ISSN 2594-5327
58º Congresso anual — Vol. 58 , num. 1 (2003)
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Plasticity-induced crack closure is the most used mechanism to explain load cycle interaction effects such as fatigue crack growth retardation or arrest after overloads. However, closure concepts cannot be used to explain some interaction effects measured under plane-strain conditions. In this work, the influence of the effective stress intensity range on the fatigue life of plane-stress dominated “thin” structures and plane-strain dominated “thick” ones is evaluated. Based on the crack closure idea, the expected fatigue life of “thin” and “thick” structures can be significantly different when both work under the same stress intensity range and load ratio. To verify this assumption, round CT specimens of different thicknesses are fatigue cycled under constant load ratio and increasing/decreasing stress intensity ranges. The crack growth rates and crack opening loads are continuously evaluated through back-face strain measurements, allowing for the computation of the effective stress intensity ranges at several crack lengths. The presented results indicate that the dominant role of crack closure in the modeling of fatigue crack growth should be revisited.
Plasticity-induced crack closure is the most used mechanism to explain load cycle interaction effects such as fatigue crack growth retardation or arrest after overloads. However, closure concepts cannot be used to explain some interaction effects measured under plane-strain conditions. In this work, the influence of the effective stress intensity range on the fatigue life of plane-stress dominated “thin” structures and plane-strain dominated “thick” ones is evaluated. Based on the crack closure idea, the expected fatigue life of “thin” and “thick” structures can be significantly different when both work under the same stress intensity range and load ratio. To verify this assumption, round CT specimens of different thicknesses are fatigue cycled under constant load ratio and increasing/decreasing stress intensity ranges. The crack growth rates and crack opening loads are continuously evaluated through back-face strain measurements, allowing for the computation of the effective stress intensity ranges at several crack lengths. The presented results indicate that the dominant role of crack closure in the modeling of fatigue crack growth should be revisited.
Palavras-chave
fatigue crack growth, crack closure, thickness effect
fatigue crack growth, crack closure, thickness effect
Como citar
Meggiolaro, Marco Antonio; Castro, Jaime Tupiassú Pinho de; Durán, Jorge Rodríguez.
ON THE REAL INFLUENCE OF THE EFFECTIVE STRESS INTENSITY RANGE IN FATIGUE CRACK PROPAGATION,
p. 666-675.
In: 58º Congresso anual,
Rio de Janeiro, Brasil,
2003.
ISSN: 2594-5327, DOI 10.5151/2594-5327-2555
