Test setup for compressive loading of confined ice thick sections viewed with in-situ cross-polarization imaging

For the topic of predicting ice-induced vibrations of vertically sided offshore structures, the rate-dependent ductile-to-brittle transitional deformation and failure behavior of ice is critical but remains superficially understood. To investigate this knowledge gap, a test setup has been designed which allows for in-situ crossed-polarization imaging of passively confined ice thick sections subjected to compressive loading. The test setup is designed to recreate the scenario of a cross-section at the leading edge of an ice sheet which is laterally confined by surrounding ice and fails in crushing against a structure. The setup comprises a linear actuator which drives a flat plate into a confinement box containing the ice thick section, which is passively confined orthogonal to the plane of loading by thick fused silica glass plates. The ice is illuminated through the glass plates with crossed-polarized light, which highlights the microstructure of the ice. Freshwater ice of columnar grain structure is prepared in the ice laboratory at Delft University of Technology, and quantified in terms of its microstructure. The ice thick sections in the test setup are subjected to a range of deformation rates at different temperatures. While similar experiments have been performed, this setup provides novelty by accentuating the dynamic microstructural deformation in-situ with crossed-polarized light. Moreover, this microstructural deformation is observed for global deformation rates relevant for ice-induced vibrations of offshore structures. A description of the test setup is presented along with preliminary experimental results.