Universal scaling laws for shear induced dilation in frictional granular media

• Published in: Granular matter Vol. 21; no. 3; pp. 1 - 9
• Main Authors: Bandi, M. M., Das, Prasenjit, Gendelman, Oleg, Hentschel, H. George E., Procaccia, Itamar
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.08.2019; Springer Nature B.V
• Subjects: Binding energy; Complex Fluids and Microfluidics; Computer simulation; Dilation; Engineering Fluid Dynamics; Engineering Thermodynamics; Foundations; Geoengineering; Granular materials; Granular media; Heat and Mass Transfer; Hydraulics; In Memoriam of Robert P. Behringer; Industrial Chemistry/Chemical Engineering; late Editor in Chief of Granular Matter; Materials Science; Original Paper; Physics; Physics and Astronomy; Rheological properties; Scaling laws; Shear rate; Shearing; Soft and Granular Matter; Strain rate; Friction; Dilation; Granular matter
• ISSN: 1434-5021; 1434-7636
• DOI: 10.1007/s10035-019-0890-x

Compressed frictional granular matter cannot flow without dilation. Upon forced shearing to generate flow, the amount of dilation may depend on the initial preparation and a host of material variables. On the basis of both experiments and numerical simulations we show that as a result of training by repeated compression-decompression cycles the amount of dilation induced by shearing the system depends only on the shear rate and on the (pre-shearing) packing fraction. Relating the rheological response to structural properties allows us to derive a scaling law for the amount of dilation after n cycles of compression-decompression. The resulting scaling law has a universal exponent that for trained systems is independent of the inter-granules force laws, friction parameters and strain rate. The amplitude of the scaling law is analytically computable, and it depends only on the shear rate and the asymptotic packing fraction.