New experimental techniques for fracture testing of highly deformable materials
A new experimental method for measuring strain fields in highly deformable materials has been developed. This technique is based on an in-house developed Digital Image Correlation (DIC) system capable of accurately capturing localized or non-uniform strain distributions. Thanks to the implemented...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Gruppo Italiano Frattura
2016-01-01
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| Series: | Fracture and Structural Integrity |
| Subjects: | |
| Online Access: | http://www.gruppofrattura.it/pdf/rivista/numero35/numero_35_art_19.pdf |
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| Summary: | A new experimental method for measuring strain fields in highly deformable materials has been
developed. This technique is based on an in-house developed Digital Image Correlation (DIC) system capable
of accurately capturing localized or non-uniform strain distributions. Thanks to the implemented algorithm
based on a Semi-Global Matching (SGM) approach, it is possible to constraint the regularity of the
displacement field in order to significantly improve the reliability of the evaluated strains, especially in highly
deformable materials. Being originally introduced for Digital Surface Modelling from stereo pairs, SGM is
conceived for performing a one-dimensional search of displacements between images, but here a novel
implementation for 2D displacement solution space is introduced. SGM approach is compared with the
previously in-house developed implementation based on a local Least Squares Matching (LSM) approach. A
comparison with the open source code Ncorr and with some FEM results is also presented. The investigation
using the present DIC method focuses on 2D full-field strain maps of plain and notched specimens under
tensile loading made of two different highly deformable materials: hot mix asphalt and thermoplastic
composites for 3D-printing applications. In the latter specimens, an elliptical hole is introduced to assess the
potentiality of the method in experimentally capturing high strain gradients in mixed-mode fracture situations. |
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| ISSN: | 1971-8993 1971-8993 |