Achievement

Newly published in Nature, are results of a collaboration between Prof. Bulbul Chakraborty’s group at Brandeis and Prof. Behringer’s group at Duke University, which show a new class of jammed states in frictional granular materials. This new class of “Shear-Jammed” states exhibits a richer phenomenology than previously seen. An initially unjammed or loose granular material can become jammed not just by increasing its density, but by applying shear strain on it while holding the density fixed. Shear-Jammed states are inherently anisotropic in their stress and grain-to-grain contact network (see photo). The transition from an unjammed to shear-jammed state is clearly marked by a percolation of the strong force chains in all directions (see video). The phenomenon of shear-jamming does not currently have a fundamental theoretical description. For more details: http://blogs.brandeis.edu/science/page/7/