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CTOD i MEASURED BY MEANS OF A MODIFIED CHARPY‐V‐SPECIMEN
Author(s) -
Reiff K.,
Ernst P.
Publication year - 1997
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.1460-2695.1997.tb00399.x
Subject(s) - crack tip opening displacement , charpy impact test , materials science , radius , extrapolation , structural engineering , composite material , mathematics , toughness , fracture mechanics , engineering , stress intensity factor , mathematical analysis , computer science , computer security
— Measurements of CTOD i on Charpy‐V‐specitnens of mild steel St 37 and pressure‐vessel steel 22NiMoCr37 have been carried out. Slotted and precracked specimens have been used besides the original V‐notched ones. A definition of CTOD = 2(R – R o ) has been proposed which corresponds to δ 45 , defining the CTOD of fatigue cracks. The symbols R o and R represent the original and the actual crack tip radii respectively. Additionally, this definition presents the opportunity to measure CTOD and CTOD i by a direct metallographic method. It is demonstrated that COD testing, based on the hinge model, can also be applied to slotted bars, delivering CTOD and CTOD i values which are equal to those evaluated by direct metallographic measurements. The results obtained on four different tip radii, R o , show a linear increase of CTOD i as a function of R o , which is steeper for the softer material St 37. The extrapolation to the tip radius R o =0 gives a CTOD i , which is equal to those determined from precracked specimens.