The Torsion Beam Suspension's Fatigue Life Research Based On The K&C Optimized Design

When vehicle runs on the earth,because of the effect of road roughness,it always causes great impact on wheels.The suspension transfers these loads to the body via spring,absorber,guiding mechanism.This not only attenuates vibration,but also can ensure the automobile running smoothly.During the process,the suspension suffers most alternating loads and after cycling many times,much fatigue damage accumulates,which results in reducing the fatigue life of the suspension and directly affects the vehicle's service life.Thus,it is very valuable and significant to research the torsion beam suspension's fatigue life under the measured road spectrum and put forward corresponding optimization design.Some passenger car's torsion beam suspension did not meet the designed range under service condition,but appeared fatigue crack.Centered on this problem,by virtue of conducting the suspension's fatigue analysis,the author starts from K&C Optimization Design and tries to seek an effective method to improve the fatigue life of the torsion beam suspension.Firstly,the author regards actual geometry mode of the torsion beam suspension as a benchmark,establish the three-dimensional model of suspension,which is imported into the finite element software to establish finite element model of the torsion beam suspension.Meanwhile,the author carries out the model accuracy correction and the Statics analysis.According to the result of analysis,the author conducts the vehicle fatigue durability test.Secondly,the author builds Macpherson front suspension,torsion beam rear suspension subsystem and so on,and complete the assembly of the coupled vehicle model according to the connection relation between subsystems.To verify the coupled model,Dynamics simulation analysis of the vehicle is conducted under the road spectrum.Extracting the suspension boundary load,the author conducts transient response analysis of the torsion beam suspension in Patran and compare the results to verify the correctness of the vehicle coupled model.Finally,the author selects MSC.Fatigue to conduct the fatigue analysis of the torsion beam suspension.According to the analysis of suspension fatigue fracture reasons,the author optimizes the helical spring installation position,efficiently reducing the helical spring vertical load,improving the fatigue life of the torsion beam suspension greatly and analyzes kinematics characteristics and compliance characteristics(K&C characteristics)of the vehicle before and after optimization.The author uses the method of combining the road test and CAE analysis to research the fatigue life of the torsion beam suspension,which ensures the accuracy of the results,and reduces the test cost,providing reference for the methods used to study fatigue problems;Based on the vehicle model rather than suspension model to study the fatigue life of suspension,improve the accuracy of the fatigue analysis;By structural optimization,it provides a feasible method to solve the problem of suspension frame fatigue crack.