Influence of the tensile static preload dependency on the dynamic lifetime prediction for an HNBR elastomer

A correlated lifetime prediction concept for load cases without static preload, which argues with crack growth and particle size distribution from 3D computer tomography, has been shown by Ludwig et al. (2015). This method is extended to non-relaxing load cases i.e. with a static preload dependency. A force controlled dynamic fatigue test for a dumbbell specimen is performed to investigate the service life. In addition, a crack growth investigation is carried out using single edge notched tensile (SENT) specimens in displacement control mode to characterize the tearing energy and crack growth rate. The study with carbon black reinforced HNBR rubber shows a correlation between the Wöhler curve and the Paris-Erdogan plot. An extension of the empirical Paris-Erdogan equation considering static preload dependency allows the prediction of uniaxial lifetime statistics by means of particle size distribution. The calculated lifetime values are in reasonable concordance with the experimental findings.