This study deals with the fatigue crack initiation under multiaxial non-proportional loadings
in a natural rubber. Push–pull, torsion and tension-compression with a superimposed static
torsion fatigue test results are presented. A short presentation of some important features
concerning short fatigue crack growth is given. Two fatigue crack criteria are proposed, the
first one based on the first and second invariant of the Cauchy stress tensor, the second,
based on the micromechanisms of crack initiation, consist of a critical plane approach under …