Fig. 3 FCG in DARVIC 110 material
plotted in terms of a) ΔK and b) Kmax. c) ΔK-R curves
for crack growth rate near thresholds showing two possible mechanisms.
d) The corresponding two L-shaped ΔK-Kmax curves with
limiting values. e)FCG trajectory for the two mechanisms.
corresponding two L-shaped ΔK-Kmax curves are shown in
Fig.3d, with limiting values at each crack growth rate. The FCG
trajectories for the material are shown in Fig.3e. Both mechanisms
deviate from the pure fatigue line, with mechanism two operating at high
R-ratios, deviating more towards the Kmax-axis.
Osorio has determined FCG for somewhat brittle Epoxy(828/959) material
also at many R-ratios. Fig. 4a shows the crack growth rates in terms of
ΔK and Fig. 4b in terms of Kmax. In contrast to PVC
material, the data for Epoxy seem to spread out in terms of both
parameters. Fig. 4c shows the plot of ΔK-R curves at low crack growth
rates, which follows a typical trend. Fig. 4