Experimental study on mechanical properties of ice shock under different states

To investigate the dynamic mechanical characterization of non-pure and non-intact ice materials under impact loads, a modified split Hopkinson pressure bar (SHPB) was used. Rapid loading, rod end cooling and waveform shaping techniques were used to ensure the stability of the ice material and achieve dynamic stress balance during loading. The impact mechanical properties of complete ice (pure water, containing 2.5%, 3.5%, 4.5% salt, containing 2.0%, 4.5%, 8.5% coconut) and spliced ice (splicing interface inclination 30°, 60°) at freezing temperature of −10 ℃ were studied. The strain rate ranges from 150−250 s⁻¹. The failure process was recorded by using the high-speed camera triggered simultaneously with the pressure rod. The correlation between the stress and strain of the sample, along with the failure process, was determined by analyzing the time history curve of sample. The failure mode of the spliced ice sample was analyzed by combining the Mohr-Coulomb strength criterion. The results show that the pure water ice exhibits the highest compressive strength, followed by the ice with coconut shreds, and both of them show a positive strain rate effect. However, the compressive strength of the ice with salt addition decreases significantly due to its loose structure and the strain rate effect is not obvious. The dynamic compressive strength of ice samples added with coconut fiber increases firstly and then decreases with the increase of coconut fiber content. Ice samples with high coconut fiber content are prone to “double peak” phenomenon due to the binding effect of coconut fiber on broken ice with small particle size. The splicing plane affects the crack growth, resulting in lower compressive strength than the intact ice sample, and affects the failure mode as well. The ice with small interface inclination is mainly damaged by interface slip, while the ice with large interface inclination is mainly damaged by whole ice, which is similar to the intact ice. The research results provide theoretical basis and method reference for the dynamic mechanical properties of non-pure and non-intact ice materials under impact loads.