Small-scale ice indentation tests with variable structural compliance

Small-scale ice indentation tests have been performed on confined polycrystalline ice specimens in order to simulate a single, stationary, high pressure zone. These tests aid in the understanding of the mechanics associated with ice failure processes and the formation of high pressure zones during ice-structure interaction. Temperature has a significant effect on the failure mode of the ice and microstructural modification of the damaged layer. Cyclic loading patterns, at frequencies as high as 250 Hz, have been linked to crushing and extrusion of ice associated with high pressure zone failures. Structural compliance was observed to aid in the development of cyclic loading patterns and the frequency has been observed to have a linear dependence on structural stiffness. A linear relationship was also observed between the indentation speed and the resulting cyclic loading frequency. A layer of damaged ice adjacent to the indenter was observed after each test and was found to contain both densely microfractured and recrystallized ice. The extent of microcracking and recrystallization present in the layer was found to depend on both the indentation rate and temperature.

► Ice indentation tests were performed on confined polycrystalline ice specimens. ► Structural feedback was investigated using compliant indentation systems. ► Cyclic loading patterns have been linked to high pressure zone failures. ► Structural compliance aids in the development of cyclic loading patterns. ► Cyclic loading frequency exhibits dependence on structural stiffness and indentation rate.