ISSN:
1460-2695
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Both experimental and analytical investigations were conducted to study crack initiation and growth of small cracks, near-threshold growth behavior of large cracks at constant R-ratio/decreasing ΔK and constant Kmax/decreasing ΔK, respectively, for 9310 steel. The results showed that a pronounced small-crack effect was not observed even at R = −1, small cracks initiated by a slip mechanism at strong slip sites. Worst-case near-threshold testing results for large cracks under several Kmax values showed that an effect of Kmax on the near-threshold behavior does not exist in the present investigation. A worst-case near-threshold test for a large crack, i.e. constant Kmax/decreasing ΔK test, can give a conservative prediction of growth behavior of naturally initiated small cracks. Using the worst-case near-threshold data for a large crack and crack-tip constraint factor equations defined in the paper, Newman's total fatigue-life prediction method was improved. The fatigue lives predicted by the improved method were in reasonable agreement with the experiments. A three-dimensional (3D) weight function method was used to calculate stress-intensity factors for a surface crack at a notch of the present SENT specimen (with r/w = 1/8) by using a finite-element reference solution. The results were verified by limited finite-element solutions, and agreed well with those calculated by Newman's stress-intensity factor equations when the stress concentration factor of the present specimen was used in the equations.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1046/j.1460-2695.2002.00512.x
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