Finite Element Simulation Analysis And Optimization Design Of A Pure Electric Bus Frame Structure

In recent years,energy and environmental protection issues have become increasingly prominent,and people are paying more and more attention to energy conservation and emission reduction.Under this trend,pure electric vehicles have become the most promising new energy technologies because of their low noise,no pollution,and high energy efficiency.However,due to the constraints of various technical conditions,pure electric vehicles still have problems such as limited driving range and high curb weight.Since there is a direct relationship between the vehicle body weight and the running resistance,the reduction of the vehicle body quality can improve the energy utilization efficiency of the pure electric vehicle.As the main load-bearing structure of a passenger car,the body frame of a passenger car can weigh approximately 30% to 40% of the total weight of the passenger car,therefore,The use of some optimized design techniques to reduce the weight of the bus body frame has important implications for increasing the passenger’s driving range and energy efficiency.In this paper,the skeleton of a pure electric vehicle is taken as the research object.Firstly,the geometric model of the passenger car skeleton is established in the three-dimensional modeling software CATIA,and then it is introduced into the HyperMesh software to establish its finite element model.The static analysis and unconstrained free-modal analysis of the passenger car body frame structure were carried out under four typical operating conditions respectively.The strength,stiffness,and low-order modal frequencies and vibration modes of the passenger car body frame structure were obtained.The parameters lay the foundation for the subsequent optimization design and verify the correctness of the established finite element model.Secondly,the optimization of the passenger car’s skeleton is optimized by using the size optimization technology.The thickness of the passenger car’s skeleton rectangle steel pipe is taken as the design variable,the mass of the passenger car body skeleton is the minimum,and the allowable stress value of each static working condition is taken as the constraint condition to the passenger car skeleton.The structural size optimization design was performed,and the thickness values of each design variable after optimization were obtained.Finally,the performance of the passenger car frame structure before and after optimization is compared and analyzed.The results show that the optimized car body frame can not only meet the structural design requirements,but also reduce the quality of 285 Kg,accounting for about 8.04% of the total weight.It can be seen that the optimized design scheme is effective and has a significant weight reduction effect,which is of great significance for improving the performance of the entire vehicle,increasing the driving range,increasing the energy efficiency,and improving the dynamic performance of the passenger vehicle.The research results of this paper can provide enterprises with the calculation model and method of structural analysis and optimization design of the passenger car body frame,improve the design level and efficiency of the enterprise,shorten the design cycle and reduce the design cost.At the same time,it also provides reference for the design of other related products,and has important guiding significance for engineering practice.