Dissipated energy density as fatigue criterion for non-relaxing tensional loadings of non-crystallizing elastomers?

Abstract The influence of the minimum load on the mechanical fatigue properties of ethylene propylene diene rubber is investigated. Force controlled fatigue experiments with two different positive ratios of minimum and maximum tensile loads are compared with results based on fully relaxing loading conditions. These tests are conducted under exclusion of other factors influencing durability (e.g. specimen temperature, deformation rate) with an axisymmetric dumbbell specimen. In order to quantify the impact of the crack initiation on the dumbbell's parting line, fully relaxing dumbbell tests are compared with fully relaxing tests using a shear specimen with internal crack initiation. The location of the crack initiation has little impact on the durability of EPDM rubber. Various end-of-life predictors are applied on the experimental database. Recently presented as a promising fatigue criterion, the dissipated energy density did not show the best results in this work.