## 1 Introduction  
Many engineering fields, such as ocean and river transportation in cold regions, energy exploration and exploitation in freezing territorial waters, and aviation and spaceflight, involve ice mechanics. Better understanding of the complex mechanical properties of ice is the foundation to predict the ice failure process and avoid potential ice threats. Many researchers have conducted extensive experiments to investigate the mechanical properties of freshwater ice, sea ice, and artificial ice under creep and quasi-static conditions; relationships between compressive strength and strain-rate, temperature, loading direction, and the internal structure of ice have been obtained [1; 2; 3; 4]. In the past ten years, many researchers have started to investigate ice mechanical behavior at high strain rates in the magnitude range of hundreds and thousands by use of split Hopkinson pressure bar (SPBH) or a high-speed jack, accompanying with a high-speed camera, and several experiments [5; 6; 7; 8; 9; 10; 11; 12; 13] have been carried out, as there is a need for high-speed impact behavior of ice in a broad range of engineering areas. Study of ice mechanics extends from low strain rates to moderate and high strain rates. Both [PERSON] [5] and [PERSON] and [PERSON] [6] conducted uniaxial compression tests on laboratory grown ice in the strain-rate range of \(10^{-1}\) to \(10\) s\({}^{-1}\), and their testing temperatures are \(-11\)\({}^{\circ}\)C and \(-10\)\({}^{\circ}\)C, respectively. Both studies showed that ice compressive strength increases with increasing strain-rate in the moderate strain-rate range. [PERSON] et al. [7] measured uniaxial compressive strength of iceberg ice over a wide range of strain-rate range from \(10^{-8}\) to \(10\) s\({}^{-1}\) at \(-10\)\({}^{\circ}\)C. Ice samples were 25 cm in height and 10 cm in diameter, with an average grain size of about 3.5 mm and lots of elongated air bubbles. Result of [PERSON] et al. showed that in the strain-rate range of \(10^{-1}\) to \(10\) s\({}^{-1}\), strength of iceberg increased with increasing strain-rate and obtained a value of about 10 MPa at \(10\) s\({}^{-1}\). [PERSON] et al. [11] investigated compressive strength in the strain-rate range of \(10^{-2}\) to \(50\) s\({}^{-1}\) and failure modes under high-velocity impact based on laboratory-grown ice. Study of [PERSON] et al. showed that strain-rate seemed to have little effect on ice compressive strength in the employed strain-rate range, and that ice strength was associated with failure modes. Ice obtained lower strength value when it failed in breaking into a small number of large fragments than when in forming longitudinal vertical cleavage crack followed by explosion of a large number of fragments. With regard to compressive strength at high strain rates, [PERSON] et al. [14] carried out drop tests on laboratory-grown ice in the strain-rate range of 100 to \(600\) s\({}^{-1}\). Cylindrical ice specimens were employed, with 4 to 8 cm in diameter and 4 to 5 cm in height. Study of [PERSON] et al. showed that in high strain-rate range ice strength increased with increasing strain-rate. [PERSON] and [PERSON] [9] investigated the compressive strength of laboratory-grown ice in the strain-rate range of 400 to \(2600\) s\({}^{-1}\) by employing a split Hopkinson pressure bar, at near melting point temperature. Ice specimens were cylindrical samples with size of about 13 mm in diameter. The compressive strength was found to be nearly uniform over the measured strain-rate range; an average value of 19.7 MPa was reported. [PERSON] et al. [10] conducted high strain-rate compression tests on laboratory fresh water ice in the strain-rate range of 60 to 1400 s\({}^{-1}\) by employing an adapted split Hopkins pressure bar at \(-10\)\({}^{\circ}\)C and \(-30\)\({}^{\circ}\)C. Both single-crystal ice and polycrystalline ice were included. Diameters of cylindrical ice were less than 2 cm and thicknesses were less than 1 cm. Strength of both types of freshwater ice increased with increasing strain-rate.