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UNSTABLE FATIGUE CRACK PROPAGATION AND FATIGUE FRACTURE TOUGHNESS OF STEELS
Author(s) -
TROSHCHENKO V. T.,
POKROVSKY V. V.,
YASNIY P. V.
Publication year - 1994
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.1994.tb00828.x
Subject(s) - materials science , fracture toughness , crack closure , fracture mechanics , crack growth resistance curve , paris' law , stress concentration , composite material , plane stress , toughness , compact tension specimen , fracture (geology) , fatigue testing , structural engineering , finite element method , engineering
This paper presents the results of fatigue crack growth and fatigue fracture toughness studies of a high‐pressure vessel steel with particular emphasis on the influence of heat treatment, low temperatures, plastic prestraining, the stress ratio and specimen dimensions. It has been shown that steels in an embrittled state, caused primarily by thermal treatment and low‐temperatures, exhibit unstable fatigue crack growth which is characterized by alternate crack jumps (cleavage zones) and zones of fatigue crack growth. The fatigue fracture toughness, which corresponds to the first crack jump, and final fracture can be appreciably lower (i.e. up to 50%) than the static fracture toughness under plane strain conditions at the corresponding temperature. An analysis has been performed of unstable and stable fatigue crack growth and a model of unstable crack propagation is proposed which accounts for the observed experimental behaviour.