Research On The Unsteady Influence Model Of The Heavy Haul Freight Train For Safe Running

Heavy haul freight train are affected by factors such as train speed,traction quality,line factors and train air brake and manipulation.The vertical impulse of train is more and more serious,which directly affects the safe operation of train.It is more meaningful to evaluate the safe operation of heavy-duty trains if the unsteady-state excitation of the air brake system,the line and the dynamic behavior of the vehicle is uniformly loaded into the train running model.Based on the joint simulation model of train air brake and longitudinal dynamics,a longitudinal force transmission model based on the vehicle particle trajectory as the natural coordinate system is established.The coordinate of the vehicle body and the coupler is constructed into the vector,and the size and direction of the hook angle are solved by the quantity product and the vector product method respectively.Based on the interaction between the buffer and the coupler,the lateral and vertical component of the coupler are solved.And the Runge-Kutta method is used to solve the dynamic behavior of the vehicle body and the angle of the coupler.According to the derailment evaluation index of single wheel,the safety evaluation method for train derailment is put forward,and the influence of coupler force is introduced in the wheel load shedding rate and overturning coefficient solving model.Based on the advantages of Fortran language development,the simulation system of TSDynamic is developed to simulate the vertical and vertical dynamic effects and evaluate the safety of train operation.Which provides a basis for further study of the influence of lateral,vertical and longitudinal dynamic coupling on the safety of train operation,and verifies the reliability of the simulation system.Developed the analysis of unsteady mechanism of train and data processing assistance analysis software.The derailment factor and axle lateral force of the bogie can be used directly and simply to evaluate the safety of the train operation.The overturning coefficient and the wheel load shedding rate need to be systematically analyzed according to the specific conditions of train running line,speed and force.The simulation results show that there is a nonlinear relationship between the longitudinal force of the coupler and the radius of the curve and the safety index.Part of the line section of Datong-Qinhuangdao line system simulation,safety indicators are within the safety limits.The change of the vehicle load and the change of the volume of the body disc are greatly influenced by the safety performance of the vehicle derailment.The K306-K326 section of Datong-Qinhuangdao Line is equipped with the optimal braking mode of the dynamic braking and the circulation brake.The unsteady coupler force can be controlled in therange of-600 k N to 200 k N.Based on the analysis of the simulation results of 10,000 tons of trains,it is proposed to reduce or mitigate the operation mode of dynamic braking,so as to reduce the impact force of the train due to the air brake and to reduce the impact between vehicles.Through the analysis of the comprehensive impact mechanism of train safety performance,it is shown that the braking timing and position on the curve line have a great influence on the smooth operation of the train.In the case of emergency braking,the derailment factor of the bogie is prone to a large value when the train is in a retractor state with a small curve radius running at low speed and a high-speed operation.It is found that the coupler force and the different operating conditions have different effects on the lateral force of the axle wheel through the simulation of the large axis train.The initial speed of the train before entering the growth ramp is yet to be further optimized.