Fatigue testing of rubber materials and articles

The mechanism of rubber fatigue in tension, based on fracture mechanics, and the relationship between crack growth measurements and fatigue tests are revised. Deviations from linearity are considered. The importance of test conditions, such as constant stress or constant strain, in development work is stressed.

Poor precision of fatigue results is noted. As frequency distributions of test results often do not follow a Gaussian pattern, fitting a Weibull distribution function to experimental fatigue results is recommended as it allows estimation of confidence intervals of parameters such as median, mean, etc., and the statistical analysis of results.

The use of master curves for extrapolation of fatigue results to low tearing energies close to fatigue limit is revised. Extension of fatigue results to other deformation modes is briefly considered.