The current work investigates the relationship between the crack growth rate (CGR) and the cyclic crack-tip opening displacement (& UDelta;CTOD) of microstructurally small fatigue cracks by using high-resolution digital image correlation (DIC). Load-controlled fatigue tests were conducted on small-scale specimens of 18%Cr body-centered cubic ferritic stainless steel. Microstructurally small fatigue crack growth was analyzed based on accurate high sample-rate measurements, starting from a sub-grain crack length up to seven times the volume-weighted grain size d(v) = 224 & mu;m. Under these experimental conditions, the high-resolution analyses reveal that variation from the otherwise linear relationship between CGR and & UDelta;CTOD on double logarithmic scale is due to the crack-tip bypassing an inhomogeneous shear strain localization zone. In this zone, & UDelta;CTOD is not able to characterize the behavior of microstructurally small fatigue cracks. Outside the shear strain localization zone, & UDelta;CTOD still is a valid crack driving force parameter.

Study of cyclic crack‐tip opening displacement of microstructurally small fatigue crack using digital image correlation / Tillikainen, Ilari; Gallo, Pasquale; Lehto, Pauli; Remes, Heikki. - In: FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES. - ISSN 8756-758X. - ELETTRONICO. - 46:11(2023), pp. 4103-4118. [10.1111/ffe.14124]

Study of cyclic crack‐tip opening displacement of microstructurally small fatigue crack using digital image correlation

Gallo, Pasquale
Secondo
;
2023-01-01

Abstract

The current work investigates the relationship between the crack growth rate (CGR) and the cyclic crack-tip opening displacement (& UDelta;CTOD) of microstructurally small fatigue cracks by using high-resolution digital image correlation (DIC). Load-controlled fatigue tests were conducted on small-scale specimens of 18%Cr body-centered cubic ferritic stainless steel. Microstructurally small fatigue crack growth was analyzed based on accurate high sample-rate measurements, starting from a sub-grain crack length up to seven times the volume-weighted grain size d(v) = 224 & mu;m. Under these experimental conditions, the high-resolution analyses reveal that variation from the otherwise linear relationship between CGR and & UDelta;CTOD on double logarithmic scale is due to the crack-tip bypassing an inhomogeneous shear strain localization zone. In this zone, & UDelta;CTOD is not able to characterize the behavior of microstructurally small fatigue cracks. Outside the shear strain localization zone, & UDelta;CTOD still is a valid crack driving force parameter.
2023
11
Tillikainen, Ilari; Gallo, Pasquale; Lehto, Pauli; Remes, Heikki
Study of cyclic crack‐tip opening displacement of microstructurally small fatigue crack using digital image correlation / Tillikainen, Ilari; Gallo, Pasquale; Lehto, Pauli; Remes, Heikki. - In: FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES. - ISSN 8756-758X. - ELETTRONICO. - 46:11(2023), pp. 4103-4118. [10.1111/ffe.14124]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11572/403649
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