Lightweight Design Of A Heavy Commercial Vehicle Frame Considering Fatigue Performance Requirements

Lightweight has become one of the important directions of automobile development,and more and more scholars carry out the research on automotive lightweight.Light weight of heavy commercial vehicle can not only reduce fuel consumption,but also increase carrying capacity and save transportation cost.As a key part of heavy commercial vehicles,the weight of the frame accounts for a large proportion of the mass of the vehicle,so the research of frame lightweight is of great engineering significance.Heavy commercial vehicles are in full-load transportation for a long time,and the main failure mode of its parts is fatigue failure.Therefore,when designing a lightweight frame,it is important to ensure that the fatigue durability of the frame can meet the requirements.In view of the above problems,In this paper,a lightweight design method of frame considering fatigue performance requirements is proposed.The main research work is as follows:(1)In order to obtain the accurate load spectrum at the junction of the frame and the chassis,the load spectrum is decomposed by a semi-experimental method combining road tests and computer-aided technology.Firstly,the target signal of a heavy commercial vehicle is measured at the Dingyuan test field,and then an accurate multi-body dynamics simulation model of the vehicle is established.Finally,the collected six-component force signal is loaded into the wheel center of the dynamic model for load spectrum decomposition.The results show that the method has high accuracy and meets engineering requirements.(2)The nominal stress method is used to analyze the fatigue life of the frame,and the difference between the fatigue life of the frame when the average stress is corrected using the Goodman model and the Geber model is compared.Considering that the simulation results need to leave sufficient safety factor,Goodman model is used to modify the frame fatigue life.The analysis results show that the fatigue of the frame will not occur within the national legal mileage.The results of the analysis are basically consistent with the test results of the road durability of the sample vehicle,which verifies the correctness of the fatigue analysis of the frame.(3)A lightweight design method of anti-fatigue of frame is proposed,which integrates topology optimization and dimension optimization.The lightweight design of a heavy commercial vehicle frame is studied by using the proposed method.The optimization results show that the frame weight is reduced while the fatigue performance requirements are met.Compared with the traditional lightweight design method,the method proposed in this paper is more reliable and ensures the safety performance of the frame.The thesis research shows that in the lightweight design of the frame,the lightweight design method of this paper is adopted to achieve the goal of lightweight design of the frame,which provides a reference for the design optimization of the later frame optimization and has certain engineering application significance.