Jamming by shear thickening.zip

A body usually fractures or breaks into discrete particles under impact. Here, we present a novel phenomenon where loose millimeter-sized particles mixed with a dense suspension of micrometre-sized particles could be rearranged into any shape but automatically consolidated into a hard solid instantaneously under impact or rapid shear. Using a Couette shear set-up, we tested the mechanical properties of this mixture and showed that the solidification was due to the occurrence of loading-rate-related jamming transition, which increased the yield stress by more than two orders of magnitude. Further, we tested the interaction force between pairs of particles and found that the phase transition was due to the discontinuous shear thickening of the suspension, an effect that increased the coefficient of rolling friction drastically and inhibited the free motion between particles. This automatic, instantaneous jamming phenomenon according to external loading conditions has prospective applications in smart manufacturing, soft robot and flexible protection.