contrainte répétée

OBS: si (...) le sens (...) ne change pas mais seule l'intensité varie [et] la valeur minimale est nulle, la contrainte est dite répétée.

OBS: when a material is subjected to many cycles of stress reversal or fluctuation (...) failure may occur, even though the maximum stress (...) is (...) less than (...) if the stress were constant.