三体摩擦界面剪切膨胀过程典型阶段的力链形态及承载特性

为研究研磨过程中颗粒体系的力链特性，该文运用离散元构建了一个双平行板剪切模型模拟无限剪切运动，并观察颗粒受剪切时相关参数变化。模拟将剪切膨胀过程分为塑性爬行阶段、脆性破坏阶段、颗粒重组阶段三部分，并运用力链在x轴与y轴的分量比值来观察力链方向性变化，用承载率-分布率曲线描述力链的分布及承载变化，用力链的形态图形来观察力链形态变化。结果显示:在剪切膨胀三阶段内，力链的形态、方向、分布及承载特性各不相同。其中，塑性爬行阶段力链的形态近似倾斜网格，分布比较集中，力链承载特性良好；而脆性破坏与颗粒重组阶段，强弱力链值相差较大，承载性差。并由此得出，在塑性爬行阶段研磨条件最好。

PATTERN AND LOAD CARRYING BEHAVIOR OF FORCE CHAINS INVOLVING THE TYPICAL SHEARING DILATANCY PROCESS IN FRICTIONAL THIRD-BODY INTERFACE

In order to study the force chains characteristics of granular flow during polishing, a parallel-plate shear cell has been constructed to simulate the shear movement of infinite parallel plate and observe the relevant parameter. The shear dilatancy process can be divided into three stages: the plastic strain stage, macroscopic failure stage and granular recombination stage. The ratio of force chains in x-component and y-component, the load-distribution rate curves and the pattern of force chains are used to describe the orientation, the load carrying behavior and the pattern of force chains respectively, which are different at the three stages. At the plastic strain stage, the force chains are like diagonal gridding, concentratedly distributed, and the load carrying behavior is better than that at macroscopic failure stage and granular recombination stage. The result shows that the polishing conditions of the plastic strain stage are better.