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CREEP‐FATIGUE STUDIES UNDER A BIAXIAL STRESS STATE AT ELEVATED TEMPERATURE
Author(s) -
Hamada Naomi,
Sakane Masao,
Ohnami Masateru
Publication year - 1984
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.1460-2695.1984.tb00407.x
Subject(s) - materials science , structural engineering , torsion (gastropod) , creep , low cycle fatigue , stress (linguistics) , von mises yield criterion , austenitic stainless steel , fatigue testing , amplitude , composite material , finite element method , engineering , corrosion , medicine , linguistics , philosophy , physics , surgery , quantum mechanics
In order to study creep‐fatigue interactions under multiaxial stress states, both push‐pull and reversed torsion low‐cycle fatigue tests were carried out using an austenitic stainless steel, SUS 304, at 923 K in air. From the tests, it is concluded that the hold‐times introduced at the peak strain reduce low‐cycle fatigue lives in the push‐pull mode, but in the torsional mode they were not so harmful. This difference in the hold‐time effect is discussed from considerations of crack formation and propagation and the stress amplitude applied to the specimen. Both maximum principal strain range, Δε 1 , and the von Mises' equivalent strain range, Δε eq , provide a nearly adequate comparison base for the assessment of biaxial low‐cycle fatigue lives in tests without strain hold‐time but are inadequate for hold‐time tests. An equivalent stress range, Δσ*, which includes the effect of the stress parallel to the fatigue crack and which was previously proposed by the authors for no hold‐time tests, is applied to the hold‐time tests in the biaxial stress state. It is found that Δσ* is a good parameter for the correlation of biaxial low‐cycle fatigue data in both no hold‐time and hold‐time tests.