Structural Reliability Analysis And Optimization Of EMU Bogie Frame

The EMU is a fast and convenient means of transportation,its reliability and safety are the basis and premise to ensure the safe and reliable operation of trains.At the same time,with the continuous improvement of train running speed,reliability and safety are increasingly concerned.Bogie frame is an important component of the running part of the EMU.Therefore,taking the bogie frame of a certain type of EMU as the research object,this paper innovatively used Monte Carlo simulation(MCS),dual response surface agent model and multi-island genetic algorithm to analyze and optimize the structural reliability of the bogie frame.The main contents of this paper are as follows:(1)Static strength and modal analysis of bogie frame.The HyperMesh software was used to build the finite element model of bogie frame through the given geometric model.According to the standards of UIC615-4 and EN13749-2011,the combination of load conditions of the frame under extraordinary working conditions was calculated and applied to the finite element model to calculate the static strength of the frame.According to the static strength assessment method specified in the standard,analyze whether the static strength calculation results of bogie frame meet the design requirements.Secondly,using the Block Lsnczos modal extraction method to extract the bogie frame 1-10 order modal value,and based on the modal analysis results of bogie fraine determine the fundamental frequency of truck frame,judge whether the frequency can effectively avoid the wheel/rail interface and car body,the natural frequency of vibration of the suspension system?to determine whether meet the requirements of preventing frame structure resonance.(2)Reliability analysis of bogie frame structure based on double response surface method.According to the results of static strength analysis,three working conditions with large stress values were selected as the main working conditions.Taking the stress and mass of bogie frame under selected working conditions as the output response?MCS method was used to analyze its sensitivity and determine the design parameters that have great influence on the stress and mass of bogie frame.Considering the uncertainty of the design parameters,and according to its probability and statistical characteristics,the optimal Latin hypercube method was used for the experimental design,and the corresponding response value was obtained by finite element calculation.The least square method was used to fit the experimental design results,and a double response surface agent model was obtained to represent the relationship between design parameters and response.Combined with the dual response surface agent model and MCS method to analyze the reliability of the steering frame,the reliability of the frame under three working conditions is obtained.This method not only improves the computational efficiency.At the same time,the uncertainty in the design and manufacturing process is considered.(3)Bogie structural optimization based on response surface method.Based on the design parameters determined by the sensitivity analysis,the Workbench software was used to optimize the bogie frame with the minimum stress as the objective and the tolerance allowable range of design parameters as the constraint.The single-objective structure optimization was carried out based on the response surface method.Based on this,Isight software was used to increase the bogie frame mass less than 1.68t as the constraint condition under the premise of consistent optimization variables,and increase the bogie frame mass minimum as the optimization objective.Based on the dual response surface method,multi-island genetic algorithm was used to optimize the bogie frame structure with multiple objectives.The results show that the reliability of the frame is basically the same before and after optimization,and the stress and mass are reduced by 5.85%and 3%respectively.CoMPared with the single-objective optimization,although the magnitude of stress reduction is not obvious,but the quality constraints of the frame are taken into account,the calculation results have more practical reference value.