The use of a lock-in amplifier to apply digital image correlation to cyclically loaded components
The use of a lock-in amplifier to apply digital image correlation to cyclically loaded components
An approach for processing strain data obtained from Digital Image Correlation (DIC) that can be used directly on components subject to cyclic loading, such as in fatigue testing, is described. A key challenge addressed herein is obtaining an accurate and precise surface strain map without recourse to expensive high speed cameras to capture data to map the load cycle. The basis of the approach is the application of a lock-in amplifier to the strain data obtained from images taken from low-cost low-frame rate cameras. The technique enables images to be captured throughout a fatigue test and hence evaluate the effect of any damage on the strain field, without interrupting the test. The methodology is assessed using an aluminium disc in diametric compression. It is demonstrated that the approach enables accurate strain maps to be obtained using a range of loading frequencies that are greater than the camera frame rate. A realistic example application of the technique on a fatigue test with an evolving crack in a T-shaped specimen is presented.
DIC, fatigue testing, damage inspection, lock-in amplifier
149-159
Fruehmann, R.K.
93d91dfe-fbde-4a2c-a608-0ea02d6b562b
Dulieu-Barton, J.M.
9e35bebb-2185-4d16-a1bc-bb8f20e06632
Quinn, S.
0805cab8-0ef5-4f65-9ed6-25fd5563d1a6
Tyler, J.P.
aac408e9-8637-4a0f-a151-5b8b402c7ef7
May 2015
Fruehmann, R.K.
93d91dfe-fbde-4a2c-a608-0ea02d6b562b
Dulieu-Barton, J.M.
9e35bebb-2185-4d16-a1bc-bb8f20e06632
Quinn, S.
0805cab8-0ef5-4f65-9ed6-25fd5563d1a6
Tyler, J.P.
aac408e9-8637-4a0f-a151-5b8b402c7ef7
Fruehmann, R.K., Dulieu-Barton, J.M., Quinn, S. and Tyler, J.P.
(2015)
The use of a lock-in amplifier to apply digital image correlation to cyclically loaded components.
Optics and Lasers in Engineering, 68, .
(doi:10.1016/j.optlaseng.2014.12.021).
Abstract
An approach for processing strain data obtained from Digital Image Correlation (DIC) that can be used directly on components subject to cyclic loading, such as in fatigue testing, is described. A key challenge addressed herein is obtaining an accurate and precise surface strain map without recourse to expensive high speed cameras to capture data to map the load cycle. The basis of the approach is the application of a lock-in amplifier to the strain data obtained from images taken from low-cost low-frame rate cameras. The technique enables images to be captured throughout a fatigue test and hence evaluate the effect of any damage on the strain field, without interrupting the test. The methodology is assessed using an aluminium disc in diametric compression. It is demonstrated that the approach enables accurate strain maps to be obtained using a range of loading frequencies that are greater than the camera frame rate. A realistic example application of the technique on a fatigue test with an evolving crack in a T-shaped specimen is presented.
Text
rkf et al 2015 olen eprints.pdf
- Accepted Manuscript
More information
Accepted/In Press date: 22 December 2014
e-pub ahead of print date: 16 January 2015
Published date: May 2015
Keywords:
DIC, fatigue testing, damage inspection, lock-in amplifier
Organisations:
Engineering Mats & Surface Engineerg Gp
Identifiers
Local EPrints ID: 378346
URI: http://eprints.soton.ac.uk/id/eprint/378346
ISSN: 0143-8166
PURE UUID: ff09cfb0-1a3a-4a6b-b8dc-adea199d5a12
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Date deposited: 01 Jul 2015 16:08
Last modified: 14 Mar 2024 20:21
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Contributors
Author:
R.K. Fruehmann
Author:
S. Quinn
Author:
J.P. Tyler
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