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Master's Dissertation
DOI
10.11606/D.18.2017.tde-09102017-161144
Document
Author
Full name
Fabio Alas Martins
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 1995
Supervisor
Committee
Spinelli, Dirceu (President)
Crnkovic, Ovidio Richard
Fernandes, Odilson Coimbra
Title in Portuguese
Fator limite de intensidade de tensão e fechamento de trinca por fadiga para a liga aeronáutica: 7050-T73651
Keywords in Portuguese
Alumínio
Fadiga
Fechamento de trinca
Liga aeronáutica
Limite de fadiga
Abstract in Portuguese
O desenvolvimento de trabalhos relacionados à compreensão do fenômeno de limiar de fadiga ou fator de intensidade de tensão limite (ΔK0), tem possibilitado a aplicação de medidas de segurança para evitar acidentes ou perdas. Estas medidas vão desde a avaliação e substituição de peças contendo falhas até o estabelecimento de prazos entre inspeções. O conhecimento mais aprofundado dos mecanismos que induzem ou promovem o fechamento de trinca por fadiga, auxilia na avaliação dos resultados obtidos para ΔK0 e permite o conhecimento mais preciso deste valor, introduzindo o parâmetro ΔK0,ef. Estudou-se o crescimento de trinca por fadiga para a liga aeronáutica 7050-T73651 com decaimento de ΔK para determinação de ΔK0. Foi considerado o efeito de fechamento de trinca para se verificar o valor de ΔK0,ef para a orientação de laminação LT. Foi verificada a eficiência das equações de Priddle e de Donahue para se prever o comportamento da curva da/dN versus ΔK em função dos parâmetros da equação de Paris e características do material.
Title in English
not available
Keywords in English
not available
Abstract in English
The recent development of works on the fatigue threshold phenomenon has provided powerful knowledge applicable to reliability practices such as the replacement of parts or the establishment of periods between inspections. A better understanding of the mechanisms leading to fatigue crack closure has permitted investigators to describe more accurately ΔK0 values, thus introducing a new ΔK0,eff parameter. In this work, fatigue crack growth was carried out on the aeronautics aluminum alloy 7050-T73651 with ΔK decreasing in order to determine ΔK0. Fatigue crack closure effects were considered as to verify the ΔK0,eff value for the LT direction. The ability of the equation of Priddle and that of Donahue to predict the behaviour of da/dN versus ΔK curves based on the parameters m and C from Paris equation and on the materials characteristics was verified.
 
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Publishing Date
2017-10-09
 
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