Full-field Strain Measurements for Microstructurally Small Fatigue Crack Propagation Using Digital Image Correlation Method

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2019-01-16
Major/Subject
Mcode
Degree programme
Language
en
Pages
9
Series
Journal of Visualized Experiments, issue 143
Abstract
A novel measurement approach is used to reveal the cumulative deformation field at a sub-grain level and to study the influence of microstructure on the growth of microstructurally small fatigue cracks. The proposed strain field analysis methodology is based on the use of a unique pattering technique with a characteristic speckle size of approximately 10 µm. The developed methodology is applied to study the small fatigue crack behavior in body centered cubic (bcc) Fe-Cr ferritic stainless steel with a relatively large grain size allowing a high spatial measurement accuracy at the sub-grain level. This methodology allows the measurement of small fatigue crack growth retardation events and associated intermittent shear strain localization zones ahead of the crack tip. In addition, this can be correlated with the grain orientation and size. Thus, the developed methodology can provide a deeper fundamental understanding of the small fatigue crack growth behavior, required for the development of robust theoretical models for the small fatigue crack propagation in polycrystalline materials.
Description
Keywords
Engineering, Issue 143, Digital image correlation, small fatigue crack, crack growth rate retardation, sub grain level, shear strain localization, strain inhomogeneity, DEFORMATION, DISLOCATION, GROWTH, Strain inhomogeneity, Shear strain localization, Small fatigue crack, Crack growth rate retardation, Sub grain level
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Citation
Malitckii , E , Remes , H , Lehto , P & Bossuyt , S 2019 , ' Full-field Strain Measurements for Microstructurally Small Fatigue Crack Propagation Using Digital Image Correlation Method ' , Journal of Visualized Experiments , vol. 2019 , no. 143 , 59134 . https://doi.org/10.3791/59134