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AN IMPROVED A.C. POTENTIAL DROP METHOD FOR DETECTING SURFACE MICROCRACKS DURING FATIGUE TESTS OF UNNOTCHED SPECIMENS
Author(s) -
VERPOEST I.,
AERNOUDT E.,
DERUYTTERE A.,
NEYRINCK M.
Publication year - 1980
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.1460-2695.1980.tb01360.x
Subject(s) - materials science , composite material , fracture (geology) , current (fluid) , drop (telecommunication) , fracture mechanics , mechanics , structural engineering , geology , engineering , physics , mechanical engineering , oceanography
—The detection and measurement of surface microcracks in unnotched specimens are becoming more important, both from the point of view of description of crack growth by linear elastic fracture mechanics and from the classical endurance limit approach. Theoretical analyses of the current distribution in a cylindrical test specimen show promise that the a.c. potential drop method will become more sensitive for surface microcracks when higher current frequencies are applied. This effect was experimentally affirmed during fatigue tests on unnotched cylindrical specimens. With a 40 kHz current frequency semicircular surface microcracks with an area of 0.0066 mm 2 (0.05% of the specimen cross‐section) were detected. For accurate and reproducible crack growth measurements, a 5 kHz current frequency is preferable.