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Examination of fatigue crack driving force parameter
Author(s) -
XIONG Y.,
KATSUTA J.,
KAWANO K.,
SAKIYAMA T.
Publication year - 2008
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.1460-2695.2008.01261.x
Subject(s) - range (aeronautics) , materials science , amplitude , structural engineering , composite material , physics , engineering , optics
Most of the previous parameters that utilized as a crack driving force were established in modifying the parameter K op in Elber's effective SIF range Δ K eff (= K max − K op ). However, the parameters that replaced the traditional parameter K op were based on different measurements or theoretical calculations, so it is difficult to distinguish their differences. This paper focuses on the physical meaning of compliance changes caused by plastic deformation at the crack tip; the tests were carried out under different amplitude loading for structural steel. Based on these test results, differences of several parameter Δ K eff in literature are analysed and an improved two‐parameter driving force Δ K drive (=( K max ) n (Δ K ∧ ) 1‐n ) has been proposed. Experimental data for several different types of materials taken from literature were used in the analyses. Presented results indicate that the Δ K drive parameter was equally effective or better than Δ K (= K max − K min ), Δ K eff (= K max − K op ) and Δ K *(= ( K max ) α (Δ K + ) 1−α ) in correlating and predicting the R ‐ratio effects on fatigue crack growth rate.