Abstract
Background: Experimental, fully three-dimensional mechanical characterization of opaque materials with arbitrary geometries undergoing finite deformations is generally challenging. Objective: We present a promising experimental method and processing pipeline for acquiring and processing full-field displacements and using them toward inverse characterization using the Virtual Fields Method (VFM), a combination we term MR-u. Methods: Silicone of varying crosslinker concentrations and geometries is used as the sample platform. Samples are stretched cyclically to finite deformations inside a 7T MRI machine. Synchronously, a custom MRI pulse sequence encodes the local displacement in the phase of the MR image. Numerical differentiation of phase maps yields strains. Results: We present a custom image processing scheme for this numerical differentiation of MRI phase-fields akin to convolution kernels, as well as considerations for gradient set calibration for data fidelity. Conclusions: The VFM is used to successfully determine hyperelastic material properties, and we establish best practice regarding virtual field selection via equalization.
Original language | English (US) |
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Pages (from-to) | 907-924 |
Number of pages | 18 |
Journal | Experimental Mechanics |
Volume | 60 |
Issue number | 7 |
DOIs | |
State | Published - Sep 1 2020 |
Externally published | Yes |
Keywords
- Elastomer
- Full field
- Magnetic resonance
- Material characterization
- Virtual fields method
ASJC Scopus subject areas
- Aerospace Engineering
- Mechanics of Materials
- Mechanical Engineering