Fatigue life prediction of natural rubber components for uniaxial and multiaxial loadings

In this paper, the fatigue lifetime of natural rubber (NR) components is investigated, and a criterion predicting the number of cycles to initiation (N-i) of a short crack is proposed. Uniaxial test results require a diagram which plot the stress amplitude versus the mean stress. A first extension to cyclic multiaxial tests was carried out using two kinds of axisymmetrical notched samples (AE5 and AE2 specimens) tested under repeated uniaxial and torsion loadings. The corresponding 2D and 3D simulations with finite element analyses (F.E.M.) give the Cauchy stress fields. The results suggest that the largest principal stress versus mean hydrostatic pressure diagram is well suited for the prediction of the cycles to initiation (N-i) in many NR components.