13th International Conference on Fracture June 16–21, 2013, Beijing, China -8- 5.1. Computed SIFs and analysis of crack growth rates Figure 8 shows the computed KI, KII and KIII computed at peak load along the 7 th crack fronts in specimens CCP5a and CCP2a. Figure 8: SIFs at peak load along the 7th crack fronts in a) Al specimen CCP5a b) steel specimen CCP2a. The crack growth rates measured at various depths in these specimens are plotted versus ΔKI on Fig. 9a and versus (1 ) 2 2 2 ν− Δ Δ = Δ +Δ + III II I eq K K K K on Fig. 9b. While ΔKI fails to correlate all the data, ΔKeq provides a much better correlation, which gives additional evidence that opening and shear modes cooperate for slanted crack growth. Figure 9: Correlation of measured crack growth rates in 7075-T6 with a) ΔKI or b) ΔKeq and in S355 steel with c) ΔKI and d) ΔKeq a) e) b) a) b) c) d)
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