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Evaluation of notch size effect on LCF life of TA19 specimens based on the stress gradient modified critical distance method
Author(s) -
Wang R.,
Liu H.,
Hu D.,
Li D.,
Mao J.
Publication year - 2018
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/ffe.12821
Subject(s) - materials science , critical distance , stress (linguistics) , striation , fracture (geology) , composite material , reliability (semiconductor) , bar (unit) , growth rate , structural engineering , mathematics , geometry , physics , acoustics , thermodynamics , linguistics , philosophy , sound power , engineering , sound (geography) , power (physics) , meteorology
In the present study, the stress gradient modified critical distance method is proposed to predict the low‐cycle fatigue lifetime of notched TA19 specimens by introducing a weight function of relative stress gradient into conventional critical distance theories. The accuracy and reliability of the proposed method were validated based on the experimental data by performing low‐cycle fatigue tests on smooth bar TA19 specimens as well as geometrically similar plate specimens containing a bore hole (BHP). Predicted results demonstrate that the mean absolute errors for entire tested specimens using the stress gradient modified critical distance method on the basis of the point method and the line method are 7.49% and 7.41% respectively. Furthermore, the fatigue striation width at the fracture surface was determined by scanning electronic microscope observations to examine the stress gradient effect on the crack growth rate.