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Deep hole residual stress measurements using Electronic Speckle Pattern Interferometry Alava, Raymond
Abstract
This research study presents the design, development and testing of a sensor which utilizes the techniques of Electronic Speckle Pattern Interferometry (ESPI) for making deep-hole residual stress measurements. ESPI is optical technique that can be used to determine deformation at the surface of an object by combining interference patterns before and after deformation occurs. Although the technique has previously been used for determining residual stresses close to the surface, it has not yet been applied to measuring stresses deep within the interior of a specimen. The deep-hole method determines interior residual stresses in a specimen by making measurement of a reference hole. Overcoring of the reference hole results in stress relief leading to deformations at the hole surface. Pre- and post-deformation measurements of the reference hole are then used to determine the original stress state. In order to make these measurements a deep hole imaging sensor has been designed. The design focuses light down a long tube to illuminate the reference hole. The hole is then imaged onto a CCD camera and the optical data provides the necessary displacement measurements. A least squares technique utilizing a series of basis functions allows explicit calculation of all six components of the stress tensor from the displacement data. The sensor was subjected to a series of tests to demonstrate its capability to make the desired optical measurements! The basic functionality of the sensor was verified through displacement tests where stable, distinctive ESPI fringe patterns were observed. However, the application of a known stress field produced large disturbances resulting in a de-correlation of the optical data. Based on the observed de-correlation, recommendations are provided for improving the rigidity and overall performance of the design.
Item Metadata
Title |
Deep hole residual stress measurements using Electronic Speckle Pattern Interferometry
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
2005
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Description |
This research study presents the design, development and testing of a sensor which utilizes the
techniques of Electronic Speckle Pattern Interferometry (ESPI) for making deep-hole residual stress
measurements. ESPI is optical technique that can be used to determine deformation at the surface of
an object by combining interference patterns before and after deformation occurs. Although the
technique has previously been used for determining residual stresses close to the surface, it has not
yet been applied to measuring stresses deep within the interior of a specimen.
The deep-hole method determines interior residual stresses in a specimen by making measurement of
a reference hole. Overcoring of the reference hole results in stress relief leading to deformations at the
hole surface. Pre- and post-deformation measurements of the reference hole are then used to
determine the original stress state. In order to make these measurements a deep hole imaging sensor
has been designed. The design focuses light down a long tube to illuminate the reference hole. The
hole is then imaged onto a CCD camera and the optical data provides the necessary displacement
measurements. A least squares technique utilizing a series of basis functions allows explicit
calculation of all six components of the stress tensor from the displacement data.
The sensor was subjected to a series of tests to demonstrate its capability to make the desired optical
measurements! The basic functionality of the sensor was verified through displacement tests where
stable, distinctive ESPI fringe patterns were observed. However, the application of a known stress
field produced large disturbances resulting in a de-correlation of the optical data. Based on the
observed de-correlation, recommendations are provided for improving the rigidity and overall
performance of the design.
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Genre | |
Type | |
Language |
eng
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Date Available |
2010-01-05
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0080756
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
2006-05
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.