We report a strain-induced anisotropy in elastic properties in columnar ice subjected to uniaxial compressive loading. Polycrystalline specimens of both freshwater ice and saline ice were produced and tested in the laboratory at - 10 °C to explore the effects of damage on mechanical behavior and elastic properties. The tests consisted of 1) imparting inelastic strain by compressing the specimens uniaxially across the columnar grains at constant strain rates, 2) measuring changes in elastic properties (by ultrasonic transmission technique) and microstructure (including damage quantification) and 3) reloading the specimens again in uniaxial compression, either parallel (x_1) or perpendicular (x_2) to the initial loading direction. We observed distinct differences in the character of stress-strain curves recorded upon reloading the specimens in the x_1 versus the x_2 directions. In freshwater ice in particular, this difference coincided with a greater (by 20 percent or more) reduction in the dynamic Young's modulus measured along x_2 compared to x_1. We quantified visible damage by measuring lengths and orientations of crack traces in thin sections cut from the prestrained freshwater ice. For each thin section analyzed, a crack density tensor was computed to compare anisotropy in damage with that measured in the elastic properties.
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