Effects of Test Conditions on Fracture Toughness and Fracture Morphology of Polycrystalline Ice

Abstract

The authors conduct experiments on fracture toughness of several types of freshwater ice under test conditions. The effects of loading rate, test temperature and specimen dimensions on the fracture-toughness value of polycrystalline ice, such as columnar-grained ice and coarse-grained ice are examined in this study. The test conditions cover the ranges of loading rate K_I=0.8∼1.0×10⁴kPa√(m)/s, test temperature T=-5∼-50°C and specimen width b=25∼200mm. Furthermore, the characteristics of fracture morphology under the above-mentioned test conditions are indicated. In the high loading-rate range, the effects of loading rate and test temperature on the fracture toughness are negligible. In the low loading-rate range, these effects are clearly observed and a transition region is confirmed. A considerable effect of the specimen width on the fracture toughness is observed. The characteristics of the macroscopic fracture surface are clearly affected by the loading rate, test temperature and specimen dimensions.