Abstract
Granular materials such as sand, powders and foams are ubiquitous in daily life and in industrial and geotechnical applications1,2,3,4. These disordered systems form stable structures when unperturbed, but in the presence of external influences such as tapping or shear they ‘relax’, becoming fluid in nature. It is often assumed that the relaxation dynamics of granular systems is similar to that of thermal glass-forming systems3,5. However, so far it has not been possible to determine experimentally the dynamic properties of three-dimensional granular systems at the particle level. This lack of experimental data, combined with the fact that the motion of granular particles involves friction (whereas the motion of particles in thermal glass-forming systems does not), means that an accurate description of the relaxation dynamics of granular materials is lacking. Here we use X-ray tomography to determine the microscale relaxation dynamics of hard granular ellipsoids subject to an oscillatory shear. We find that the distribution of the displacements of the ellipsoids is well described by a Gumbel law6 (which is similar to a Gaussian distribution for small displacements but has a heavier tail for larger displacements), with a shape parameter that is independent of the amplitude of the shear strain and of the time. Despite this universality, the mean squared displacement of an individual ellipsoid follows a power law as a function of time, with an exponent that does depend on the strain amplitude and time. We argue that these results are related to microscale relaxation mechanisms that involve friction and memory effects (whereby the motion of an ellipsoid at a given point in time depends on its previous motion). Our observations demonstrate that, at the particle level, the dynamic behaviour of granular systems is qualitatively different from that of thermal glass-forming systems, and is instead more similar to that of complex fluids. We conclude that granular materials can relax even when the driving strain is weak.
This is a preview of subscription content, access via your institution
Relevant articles
Open Access articles citing this article.
-
Key connection between gravitational instability in physical gels and granular media
Scientific Reports Open Access 15 April 2022
-
Additive rheology of complex granular flows
Nature Communications Open Access 19 March 2020
Access options
Access Nature and 54 other Nature Portfolio journals
Get Nature+, our best-value online-access subscription
$29.99 per month
cancel any time
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Rent or buy this article
Get just this article for as long as you need it
$39.95
Prices may be subject to local taxes which are calculated during checkout




References
Jaeger, H. M., Nagel, S. R. & Behringer, R. P. Granular solids, liquids, and gases. Rev. Mod. Phys. 68, 1259–1273 (1996)
Duran, J. Sands, Powders, and Grains: An Introduction to the Physics of Granular Materials (Springer, 2012)
Coniglio, A ., Fierro, A ., Herrmann, H. J. & Nicodemi, M. Unifying Concepts in Granular Media and Glasses (Elsevier, 2004)
Anthony, J. L. & Marone, C. Influence of particle characteristics on granular friction. J. Geophys. Res. 110, B08409 (2005)
Binder, K. & Kob, W. Glassy Materials and Disordered Solids: An Introduction to their Statistical Mechanics (World Scientific, 2011)
Bramwell, S. T. The distribution of spatially averaged critical properties. Nat. Phys. 5, 444–447 (2009)
Mueth, D. M. et al. Signatures of granular microstructure in dense shear flows. Nature 406, 385–389 (2000)
Dijksman, J. A., Rietz, F., Lorincz, K. A., Van Hecke, M. & Losert, W. Refractive index matched scanning of dense granular materials. Rev. Sci. Instrum. 83, 011301 (2012)
Panaitescu, A., Reddy, K. A. & Kudrolli, A. Nucleation and crystal growth in sheared granular sphere packings. Phys. Rev. Lett. 108, 108001 (2012)
Pouliquen, O., Belzons, M. & Nicolas, M. Fluctuating particle motion during shear induced granular compaction. Phys. Rev. Lett. 91, 014301 (2003)
Ren, J., Dijksman, J. A. & Behringer, R. P. Reynolds pressure and relaxation in a sheared granular system. Phys. Rev. Lett. 110, 018302 (2013)
Paulsen, J. D., Keim, N. C. & Nagel, S. R. Multiple transient memories in experiments on sheared non-Brownian suspensions. Phys. Rev. Lett. 113, 068301 (2014)
Dauchot, O., Marty, G. & Biroli, G. Dynamical heterogeneity close to the jamming transition in a sheared granular material. Phys. Rev. Lett. 95, 265701 (2005)
Slotterback, S. et al. Onset of irreversibility in cyclic shear of granular packings. Phys. Rev. E 85, 021309 (2012)
Radjai, F. & Roux, S. Turbulent-like fluctuations in quasistatic flow of granular media. Phys. Rev. Lett. 89, 064302 (2002)
Bi, D., Zhang, J., Chakraborty, B. & Behringer, R. P. Jamming by shear. Nature 480, 355–358 (2011)
Royer, J. R. & Chaikin, P. M. Precisely cyclic sand: self-organization of periodically sheared frictional grains. Proc. Natl Acad. Sci. USA 112, 49–53 (2015)
GDR MiDi . On dense granular flows. Eur. Phys. J. E 14, 341–365 (2004)
Xia, C. et al. The structural origin of the hard-sphere glass transition in granular packing. Nat. Commun. 6, 8409 (2015)
Mailman, M., Harrington, M., Girvan, M. & Losert, W. Consequences of anomalous diffusion in disordered systems under cyclic forcing. Phys. Rev. Lett. 112, 228001 (2014)
Bouchaud, J. P. & Georges, A. Anomalous diffusion in disordered media: statistical mechanisms, models and physical applications. Phys. Rep. 195, 127–293 (1990)
Singh, A., Magnanimo, V., Saitoh, K. & Luding, S. The role of gravity or pressure and contact stiffness in granular rheology. New J. Phys. 17, 043028 (2015)
Kumar, N. & Luding, S. Memory of jamming—multiscale models for soft and granular matter. Granul. Matter 18, 58 (2016)
Henann, D. L. & Kamrin, K. Continuum modeling of secondary rheology in dense granular materials. Phys. Rev. Lett. 113, 178001 (2014)
Caballero-Robledo, G. A., Goldenberg, C. & Clement, E. Local dynamics and synchronization in a granular glass. Granul. Matter 14, 239–245 (2012)
Kob, W. & Andersen, H. C. Testing mode-coupling theory for a supercooled binary Lennard–Jones mixture I: the van Hove correlation function. Phys. Rev. E 51, 4626–4641 (1995)
Doliwa, B. & Heuer, A. The origin of anomalous diffusion and non-Gaussian effects for hard spheres: analysis of three-time correlations. J. Phys. Condens. Matter 11, A277–A283 (1999)
Larson, R. G. The Structure and Rheology of Complex Fluids (Oxford Univ. Press, 1999)
Kamrin, K. & Koval, G. Nonlocal constitutive relation for steady granular flow. Phys. Rev. Lett. 108, 178301 (2012)
Donev, A. et al. Improving the density of jammed disordered packings using ellipsoids. Science 303, 990–993 (2004)
Titow, M. PVC Technology 1189–1191 (Springer, 1984)
Johnson, K. L. & Johnson, K. L. Contact Mechanics 92–95 (Cambridge Univ. Press, 1987)
Hansen, J. P. & McDonald, I. R. Theory of Simple Liquids (Elsevier, 1990)
Chaudhuri, P., Berthier, L. & Kob, W. Universal nature of particle displacements close to glass and jamming transitions. Phys. Rev. Lett. 99, 060604 (2007)
Umarov, S., Tsallis, C. & Steinberg, S. On a q-central limit theorem consistent with nonextensive statistical mechanics. Milan J. Math. 76, 307–328 (2008)
Picoli, S., Mendes, R. S., Malacarne, L. C. & Santos, R. P. B. q-Distributions in complex systems: a brief review. Braz. J. Phys. 39, 468–474 (2009)
Acknowledgements
Some of the preliminary experiments were carried out at BL13W1 beamline of Shanghai Synchrotron Radiation Facility. The work is supported by the National Natural Science Foundation of China (numbers 11175121, 11675110 and U1432111), Specialized Research Fund for the Doctoral Program of Higher Education of China (grant number 20110073120073) and ANR-15-CE30-0003-02. W.K. is member of the Institut Universitaire de France.
Author information
Authors and Affiliations
Contributions
Y.W. and W.K. designed the research. B.K., Y.C., J.L., C.X., Z.L., H.D., A.Z., J.Z. and Y.W. performed the experiment. B.K., W.K. and Y.W. analysed the data and wrote the paper.
Corresponding authors
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Additional information
Reviewer Information Nature thanks R. Behringer and the other anonymous reviewer(s) for their contribution to the peer review of this work.
Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Extended data figures and tables
Extended Data Figure 1 Trajectories of 20 particles in the central region of the sample.
The strain amplitude is γ = 0.26 and the length of the trajectory is 615 cycles, the total length of the experiment for this γ. Time is represented by the colour scale. The short axis of the particles is 2b.
Extended Data Figure 3 Evolution of the volume fraction Φ of the system during the cyclic shear measurements at different γ.
For γ = 0.10 we have two curves that stem from two completely independent measurements. The fact that the corresponding packing fractions are compatible shows that sample-to-sample fluctuations are small.
Extended Data Figure 4 The normalized local number density ρi/〈ρi〉 in the system as a function of i, for i ∈ {x, y, z}, for different γ.
The vertical dashed lines denote the boundaries of the central region that we chose for the subsequent analysis.
Extended Data Figure 5 Time dependence of the self (Fs(q, t); large open symbols) and collective (F(q, t); small closed symbols) intermediate scattering functions (equation (4)), for different γ.
a, q = 3.49b−1. b, q = 4.46b−1. The correlators decay without any sign of a two-step relaxation, thus showing that in this system the particles are not caged.
Extended Data Figure 6 PDF in the y direction for γ = 0.26.
a, Comparison of the fits with the Gumbel distribution (black line) and the q-Gaussian distribution (pink line) for the whole accessible range in the displacement. b, An enlarged view of the area indicated by the blue rectangle in a. c, d, The ratio between the logarithm of the PDF for the data (ln(P(dy))) and for the Gumbel distribution (ln(Pg); c), and for the data and the q-Gaussian distribution (ln(Pq); d).
Supplementary information
The dynamics of the particles during the cycling experiment (γ=0.26): Top view.
The video shows a view of the system from the top. It shows a horizontal cut through the middle of the sample and only the particles in the lower half of the central region of the box are displayed. The value of γ is 0.26 and the video covers the 615 cycles of the measurement with the CT scanner. Note that on the time scale considered, most of the particles move less than their long axis (see Fig. 1b of the main text) (MOV 6585 kb)
The dynamics of the particles during the cycling experiment (γ=0.26): Side view.
The video shows a side view of the same system of Supplementary Video 1. We made a vertical cut through the middle of the sample and show only the particles in the sector with large x. Note that the system shows no evident signature for convective motion. (MOV 3672 kb)
Rights and permissions
About this article
Cite this article
Kou, B., Cao, Y., Li, J. et al. Granular materials flow like complex fluids. Nature 551, 360–363 (2017). https://doi.org/10.1038/nature24062
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/nature24062
This article is cited by
-
Rheological behaviors of spherical granular materials based on DEM simulations
Acta Mechanica Sinica (2023)
-
Key connection between gravitational instability in physical gels and granular media
Scientific Reports (2022)
-
Microscopic origin of shape-dependent shear strength of granular materials: a granular dynamics perspective
Acta Geotechnica (2022)
-
A machine learning-based multi-scale computational framework for granular materials
Acta Geotechnica (2022)
-
Granular wave-solid state: an accident of density inversion?
Granular Matter (2022)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.