Finite Element Analysis And Structural Optimization Of New Type Aluminum Alloy Coal Hopper Car

With the development of railway vehicles towards high speed and heavy load,higher requirements are put forward for the reliability and safety of railway freight trains.In the face of the increasing number of customized trains and the complex random load environment,how to ensure that the new freight trains meet the requirements of users,meet the load conditions specified in the standard,and achieve the lightweight design of the structure as much as possible is the main problem to be solved.Therefore,this work takes the new aluminum alloy coal hopper car body as the research object.The comprehensive analysis of the initial car body performance is realized with the help of finite element analysis and fatigue life evaluation method on the basis of summing up the traditional design experience.On this basis,the response surface surrogate model,intelligent optimization algorithm and test verification are used to complete the structural optimization and performance evaluation of the initial vehicle body.Through the optimization design of the car body structure,and the test verification,in order to improve the overall structure performance level,so as to ensure the safe and reliable operation of freight train.The main research contents are as follows:Firstly,the statics analysis of the car body structure was carried out based on TB/T1335-1996 standard.According to the three-dimensional geometrical model of the car body,the structural features are processed,the main performance parameters are extracted,and the finite element model is constructed.According to TB/T1335-1996 standard,the loading load of the car body is calculated and its constraint conditions are determined.ANSYS software was used to calculate the static strength and stiffness of the finite element,and the result data was extracted and compared with the allowable value stipulated in the standard,and the static strength and stiffness of the car body was evaluated.Secondly,the modal analysis and stability check of the car body structure are carried out.In order to avoid the resonance of the vehicle body during operation,based on the modal analysis theory and combined with the finite element model of the vehicle body,the modal analysis of the vehicle body under unconstrained conditions was completed,and the natural vibration frequency and mode of the first 16 modes of the vehicle body were obtained and checked.In addition,in order to analyze the structural stability of the car body,the linear buckling analysis was carried out for the car body structure under compression condition based on the buckling stability principle,and the relatively weak position and buckling factor of the car body were determined.Through comparative analysis,the stability of the car body structure is checked.Thirdly,the fatigue life evaluation of vehicle body structure based on AAR standard is presented.According to AAR standard,the load spectrum of fatigue life evaluation of new aluminum alloy coal hopper car body is selected according to the proportion relation,and the load condition of fatigue evaluation is extracted according to the standard.On this basis,combined with the finite element model of the car body,the distribution of the first principal stress under the condition of the fatigue load of the car body is calculated,and the types and positions of the welding seams that have great influence on it are determined.Based on the linear cumulative damage theory,the s-N curve in AAR standard was used to evaluate the fatigue life of key welds and compare it with the specified service life of newly built trucks.Finally,the optimal design and test verification of the car body structure are carried out.According to the comprehensive evaluation result of the hopper car body,the parts that have great influence on it are determined and its structure is optimized.First of all,the scheme optimization design is carried out for the parts exceeding the standard in the process of performance analysis of the car body,so as to realize that the mechanical properties of the car body structure meet the standard requirements.On that base,the structure stress under the worst working condition is taken as the object,and the response surface model of the body structure size with respect to the maximum stress is established.Three optimize algorithms Screening,MOGA,NLPQL are used to solve the mathematical model.Then the car body model is changed again based on the optimal design scheme.the feasibility of the optimal design model is verified by comparing with the initial car body structure performance.At the same time,the weight of the car is reduced.Finally,the prototype of the optimized design model is trial manufactured,and the static strength test of the car body is carried out.Through the comparative analysis of the test and simulation results,the accuracy of the simulation results is verified,which further proves the feasibility of the optimal design scheme.