Effect of temperature and filler ratio on fatigue life of rubber

Natural rubber is widely used in the automotive industry in order to isolate noise and damp vibrations, e.g., suspension bushings, engine mounts, top mounts, exhaust hangers, and radiator mounts to mention but a few. Fatigue life of rubber components are influenced by many factors such as loading history, environmental conditions, rubber formulation, and dissipative mechanisms in the rubber compound. The operating temperature of rubber components is related to their position on the vehicle. The rubber components such as the engine mounts and the exhaust hangers are subjected to high temperatures during service. Consequently, the role of the temperature on the fatigue life of such components becomes decisive in compound selection. In this study, fatigue life variation with respect to temperature and filler ratio has been investigated by using EPDM and NR compounds. We perform constant amplitude fatigue tests for grubber compounds with different filler ratios at room and elevated temperatures. Crack surfaces resulting from fatigue cracks and the three dimensional CT-scans of the dumbbell specimens are demonstrated. It is shown that temperature and filler ratio play an important role in the fatigue life of rubber components.