Effect of C-axis direction on fracture toughness of single-crystal ice

The effect of the direction of the crystal axis (C-axis) on fracture toughness of single-crystal ice specimens was investigated by the three-point bending test at -10°C. The loading rate KI was about 200 kPa√m/s. Four types of single-crystal ice specimens were used in which the C-axis direction of the crystal was placed at an angle θ equalling 0°, 45°(I), 45°(II) and 90°, respectively, to the notch plane. These specimens have a sharp edge notch made by pressing the edge of a razor blade on the bottom of the saw-cut slot. In advance of the test using single-crystal ice specimens, the effect of pressing the razor blade on fracture toughness was examined using columnar grained ice specimens under the loading rate KI ranging from 1.0 to 1.0 × 104 kPa√m/s at -10°C.