Some experimental observations of crack-tip mechanics with displacement data

In the past two decades, crack-tip mechanics has been increasingly studied with full-field techniques. Within these techniques, Digital Image Correlation (DIC) has been most widely used due to its many advantages, to extract important crack-tip information, including Stress Intensity Factor (SIF),...

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Main Authors: M. Mokhtari, P. Lopez-Crespo, B. Moreno, M. Zanganeh
Format: Article
Language:English
Published: Gruppo Italiano Frattura 2015-07-01
Series:Fracture and Structural Integrity
Subjects:
Online Access:http://www.gruppofrattura.it/pdf/rivista/numero33/numero_33_art_18.pdf
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author M. Mokhtari
P. Lopez-Crespo
B. Moreno
M. Zanganeh
author_facet M. Mokhtari
P. Lopez-Crespo
B. Moreno
M. Zanganeh
author_sort M. Mokhtari
collection DOAJ
description In the past two decades, crack-tip mechanics has been increasingly studied with full-field techniques. Within these techniques, Digital Image Correlation (DIC) has been most widely used due to its many advantages, to extract important crack-tip information, including Stress Intensity Factor (SIF), Crack Opening Displacement, J-integral, T-stress, closure level, plastic zone size, etc. However, little information is given in the literature about the experimental setup that provides best estimations for the different parameters. The current work aims at understanding how the experimental conditions used in DIC influence the crack-tip information extracted experimentally. The influence of parameters such as magnification factor, size of the images, position of the images with respect the crack-tip and size of the subset used in the correlation is studied. The influence is studied in terms of SIF and T-stress by using Williams’ model. The concept of determination of the K-dominance zone from experimental data has also explored. In this regard, cyclic loading on a fatigue crack in a compact tension (CT) specimen, made of aluminium 2024-T351 alloy, has been applied and the surface deformation ahead of the crack tip has been examined. The comparison between theoretical and experimental values of KI showed that the effect of subset size on the measured KI is negligible compared to the effect of size of the image.
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spelling doaj-art-4f903a0f715d47799cfa6c08dd33f6282025-08-20T02:51:42ZengGruppo Italiano FratturaFracture and Structural Integrity1971-89931971-89932015-07-0193314315010.3221/IGF-ESIS.33.18Some experimental observations of crack-tip mechanics with displacement dataM. Mokhtari0P. Lopez-Crespo1B. Moreno2M. Zanganeh3University of Malaga,SpainUniversity of Malaga,SpainUniversity of Malaga,SpainORAU,USAIn the past two decades, crack-tip mechanics has been increasingly studied with full-field techniques. Within these techniques, Digital Image Correlation (DIC) has been most widely used due to its many advantages, to extract important crack-tip information, including Stress Intensity Factor (SIF), Crack Opening Displacement, J-integral, T-stress, closure level, plastic zone size, etc. However, little information is given in the literature about the experimental setup that provides best estimations for the different parameters. The current work aims at understanding how the experimental conditions used in DIC influence the crack-tip information extracted experimentally. The influence of parameters such as magnification factor, size of the images, position of the images with respect the crack-tip and size of the subset used in the correlation is studied. The influence is studied in terms of SIF and T-stress by using Williams’ model. The concept of determination of the K-dominance zone from experimental data has also explored. In this regard, cyclic loading on a fatigue crack in a compact tension (CT) specimen, made of aluminium 2024-T351 alloy, has been applied and the surface deformation ahead of the crack tip has been examined. The comparison between theoretical and experimental values of KI showed that the effect of subset size on the measured KI is negligible compared to the effect of size of the image.http://www.gruppofrattura.it/pdf/rivista/numero33/numero_33_art_18.pdfDigital image correlationStress intensity factorT-stressCrack tip displacement field
spellingShingle M. Mokhtari
P. Lopez-Crespo
B. Moreno
M. Zanganeh
Some experimental observations of crack-tip mechanics with displacement data
Fracture and Structural Integrity
Digital image correlation
Stress intensity factor
T-stress
Crack tip displacement field
title Some experimental observations of crack-tip mechanics with displacement data
title_full Some experimental observations of crack-tip mechanics with displacement data
title_fullStr Some experimental observations of crack-tip mechanics with displacement data
title_full_unstemmed Some experimental observations of crack-tip mechanics with displacement data
title_short Some experimental observations of crack-tip mechanics with displacement data
title_sort some experimental observations of crack tip mechanics with displacement data
topic Digital image correlation
Stress intensity factor
T-stress
Crack tip displacement field
url http://www.gruppofrattura.it/pdf/rivista/numero33/numero_33_art_18.pdf
work_keys_str_mv AT mmokhtari someexperimentalobservationsofcracktipmechanicswithdisplacementdata
AT plopezcrespo someexperimentalobservationsofcracktipmechanicswithdisplacementdata
AT bmoreno someexperimentalobservationsofcracktipmechanicswithdisplacementdata
AT mzanganeh someexperimentalobservationsofcracktipmechanicswithdisplacementdata