Lightweight Design For Swing Arm Of Suspension System Based On Customer Driving Load Spectrum

In design and development process of components in domestic vehicle manufactories,high security coefficients are usually attached to structural components of automobile in consideration of security,and the design standards for reference are generally introduced from abroad.This design method brings about surplus intensity of automobile structure without considering load feature,especially Chinese customer driving load feature on automobile structures' fatigue life,which is not good for realize automobile lightweight.In this paper,a suspension swing arm of a sedan was taken as the study subject.Research of swing arm lightweight design process was carried out based on Chinese customer driving load spectrum and low-amplitude load strengthening theory.Finally,a proper structure of later swing arm was designed,which could satisfy the use requirement of Chinese users with 99% reliability and reduced weight by 20%.The main study focused on the following aspects.Firstly,devising suitable schemes to collect customer driving load spectrum.Secondly,extrapolating the load spectrum to obtain the load model of Chinese 300,000 kilometers customer driving road with 99% reliability.Then establishing fatigue life S-N curve and low-amplitude load strengthening characteristics surface based on research the fatigue and low-amplitude load strengthening properties of the swing arm.Fitting out the relationship among acceleration of axle head,service load of wheel centre,service load of swing arm and working stress of swing arm by simulation analysis.Establishing a quick calculation method of swing arm working stress with different size.Calculating the surplus of primary structure by working stress load spectrum,then carrying out lightweight design by constraints of cumulative damage value.And the minimum size requirement for life was designed by using the active design principle of load spectrum design methods.Innovations of this paper are as follows:(1)Proposing a lightweight design process based on Chinese customer driving load spectrum and low-amplitude load strengthening theory with full consideration on the influence of load feature to fatigue life of automobile structures.(2)Establishing a quick calculation method of swing arm working stress by a series of iterations based on simulation analysis.The result of this lightweight design process will provide the technical basis for developing components of automobile,and also supply the technical support for the advance design methods and competitive ability of the independent brands automobile.