Lifetime prediction with temperature dependence for EPDM and NR elastomers based on fatigue crack growth mechanical measurements and filler distribution

A fracture mechanical model extended towards thermal dependence and validated for two technical elastomers based on EPDM and NR elastomers reinforced with an amount of 50 phr carbon black (CB). Both materials were characterized for fatigue to failure (FTF) and for fatigue crack growth (FCG) behavior. Both methods were performed at three different test temperatures. The particle size distribution of both compounds was counted using computed tomography (CT). The mean value of the experimental data and the calculation show a deviation up to one decade for EPDM and NR elastomer at 23 degrees C. However, for both materials the mean value of the experimental data and the calculation from the developed concept are in the confidence limits at 90 degrees C of the number of cycles.

Automated summary

This study extended a fracture mechanical model to incorporate thermal dependence for technical elastomers based on EPDM and NR, reinforced with 50 phr carbon black. The experimental data and calculations showed significant deviation at 23 degrees C, but were within confidence limits at 90 degrees C for both materials. The study also utilized computed tomography to analyze particle size distribution of the compounds.