Experiment And Simulation Study On Fatigue Characteristics Of Metal Rubber Vibration Isolators

Metal rubber materials have good elasticity,large damping characteristics,radiation resistance,high temperature resistance and corrosion resistance.They have been widely used as vibration isolation materials in many key areas.In recent years,the fatigue and reliability issues of metal rubber vibration isolators have been drawn attention as the requirement of their extending service life in the deepening applications.In the existing research,the research method of the fatigue behavior of metal rubber isolator mainly relied on tests to obtain the formulas for calculating the service life.However,there is little research on the performance degradation law and internal fatigue mechanism of the fatigue failure process.Especially the impacts of environment temperature on the degradation performance of metal rubber vibration isolators have not been identified.This research studies the fatigue failure process of a certain type of metal rubber isolator under different temperature conditions,summarizes the degradation laws and analyzes the internal causes of fatigue and the dynamic response of the system through the method of combining tests and finite element analysis.This study proposes the performance parameters of the non-linear characteristics of the metal rubber isolator and uses the perturbation method to analyze the related theory of the mechanical properties change caused by the metal rubber fatigue.The fatigue of the metal rubber isolator is tested at different temperatures.According to the test result,the variation rules of stiffness,damping,resonance frequency and transmission rate of metal rubber isolators in the soft and hard phases change over service time.This reveals the effect of high and low temperature environment on fatigue failure of metal rubber: low temperature environment can slow down the damping characteristics of metal rubber Decay;high temperature environment will aggravate the permanent deformation of metal rubber.Based on the analysis of microscopic characteristics of the fatigued metal rubber,the internal cause of fatigue failure points to the fatigue fracture and friction,the wear of the micro-element spring structure and the interaction between these two parts.Using the finite element simulation method: S-N curve method,virtual crack propagation technology and low cycle fatigue simulation method,to simulate the crack initiation and the crack propagation process of the micro element spring structure under different load forms.The test shows two results : the S-N curve of micro element spring structure can be obtained;the law of performance attenuate as the crack deepens further.The dynamic simulation study of the metal rubber vibration isolation system is carried out.The dynamic simulation method of vibration isolation system is established.The properties of metal and rubber nonlinear materials are defined based on the ABAQUS user-defined material(UMAT)function.The finite element model of vibration isolation system is established.The dynamic response of metal rubber vibration isolator is obtained.A simulation analysis of the effect of metal rubber fatigue on the dynamic characteristics of the vibration isolator at different preloads and different temperatures is performed.By comparing the test and simulation results,the performance degradation law of metal rubber fatigue failure is fully obtained.