ABSTRACT

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^oC, 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 ∼ 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.

摘要

虽然在两个准静态下的冰的抗压强度[M。Arakawa和N. Maeno，单轴压缩下多晶冰的机械强度。冷注册 科学 Tech 26（1997），第215-229页。]和动态[X. Wu和V.Prakash，《低温下冰的动态压缩行为》。冷注册 科学 Tech 118（2015），第1–13页。]荷载显示出异常的温度效应，即在低于-100 ^o的特定温度范围内，压缩强度对温度不敏感仍然不清楚在低温下冰的拉伸强度是否存在异常温度。本文通过分子动力学模拟研究了冰在冲击载荷作用下1 h的动态拉伸强度。有趣的是，冰的动态拉伸强度表现出相似的反常温度效应，即它对117〜163 K范围内的温度几乎不敏感，这可以用冲击诱导的粉碎与融化之间的竞争机制来解释。 。随着温度降低，还观察到五边形-七边形缺陷的演变以及韧性到脆性转变，从而导致冰在冲击下具有独特的动态拉伸行为。