小筒仓内颗粒中探测棒受到的最大静摩擦力

STATIC FRICTION FORCE ON PROBING ROD IN GRANULARPILE IN SMALL CONTAINER

用实验方法研究了简仓内大小均匀的颗粒堆中央的竖直探测棒被提拉时受到的最大静摩擦力F.研究发现当筒仓的器壁和探测棒之间的距离小于50个颗粒直径时,F明显大于连续介质模型得出的结果;当筒仓直径D较小时F还与探测棒的形状有关,F的奇异变化主要是因为D较小时离散的颗粒体系不能近似为连续介质,颗粒堆中力链起主要作用。

Experiments were conducted to investigate the maximum static friction force on a dragged probing rod in the uniform granular pile contained in a cylindrical vessel. It is observed that the force obtained is greater than that of Jassen Model, when the gap between the wall and the rod is smaller than 50 times of the spheres diameter. When the diameter of vessel is small, the force is related to the shape of the detecting rod. This strange behavior is due to the fact that the scattered granular can not be approximated as a continuum medium when the diameter （D） is smalh The force chain in the granular pile plays a major role.