A method for calibrating a digital image correlation system for full-field strain measurements.pdf (1.02 MB)
A method for calibrating a digital image correlation system for full-field strain measurements during large deformations
journal contribution
posted on 2019-10-21, 10:43 authored by Robert Blenkinsopp, Jonathan RobertsJonathan Roberts, Andy HarlandAndy Harland, Paul SherrattPaul Sherratt, Paul Smith, Tim LucasNumerous variables can introduce errors into the measurement chain of a digital image correlation (DIC) system. These can be grouped into two categories: measurement quality and the correlation principle. Although previous studies have attempted to investigate each error source in isolation, there are still no comprehensive, standardized procedures for calibrating DIC systems for full-field strain measurement. The aim of this study, therefore, was to develop an applied experimental method that would enable a DIC practitioner to perform a traceable full-field measurement calibration to evaluate the accuracy of a particular system setup in a real-world environment related to their specific application. A sequence of Speckle Pattern Boards (SPB) that included artificial deformations of the speckle pattern were created, allowing for the calibration of in-plane deformations. Multiple deformation stages (from 10% to 50%) were created and measured using the GOM ARAMIS system; the results were analysed and statistical techniques were used to determine the accuracy. The measured strain was found to be slightly over-estimated (nominally by 0.02%), with a typical measurement error range of 0.34% strain at a 95% confidence interval. Location within the measurement volume did not have a significant effect on error distributions. It was concluded that the methods developed could be used to calibrate a DIC system in-situ for full-field measurements of large deformations. The approach could also be used to benchmark different DIC systems against each other or allow operators to better understand the influence of particular measurement variables on the measurement accuracy.
Funding
adidas AG.
History
School
- Mechanical, Electrical and Manufacturing Engineering
Published in
Applied SciencesVolume
9Issue
14Publisher
MDPI AGVersion
- VoR (Version of Record)
Rights holder
© The authorsAcceptance date
2019-07-11Publication date
2019-07-16Copyright date
2019eISSN
2076-3417Publisher version
Language
- en
Depositor
Dr Jonathan Roberts. Deposit date: 18 October 2019Article number
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