An energetic criterion for the fatigue of rubbers: an approach based on a heat build-up protocol and u-tomography measurements

摘要

The temperature of rubber-like materials increases under cyclic loadings due to their dissipative behavior and low thermal conductivity. This well-known phenomenon, called "heat build-up" in the rubber community, has attracted the attention of researchers for a long time. But, to our knowledge, no published studies have tried to link the temperature rise to a fatigue behavior, as already done on some metallics. Two main points are discussed in this paper. The first one is dedicated to heat buildup measurements: a dedicated experimental protocol is developed to capture the instantaneous heat build-up (taking into account the thermomechanical couplings) and, based on this protocol, a heat build-up experiment is defined in order to link the steady-state temperature to the maximum principal strain. A discussion on the correlation between these results and the fatigue behavior is opened and illustrated for several industrial materials. The second point investigates the ability to couple X-ray u-tomography measurements presented in another paper [1] to the former heat build-up results in order to predict the initiation lifetime. An approach based on a critical energy criterion is proposed and the comparison to a classic Wohler curve approach gives good results.