A method for calibrating a digital image correlation system for full-field strain measurements.pdf (1.02 MB)
Download file

A method for calibrating a digital image correlation system for full-field strain measurements during large deformations

Download (1.02 MB)
journal contribution
posted on 21.10.2019, 10:43 by Robert Blenkinsopp, Jonathan RobertsJonathan Roberts, Andy HarlandAndy Harland, Paul SherrattPaul Sherratt, Paul Smith, Tim Lucas
Numerous 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 Sciences

Volume

9

Issue

14

Publisher

MDPI AG

Version

VoR (Version of Record)

Rights holder

© The authors

Acceptance date

11/07/2019

Publication date

2019-07-16

Copyright date

2019

eISSN

2076-3417

Language

en

Depositor

Dr Jonathan Roberts. Deposit date: 18 October 2019

Article number

2828

Usage metrics

Categories

Licence

Exports