Research On Configuration And Evolution Of Force Chains In The Frictional Granular Flow System Filling In Parallel Plates

The friction, colliding and squeezing such as microscopic movement of the granules are used in lubrication and finishing as the granular matter existing in the friction interstice. The granules have a positive impact on systems of aircraft engine auxiliary bearings and grinding and polishing finishing. Because of the traditional theory cannot apply to the granular system, more and more scholars focus on this field. In order to study the inherent laws of granular system in parallel plates, the research on configuration and evolution of force chains is conducted to reveal the laws in mesoscopic scale. First, the PFC2D software is used to construct model of the frictional granular flow system filling in parallel plates, the granular system with low layer is arranged in ideal state. The periodic boundary condition are applied on both ends of parallel plates so that the granular system can flow circularly. The parameters of model are set on the basis of the polishing experimental equipment and processing materials. Then, the simulation is proceeded by controlling simple variable. The influence of variable on force chains is obtained by comparing the output result. The input variables include loading, velocity, the friction coefficient between particles, granular layer and particle diameter. The output parameters include the shear dilatancy in granular system, the distribution rate and load carrying rate of weak force chains, the orientation of force chains, the load carrying behavior of force chains, the pattern of force chains, etc. The results of simulation show that:the shear dilatancy process can be divided into the plastic strain stage, macroscopic failure stage and granular recombination stage. During the shear dilatancy process, the load carrying behavior of plastic strain stage is the best, and the orientation of force chains with low layer is close to the driving force. The change of input variables have influence on the shear dilatancy process and cause the movement of overall granular system. The loading and granular layer have the biggest influence on the load carrying behavior of force chains in shear dilatancy process. The friction coefficient between particles has the biggest influence on the load carrying behavior of force chains in the movement of overall granular system. The velocity has the smallest influence on the load carrying behavior of force chains.Taking the frictional granular flow system filling in parallel plates as the object of the study, the granular flow model was established to do some exploratory researches about configuration and evolution of force chains. It lays a good foundation for further researching the evolution properties of force chains in granular flow system.