the principle of main effect,it is found that the wave depth has the greatest impact on the comfort of passengers,followed by the order,and the least impact on driving speed.The analysis results show that the vertical acceleration of the front equivalent human body is significantly higher than that of the vehicle body under the excitation of low-order and low wave depth wear wheel sets.Therefore,the ride comfort should be evaluated by the vibration response of the equivalent human body rather than the vehicle body.This study can provide theoretical and practical significance for the relevant analysis of train wheel wear and train vibration response.