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Variable amplitude loading in the very high‐cycle fatigue regime
Author(s) -
STANZLTSCHEGG S. E.,
MAYER H.,
STICH A.
Publication year - 2002
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 - 10.1046/j.1460-2695.2002.00570.x
Subject(s) - amplitude , materials science , ultrasonic sensor , fatigue limit , aluminium , paris' law , intensity (physics) , structural engineering , stress (linguistics) , fatigue testing , constant (computer programming) , composite material , alloy , metallurgy , fracture mechanics , crack closure , acoustics , engineering , physics , optics , programming language , linguistics , philosophy , computer science
ABSTRACT Ultrasonic fatigue testing is appropriate to perform random loading tests in the regime of very high numbers of cycles. It has been shown that neither an endurance limit nor a threshold stress intensity exists under loading with randomly varying amplitudes even for materials that do show these limits under constant amplitude loading conditions. The technical features of the ultrasonic testing technique in order to perform random fatigue tests are shortly described. Endurance tests were performed on smooth specimens of AlSi7Mg (A356.0) aluminium alloy and on notched AISI 4142 and C45 steel specimens. The previous studies of crack propagation and threshold behaviour on AISI 420 ferritic chromium steel and GGG 100‐B cast iron are included. Experimental results on lifetime and fatigue crack growth measurements under randomly varying amplitudes, as well as lifetime predictions, based on constant amplitude measurements and damage accumulation calculations are reported.