Design And Optimization Of The Aluminum Body Frame Of A Pure Electric City Bu

With the advocacy of ’energy conservation and emission reduction’ policy and the steady development of urban public transport,the research of pure electric city bus has become a hot spot.Due to the heavy weight of the pure electric city bus,the energy consumption of the bus is large and the driving distance is limited.In order to ensure the performance of the body structure and reduce the weight of the body frame,this paper designs and optimizes the All-aluminum body frame of the pure electric city bus.According to the similar structure of the traditional city bus,the simplified threedimensional model of the all-aluminum body frame of the pure electric city bus is designed by UG,and the finite element model of the body frame is established by Hypermesh preprocessing.By using four typical working conditions,the static analysis and mode analysis of the body frame are carried out to determine the reliability of its stiffness,strength and dynamic performance.Through setting up the topology optimization parameters,the joint topology optimization of the multi-condition is carried out.aiming at the skeleton of the weak area of the body performance,the redesign is carried out in UG to obtain the body skeleton with more stable structure.At the same time,the cross beam of roof skeleton is topologized separately,and the cavity of the cross beam of the roof skeleton is redesigned to increase the stiffness of the roof skeleton.The empirical scheme is compared with the topology optimization scheme to verify the rationality of topology optimization.In order to take full advantage to the stiffness and strength performance of the body skeleton,the idea of modular grouping is adapted to improving the operation efficiency,and the sensitivity analysis of the body skeleton is carried out.According to the relative sensitivity value,the variable group of size optimization is selected to carry out the size optimization design.The cluster of variables of the all-aluminum body skeleton of the pure electric city bus are established,which to reduce the quality of the body skeleton while ensuring the structural performance of the body skeleton.The results show that the structural performance of the body frame is improved after topology optimization.Based on the method of modular grouping,sensitivity analysis and size optimization,the anti-deformation capability of the body frame has increased.And the weight of the body frame has reduced,this measure also avoids the possibility of local resonance.Finally,the weight of the body frame is reduced by 244 kg,which verifies the rationality of the design and optimization.