Cyclic loadings and crystallization of natural rubber: An explanation of fatigue crack propagation reinforcement under a positive loading ratio

▶ Crack branching extending in a fractal-like behavior across the scales. ▶ Crack branching reduces significantly the crack growth rate. ▶ Cyclic hardening can be observed on natural rubber under particular loading conditions. ▶ Cyclic hardening is induced by accumulation of strain induced crystallisation. ▶ Crack branching is induced by accumulation of strain induced crystallisation.