Abstract
The creep fracture behaviour of a notched specimen was studied for materials with prevailing Norton-type creep. New global parameters defining properties of stress and strain field in the whole notch region are introduced and calculated. It is concluded that there are two parameters controlling the lifetime of notched specimens: the first one is connected with the lifetime of smooth specimens and corresponds to applied load level, the second one expresses the influence of the size and geometry of the notch. The results of numerical simulations are compared with experimental findings for P91 steel.

Key words
fracture creep, stress triaxiality, creep strain rate, finite element method, P91 steel, two parameter description

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