Grad Student Zhao and Colleagues in APS Viewpoint

Thursday, October 10, 2019

Graduate student Yiqiu Zhao and colleagues have been featured in an APS Viewpoint. Zhao summarizes: Granular matter can behave like solid or liquid. A phase diagram that predicts the behavior of granular matter based on control parameters is important but not well established. Part of the difficulty is, granular matter develops spatial heterogeneity known as shear band under shear, making it hard to build connections between state variables since a well-defined “state” should be homogeneous. In this work, we solve this problem using a novel Couette shear setup which can apply shear to a layer of photoelastic disks using not only boundaries but also movable bottom rings. This setup creates uniform sheared state to build a phase diagram that clarifies the conditions for granular matter to be in unjammed (liquid-like),  shear-jammed (solid-like), or fragile (solid-like under forward shear but liquid-like if the direction of shear is reversed) phase.

Read the article "Jamming Grains Come Full Circle" online here.