Research On Crash Safety Of Pure Electric City Bus

Vigorously developing new energy vehicles can effectively alleviate the problems of energy shortage and environmental pollution.Pure electric city bus has the characteristics of zero emission and high energy efficiency,which is the pioneer of new energy vehicle industrialization.Compared with the traditional bus,the pure electric bus uses high energy density power battery,which has serious security risks,and the city bus has a large number of passengers and high utilization rate.Once an accident occurs,it will have a significant impact.Therefore,it is of great significance to study the structural safety of pure electric city bus under collision conditions.This paper takes a pure electric city bus as the research object,establishes the finite element model of the body frame and battery box,and carries on the modal analysis.Based on this model,the frontal 100% rigid wall impact simulation tests with initial velocities of 30km/h and 50km/h are carried out.The comparative analysis is carried out from four aspects: body frame structure deformation,energy absorption characteristics,B-pillar acceleration response and rigid wall reaction.When the initial speed is 50km/h,the driving space is reduced by63.86%,and his life safety is threatened.In order to improve the collision safety,according to the deformation characteristics and energy absorption law in the collision process,the structural improvement scheme is proposed,including the use of an energy absorption box with induction slot with good energy absorption characteristics,and reasonable arrangement of high-strength steel materials.The improvement scheme is verified by 50km/h collision condition,and the simulation results show that the energy absorption of the front wall increases by 17.34%,the driving space increases by 57.46%,and the peak acceleration of the B-pillar decreases by 24.8%.In order to further study the collision safety of electric bus battery box,a moving deformable barrier model is established,and the rear end collision simulation tests with 20%,30%,40%,50% and 60% overlap rate are completed.Through the quantitative analysis of the deformation characteristics,energy absorption characteristics,acceleration of the battery box and the stress of the mounting seat under different overlap rates,the safety of the battery box under different overlap rate collision conditions is explored.The results show that the 20% overlap rate rear end collision condition is the most dangerous,and there may be potential safety hazards.In order to solve this problem,the structure and material of the rear part of the bus are improved.After the improvement,the deformation degree of the bus body under the impact condition with20% overlap rate is significantly reduced,the energy absorption of the rear wall is increased by38.11%,the peak longitudinal acceleration of the battery box is reduced by 48.41%,and the peak vertical acceleration is reduced by 82.30%.The collision safety of the electric bus is significantly improved.