Onset of mechanical failure in shear-jammed dense suspensions

Dense suspensions are a broad class of matter that have the capacity for shear thickening and solidification when subject to stress, but little is known about the properties of solidified dense suspensions and the mechanisms contributing to their mechanical failure, in the form of fracture. We experimentally characterize the onset of crack formation in dense cornstarch suspensions under impact of known strain to investigate the mechanical failure of dynamically-jammed suspensions. There is a critical particle volume fraction, below which fracture will not occur. Above this critical value, the stress at which a shear-jammed solid will fracture varies with both depth and velocity of impact, suggesting that mechanical failure can occur in dynamically-jammed solids with a range of material properties.