The Reliability And Sensitivity Analysis For Car Front Sub-frame And Size Optimization

With the improvement of living standards,cars have become an indispensable part for people.Designers have to face the complex design requirements. good handling, a comfortable rideenvironment, low energy consumption, ensure passenger safety,and so on. Subframe asregulating the handling and comfort of the cars, the reliability need to get enough attention.This article take the Shanghai Volkswagen sub-frame as research object. Parametric finiteelement model of the sub-frame was established and finished analysis of the brake conditionreliability and sensitivity..Optimized the sub-frame structure parameters to achieve lightest setunder the conditions of enough strength.First of all,obtrain CAD model throught reverse engineering.Simplifid the sub-framestructure and developed modeling program of sub-frame,acheive the parametric finate elementmodel. Result of normal modal analysis of subframe was used for vehicle dynamics and transientkinetic analysis. A full vehicle model was built in MotinView,the five conditions were simulatedand analyzed to obtain subframe load spectrum. In ANSYS transient dynamics analysis of thesub-frame, obtain the maximum stress occurs in the braking conditions. For braking conditions,the12structural modeling parameters and three material properties were chosen as randomvariables, using ANSYS PDS module analyzed the reliability and sensitivity of the subframe.Get each sub-frame structure variable sensitivity of reliability and mass, the6most importantstructural parameters affected the strength and mass were selected as variables to optimize themass of the goal to minimum, with sufficient strength as constraint. The end result reduce the8.11%by mass. Fatigue simulation on the result of optimination was used for check the efect,that the result meet the requirement, due to the stress concentration after simplification resultingand position near the loading position were less, optimize good effect.Results of this study provide a basis analysis for optimization and improvement ofsub-frame. For the products that have complex shape and hard to get CAD models,this articlealso has some reference value to build finate element models.