The Study On Dynamic Design And Optimization Of Multi-stage Suspension Accessory Equipment Of High Speed Train

With the rapid development of China's high-speed railway,the vibration of high-speed train is becoming more and more serious due to the continuous improvement of operational speed.The ride comfort and the working environment of the equipment have been deteriorated to some extent with the light weight design and power dispersion technique being used widely in vehicle manufacturing.Whether the suspension parameters of the underfloor equipment is reasonable or not is directly related to the ride comfort of the vehicle,fatigue life of the suspension mechanism and the working vibration environment of the equipment itself.There is no corresponding industry standard for the design of suspension parameters of vehicles underfloor.,In addition,many factors,such as various types of equipment,different suspension modes and complex device incentives,have made it difficult to design the equipment suspension parameters.This paper takes the single stage hanging traction transformer and the double stage hanging cooling fan as research object.And a dynamic design method has been put forward in this paper.First,the vehicle-equipment system modle is established,and the system history and frequency vibration response are derived respectively.According to the criterion of vibration index of vehicle system,the best suspendion frequency ratio of equipment which satisfies the vehicle ride comfort and the equipemnt working environment is selected,?y1:0.9?1.01,?k1:0.75?0.89,?f1:1.86?2.The caculate results of the two models can be used to determine the hanging frequency ratio of the equipment.Secondly,the BGCI vector method is introduced to research the relationship between vehicle vibration and modal.the result shows that vertical bending mode,torsion mode,rhombus mode have a great effect on vehicle vibration.Then,the excitation mechanism of track irregularity on the vehicle-equipment vibration modal is analysised,and the wave filter of vehicle-equipment model is established to elaborate the wave filter effect on the vehicle response on the power spectrum function method.The traction transformer suspension frequency is determined 9.8Hz based on geometric filtering effect considering the design of a 250km/h high-speed train.The caculation result shows that the vibration response in not only related to suspension frequency,but also to vehicle operational speed.This method can reduce the vehicle vibration effectively.At last,the six freedom degree traction transformer with single-layer vibration isolation system mathematic model and twenlve freedom degree traction motor cooling fan with double-layer vibration isolation system model are eatablished respectively.The muilti-objective function with dynamic force of the isolator,equipment severity and equipment hanging frequency are determined.At last,the optimal isolator parameter are obtained using dynamic optimal design combining restrictions of isolator static compression,0.8(frame suspension frequency ratio),1.9(the ratio of longitudinal vertical of frame),1.9(the ratio of cooling fan suspension frequency),1.5(the ratio of longitudinal vertical of cooling fan):2142 N/mm(the first set of isolators vertical stiffness of traction transfoemer)?1.3(traction transformer p)?2.5(traction transformer q)?1.7(traction transformer m))?0.5(traction transformer n).This paper determine the two factors speed and equipment suspension frequency should be considered in designing suspension parameters,also the wheel-rail incentive and equipment incentive itself on the influence of vehicle vibration is considered.And the elastic modal contribution value has carried on the quantitative calculation.This method fills the domestic high-speed train equipment blank of suspension design standards and industry specification.It can be applied to design equipment suspension parameter under high-speed train in engineering practice,provides guidance basis for equipment designing underfloor.