Mechanical Behavior Laboratory University of Nevada, Reno

Paper

[J48] Kalnaus, S., Fan, F., Vasudevan, A.K., and Jiang, Y., 2008, "An Experimental Investigation on Fatigue Crack Growth of AL6XN Stainless Steel," Engineering Fracture Mechanics, Vol.75, pp.2002-2019. doi: 10.1016/j.engfracmech.2007.11.002

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Paper Abstract

The crack growth behavior of AL6XN stainless steel was experimentally investigated using round compact tension (CT) specimens. The influences of the R-ratio (the ratio of the minimum load over the maximum applied load in a cycle), the tensile and compressive overloads, and the loading sequence on crack growth were studied in detail. The results from the constant-amplitude experiments show a sensitivity of the crack growth rate to the R-ratio. The application of a tensile overload has a profound effect on crack growth, resulting in a significant retardation in the crack propagation rate. A compressive overload (underload) leads to a short-lived acceleration in crack growth. Results from the two-step high-low loading reveal a period of crack growth retardation at the beginning of the lower amplitude step, an effect similar to that of a single overload. A crack driving force parameter together with a modified Wheeler model is found to correlate the crack growth experiments well.

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Paper Figures

Fig. 5

Fig. 5. Stress intensity factor obtained by Eq. (1) and by the finite element method (Download data).

Fig. 6

Fig. 6. Crack growth under constant-amplitude loading with the R-ratio effect (Download data).

Fig. 8

Fig. 8. Overload effect on crack growth. Markers represent the results of experiment and solid lines represent the results of prediction (Download data).

Fig. 9

Fig. 9. Effect of underload on crack growth (Download data).

Fig. 10

Fig. 10. Crack growth under high-low sequence loading. Markers represent the results of experiment and solid lines represent the results of prediction (Download data).

Fig. 11

Fig. 11. Crack growth under constant-amplitude loading with application of Eq. (3) (Download data).

Fig. 13

Fig. 13. Prediction of overload effect on crack growth based on the Wheeler model (Download data).

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