Research On The Optimization Of Rail Vehicle Running Stability Based On Elastic Carbody

The development demand of high-speed and comfort of rail vehicles have put forward the design requirements for the structure and performance,vehicle running stability and passenger ride comfort are the important factors affecting people's choice of travel mode,so,it is of great significance to study the optimization of vehicle running stability.There is a close relationship between the vibration of the vehicle system especially of the carbody and the vehicle running stability,in the traditional research method,the carbody is regarded as a rigid body,but with application of the light structure and the increase of the vehicle running speed,the influence of the elastic deformation of the carbody can not be ignored.And the vehicle suspension system is an important part of the load transfer between the vehicle body and bogie,the reasonable choice of the structural form and design parameters directly affects the dynamic performance,especially the running stability of the vehicle.However,there are some complicated nonlinear problems between the suspension parameters and the vehicle dynamic performance,which may affect the difficulty of the solution,and considering the flexibility of the carbody,the calculation scale of vehicle dynamic performance increases exponentially.The surrogate model technology can be used to construct the approximate model of the relationship between the design variables and the optimization objectives,which could replace the complex dynamics calculation process under the condition of satisfying certain precision requirements.Therefore,this paper studies the problem of the optimization of the rail vehicle running stability considering the flexibility of the carbody by using the surrogate model technology,and get the optimal performance of the vehicle by optimizing the reasonable combination of suspension parameters.This paper first takes the evaluation index of vehicle running stability as the objective function,the relevant provisions of vehicle stability and safety as boundary conditions,and the vehicle suspension parameters as design variables,conducts the rail vehicle running stability optimization model;takes the middle trailer of a certain type of EMU in China as the research object,establish a rigid model and a flexible carbody,rigid bogie rail vehicle dynamics simulation model,set up the rigid/elastic vehicle simulation model with the same original design parameters;with the surrogate model technology,this paper constructed the approximate model of the relationship between the suspension parameters and the rail vehicle dynamics evaluation index to replace the vehicle dynamics simulation model;optimization calculation with Isight software,and got various optimization solutions of the objective function by chosing different weight factors,take the optimization results into the simulation model which show that the vehicle running stability after optimization has improved significantly,the curve decreased slightly but still in the allowable range,then combined with the different application conditions this paper gives the relevant proposal of the vehicle running stability optimization.This paper studies the factors of the elastic carbody deformation effects in the process of vehicle dynamics simulation modeling,and demonstrates the importance of considering this factor by comparing with rigid body simulation model.The surrogate model technology,avoids the repeated operation of dynamic simulation,and it could meet the engineering accuracy requirements,improve the computational efficiency;using Pareto genetic algorithm solve the multi-objective optimization problem effectively at the same time.