Abstract
Master fatigue life curve for rubber vulcanizates has been constructed from applied stress σ and fatigue life tb normallized by stress at break σb and time until break τb under simple elongation. If temperature dependence of σb and τb is approximated by exponential function, the fatigue life (tb)σ, T of vulcanizates at a given stress σ and temperature T can be estimated by the next equation.
log(tb)σ, T=log(tb)σs, Ts+mlogσ/σs+(ΔEε/R-mΔEσ/R)(1/T-1/Ts)
Here, (tb)σs, Ts is the fatigue life of vulcanizates under standard stress σs and temperature Ts. m is a constant and R is the gas constant. ΔEσ and ΔEε are the apparent activation energy for the temperature dependence of the strength and elongation of vulcanizates under thermal degradation, respectively.
