Shock waves, crack propagation and cavitation inception upon high-energy impact on a shear-thickening fluid

Particle suspensions, such as a mixture of cornstarch and water, exhibit shear-thickening properties that have various applications in safety equipment, such as motorcycle or ski helmets, as they can reduce the impact energy. However, at high concentrations of particles, these fluids can become solid-like and even crack when subjected to severe impacts. It is also likely that cavitation will occur during high-velocity impacts, contributing to the formation and propagation of cracks and shock waves. However, at these concentrations, shear-thickening fluids become opaque, hindering the visualisation of crack formation with conventional imaging techniques. We therefore propose to perform high-speed in-situ X-ray imaging of shear-thickening fluids impacted by high-energy shocks to study the formation of cracks in such mixtures and the possible onset and dynamics of cavitation bubbles.