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Evaluation of three current methods for including the mean stress effect in fatigue crack growth rate prediction
Author(s) -
Duran J. A. R.,
Hernandez C. T.
Publication year - 2015
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.12242
Subject(s) - stress intensity factor , paris' law , materials science , constant (computer programming) , enhanced data rates for gsm evolution , range (aeronautics) , amplitude , stress (linguistics) , structural engineering , growth rate , intensity (physics) , regression analysis , fracture mechanics , mechanics , crack closure , mathematics , statistics , geometry , composite material , engineering , physics , computer science , optics , telecommunications , linguistics , philosophy , programming language
The fatigue crack growth rates curves of engineering materials depend on two parameters. In addition to the dependence on the classical stress intensity factor (SIF) range Δ K , there is a dependence on the mean load (or mean SIF), mainly in the near‐threshold region. The present paper provides some useful suggestions and good practices for using three of the current available methods to reduce this second dependence through the use of tuning constants. The methods considered here are the Elber, Walker and Vasudevan (or unified approach). For each approach, multiple regression analyses are performed on experimental data from the literature, and the correlations in two and three dimensions are graphically analyzed. Numerical examples of crack growth analysis for cracks growing under nominal stresses of constant amplitude in single‐edge and notch/hole geometries are performed, assuming an identical material component to that of the available experimental data. The resulting curves of crack size versus number of cycles ( a versus N ) are then compared. All three models gave approximately the same ( a versus N ) curves in both geometries. Differences between the behaviors of the ( a versus N ) curves in both geometries are highlighted, and the reasons for these particular behaviors are discussed.