Analysis of Fatigue Crack Growth Life for Rubber Vibration Damper

The fatigue crack growth tests for pure shear specimens of NR68 rubber are carried out and the results show that a power relationship exists between crack growth rate and tearing energy.Based on the theory of cumulative fatigue damage,a fatigue life prediction model for rubber with the tearing energy range as damage parameter is built.Model parameters are obtained from fitting fatigue crack growth test data of NR68 rubber by regression analysis.The method of calculating tearing energy of elastic damping components is put forward by using finite element structural analysis,equivalent stress calculation of rubber materials and stress-strain data of single edge notched tensile(SENT) specimens in tensile tests,and fatigue of elastic damping components in complex stress state can be changed into fatigue of rubber material in uniaxial stress state.The fatigue life of a cone-shaped rubber spring is analyzed by using the model and verified by fatigue bench test result of the rubber spring.The result shows that the predicted fatigue life is 1.33 times that of the fatigue test life.So,the prediction accuracy is good.