Atomistic study on the anomalous temperature-dependent dynamic tensile strength of ice under shock loading

Although the compressive strength of ice under both quasi-static [M. Arakawa and N. Maeno, Mechanical strength of polycrystalline ice under uniaxial compression. Cold Reg. Sci. Tech 26 (1997), pp. 215-229.] and dynamic [X. Wu and V. Prakash, Dynamic compressive behavior of ice at cryogenic temperatures. Cold Reg. Sci. Tech 118 (2015), pp. 1-13.] loadings shows an anomalous temperature effect that the compression strength is insensitive to temperature in a specific temperature range below -100(o)C, it is still unclear whether the anomalous temperature exists for the tensile strength of ice at cryogenic temperatures. In this paper, the temperature-dependent dynamic tensile strength of ice 1 h under shock loading is investigated by molecular dynamics simulations. It is intriguing to see that the dynamic tensile strength of the ice exhibits a similar anomalous temperature effect, i.e. it is almost insensitive to temperature in the range 117 similar to 163 K, which could be interpreted by the competitive mechanism between shock-induced pulverisation and melting. The evolution of the pentagonal-heptagonal defects and the ductile-to-brittle transformation are also observed with decreasing temperature, leading to the unique dynamic tensile behaviour of ice under shock.