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A CRACK CLOSURE STUDY TO PREDICT THE THRESHOLD BEHAVIOUR OF SMALL CRACKS
Author(s) -
Journet B. G.,
Lefrancois A.,
Pineau A.
Publication year - 1989
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.1460-2695.1989.tb00530.x
Subject(s) - materials science , crack closure , closure (psychology) , alloy steel , stress intensity factor , crack growth resistance curve , fracture mechanics , alloy , composite material , mechanics , metallurgy , structural engineering , engineering , physics , economics , market economy
— The small crack problem is addressed within the applicability of Linear Elastic Fracture Mechanics as the result of crack closure phenomenon. The variation of crack closure stress intensity factory K op as a function of crack length, a , was determined in two materials, namely a A508 steel and a 2024A1 alloy. These results were obtained on two‐dimensional small cracks ( a ≫ 0.1 mm) which were machined from long fatigue cracks. These measurements of K op in addition to data published in the literature on a nodular cast iron and a 9Cr–1Mo steel yield to a unique characteristic function: K op / K o = 1 –exp(– ka ) in which k is the only parameter to characterize the small crack effect. A prediction of the threshold behaviour of small and long cracks on A508 steel is made using the results of crack closure measurements.