The response of geo-materials to high-speed liquid drop impact

• Single drop impact jet apparatus is utilized for the simulation of drop impacts (885 m/s) on six geo-materials.
• Highest correlation exists between removed volume and fracture toughness.
• SEM inspections revealed a variation of brittle failure features, but barely any signs of plastic response.
• Simple threshold criteria are derived, indicating that hard and brittle rocks respond entirely elastically to the impact.
• A brittle material resistance function is derived, combining fracture toughness, Young's modulus and density.

The subject of the investigation is the response of geo-materials, namely rocks and cementitious composites, to the impact of liquid drops at very high velocities. A single drop impact jet apparatus is utilized for the simulation of drop impacts with a velocity of 885 m/s. The response of six materials (igneous, sedimentary and metamorphic rocks; concretes) with defined mechanical parameters is investigated. The removed volume is measured, and it is related to material parameters, namely uniaxial compressive strength, splitting tensile strength, Young's modulus, mode-I fracture toughness, and elastic strain energy density. The highest correlation exists between removed volume and fracture toughness. SEM inspections revealed a variation of brittle failure features, but barely any signs of plastic response. Threshold criteria are derived, which indicate that hard and brittle rocks respond entirely elastically to the impact in the investigated loading case. A brittle material resistance function is derived, which combines fracture toughness, Young's modulus and density. The results of this study can be used to approximate the resistance of geo-material against high-speed liquid impact, when brittle fracture dominates the material removal process.