Research On Weight Reduction And Optimization Design Of New Materials For EMU Body

It is one of the main research contents in the design process of EMU to realize the vehicle body lightweight and optimize the vehicle body performance.Reducing the train weight is an important measure to reduce the traction power demand of high-speed EMU.Improving the vehicle body performance can ensure the safe,stable and comfortable operation of the vehicle body.The newly developed representative carbon fiber composite has the characteristics of light weight,high specific strength and specific stiffness,corrosion resistance and fatigue resistance.Its application in EMU can solve the problem of vehicle body lightweight and improve the performance of vehicle body.The main contents of this paper are as follows:(1)The finite element model of aluminum alloy car body of a EMU is established.According to the European standard “EN12663-2010”,the strength of aluminum alloy car body under the condition of servicing and overloading is calculated and analyzed,and the mode of aluminum alloy car body under the condition of servicing is calculated.The results show that the strength and mode of car body meet the requirements of relevant standards.(2)Based on the finite element model of the car body,the weight reduction effect of the car body with carbon fiber sandwich composite structure is analyzed.Taking t300-1k carbon fiber laminate as the panel and aluminum honeycomb as the core of the composite structure as the main structure of the car body,the car body mode of the new carbon fiber sandwich composite structure is calculated and analyzed.(3)The influence of the ply angle of the carbon fiber composite panel on the vehicle modal is studied.The influence of the laying angle between the inner layers of four kinds of carbon fiber composite panels on the first six modal frequencies and vibration modes of the car body is calculated and analyzed.It is determined that the laying method([0 / + 45 / 90 /-45 / 0 / + 45 / 90 /-45] s)can best meet the design requirements.(4)The sensitivity of the low-order critical modal frequency of the car body to the thickness of each layer of the carbon fiber composite panel under the condition of servicing is studied.Taking the thickness of each layer in the carbon fiber composite panel of each part of the car body in the servicing state as the design variable,a total of 64 design variables are calculated.The sensitivity of the modal frequency of a diamond and the first-order vertical bending of the servicing car body to the thickness of each layer is calculated by using the numerical differentiation method.(5)The optimization design of the car body with carbon fiber aluminum honeycomb sandwich composite structure is realized.Based on the sensitivity analysis,aiming at improving the anti rhombus and anti bending rigidity of the car body,taking the thickness of(6)each layer of the carbon fiber composite panel of the side wall,roof and underframe as the design variables,taking the weight and the first two modal frequencies of the whole car body as the constraint conditions and the objective function,through the comparative analysis of multiple optimization schemes,the weight reduction optimization design of the carbon fiber composite structure car body is realized Now the purpose of reducing the body structure quality by more than 40%.(7)The optimized mode and strength of the car body are checked.The first two modes of the optimized composite structure car body under the condition of servicing are calculated and analyzed,and the strength of the optimized composite structure car body under the condition of overload is calculated and analyzed.The calculation results show that the car body mode and strength meet the requirements.The results show that,based on the sensitivity analysis,the carbon fiber aluminum honeycomb composite structure car body obtained by the modal frequency optimization design not only achieves the purpose of reducing 40% of the weight of the car body,but also significantly improves the first two modal frequencies of the whole car body.Compared with the aluminum alloy car body,the comprehensive performance of the car body has been greatly improved.