Design and Optimisation of a Double Wishbone Independent Suspension System for an L6 electric Vehicle: A Response Surface Methodology- based design application

Suspensions are vital vehicle subsystems that provide ride comfort, stability and handling while absorbing shocks caused by road irregularities. Their designs require careful consideration of structural integrity, weight reduction and performance optimisation. In light electric vehicles, such as those in the L6 class, the design and optimisation of suspension systems becomes even more critical due to design compactness and functionality. The aim of this study is to design a front independent suspension system for an electric L6 class vehicle and to outline an optimisation-based design process of this design by Finite Element Analysis (FEA). In the first stage of the study, various load cases and the effects of these loads on the connection points were determined and force analyses were performed. Then, a preliminary design was built to withstand the types of loading to which it will be subjected. Afterwards, FEA was performed on the preliminary design using the data obtained from the force analysis. As a result of this analysis, critical load case and critical regions were identified. In the optimisation stage, the outer diameter (D), wall thickness (t) and radius of curvature (R) were defined as input parameters, while mass, equivalent stress and total deformation were selected as output parameters. As a result of the optimisation-based design, a stress reduction of approximately 43% was observed at the critical region. In addition, the percentage of the influence was investigated in order to better understand the effects of the basic design parameters. Among the parameters, the wall thickness was found to be the design parameter which has the highest effect on stress distribution and part mass.