Fatigue behavior characterization and life prediction for elastomeric components

Failure behavior characterization and prediction of fatigue life of elastomers became important issues due to the wide usage of elastomeric components in Aerospace applications. Thus, the understanding of the fatigue crack initiation micro-mechanisms and their link to the local stress or strain history were particularly essential. Crackscould initiate and propagate over a long period of time since 90% of the fatigue life was spent in the crack stage. Cracks were found to initiate at defects associated with the sample geometry and processing, then propagated systematically in the direction given by the maximal principal strain reached during the cycle, evenunder non-proportional loading. In this study a general methodology derived fromcontinuum damage mechanics and the material fatigue damage to the number of cycles was proposed, in which the Mullin´s effect was also discussed. The shell shape specimen was used for fatigue life prediction based on FE simulation using Ogden hyperelastic material model determined from the tensile, shear and biaxial tension tests of the natural rubber. lt was shown that the fatigue life prediction results were good agreement with the experimental results.