Penetration and bouncing during impact in shallow cornstarch suspensions

Abstract

The impact-activated solidification of cornstarch suspensions has proven to be a multi-faceted problem and a complete explanation of the different phenomena observed during this process remains elusive. In this work, we revisit this rich problem and focus on impact on shallow suspension baths where the solidification partly leads to bouncing of the impactor. We systematically vary the depth and solid fraction of the suspension, the mass of the impactor, and the impact velocity to determine which conditions lead to bouncing. For cases where bouncing occurs we observe distinctly different dynamics as compared to those cases without it. Our results allow us to connect the velocity oscillations and stop-go cycles that were observed during settling in a deep layer, with more recent work dealing with high-force and high-speed impact on a cornstarch suspension.