Finite Element Analysis And Optimization Of Hydrogen Fuel Cell Bus Body

The body frame is the main load-bearing part of the bus.The fuel cell bus modified from the existing vehicle model by the traditional design method often has some problems,such as insufficient structural local strength,material redundancy or poor performance of the whole vehicle.Therefore,under the requirements of the strength and rigidity of the body frame,the structural optimization design and lightweight design of the body frame structure by using modern design methods are of great significance to the improvement of the overall performance of the bus.Taking the body frame of a fuel bus as the research object,according to the 2D drawing of the body frame,the geometric model of the body frame is built by using the 3D modeling software Creo,and then the finite element model of the bus body skeleton is established by using Hypermesh software.According to the finite element analysis theory,the static strength analysis under four typical working conditions of the body frame(horizontal bending condition,extreme torsion condition,emergency turning condition and emergency braking condition)is completed,obtaining the stress distribution and the deformation situation of the body frame structure,and the results are analyzed and evaluated,based on the stiffness and strength evaluation indicators.Based on the modal analysis theory,the free modal analysis of the vehicle body skeleton is carried out,and the influence of low-order frequency on the vibration characteristics of the vehicle body skeleton is analyzed,which provides reference data for the optimization design of the vehicle body skeleton structure.On the basis of static strength analysis and modal analysis of the body frame,sensitivity analysis is carried out on the roof and chassis frame structures of passenger cars,and a total of 43 bar thickness parameters sensitive to the body quality are selected.Based on the sensitivity analysis results,with the minimum mass of the vehicle as the objective function,the first-order torsional stiffness and the first-order torsional frequency as the constraints,the size optimization method is used to optimize the structure of the vehicle body skeleton.The results show that,on the premise of meeting the performance requirements of the body,the weight reduction of the body skeleton is 0.345 t and the weight reduction ratio is 8.79%.The lightweight effect is remarkable,and the structural optimization design scheme is feasible.