Fatigue characteristics of vulcanized natural rubber for antivibration (2nd report, A study on the fatigue life prediction under uniaxial variable loading)

In order to investigate fatigue characteristics of vulcanized natural rubber (NR), fatigue tests are carried out under various stress ratios R and variable loading. In this paper, fatigue crack propagation life is predicted depending on fatigue crack propagation behavior, because the fatigue life is almost the fatigue crack propagation life. Two essential assumptions for the application of Miner's rule are satisfied. It is considered that Miner's rule can predict the fatigue life safely under two-step loading, because the fatigue damage location is depending on R. Under complex variable loading, it is considered that the crack growth rate under 0<R< 1 condition is accelerated because of disappearance of crystallization effect. So, it is necessary to make up the modified constant life diagram. The fatigue crack propagation life can be predicted using the modified constant life diagram and Miner's rule.