Upstream jetting phenomenon in planar shock wave experiments with ceramic powders

Jetting along upstream impact direction was observed in the experiments that were designed to study the response of ceramic powder materials to planar shock loading generated by impact. The jet formed catastrophically above certain impact stress level at the center of the impacted area and perforated upstream metal cover and flyer plates. Experiments were conducted with different impact stress levels, powder particle sizes, and geometrical parameters. Consistently repeatable results were obtained and effects arising from particle size, initial porosity, impact stress, and reflected wave were assessed. A simple mechanism-based model is used to explain the formation of the jet and estimate the jet velocity.