Lightweight Design And Research Of Vehicle Subframe

With the development of automobile technology, people have imposed more and morenew requirement on ride comfort. As the most important load-bearing body of chassis in themainstream vehicle, subframe is connected with the body, suspension system and enginemounting. It improves not only ride comfort, stiffness and strength of chassis, controllability,but also assembly convenience and design versatility. This paper studies the progress oflightweight design around the direction of vehicle lightweight. Participating in front subframestructure exploitation of plug-in hybrid vehicle, we carry on the design of structureoptimization and performance verification, which has achieved good results of lightweight.The paper has summarized overseas and domestic research status of lightweighttechnology, outlined application and characteristic of subframe structure, raised its contentsand technology route of the research. Multi-body dynamics model and simulation in typicalloadcases for the subframe have been taken, and the resulting data of body load is obtained bycalculation, which provides the accurate boundary conditions for subframe structureoptimization. Then we have established reasonable finite element model of subframe, andanalysed its performance including modal, strength based on FEA, to validate reliability andperformance demand of FE model, which provides reference points for structure optimizationafter that. Size optimization of subframe structure is aimed at obtaining the optimal group ofthe thickness of plates. Based on making design variables, constraints and design targets clear,we have done sensitivity analysis on the base of design of experiment(DOE), to study theimpact the thickness of plates have on response variables. So we have choosed somethickness variables with high sensitivities as the design variables of size optimization, anddone another DOE with more levels considering the amount of design variables and therequirements of approximation models to get more sample points. After that, we build anapproximation model with high fitting precision, get the optimal group of thickness of platesusing multi-objective optimization method to achieve optimal performance of subframestructure in the constraint of mass.The performance of subframe optimization design is analysed and verified based on finite element method, including modal, strength and fatigue life. Result shows thatlightweight design method of subframe in this paper has put multiple optimization andanalysis techniques into use, which can provide ideas of lightweight design for designers.Themethod is significant for the future design and optimization of chassis structure.