Investigation of different influences on the fatigue behaviour of industrial rubbers

Load conditions used typically for fatigue life investigations can differ strongly from the conditions for real rubber products. For example, the frequency of the laboratory measurements is increased and the product load curve is simplified to a sine. In this paper, industrial rubber blends (SBR/BR/NR blends) under tension-compression load are used. First, the influence of a higher frequency (5 Hz) compared to the product relevant frequency (1 Hz) is investigated. A higher frequency does not influence the fatigue life but certainly the sample temperature and material behaviour. This is further investigated by varying the ambient temperature for 1 Hz measurements and the strain rate. Second, a non-sinusoidal wave form depicting the product loading case is selected. The load oscillates between tension and compression with dwell periods in every cycle. The results are comparable to those of a sine wave with the same frequency.