2D mapping of plane stress crack-tip fields following an overload
The evolution of crack-tip strain fields in a thin (plane stress) compact tension sample following an overload (OL) event has been studied using two different experimental techniques. Surface behaviour has been characterised by Digital Image Correlation (DIC), while the bulk behaviour has been cha...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Gruppo Italiano Frattura
2015-07-01
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| Series: | Fracture and Structural Integrity |
| Subjects: | |
| Online Access: | http://www.gruppofrattura.it/pdf/rivista/numero33/numero_33_art_19.pdf |
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| Summary: | The evolution of crack-tip strain fields in a thin (plane stress) compact tension sample following an
overload (OL) event has been studied using two different experimental techniques. Surface behaviour has been
characterised by Digital Image Correlation (DIC), while the bulk behaviour has been characterised by means of
synchrotron X-ray diffraction (XRD). The combination of both surface and bulk information allowed us to
visualise the through-thickness evolution of the strain fields before the OL event, during the overload event,
just after OL and at various stages after it. Unlike previous work, complete 2D maps of strains around the
crack-tip were acquired at 60m spatial resolution by XRD. The DIC shows less crack opening after overload
and the XRD a lower crack-tip peak stress after OL until the crack has grown past the compressive crack-tip
residual stress introduced by the overload after which the behaviour returned to that for the baseline fatigue
response. While the peak crack-tip stress is supressed by the compressive residual stress, the crack-tip stress
field changes over each cycle are nevertheless the same for all Kmax cycles except at OL. |
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| ISSN: | 1971-8993 1971-8993 |