Compressive Properties of Ice Containing Cotton at Low Strain Rates

Aviation aircraft inevitably encounter threat of hail impact during flight, which seriously endangers flight safety of aircraft. At present, impact characteristics of natural ice materials are still unclear, this paper studies mechanical properties of natural ice materials under different strain rates. However, natural ice has the characteristics of low density and high strength compared with artificial hail. According to the hail preparation standard ASTM F320-21 “Ice Impact Testing of Transparent Shells for Aviation and Aerospace”, icicle specimens containing cotton fiber with mass fractions of 0, 3%, 6% and 12% were prepared. The icicle specimens were subjected to compression experiments with strain rates of 10⁻⁴, 10⁻³, and 10⁻² s⁻¹ using a universal testing machine, and effects of cotton fiber mass fraction and strain rate on their compressive mechanical properties, as well as a relation between damage form and critical strain energy density change, were analyzed. The results show that the transparent icicles without cotton fiber transforms from ductility to brittleness at a strain rate of about 10⁻³ s⁻¹, and that the addition of cotton fiber increases the compressive yield strength of ice, resulting a phenomenon of “cracking but not breaking” during the compression process. Under quasi-static compression, less energy is required to convert to crack surface energy than to plastic energy.