کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9703968 | 1463869 | 2005 | 12 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Growth of naturally initiated fatigue cracks in ferritic gas turbine rotor steels
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
سایر رشته های مهندسی
مهندسی مکانیک
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Growth of naturally initiated fatigue cracks in ferritic gas turbine rotor steels Growth of naturally initiated fatigue cracks in ferritic gas turbine rotor steels](/preview/png/9703968.png)
چکیده انگلیسی
Smooth test specimens of 12% CrNiMoV and 1% CrMoV steel have been subjected to strain-controlled low-cycle fatigue loading. Several specimens were instrumented with potential drop probes. As fatigue cracks grew deeper than 0.2-0.3 mm, they caused a steadily increasing potential drop over the length of the specimen. These LCF tests were terminated after a certain fraction of the nominal life. A stepwise increasing high-cycle fatigue load was subsequently used to propagate the crack to fracture. The contour of the low-cycle fatigue crack could be identified on the fracture surface. In agreement with a model suggested by Tomkins, its growth rate was found to be proportional to the crack depth and to be a power function of the plastic strain amplitude. For an assumed initial crack depth of 50 μm, this relationship generally provided conservative life predictions deviating from the observed number of cycles by less than a factor of 5. A second model assumed the crack growth rate to be proportional to a power of the cyclic J integral. Using standard Paris type crack growth data, this model also tended to give conservative predictions, in particular for the longer lives. The deviation from the observed number of cycles was generally less than a factor of 3. The high-cycle fatigue tests permitted the fatigue limit of the cracked specimens to be determined. The threshold stress intensity range obtained from these tests consistently fell below that from tests with standard fatigue crack growth specimens.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Fatigue - Volume 27, Issue 6, June 2005, Pages 715-726
Journal: International Journal of Fatigue - Volume 27, Issue 6, June 2005, Pages 715-726
نویسندگان
Gunnar HärkegÃ¥rd, Josef Denk, Klaus Stärk,