Numerical Analysis And Experimental Study On The Fatigue Of Torsion Beam Rear Suspension Based On Shot Peening

Suspension is an important part of the vehicle structure,and the torsion beam suspension as a semi independent suspension is widely used in automotive rear suspension because of its simple structure and convenient maintenance.Automotive lightweight design philosophy makes the strength and stiffness of the auto parts decreased,affecting the safety car ride,Therefore,it is necessary to check the relative performance of the lightweight design of automobile parts,especially the fatigue life.In the past,it is mainly to test the fatigue life of auto parts by bench test or vehicle road test which needs to spend a lot of time and cost.With the development of the computer,the simulation technique that shorten the development cycle of the automobile parts and save the cost is used to analyze the fatigue life.This paper mainly aims at the problem that the torsion fatigue life of torsion beam rear suspension is not up to standard and the treatment scheme of shot peening on the beam of the torsion rear suspension is presented.The fatigue life is up to the standard,and the numerical simulation is carried out.UG software was used to establish the three-dimensional model of the torsion beam rear suspension,and the CAE model for finite element analysis of the torsion beam rear suspension was obtained by the geometric cleaning,meshing and so on.Static modal analysis of the finite element CAE model of the torsion beam rear suspension was carried out and the modal parameters that include the natural frequencies and the corresponding vibration modes of the free state were obtained.The mathematical model which can truly reflect the actual structure of the torsion beam rear suspension was established to carry out the static mode test on the torsion beam rear suspension.The natural frequencies and vibration modes of the torsion beam rear suspension were obtained by using the PolyMAX data processing method to deal with the modal test data.The experimental results were consistent with the results of finite element analysis,and verify the correctness of the finite element CAE model of the torsion beam rear suspension.The numerical simulation of torsion fatigue test bench of torsion beam rear suspension was carried out.The torsion fatigue life of the torsion beam rear suspension was predicted to reach the bench test standard,and the position of the damage occurred in the welding of the beam and the longitudinal arm.The torsion fatigue bench test was carried out on the torsion beam strengthened by shot peening.The test results which were in agreement with the numerical simulation show that the fatigue life of the torsion beam strengthened by shot peening had reached the standard of bench test.The accuracy of numerical simulation of torsion fatigue test bench test on torsion beam rear suspension was verified.The torsion fatigue life of torsion beam rear suspension had been compared before and after shot peeningand find that in the two cases of S=±30mm and S=±40mm,the fatigue life of shot peening specimens were 2 and 4 times of the sample without shot peening.It was concluded that shot peening can significantly improve the fatigue life of torsion beam rear suspension,and the torsion beam rear suspension which was strengthened by shot peening can meet the requirement of lightweight design and reached the standard of bench fatigue test,which can be put into use.