Experimental study on ice-on-ice friction and compressive properties of high-density snow

冰的摩擦系数随温度和相对速度的变化而变化。因此，我们研究了摩擦系数对雪阻力的影响。压痕施加的阻力已被测量到低于400 kg/m^3的密度。然而，高密度雪(&gt；400 kg/m^3)产生的阻力现在对于雪崩、道路上的压缩雪和结冰的卫星的雪屑来说是重要的。为此，我们进行了压痕试验，以阐明高密度积雪的力学行为，并测量了冰粒流动产生的阻力，以研究冰摩擦系数与雪阻力之间的关系。在流速为0.50~500 mm/S的范围内，用不同深度的圆柱体在-10℃处测量了雪的阻力，发现阻力随流速的增加而减小。但是，在-50℃下进行的测试中没有发现相同的速度依赖关系：它是一个常数。D…的速度依赖性冰面摩擦系数随速度的变化可以解释-10℃时较大的拉格力。冰的摩擦系数随着速度的增加而减小，这是因为边界处的摩擦融化减少了摩擦力。压缩测量是用一根棍子穿透高密度的雪进行的。变形分为塑性变形和破坏性变形两种类型。在塑性型变形中，应力和应变率之间的关系是非线性的，因此，这种变形不是牛顿的，而是用幂定律来表示的。这表明，除了在低密度雪中起作用的颗粒重排外，冰粒的塑性变形和破坏也是重要的。当雪密度为550、640和730 kg/m~3时，两种变形类型的临界侵彻速度分别为0.33~0.83、0.83~1.67和1.67~3.33 mm/。功率随密度增大而增大，接近3，相当于穿透冰层所需的功率。较少

Friction coefficient of ice changes with the temperature and the relative velocity. So, we have studied the effect of friction coefficient on the snow drag force. The drag force exerted by indentation has been measured below the density of 400kg/m^3. However, the drag force generated in the high-density snow (>400kg/m^3) is now important for the snow debris of avalanche, compressed snow on the road, and icy satellites. Therefore, we made indentation tests to clarify the mechanical behavior of the high-density snow and measured the drag force generated by ice granular flow to study the relationship between the ice friction coefficient and the snow drag force. Snow drag force was measured by using cylinder set in a various depth at -10℃ for the flow speed from 0.5 to 500mm/s. Thus, we have found that the drag force decreased with increasing the flow velocity. But, the same velocity dependence was not found in the test conducted at -50℃: it was a constant. The velocity dependence of the d … More rag force at -10℃ could be explained by the velocity dependence of the ice friction coefficient. The ice friction coefficient decreases with increasing the velocity because of the frictional melting at the boundary to reduce the friction. Compression measurements were conducted by using a rod to penetrate high-density snow. Two types of deformation were recognized plastic-type and destructive-type deformations. In the plastic-type deformation, the relation between the stress and strain rates was nonlinear, hence, this deformation is not Newtonian and is expressed by a power law. This suggests that in addition to the particle rearrangement operative in low-density snow, plastic-type deformation and destruction of ice particles are also important. The critical penetration speeds between the two deformation types were 0.33-0.83, 0.83-1.67, and 1.67-3.33 mm/ for snow densities of 550, 640, and 730 kg/m^3, respectively. The power increased with density and approached 3, which correspond to that required for penetrating ice. Less