Premium
Empirical model for plasticity‐induced crack closure based on K max and Δ K
Author(s) -
Antunes F. V.,
Chegini A. G.,
Camas D.,
Correia L
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.12298
Subject(s) - closure (psychology) , plasticity , materials science , crack closure , range (aeronautics) , stress (linguistics) , empirical modelling , fracture mechanics , constant (computer programming) , mathematics , thermodynamics , physics , composite material , engineering , computer science , economics , simulation , linguistics , philosophy , market economy , programming language
The mean stress has a significant effect on crack propagation life and must be included in prediction models. However, there is no consensus in the fatigue community regarding the dominant mechanism explaining the mean stress effect. The concept of crack closure has been widely used and several empirical models can be found in literature. The stress ratio, R , is usually the main parameter of these models, but present numerical results showed a significant influence of K max . A new empirical model is therefore proposed here, dependent on K max and Δ K , with four empirical constants. The model also includes the effect of material's yield stress, and two additional parameters were defined to account for stress state and crack closure parameter. A comparison was made with Kujawski's and Glinka's parameters, for a wide range of loading conditions. Δ K eff lies between Kujawski's and Glinka's parameters, and some agreement is evident, although the concepts are quite different. The crack opening model was applied to literature results and was able to collapse d a /d N –Δ K curves for different stress ratios to a single master curve.