Load Interaction Effects on FCG: Master Curve Approach 2007-01-3676
The majority of fatigue crack growth (FCG) data associated with load interaction effects have been interpreted in terms of plasticity effects at the crack wake. This paper presents a new approach by which the FCG behavior for different R-ratios can be predicted using the master curve. In this approach, the stress intensity factor (SIF) range, ΔK, is normalized in terms of ΔK at R=0. The corresponding mean value of SIF, Km, is normalized by the SIF amplitude, Ka. A curve is plotted for this normalized SIF data, which collapses all the R-ratios into a master curve and therefore enables the prediction of other R-ratios. From the analyses of different materials taken from literature it is demonstrated that the master curve approach is very effective in predicting the R-ratio effects on fatigue crack growth behavior.
