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Development of a fatigue crack growth testing apparatus and its application to thin titanium foil
Author(s) -
Lee C.W.,
Liu L.,
Holmes J. W.
Publication year - 2013
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.12086
Subject(s) - materials science , paris' law , foil method , composite material , stress intensity factor , cyclic stress , crack closure , tension (geology) , titanium , ceramic , stress (linguistics) , ultimate tensile strength , metallurgy , fracture mechanics , linguistics , philosophy
A low‐cost experimental apparatus has been developed to investigate the mode I fatigue crack growth behaviour of thin metallic foils and sheets. The apparatus utilizes magnetic coupling between a ceramic magnet and a rotating steel disc to induce cyclic tensile loads in notched rectangular specimens. To illustrate the testing apparatus, mode I fatigue crack growth in 30‐µm‐thick high‐purity titanium foils was studied. Experiments were performed at ambient temperature using a loading frequency of 2 Hz and a nominal stress ratio of 0.1. The cyclic crack growth data could be fit to a Paris relationship between crack growth rate and stress intensity range. The stress intensity factor exponent, m , in the Paris relationship was between 4 and 6, which is comparable with the relatively high values found in the literature for the tension–tension fatigue of other metallic bulk materials. Incomplete self‐similarity analysis was used to explain the observed higher m values for thin metallic foils.