Development of Fatigue Life Equation for NBR Material and Estimating Fatigue Life Using Fea

摘要

Rubber materials are used in many pneumatic applications. Rubber has excellent damping characteristics and it experiences large reversible elastic deformation. For the safety and reliability of rubber components, it is important to predict the behaviour of rubber. In this research, fatigue life of rubber components is predicted by finite element analysis and developed fatigue life equation. Mechanical tests such as uniaxial tension, uniaxial compression and pure shear test were performed on NBR material for the material characterisation in ANSYS. A hyperelastic model was selected by performing the curve fitting in ANSYS. Fatigue tests on a standard dumbbell specimen of NBR material were performed at different strains, and fatigue life equation was derived with least square fit method and fatigue test data. Then the maximum principal elastic strain obtained through FEA was used as the fatigue damage parameter as mentioned in the literature. Maximum principal elastic strain was substituted in the obtained fatigue life equation and fatigue life of rubber spring was predicted. The results were validated by performing the fatigue test on rubber spring.