Fatigue Analysis Of A Rubber Shock Absorber Under Stochastic Loading Condition

Rubber is characterized by its high elasticity,large deformability and damping property,thus making it a great material out of which shock absorbers and dampers are made.Dampers consist of silicon rubber are widely used in aeronautics and astronautics,under which situation durability of rubber is a big concern since dampers are subjected to complex loading conditions during the whole life.It is of great importance for the engineers to analyze the fatigue problem of rubber material and predict the fatigue life of rubber component before it comes into products level.In this research,the constitutive behavior of rubber,the fatigue prediction theory and theory of stochastic vibration are taken into consideration.Two methods are propoesd to build the FEA model of the rubber damper in time domain and in frequency domain separately.The fatigue analyses of rubber damper are conducted after the FE analysis.Reasonable results are achieved from the fatigue life prediction of the rubber component.Tests on rubber material are performed at the first place to obtain parameters of material used in FE analysis,including hyper-elasticity,visco-elasticity and fatigue crack growth behavior.Meanwhile acceleration loading sequence is generated from the stochastic loading condition described as acceleration PSD spectrum.Fatigue analysis is conducted based on the CED theory and critical plane analysis using Endurica rubber fatigue analyzer.Fatigue life of each element of rubber is calculated.On the other hand,the FE model of the rubber damper is built for the random vibration analysis,and the stress PSD responses of each element are obtained,upon which the fatigue analysis is conducted based on the frequency domain method.Results show an obvious relativity between time domain method and frequent domain method.Same distribution of the predicted fatigue life demonstrates the validity of these two methods.