Structural Design And Optimization Of Hydrogen-fueled Medium Truck Frame

In the transportation industry,hydrogen-fueled truck is the pioneer of energy transformation development in our country,and its emission pollution-free characteristic is unattainable by traditional fuel cars.As an important bearer,truck frame performance directly affects the safety and ride of the vehicle.The frame design is not entirely able to have the best performance through some precise theory,and it requires a variety of design,analysis and experimental verification.Relying on Shanxi Provincial Science and Technology Major Special Project ——Medium Truck Platform Fuel Cell Power System and Vehicle Integration Technology,we introduce topology optimization and size optimization technology to carry out the special design of hydrogen-fueled truck frame according to the vehicle power system layout form,operating conditions requirements and other characteristics.Firstly,a medium hydrogen-fueled truck was taken as the research object,and a finite element model equivalent to the original frame was established.Four typical static working conditions were selected to check the static strength of the original frame.The low-order modal parameters of the original frame were extracted for dynamic characteristic evaluation,and the reliability of the simulation model was verified by experimental modal analysis.Then,large structural attachments on the frame such as hydrogen storage devices,fuel cells and power batteries,were retained,and the initial model of structural topology optimization was established based on the original frame size.According to the compromise programming method and the efficiency function method,the optimization problem of high stiffness in static multi-working conditions was transformed into the study of minimizing the flexibility of the structure,while maximum average eigenvalue of the dynamic low order natural frequency was obtained by spectral transformation.A unified single objective optimization evaluation function then was constructed to solve the hybrid problem of static and dynamic multi-objective optimization direction.Variable density method with penalty factor was used to optimize the topology model in Opti Struct.According to the results of topology,the new frame structure was designed,and the static and dynamic characteristics of the new frame were analyzed.Finally,based on the sensitivity analysis of the beams and the connecting plates,the dimensions of new frame components were optimized.The final mass of the lightweight new frame is reduced by 12.3%,the peak stress of the most dangerous static condition is reduced by 35.9%,and the dynamic lowest order frequency is increased by 2.2Hz.The lightweight new frame has better static and dynamic characteristics,which realizes the special and lightweight design of hydrogen-fueled medium truck frame.