Structural Analysis And Lightweight Study Of A Pure Electric Bus

With the widely use of the traditional internal combustion engine vehicles,the problems of environmental pollution and energy shortage are becoming more and more serious.As the representative of the clean and environmentally-friendly vehicles,pure electric bus is becoming more and more popular.At present,most of the pure electric buses have some disadvantages such as large weight,unreasonable distribution of structure strength,short driving mileage and so on.In this paper,a 12-meter long pure electric bus is chosen as the study object.Based on the finite element method,the structure of the bus is analyzed.At the same time,the research on the light weight of the bus is carried out.The structural analysis is based on the finite element method.The finite element modeling of the bus is completed in HyperMesh,and the accuracy of the model is verified by static tests.The strength,stiffness analysis under five typical road conditions and the free modal analysis are carried out in Nastran solver.The results show that all performance indexes of the bus can satisfy the requirements,and its strength has much surplus.So it is possible to achieve weight reduction of the bus.A scheme to reduce the weight of the electric bus is based on size optimization.The components on the body structure are filtered and grouped according to the results of finite element analysis.In order to do optimization to approve the lightest mass of the bus by size optimization,the thicknesses of the components are made as design variables,the maximum stress of the bus,the deformation of the main opening in the structure and the first order torsional frequency are used as constraints.Finally the weight of the bus body structure is reduced theoretically from 3012 kg to 1677 kg;weight is reduced by 44.3%.The body structure of the bus is lightweight redesigned based on the composite material for the first time.The composite layer scheme is designed firstly.Then the material of the bus body is replaced with composite material.Partial layers of the composite are improved minorly according to the finite element analysis and the strength failure criterion of composite materials.Finally the weight of the bus body is reduced theoretically from 3012 kg to 858.4 kg;weight is reduced by 71.5%.