Research On Running Stability Of Heavy Haul Vehicles Under Longitudinal Force

Since the 21 st century,the rapid development of China’s national economy,the rapid increase in the volume of bulk cargo transportation,put forward higher and higher requirements for railway freight capacity.Therefore,the development of heavy haul railway transportation has become the inevitable way of railway freight development.In the process of carrying out heavy haul railway transportation,there are many problems,among which the running stability of freight cars is a very important subject.The running stability mainly includes lateral stability and vertical stability.In this paper,the influence of longitudinal force on the running stability of heavy haul vehicles is studied.This paper collects,analyzes and processes the experimental data of longitudinal coupler force of a heavy haul line,obtains the corresponding longitudinal force acting on the heavy haul freight car,and loads it into the model to analyze the stability index under various operating conditions.Using SIMPACK dynamic simulation software and multi rigid body system dynamics theory,the dynamic models of single vehicle and two vehicles of C80 heavy haul vehicle are established.Two kinds of different lines,straight line and curve,are established,and the U.S.five level track spectrum is used as external excitation.SIMPACK software is used to program the evaluation method to realize the rapid calculation and result display of train stability index under different working conditions.The longitudinal force is applied to several operating conditions,such as single section vehicle running at different speed in straight line;single section vehicle running at constant speed on curve;two section vehicle with empty and loaded vehicle running at constant speed on curve.In this paper,the lateral and vertical stability of single empty car and heavy vehicle running on straight line and curve are compared,and the difference of vehicle stability under different working conditions under the action of longitudinal force is analyzed.The results show that when the longitudinal force is applied to a single car and a two car vehicle running at different speeds in a straight line,the ride comfort of the empty car is not affected much,but the stability index of the loaded vehicle will be significantly increased by7% and 10% respectively.When a single car or two section vehicle is running at a constant speed on the curve,the stability of empty vehicle will not be affected obviously,but the stability index of heavy vehicle will become larger,which will affect the evaluation grade of stability index.The increase range of stability index is 15% and 11%.For the empty and heavy vehicles,the stability is affected,and the heavy vehicle is more affected.In this simulation test,we can see that the influence of longitudinal force on the stability can not be ignored.