| Bogie frame is an important bearing part of rail vehicle,its safety and reliability directly affect the service life of the train and the safety and reliability of the operation,while the traditional optimal design is difficult to take into account the lightweight design of railway freight car bogie and the reliability of the operation.Therefore,under the condition of meeting the reliability safety index,it is of positive significance to optimize the structure performance of the bogie frame and realize the lightweight design.Based on the theory of static strength,structural reliability and optimization design,this paper takes the three-axle bogie frame of a train as the research object and completes the structural strength and reliability analysis and optimization design of the bogie frame based on numerical simulation and intelligent optimization algorithm.The main research contents of this paper are as follows:In order to ensure the safety of truck three-axle bogie frame in operation,the structural reliability analysis is carried out.The static strength of a finite element model of a three-axle bogie frame under abnormal load in UIC 510-3 is analyzed.NESSUS software was used to analyze the sensitivity of the equivalent stress of the structure,and the factors that had significant influence on the stress were selected as the basic variables.Then,through the cosimulation of MATLAB and ANSYS software,the iterative solving process of GPR-FORM method was completed.The results show that the structural reliability of the three-axis bogie frame is 95.05%,compared with the traditional MCS,the relative error is 2%,which verifies that the GPR model can effectively fit the implicit function through the iterative process and accurately solve the structural reliability under the condition of only a few sample points.By using PSO-GPR collaborative optimization algorithm,the single objective optimization design of the bogie frame is realized.The mass sensitivity analysis of the frame is carried out,and the factors that have significant influence on the quality are selected as the design variables,and then the GPR model of the bogie frame quality is fitted and the accuracy is evaluated.Aiming at the deficiency of local optimization ability of traditional PSO algorithm,a collaborative optimization algorithm of PSO-GPR was proposed by combining PSO algorithm,Newton method and GPR model.The reliability optimization model under the constraint of reliability index was established,and the iterative optimization was conducted by PSO algorithm and PSO-GPR algorithm respectively.Under the premise of ensuring the reliability of the bogie frame structure,the lightweight design of the bogie frame was realized.Gaussian response surface and improved NSGA-II algorithm were used for reliability multi-objective optimization.A composite proxy model combining GPR model and secondorder polynomial response surface was proposed and its accuracy was verified to further improve the fitting accuracy of GPR.Considering the instability of Pareto front and low optimization efficiency of the original NSGA-Ⅱ algorithm,a chaotic adaptive T-distribution variant NSGA-II algorithm is proposed,and the original NSGA-II algorithm and the improved algorithm are used to solve and compare the multi-objective reliability optimization mathematical model.The optimal scheme of Pareto frontier is determined according to the principle of nearest origin,and the optimized results are analyzed and verified by re-modeling and analysis according to the design variables of the optimized scheme.Based on Gaussian process regression model,this paper proposes a reliability analysis method suitable for three-axle bogie frame,studies the improved algorithm of structural reliability optimization design,and gets a multi-objective reliability optimization design scheme of three-axle bogie frame,which provides a theoretical basis and reference for the optimization design of bogie frame. |
