Crack initiation and endurance limit of hard steels under multiaxial cyclic loads
The endurance limit and the mechanisms o f fatigue crack initiation in the high cycle regime were investigated using round specimens o f the bearing steel 52100 under longitudinal forces and torsional moments and combinations o f these loads. Three specimen types were examined: smooth specimens a...
Збережено в:
| Дата: | 2008 |
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| Автори: | , , , , |
| Формат: | Стаття |
| Мова: | English |
| Опубліковано: |
Інститут проблем міцності ім. Г.С. Писаренко НАН України
2008
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| Назва видання: | Проблемы прочности |
| Теми: | |
| Онлайн доступ: | http://dspace.nbuv.gov.ua/handle/123456789/48237 |
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| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Crack initiation and endurance limit of hard steels under multiaxial cyclic loads / H. Bomas, R. Kienzler, S. Kunow, G. Loewisch, S. Schroeder // Проблемы прочности. — 2008. — № 1. — С. 14-19. — Бібліогр.: 4 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| Резюме: | The endurance limit and the mechanisms o f fatigue crack initiation in the high cycle regime were
investigated using round specimens o f the bearing steel 52100 under longitudinal forces and
torsional moments and combinations o f these loads. Three specimen types were examined: smooth
specimens and specimens with circumferential notches with radii o f 1.0 and 0.2 mm. The influence
ofmean and multiaxial stresses on the endurance limit can be understood by consideration ofcrack
initiation mechanisms and micro-mechanics. Crack initiation took place at oxides, carbonitrides
and at the surface. The mechanisms ofcrack initiation could be related to the load type: Loads with
rotating principal stresses are more damaging fo r nitrides than fo r oxides. Increasing maximum
stresses are more dangerous fo r nitrides than fo r oxides, and introduce more damage to the surface
than to the nitrides. Normal stresses are more damaging fo r oxides than shear stresses. The
endurance limits were calculated by means o f an extended weakest-link model which combines
volume and surface crack initiation with related fatigue criteria. For volume crack initiation the
criterion o f Dang Van was used. For the correct description o f the competing surface crack
initiation, a new criterion was applied. With this concept, a prediction o f the endurance limit is
possible fo r loads which produce critical planes and range within a limited regime ofstress ratios. |
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