کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9703892 | 1463865 | 2005 | 11 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Analysis of vacuum fatigue crack growth results and its implications
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
سایر رشته های مهندسی
مهندسی مکانیک
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Conventionally, the reduction of ÎKth with load ratio R has been interpreted in terms of crack closure arising from plasticity, oxide or crack surface roughness. Since, plane-strain conditions exist near-threshold, plasticity-induced closure is absent. Therefore, to account for R-ratio effects near-threshold, the oxide and roughness closure mechanisms have been proposed. Further analysis has shown that these other two closure effects also are small, when the results taken in vacuum were included. The present analysis shows that there is a unique relation of the oxide thickness with a threshold Kmax, rather than with a threshold ÎK. This threshold Kmax (K*max,th) depends on environment. When the applied KmaxK*max,th. Thus, the oxide thickness-Kmax relation seems to have a bearing on the criterion for crack growth in the presence of the environment. Oxide formation passivates the crack surfaces and retards the environmental damage ahead of the crack-tip. Examples from CrMo and NiCrMo steels support this viewpoint and suggest that there is a pressing need for quantifying the crack-tip environmental effects and fatigue thresholds.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Fatigue - Volume 27, Issues 10â12, OctoberâDecember 2005, Pages 1519-1529
Journal: International Journal of Fatigue - Volume 27, Issues 10â12, OctoberâDecember 2005, Pages 1519-1529
نویسندگان
A.K. Vasudevan, K. Sadananda, R.L. Holtz,