Numerical Simulation And Study Of Vibration Screening Process Based On DEM

This paper analyzes the development of the vibration sieve and the theory related to discrete element method (DEM) and the research status at home and abroad about them. DEM is a numerical method to study the structure and the movement of discontinuous particulate matter, which is based on Newton’s second law of motion. It was presented by Cundall and Strack in1979. At first, DEM was not widely applied due to the large amount of calculation and the higher requirement of computer hardware in analysing multi particle motion. Along with the development of science and technology especially the computer hardware technology and the continuous innovation in the parallel computing algorithm, DEM has already preliminarily applied in fluid mechanics and the corresponding mechanics of granular media, and achieved certain results.First of all, due to contact model of discrete material is the basis of discrete element in the discrete element theory, therefore linear contact model and the nonlinear contact model of DEM is compared, and the main characteristic of the research object in the process of screening is analyzed. Finally, the Cundall’s spring-damper-sliding contact model is selected as our main application model in this article.Secondly, motion principle and screening principle of the linear vibrating screen is analyzed, ground on this analysis, linear vibration screen simulation program based on the DEM is programmed. And the corresponding research about the generation, contact judgment and stress calculation algorithm of the discrete element ball in the simulation process has done. At the same time, the logical structure in each step and data structure is also studied to improve the efficiency of operation. And the advantage and disadvantage of the algorithm between the program implementation stage is discussed, including discrete element material generation algorithm, a collision judging algorithm, ect. The optimization of application of CUDA technology on vibration screening process simulation is studied.Finally, plane elastic motion, elastic-plastic movement and sliding of the single particle; motion characteristics of a single particle in different vibration screening conditions, namely the different vibration parameters on the effects of particle velocity, throwing height; different vibration parameters on the effects of screening efficiency in the linear vibration sieving process are all simulated in this paper. And based on the simulation results the methods to improve the efficiency of linear vibration screen are given.