Studv Of Contacting Discrete Element Model Based On Superquadrics

Discrete element method is a kind of numerical calculation which describes the movement of particle system. However, many contacting discrete element models are used for dry particle system with spherical particle and wet particle system with the same particle size.In this paper particles with complex shape had been described by superquadrics. A contacting discrete element model based on this method has been established to simulate the mechanical behavior of both dry particle and wet particle systems. The main contents are as follows:(1) A dry contact model of discrete element method has been established which is based on superquadrics by the kinematics and dynamics analysis from the contact process of dry particle system. The model made the mathematic description of the relationship of force and deformation between particles closer to the reality of the movement of particle system. The limitation coming from using spherical-contact model has been avoid to describe the contact of particles so that it made the contacting discrete element model closer to physical reality and a numerical method has been proposed to calculate the model to achieve the simulation of dry particle system with complex particle shape.(2) A wet contacting discrete element model has been established reasonably to analyze liquid bridge force between particles based on physical reality. The expressions of the liquid configuration and liquid bridge force are derived to realize the simulation of wet particle system in this paper by building a improved mechanical model which analyses the force a of the liquid bridge by assuming that the liquid bridge profile is circular in shape, characterizing the liquid bridge between two unequal-sized spheres, and considering the distance between two particles and the non-zero contact angle.(3) A program is developed which contains the proposed contacting discrete element model. The feasibility and correctness of the model established in the paper had been proved by testing the validity of the model and the algorithms.As a new numerical calculation method to study particle system, the model described in the paper can simulate the real motion of complex particle system accurately.