A prediction methodology of fatigue strength of polymer composites for an arbitrary frequency, stress ratio, and temperature is introduced. The methodology is based upon the three hypotheses ; (A) Same time-temperature superposition principle holds for CSR (constant strain-rate), creep, and fatigue strengths, (B) Linear cumulative damage law is applicable under monotonic loading history, and (C) fatigue strength shows linear dependence upon stress ratio. The validity of hypotheses A, B, C, and the applicability of this prediction methodology were discussed. Finally, the future issues which should be solved for the practical use to the durability design are listed.
