Ice breaking by low-velocity impact with a rigid sphere

Penetrator-ice plate impact subjected to dynamic loading constitutes many scientific applications for ice, such as controlling ice disasters by penetrating the ice cover and then entering underwater to explosive ice breaking on Earth, and life detection and resource development under water ice sheet on outer space planets. We present experimental results of brittle damage induced by a small spherical projectile impacting an ice plate with a thickness of 6-50 mm using a drop ball test device or a vertical gas gun. The corresponding impact velocities vary from 2 to 74 m/s. Crater parameters, residual velocity and energy absorption are investigated and assessed. The main fracture patterns and crater formation are captured by two high-speed cameras. A dynamic recrystallization phenomenon of polycrystalline ice is observed, and its formation mechanism is preliminarily analysed. The effects of the impact velocity, ice sample thickness, and restriction conditions on dynamic fracture processes and failure modes are systematically explored. These results improve our understanding of dynamic fracturing mechanism in ice engineering applications.