ABSTRACT
This chapter deals with mean stress corrections for locally uniaxial non relaxing loads. It also deals with the characterization of a filled natural rubber under relaxing and non-relaxing loads using crack initiation and crack propagation approaches. Crack growth curves are then used to predict the measured Wohler curves. From a classical theoretical point of view, fatigue failure should be dissociated in two phases: crack nucleation and crack propagation. Though lacking concrete understanding of the physical crack nucleation mechanisms in filled natural rubbers, most authors introduce a homogeneous distribution of pre-existing flaw in the rubber matrix. The mean-value size of this distribution is assumed to be characteristic of the material and the mixing/molding process. The material used is a carbon black-filled natural rubber. The comparison of crack initiation results and extrapolation of crack propagation law to crack initiation, whatever the kind of loading, is satisfactory.
