Robert Behringer
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View article: Erratum: Obtaining self-similar scalings in focusing flows [Phys. Rev. E <b>92</b>, 043016 (2015)]
Erratum: Obtaining self-similar scalings in focusing flows [Phys. Rev. E <b>92</b>, 043016 (2015)] Open
This corrects the article DOI: 10.1103/PhysRevE.92.043016.
View article: Shear-Jammed, Fragile, and Steady States in Homogeneously Strained Granular Materials
Shear-Jammed, Fragile, and Steady States in Homogeneously Strained Granular Materials Open
We study the jamming phase diagram of sheared granular material using a novel Couette shear setup with a multiring bottom. The setup uses small basal friction forces to apply a volume-conserving linear shear with no shear band to a granula…
View article: Dynamics of a grain-scale intruder in a two-dimensional granular medium with and without basal friction
Dynamics of a grain-scale intruder in a two-dimensional granular medium with and without basal friction Open
We report on a series of experiments in which a grain-sized intruder is pushed by a spring through a two-dimensional granular material composed of photoelastic disks in a Couette geometry. We study the intruder dynamics as a function of pa…
View article: Thermal Marangoni-driven dynamics of spinning liquid films
Thermal Marangoni-driven dynamics of spinning liquid films Open
Spin coating of thin films of viscous liquids on a rotating substrate is a\ncore technological component of semiconductor microchip fabrication. The\nthinning dynamics is influenced by many physical processes. Specifically\ntemperature gra…
View article: Seismicity in sheared granular matter
Seismicity in sheared granular matter Open
We report on experiments investigating the dynamics of a slider that is pulled by a spring across a granular medium consisting of a vertical layer of photoelastic disks. The motion proceeds through a sequence of discrete events, analogous …
View article: Crackling to periodic dynamics in granular media
Crackling to periodic dynamics in granular media Open
We study the local and global dynamics of sheared granular materials in a stick-slip experiment, using a slider and a spring. The system crackles, with intermittent slip avalanches, or exhibits irregular or periodic dynamics, depending on …
View article: Dynamics of oblique impact in a photoelastic granular medium
Dynamics of oblique impact in a photoelastic granular medium Open
When a solid projectile impacts a granular target, it experiences a drag force and abruptly comes to rest as its momentum transfers to the grains. An empirical drag force law successfully describes the force experienced by the projectile, …
View article: Particle scale force sensor based on intensity gradient method in granular photoelastic experiments
Particle scale force sensor based on intensity gradient method in granular photoelastic experiments Open
The intensity gradient method ( G ^2 method), namely computing the light intensity gradient-squared, is a widely used non-invasive experimental method to extract stress information from quasi-two-dimensional photoelastic granular materials…
View article: Sinking in a bed of grains activated by shearing
Sinking in a bed of grains activated by shearing Open
We show how a weak force f enables intruder motion through dense granular materials subject to external mechanical excitations, in the present case, stepwise shearing. A force acts on a Teflon disk in a two-dimensional system of photoelast…
View article: An instrument for studying granular media in low-gravity environment
An instrument for studying granular media in low-gravity environment Open
A new experimental facility has been designed and constructed to study driven granular media in a low-gravity environment. This versatile instrument, fully automatized, with a modular design based on several interchangeable experimental ce…
View article: Characterizing granular networks using topological metrics
Characterizing granular networks using topological metrics Open
We carry out a direct comparison of experimental and numerical realizations of the exact same granular system as it undergoes shear jamming. We adjust the numerical methods used to optimally represent the experimental settings and outcomes…
View article: Local and global avalanches in a two-dimensional sheared granular medium
Local and global avalanches in a two-dimensional sheared granular medium Open
We present the experimental and numerical studies of a two-dimensional sheared amorphous material composed of bidisperse photoelastic disks. We analyze the statistics of avalanches during shear including the local and global fluctuations i…
View article: Topology of force networks in granular media under impact
Topology of force networks in granular media under impact Open
We investigate the evolution of the force network in experimental systems of\ntwo-dimensional granular materials under impact. We use the first Betti number,\n$\\beta_1$, and persistence diagrams, as measures of the topological properties\…
View article: Force and Mass Dynamics in Non-Newtonian Suspensions
Force and Mass Dynamics in Non-Newtonian Suspensions Open
Above a certain solid fraction, dense granular suspensions in water exhibit non-Newtonian behavior, including impact-activated solidification. Although it has been suggested that solidification depends on boundary interactions, quantitativ…
View article: Avalanches in a granular stick-slip experiment: detection using wavelets
Avalanches in a granular stick-slip experiment: detection using wavelets Open
\nAvalanches have been experimentally investigated in a wide range of physical systems from granular physics to friction. Here, we measure and detect avalanches in a 2D granular stick-slip experiment. We discuss the conventional way of sig…
View article: Tuning strain of granular matter by basal assisted Couette shear
Tuning strain of granular matter by basal assisted Couette shear Open
\nWe present a novel Couette shear apparatus capable of generating programmable azimuthal strain inside 2D granular matter under Couette shear. The apparatus consists of 21 independently movable concentric rings and two boundary wheels wit…
View article: Refractive index matched scanning and detection of soft particles
Refractive index matched scanning and detection of soft particles Open
We describe here how to apply the three-dimensional imaging technique of refractive index matched scanning to hydrogel spheres. Hydrogels are water based materials with a low refractive index, which allows for index matching with water-bas…
View article: Collisional model of energy dissipation in three-dimensional granular impact
Collisional model of energy dissipation in three-dimensional granular impact Open
We study the dynamic process occurring when a granular assembly is displaced by a solid impactor. The momentum transfer from the impactor to the target is shown to occur through sporadic, normal collisions of high force carrying grains at …
View article: Collisional model of the drag force of granular impact
Collisional model of the drag force of granular impact Open
\nA dense, dry granular target can cause a free-falling intruding object to come to an abrupt stop as its momentum is lost to the grains. An empirical force law describes this process, characterizing the stopping force as the sum of depth-…
View article: Jamming by compressing a system of granular crosses
Jamming by compressing a system of granular crosses Open
A disordered stress-free granular packing can be jammed, transformed into a mechanically rigid structure, by increasing the density of particles or by applying shear deformation. The jamming behavior of systems made of 2D circular discs ha…
View article: Jamming by compressing a system of granular crosses
Jamming by compressing a system of granular crosses Open
A disordered stress-free granular packing can be jammed, transformed into a mechanically rigid structure, by increasing the density of particles or by applying shear deformation. The jamming behavior of systems made of 2D circular discs ha…
View article: Structure of hexapod 3D packings: understanding the global stability from the local organization
Structure of hexapod 3D packings: understanding the global stability from the local organization Open
Aggregates of non-convex particles have shown to be particularly stable which makes them good candidates to design new lightweight and reversible structures. However, few is known about the fundamental reason of their stability. In this pa…
View article: Tuning strain of granular matter by basal assisted Couette shear
Tuning strain of granular matter by basal assisted Couette shear Open
We present a novel Couette shear apparatus capable of generating programmable azimuthal strain inside 2D granular matter under Couette shear. The apparatus consists of 21 independently movable concentric rings and two boundary wheels with …
View article: Vibrational Collapse of Hexapod Packings
Vibrational Collapse of Hexapod Packings Open
Columns made of convex noncohesive grains like sand collapse after being released from a confining container. However, structures built from non-convex grains can be stable without external support. In the current experiments, we investiga…
View article: Pulling an intruder from a granular material: a novel depinning experiment
Pulling an intruder from a granular material: a novel depinning experiment Open
\nTwo-dimensional impact experiments by Clark et al. [2] identified the source of inertial drag to be caused by ‘collisions’ with a latent force network, leading to large fluctuations of the force experienced by the impactor. These collisi…
View article: Avalanches in a granular stick-slip experiment: detection using wavelets
Avalanches in a granular stick-slip experiment: detection using wavelets Open
Avalanches have been experimentally investigated in a wide range of physical systems from granular physics to friction. Here, we measure and detect avalanches in a 2D granular stick-slip experiment. We discuss the conventional way of signa…
View article: A Granular System of Ellipses under Linear Shear
A Granular System of Ellipses under Linear Shear Open
\nShear of granular systems of disks (in 2D) and spheres (3D) has been studied extensively. However, less is known about systems of non-spherical particles, i.e., ellipses and polygons, etc. Here we studied a quasi 2D granular system compo…