Tensile strength and elastic properties of fine-grained ice aggregates: Implications for crater formation on small icy bodies
Tensile strength and elastic properties of fine-grained ice aggregates: Implications for crater formation on small icy bodies
复制标题
细粒冰聚集体的拉伸强度和弹性特性：对小冰体上火山口形成的影响
DOI：
10.1016/j.icarus.2021.114646
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发表时间：
2021
期刊：
影响因子：
3.2
通讯作者：
Arakawa Masahiko
中科院分区：
文献类型：
--
作者：
Shimaki Yuri;Arakawa Masahiko
冰团聚体的力学和弹性性质在冰体上的雪崩和陨石坑形成的物理学中很重要，例如结冰的卫星和彗星核。在这里，我们对人造细粒冰聚集体(雪)进行了单轴拉伸测试和弹性波速度测量，以推断在小冰体上形成陨石坑的可能性。在−15°C下，对填充因子f在0.30~0.59范围内的人造雪进行了单轴拉伸试验，结果表明，人工雪的抗拉强度Yt取决于其填充因子，由此得到的经验公式Yt=1.035f3.5(单位kpa)，与天然雪的抗拉强度上限一致。用超声脉冲速度法测量了f≥为0.4的人造雪的纵波和横波速度。弹性波速度随f值的减小而线性减小。由弹性波速测量得到的人造雪的杨氏模数比拉伸试验的计算结果高出10-40倍，这表明了细粒冰团聚体的速率相关特性。基于我们的结果和强度占主导地位的陨石坑标度定律，我们提出了一个通过人工撞击彗星表面的拉伸强度估算方法。
The mechanical and elastic properties of ice aggregates are important in the physics of avalanches and crater formation on icy bodies, such as icy satellites and cometary nuclei. Here we conducted uniaxial tensile tests and elastic-wave velocity measurements on artificial fine-grained ice aggregates (snow) to infer the potential for crater formation on small icy bodies. The uniaxial tensile tests on the artificial snow with filling factors (f) in the 0.30–0.59 range at− 15° C demonstrate that the tensile strength (Y t) depends on its filling factor; we obtained the empirical equation Y t= 1 0 3. 5 f 3. 5 (in kPa) based on our results, which is consistent with the upper limit of natural snow’s tensile strength. The compressional-and shear-wave velocities of artificial snow with f≥ 0.4 were measured via the ultrasonic pulse velocity method. The elastic-wave velocities decrease linearly with decreasing f values. Our calculations for the Young’s moduli of the artificial snow from the elastic-wave velocity measurements are 10–40 times higher than those from the tensile tests, which indicate the rate-dependent properties of the fine-grained ice aggregates. We propose a tensile strength estimation of a cometary surface via an artificial impact based on our results and a crater-scaling law in the strength-dominated regime.