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AN EXPERIMENTAL STUDY ON THE OPENING AND CLOSURE BEHAVIOUR OF FATIGUE SURFACE, CORNER AND THROUGH‐THICKNESS CRACKS AT NOTCHES
Author(s) -
Savaidis G.,
Seeger T.
Publication year - 1994
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.1460-2695.1994.tb00222.x
Subject(s) - materials science , crack closure , strain gauge , composite material , crack tip opening displacement , crack growth resistance curve , structural engineering , closure (psychology) , stress (linguistics) , surface (topology) , amplitude , stress concentration , fracture mechanics , geometry , mathematics , optics , engineering , physics , market economy , linguistics , philosophy , economics
— The opening and closure behaviour of surface, corner and through‐thickness cracks in thin notched plates of FeE460 ( K t = 2.5) and A15086 ( K t = 3.4) was experimentally studied. The cracks were initiated and examined under uniaxial fully reversed constant amplitude and two‐step loading. Crack opening load values were measured during crack growth in notch sections with a nonuniform stress distribution using small strain gauges glued to the specimen surface, very close to the crack tip. The results represent a comprehensive set of experimental data for crack opening load values in dependence on crack lengths a, c and load level including the influence of overloads and covering all types of cracks. The results indicate uniform relationships between crack opening load levels and all crack types. Crack opening and closure occur at nearly the same strain level, which depends on the applied load level. The crack opening load values measured at large notched specimens differ from those measured at similar smaller specimens because of the different local stress gradients.