Elastomeric materials are often used as components that undergo cyclic loading during application, such as tires, seals, and hoses. For this reason, the long-term performance, or more precisely the crack growth behavior, is of great importance. Even though several studies investigated the fatigue behavior of rubber materials during the last 80 years, this topic is still widely under discussion and remains of great interest among scientists. Mars and Fatemi reviewed the developments of the field in the beginning of 2000, however, this paper considers the overall development including new findings to serve as a guide for further investigations in the field of fatigue of elastomers. For this purpose, the usual measurement methods and their evaluation, as well as the most important factors influencing the fatigue behavior, like the formulation of the rubber compound or the application and testing conditions, are explained in detail. Furthermore, an outlook is given on parameters that still need to be scientifically investigated, such as the influence of filler orientations or the selected manufacturing method, in order to fully understand fatigue crack growth.

The fatigue behavior of a filled non-crystallizing elastomer was investigated on axisymmetric dumbbell specimens. By plotting relevant Wöhler curves, a power law behavior was found. In addition, temperature increases due to heat build-up were monitored. In order to distinguish between initiation and crack growth regimes, hysteresis curves, secant and dynamic moduli, dissipated and stored energies, and normalized minimum and maximum forces were analyzed. Even though indications related to material damaging were observed, a clear trend to recognize the initiation was not evident. Further details were revealed by considering a fracture mechanics. The analysis of the fracture surfaces evidenced the presence of three regions, associated to initiation, fatigue striation, and catastrophic failure. Additional fatigue tests were performed with samples in which a radial notch was introduced. This resulted in a reduction in lifetime by four orders of magnitude; nevertheless, the fracture surfaces revealed similar failure mechanisms. A fracture mechanics approach, which considered the effect of temperature, was adopted to calculate the critical defect size for fatigue, which was found to be approximately 9 μm. This value was then compared with the particle size distribution obtained through X-ray microcomputed tomography (μ-CT) of undamaged samples and it was found that the majority of the initial defects were indeed smaller than the calculated one. Finally, the evaluation of J-integral for both unnotched and notched dumbbells enabled the assessment of a geometry-independent correlation with fatigue life.