Performance Analysis And Structure Optimization For Metro Head

With the increasing operation lines of subway in China,more and more metro vehicles are put into service,and the performance of metro heads has attracted more attention.As the control center of a metro vehicle,metro head provides drivers with the necessary working space.When external load exceeds a certain limit,its structure will be destroyed,which will affect the safety of driving.In the case of an accident in the subway,the front part of metro head will be subjected to a huge load.Then,plastic deformation occurs in the driver's cab protection beam,which will effectively protect the safety of drivers and passengers.Therefore,in order to ensure the metro vehicle's routine operation,it is necessary to analyze the strength and stiffness of the metro head under the operating conditions.For the extreme case,it is also significant to calculate the maximum deformation and stiffness reliability of the driver's cab protection beam.Then,under the premise of satisfying the strength and other performance indicators,high stiffness of FRP and high reliability and light weight of the driver's cab protection beam are researched.On the basis of these,author applies finite element theory,classical laminate theory,structural reliability theory and structural optimization theory and so on,and adopts simulation analysis method to research on the performance analysis and structure optimization for metro head.The main works are as follows:(1)Performance simulation analysis for metro head.According to the data provided by the project task book,the corresponding finite element model is established in HyperMesh.And the strength and stiffness analysis results of the metro head under operating conditions are obtained by static analysis in ANSYS.Then,we can make strength check and confirm the most dangerous condition with maximum deformation.Next,the plastic deformation of the driver's cab protection beam under extreme experimental condition is calculated by geometric and nonlinear analysis in ANSYS.Then,we can prove that it satisfies the experimental requirements.(2)Stiffness optimization design for FRP.Taking the most dangerous operating condition as the research object,only the components that contribute to the maximum deformation of the metro head are retained.On the basis,this thesis calculates the maximum deformation's sensitivities to different areas.Stiffness optimization model is established by taking the lamination angle in the areas with the largest sensitivities as the design variables and the maximum deformation as the target performance response.Author adopts PSO in continuous and discrete variables optimization designs to obtain the optimal lamination angle scheme.Then,we can compare and analyze the optimization results.Finally,the static analysis of the optimized metro head under the operating conditions is performed to verify its feasibility.(3)Multi-objective optimization design based on reliability for driver's cab protection beam.This thesis considers the uncertainty factors' influence on plastic deformation of driver's cab protection beam in processing and manufacturing.Based on the requirements of limit state experiment,the limit state function and stiffness reliability analysis model are established to calculate stiffness reliability by Monte Carlo-Response Surface hybrid simulation.On this basis,with the targets of driver's cab protection beam's minimum total mass and plastic deformation,constrained by stiffness reliability greater than 99%,the multi-objective optimization model is established.Then,author adopts NSGA-II to optimize the sizes for the best thicknesses combination.The calculation results show that the optimized driver's cab protection beam not only satisfies the reliability requirement but also takes into account the light quantization.In conclusion,the optimization effect is fine.