Strength Analysis And Fatigue Life Prediction Of A Certain Type Of Automobile Shock Absorber

Shock absorber,as an important part of automobile suspension system,has local cracks in the process of use,such as piston rod and hydraulic cylinder,which leads to the occurrence of shock absorber oil leakage phenomenon and seriously affects its service life.This topic takes a certain type of automobile shock absorber as the research object,aiming at the actual engineering problem of the piston rod and the bottom of the cylinder of the shock absorber crack,combined with the finite element analysis theory,static strength analysis theory and fatigue life related theory to carry out the related research,has a certain theoretical and practical significance.Firstly,the finite element model of the shock absorber was established,including 3D model creation,Hyper Mesh meshing and ABAQUS finite element model pre-processing,and the free modal analysis was carried out.Combined with the external excitation frequency of the car shock absorber,it is found that the natural frequency of the shock absorber is far greater than the external excitation frequency,which excludes the possibility of resonance failure of the shock absorber in the use process.Secondly,the dynamics simulation software to establish the model of using ADAMS/Car after Car torsion beam dynamics model of suspension system,extract the shock absorber pit in the vehicle and the reversing impact under the limit state of static load data,in ABAQUS rebound stroke and the compress stroke condition of static strength analysis,and intensity of shock absorber parts,The results show that each component of the shock absorber meets the requirements of static strength design and does not produce static strength damage.Among them,the piston rod and the bottom of the cylinder of the shock absorber under the condition of recovery stroke produce the largest stress,which is the position where the shock absorber is prone to crack.Finally,based on the static strength analysis of calculation results,select the maximum equivalent stress value larger rebound stroke condition,based on a 106-cycle fatigue life of the target number of piston rod and cylinder fatigue safety coefficient calculation,found that the shock absorber of the hydraulic cylinder safety coefficient is 0.939,less than 1,failed to achieve the objectives of the fatigue life requirements;The safety factor of the piston rod is1.039,which basically meets the target requirements of fatigue life,but the safety factor is small.Therefore,the subject of shock absorber piston rod and hydraulic cylinder for structural or material parameters adjustment,improve the safety factor of piston rod and hydraulic cylinder and shock absorber fatigue life.