圆锥探头在准二维颗粒介质中匀速穿行的受力研究

 研究圆锥状探头匀速压入准二维颗粒介质过程中所受阻力随深度的变化，发现阻力曲线在不同深度区域呈现不同的变化规律，存在凹—凸—凹的转变。针对本实验条件下观测到的现象，分析并讨论曲线凹—凸—凹转变中出现两个拐点的物理机制，认为阻力曲线的变化来源于侵入物自身的体积效应和容器底部对颗粒结构的影响。研究表明，一般流体的静水压力描述并不适用于颗粒介质的慢速阻力行为，颗粒介质存在自身的结构规律。

Experimental Research About Force on a Conical a Probe Passing Through a Quasi-two-dimensional Granular Bed with a Constant Velocity

The movement of an intruder in a granular medium may result in interior reorganization of the force chain structure. The form of drag force experienced by the intruder reflects the macro effect of reorganization. By measuring the slowly-pushing force of the cone intruding vertically into a quasi-two-dimensional granular bed, the depth dependence of the vertical drag force in the granular medium is studied experimentally. It is found that the drag force curve has a concave-convex-concave transition with the increasing penetration depth and the drag force follows different depth dependence in different regimes. By studying the properties of two inflection points of the concave-convex-concave transition, it is shown that the front inflection point of the curve is the result of the volume effect of the intruder in the granular medium, and the rear inflection point of the curve is the result of the bottom boundary support. The depth of the front inflection point is independent of the packing height of the granular medium, however, the depth of the rear inflection point is linear with the packing height of the granular medium.