A Self-Correcting Strategy of the Digital Volume Correlation Displacement Field Based on Image Matching: Application to Poor Speckles Quality and Complex-Large Deformation

TL;DR

This paper introduces a self-correcting strategy for digital volume correlation (DVC) that enhances displacement field accuracy in poor speckle quality and complex-large deformation scenarios, demonstrated through CT tests on geomaterials.

Contribution

It proposes a novel self-correcting method based on image matching that improves DVC accuracy without altering original parameters, especially for challenging geomaterial conditions.

Findings

Effectively improves DVC displacement field accuracy.

Reduces gray residue indicating better correlation.

Accurately estimates displacement field precision.

Abstract

Digital Volume Correlation (DVC) is widely used for the analysis of three-dimensional displacement and strain fields based on CT scans. However, the applicability of DVC methods is limited when it comes to geomaterials: CT speckles are directly correlated with the material's microstructure, and the speckle structure cannot be artificially altered, with generally poor speckle quality. Additionally, most geomaterials exhibit elastoplastic properties and will undergo complex-large deformations under external loading, sometimes leading to strain localization phenomena. These factors contribute to inaccuracies in the displacement field obtained through DVC, and at present, there is a shortage of correction methods and accuracy assessment techniques for the displacement field. If the accuracy of the DVC displacement field is sufficiently high, the gray residue of the two volume images before and after deformation should be minimal, utilizing this characteristic to develop a correction method for the displacement field is feasible. The proposed self-correcting strategy of the DVC displacement field based on image matching, which from the experimental measurement error. We demonstrated the effectiveness of the proposed method by CT triaxial tests of granite residual soil. Without adding other parameters or adjusting the original parameters of DVC, the gray residue showed that the proposed method can effectively improve the accuracy of the displacement field. Additionally, the accuracy evaluation method can reasonably estimate the accuracy of the displacement field. The proposed method can effectively improve the accuracy of DVC three-dimensional displacement field for the state of speckles with poor quality and complex-large deformation.