Integral Body Structure Design Of Electric Bus

Along with the rapid development of high-speed train,the long-distance highway passenger transportation is being replaced gradually.The new energy bus has also been rapid development in China.The pure electric bus occupying the absolute dominance of the new energy bus.However,the domestic research and development of the pure electric bus structure is still currently in the initial stage,mainly obtained by substituting the powertrain and local modification based on the traditional bus structure,and the unscientific design leads to high body structure mass,which has violated the lightweight design concept.Due to the difference of the load distribution with the original body,the strength of the local structure can not meet the requirements.According to the current situation of pure electric bus’ s R&D and market demand,taken the body structure of 7 meters pure electric bus as design object.The vehicle performance and the structure were analyzed and optimized by CAE analysis.According to the optimization results,the prototype vehicle was made and the static strength test was carried out to verify the safety.Firstly,the finite element model of the bus frame was established in the HyperWorks software,according to the three-dimensional model of the bus structure established in UG.The natural frequencies,modal shapes,bending and torsional stiffness were calculated and used as the initial values.The stress distributions of bus structure under four typical situations were analyzed,such as bending,emergency braking,torsion and emergency turning.And the improvement scheme was put forward for high stress area.The results of the improved bus structure strength analysis showed that the stress concentration area was improved,and the maximum stress value in each condition was reduced..Body frame weight reduced by 22.5kg,and there are still more rods can beoptimized.The original bus structure is a three-section chassis frame,which has larger quality and strength and stiffness are weaker than the integral body structure.Furthermore,the chassis and sidewall were selected as the optimization area,because of the higher optimization potential.Under the most typical driving conditions of bending and torsion,the topology optimization was carried out.According to the results of optimization,the integral body structure was designed.The modal,stiffness and strength of the optimized body frame were analyzed.Compared with the original structure,the bending stiffness of integral body structure is increased by 69.9%,and the torsional stiffness was increased by 91.2%.The results of strength analysis showed that the maximum stress of the whole vehicle was significantly decreased,and the structural performance was obviously enhanced.The quality has reduced 96 kg,a decline to 10.16%compared with the original body structure.Finally,the body in white was produced with the help of GOLDEN DRAGON,and the static strength was tested.The most stressful emergency torsion condition was selected as the test condition.The results showed that the stress value of error for the test and simulation was less than 20%,and the simulation results have high reliability.The optimized body structure can meet the stress requirements.The analysis showed that the design of integral body structure is feasible.