A new (ΔK+Kmax)0.5 driving force parameter for crack growth in aluminum alloys

In this paper, a new mechanical driving force parameter for long- and short-crack growth rate correlation is proposed. This new parameter, (DeltaK(+)K(max))(0.5) does not utilize disputable crack closure data, instead it is calculated as a geometric mean of the positive part of the applied stress intensity factor (SIF) range, DeltaK(+), and the corresponding maximum value of the SIF K-max. The proposed parameter correlates fairly well the R-ratio effects on the threshold condition and fatigue crack growth rate at the low and intermediate stress intensities for six aluminum alloys investigated. (C) 2001 Elsevier Science Ltd. All rights reserved.