Using MR elastography to image the 3D force chain structure of a quasi-static granular assembly

• Published in: Granular matter Vol. 11; no. 1; pp. 1 - 6
• Main Authors: Sanfratello, Lori, Fukushima, Eiichi, Behringer, Robert P.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 2009; Springer Nature B.V
• Subjects: Complex Fluids and Microfluidics; Engineering Fluid Dynamics; Engineering Thermodynamics; Foundations; Geoengineering; Heat and Mass Transfer; Hydraulics; Industrial Chemistry/Chemical Engineering; Materials Science; NMR; Nuclear magnetic resonance; Physics; Physics and Astronomy; Rheology; Soft and Granular Matter; Force chains; MR elastography; Granular; MRI
• ISSN: 1434-5021; 1434-7636
• DOI: 10.1007/s10035-008-0112-4

We have developed a magnetic resonance elastography (MRE) technique to experimentally investigate the force chain structure within a densely packed 3D granular assembly. MRE is an MRI technique whereby small periodic displacements within an elastic material are measured. We verified our MRE technique using a gel phantom and then extended the method to image the force carrying chain structure within a 3D granular assembly of particles under an initial pre-stressed condition, on top of which is superimposed a small-amplitude vibration. We find that significant coherent displacements form along force chains, where spin phase accumulates preferentially, allowing visualization. This work represents the first time that the internal force chain structure of a dry assembly of granular solids has been fully acquired in three dimensions.