Yield stress modification in the strip yield model

• Autorzy: Machniewicz T.

Warianty tytułu

PL

Modyfikacja granic plastyczności w modelu pasmowego płynięcia

• Języki publikacji: EN

Abstrakty

EN

From among of the deterministic models for fatigue crack growth predictions suitable for metallic materials a Strip Yield (SY) model can be considered the most general and powerful crack growth prediction tool owing to its applicability to arbitrary variable amplitude load histories. The SY model based on the conception of plasticity at the crack tip according to Dugdale, modified to accounting for the crack closure phenomena. The original Dugdale model is only valid for plane stress state conditions at the crack tip. Accounting for the triaxial stress conditions at the crack tip requires the yield stress modification, what is usually realized by using the suitable constraint factors. In the paper several concepts of the yield stress modification in the SY model have been described and notified. As it has been concluded the another important role of the constraint factors, in addition to accommodating in the SY model the triaxial stress state, is covering indirectly various processes which do affect crack growth, but cannot be treated in a rigorous way.

PL

Spośród deterministycznych modeli do prognozowanie rozwoju pęknięć zmęczeniowych za koncepcję najbardziej ogólną uważany jest model pasmowego płynięcia (model SY), który może być zastosowany w przypadku dowolnych zmiennoamplitudowej historii obciążenia. Opiera się on na modelu plastyczności w wierzchołku pęknięcia wg Dugdale'a zmodyfikowanym w celu uwzględnienia zjawiska zamykania się pęknięcia spowodowanego uplastycznieniem materiału. Oryginalny model Dugdale'a odnosi się jedynie do płaskiego stanu naprężenia. Uwzględnienie trójosiowego charakteru stanu naprężenia wymaga w związku z tym odpowiedniej modyfikacji granic plastyczności, co dokonywane jest na ogół przy użyciu odpowiednich współczynników skrępowania. W artykule omówiono i poddano ocenie istniejące koncepcje modyfikacji granic plastyczności w modelu pasmowego płynięcia. Wykazano, że poza uwzględnieniem trójosiowego charakteru stanu naprężenia dodatkową istotną rolą współczynników skrępowania w modelu pasmowego płynięcia jest odzwierciedlenie w sposób pośredni szeregu zjawisk wpływających na proces zmęczeniowego rozwoju pęknięcia, których nie można uwzględnić w sposób ścisły.

Słowa kluczowe

EN

fatigue crack growth prediction; strip yield model; constraint factors

PL

przewidywanie rozwoju pęknięć zmęczeniowych; model pasmowego płynięcia; współczynniki skrępowania

• Wydawca: AGH University of Science and Technology Press
• Czasopismo: Mechanics and Control
• Rocznik: 2012
• Tom: Vol. 31, no. 4
• Strony: 150--157
• Opis fizyczny: Bibliogr. 29 poz., rys.

Twórcy

autor

Machniewicz T.

• AGH University of Science and Technology, Faculty of Mechanical Engineering and Robotics, Kraków, Poland

Bibliografia

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