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Low cycle thermo‐mechanical fatigue: damage operator approach
Author(s) -
NAGODE M.,
HACK M.,
FAJDIGA M.
Publication year - 2010
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.1460-2695.2009.01424.x
Subject(s) - isothermal process , low cycle fatigue , constant (computer programming) , materials science , structural engineering , cycle count , stress (linguistics) , fatigue testing , mathematics , composite material , computer science , engineering , thermodynamics , physics , linguistics , philosophy , operations research , programming language
The strain‐life approach is standardized and widely accepted for determining fatigue damage under strain‐controlled low cycle fatigue (LCF) loading. It was first extended to non‐isothermal cases by introducing an equivalent temperature approach (ETA). The paper presents its extension that is the damage operator approach (DOA) enabling online continuous damage calculation for isothermal and non‐isothermal loading with mean stress correction. The cycle closure point, cycle equivalent temperature, threshold temperature and separate rainflow counting obligatory for the ETA are not necessary for the DOA any more. Both approaches are equivalent for the second and subsequent runs of block loading if temperature is constant. However, for non‐isothermal cases, the DOA is within the worst and the best case scenarios of the ETA. The approaches are compared to the simple stress histories and several thermo‐mechanical fatigue (TMF) cycle types.