The Dynamic Analysis Of Inertial Flip-flow Screen

Inertial flip-flow screen is one kind of dry deep screening equipment for moist fine coal. It mainly uses the relaxation motion of the polyurethane screen surface. The relative motion of the fixed screen frame and the floating screen frame drives the screen surface to do large deflection deformation movement. It breaks the traditional structure mode in which the rigid screen surface in screening machine doesn’t do the relative movement. Compared with other fine particle screening equipment, it has the advantages of small size, small dynamic stress, low noise, low power consumption, high screening efficiency and so on. Under the condition of small displacement amplitude of the fixed screen frame and the floating screen frame, inertial flip-flow screen use double vibration principle to make the screen surface with greater intensity of projection, thus promoting the looseness and stratification of materials. Therefore, it is of great practical significance for doing dynamic analysis of inertial flip-flow screen to improve the efficiency of screening of moist fine coal.In this paper, the mechanics model and the mathematical model of inertial flip-flow screen was built firstly. Based on the dynamic analysis method of near resonance inertial vibrating screen and forced vibration model of multi degree of freedom system, theoretical analysis of vibration characteristics of flip-flow screen was carried out. Meanwhile, through selecting appropriate design parameters, the oscillatory differential equation of flip-flow screen system was solved by using dynamic simulation module in MATLAB/SIMULINK. Then the total response of the vibration system was obtained. It can provide the necessary theoretical support for the structure design of inertial flip-flow screen.Simplifying 3D model of flip-flow screen properly, and based on ANSYS Workbench multi-rigid-body dynamics analysis of the screen main frame structure was carried out. Sieve machine from start to stable work, the vibration characteristics of fixed screen frame and floating screen frame over time from start to work stably were obtained. The conclusions verified the rationality of the mechanical models of flip-flow screen. Besides, finite element model of flip-flow screen main frame structure was build, and the modal analysis and harmonic response analysis was done. The first 10 order natural frequency and mode shape were obtained through the modal analysis. And through the harmonic response analysis, displacement response and the dynamic stress distribution nephogram of the screen main frame structure under the working frequency were got. Meanwhile, displacement responses of the fixed beam and the floating beam in frequency scanning range of 0 to 15 Hz were obtained.Based on SAMCEF MECANO, finite element model of flip-flow screen surface was established, and by using the implicit nonlinear module dynamic analysis of screen surface was carried out. Vibration response of the screen surface midpoint and acceleration vector nephogram of entire screen surface were obtained when damping ratio of the flip-flow system are 0 and 0.1. Furthermore, the effect of relative motion of the fixed screen frame and the floating screen frame on dynamic characteristics of screen surface were studied, the effect of equivalent damping on dynamic characteristics of screen surface were also studied. Finally, the maximal displacement, speed and dynamic stress of the screen surface were analyzed to fully understand its dynamic characteristics.In order to make the simulation result is more close to reality, average force the coal particles act on screen surface was obtained by using the particle simulation platform in EDEM. Statical analysis of inertial flip-flow screen main frame structure was carried out by building coupling simulation project of EDEM and the Static Structural in ANSYS Workbench. Then total deformation nephogram and equivalent stress nephogram were obtained. What’s more, based on the result of statical analysis, fatigue life analysis of inertial flip-flow screen was done by the use of fatigue toolkit.