A novel fatigue life prediction method of carbon black filled rubber based on hysteresis loss of steady state under various load ratios

Carbon black (CB) filled rubber specimens were experimentally investigated to examine the effect of loading conditions on the self-heating and fatigue life. The self-heating was analyzed by implementing dynamic mechanical tests on cylindrical specimen, and the fatigue life was obtained by conducting a force-controlled fatigue test on hourglass specimen. In addition, the surface temperatures of the specimens were recorded with a ThermaCAM SC3000 infrared camera. Furthermore, this study explored the relationship between the hysteresis loss and the steady state temperature, finding that the steady state temperature would rise with the increase of the hysteresis loss. Traditionally, in the process of fatigue life prediction, such factors as maximum principal stress, strain energy density and temperature rise were used as fatigue parameters. In this study, a linear relationship between the hysteresis loss and the steady state temperature was established; then, by substituting the linear relationship into the traditional fatigue life equation, an empirical equation based on the hysteresis loss was derived. The results show that the proposed equation could predict the fatigue life in a satisfactory manner. Moreover, in this study, the cycles needed to reach the steady hysteresis loss state are far less than the fatigue life. Therefore, the proposed method provides a new choice for evaluating the fatigue life in a quick and cheap way.