Research On Optimal Design Of Electric Bus Skeleton Considering Crash Safety And Light Weight

Safety,energy saving and environmental protection are closely related to people's life.Pure electric bus quickly occupy the new energy bus market due to its low pollution and low energy consumption.Compared with traditional bus,although the engine and other fuel system is less,but increased the battery assembly and motor assembly,so it still faces the problem of high energy consumption caused by the large quality of reconditioning.As the battery assembly is generally placed on the side,back and front of the bus,and according to statistics,the bus accident form to the front,side impact,rear-end and roll-over.In order to ensure the safety,energy saving and environmental protection performance of pure electric bus,this paper takes a type of pure electric bus as the research object and puts forward two kinds of lightweight optimization methods,aiming at providing a more reasonable optimization scheme for the design of body frame.Static,modal analysis and side impact simulation analysis of the body frame.The stress and strain distribution and dynamic performance of the frame are obtained by static and modal analysis of the frame.In order to provide a theoretical basis for the subsequent lightweight design;Through the side impact simulation analysis,the anti-collision effect is obtained of the body frame,which provides reference for the subsequent design.Optimization design of lightweight based on side impact simulation and relative sensitivity analysis.Grouping the bus body frame according to the results of side impact simulation analysis,and a method of strengthening the side battery anti-collision beam is proposed,the method of relative sensitivity analysis is used to determine the design variables required for size optimization.Consider two extreme working conditions,comparative analysis of static,modal and side-impact simulations before and after optimization of bus frame has been done.The results show that under the premise of meeting the safety performance requirements,the weight reduction of the bus body frame is 136.4kg,with weight reduction of 13.2%.Research on lightweight method based on surrogate model and Sequential Quadratic Programming(SQP)method.First,collecting the sample points of the finite element model of the pure electric bus by the Latin hypercube test design method,combine the polynomial response surface method in order to establish surrogate model about vehicle mass,low order mode frequency,stress,strain and side battery protection beam frame intrusion.Taking the vehicle mass surrogate model as the optimization objective and the other surrogate models as the constraint condition,the SQP method is used to optimization design for surrogate model,and comparing the performance before and after optimization.The results show that within the limits of reduced safety requirements of the structural strength and stiffness performance of the body frame,maintaining the modal performance and anti-collision performance,at the same time the weight reduction of the bus body frame is 125.2kg,with weight reduction of 12.1%.