Experimentally Achievable Accuracy Using a Digital Image Correlation Technique in measuring Small-Magnitude (<0.1%) Homogeneous Strain Fields.

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Abstract

Measuring small-magnitude strain fields using a digital image correlation (DIC) technique is challenging, due to the noise-signal ratio in strain maps. Here, we determined the level of accuracy achievable in measuring small-magnitude (<0.1%) homogeneous strain fields. We investigated different sets of parameters for image processing and imaging pre-selection, based on single-image noise level. The trueness of DIC was assessed by comparison of Young&rsquo;s modulus (E) and Poisson&rsquo;s ratio (&nu;) with values obtained from strain gauge measurements. Repeatability was improved, on average, by 20⁻25% with experimentally-determined optimal parameters and image pre-selection. Despite this, the intra- and inter-specimen repeatability of strain gauge measurements was 5 and 2.5 times better than DIC, respectively. Moreover, although trueness was also improved, on average, by 30⁻45%, DIC consistently overestimated the two material parameters by 1.8% and 3.2% for E and &nu;, respectively. DIC is a suitable option to measure small-magnitude homogeneous strain fields, bearing in mind the limitations in achievable accuracy.

Original languageEnglish
Pages (from-to)1-14
Number of pages14
JournalMaterials
Volume11
Issue number5
DOIs
Publication statusPublished - May 8 2018

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Strain gages
Image processing
Imaging techniques

Keywords

  • accuracy
  • calcium phosphate cements
  • digital image correlation
  • homogeneous strain
  • precision
  • small deformation level

Cite this

@article{57d884f9299841ec8c81b06e5a76f8ff,
title = "Experimentally Achievable Accuracy Using a Digital Image Correlation Technique in measuring Small-Magnitude (<0.1{\%}) Homogeneous Strain Fields.",
abstract = "Measuring small-magnitude strain fields using a digital image correlation (DIC) technique is challenging, due to the noise-signal ratio in strain maps. Here, we determined the level of accuracy achievable in measuring small-magnitude (<0.1{\%}) homogeneous strain fields. We investigated different sets of parameters for image processing and imaging pre-selection, based on single-image noise level. The trueness of DIC was assessed by comparison of Young&rsquo;s modulus (E) and Poisson&rsquo;s ratio (&nu;) with values obtained from strain gauge measurements. Repeatability was improved, on average, by 20⁻25{\%} with experimentally-determined optimal parameters and image pre-selection. Despite this, the intra- and inter-specimen repeatability of strain gauge measurements was 5 and 2.5 times better than DIC, respectively. Moreover, although trueness was also improved, on average, by 30⁻45{\%}, DIC consistently overestimated the two material parameters by 1.8{\%} and 3.2{\%} for E and &nu;, respectively. DIC is a suitable option to measure small-magnitude homogeneous strain fields, bearing in mind the limitations in achievable accuracy.",
keywords = "accuracy, calcium phosphate cements, digital image correlation, homogeneous strain, precision, small deformation level",
author = "Alice Acciaioli and Giacomo Lionello and Massimiliano Baleani",
year = "2018",
month = "5",
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doi = "10.3390/ma11050751",
language = "English",
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T1 - Experimentally Achievable Accuracy Using a Digital Image Correlation Technique in measuring Small-Magnitude (<0.1%) Homogeneous Strain Fields.

AU - Acciaioli, Alice

AU - Lionello, Giacomo

AU - Baleani, Massimiliano

PY - 2018/5/8

Y1 - 2018/5/8

N2 - Measuring small-magnitude strain fields using a digital image correlation (DIC) technique is challenging, due to the noise-signal ratio in strain maps. Here, we determined the level of accuracy achievable in measuring small-magnitude (<0.1%) homogeneous strain fields. We investigated different sets of parameters for image processing and imaging pre-selection, based on single-image noise level. The trueness of DIC was assessed by comparison of Young&rsquo;s modulus (E) and Poisson&rsquo;s ratio (&nu;) with values obtained from strain gauge measurements. Repeatability was improved, on average, by 20⁻25% with experimentally-determined optimal parameters and image pre-selection. Despite this, the intra- and inter-specimen repeatability of strain gauge measurements was 5 and 2.5 times better than DIC, respectively. Moreover, although trueness was also improved, on average, by 30⁻45%, DIC consistently overestimated the two material parameters by 1.8% and 3.2% for E and &nu;, respectively. DIC is a suitable option to measure small-magnitude homogeneous strain fields, bearing in mind the limitations in achievable accuracy.

AB - Measuring small-magnitude strain fields using a digital image correlation (DIC) technique is challenging, due to the noise-signal ratio in strain maps. Here, we determined the level of accuracy achievable in measuring small-magnitude (<0.1%) homogeneous strain fields. We investigated different sets of parameters for image processing and imaging pre-selection, based on single-image noise level. The trueness of DIC was assessed by comparison of Young&rsquo;s modulus (E) and Poisson&rsquo;s ratio (&nu;) with values obtained from strain gauge measurements. Repeatability was improved, on average, by 20⁻25% with experimentally-determined optimal parameters and image pre-selection. Despite this, the intra- and inter-specimen repeatability of strain gauge measurements was 5 and 2.5 times better than DIC, respectively. Moreover, although trueness was also improved, on average, by 30⁻45%, DIC consistently overestimated the two material parameters by 1.8% and 3.2% for E and &nu;, respectively. DIC is a suitable option to measure small-magnitude homogeneous strain fields, bearing in mind the limitations in achievable accuracy.

KW - accuracy

KW - calcium phosphate cements

KW - digital image correlation

KW - homogeneous strain

KW - precision

KW - small deformation level

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