Research On Dynamic Performance Of High-speed Freight EMU

Based on the original parameters of freight emu of over 250km/h provided by CRRC Tangshan locomotive & rolling stock plant,the dynamic model of freight emu is established with SIMPACK.In view of the characteristics of high center of gravity,heavy load,complex and diverse operation environment and lines of freight emu,the following targeted research is carried out on freight emu:Firstly,according to the characteristics of high center of gravity and heavy load of freight emu,in this paper,the distance between the rolling center of the vehicle body and the center of gravity of the vehicle body under different height of the center of gravity of the vehicle body is derived from the formula;the influence of the height of the center of gravity on the suspension mode is analyzed;based on the safety of the curve under the condition of anti-roll bar failure,the reasonable height of the center of gravity of the freight emu with and without lateral deviation is calculated.Secondly,according to the complexity and diversity of the operation environment and the line of the freight car,in this paper,the dynamic performance and safety indexes of the vehicle under three failure conditions,namely,the change of stiffness of the positioning node of the transfer arm,the loss of air spring and the failure of the anti-snake shock absorber,are studied.Finally,a rigid-flexible coupling model based on elastic wheelset is established;based on this model,the response of each part of freight emu under the condition of polygonal wheel wear is analyzed;when the characteristic frequency of polygon vibration is close to the natural mode of wheel pair,the vertical force of wheel and rail will increase sharply;the polygonal depth limit of freight emu is calculated according to the maximum vertical force of wheel and rail specified in the safety index of vehicle operation.