Research On Large Vibrating Screen System And Structural Dynamics

Vibrating screen is widely used in industrial enterprises such as metallurgy, coal, petroleum, chemical industry, etc. The motion of vibrating screen influences screening efficiency of screening device and productivity directly. In working process, the main parts endure long time high-frequency alternating loads, often resulting in crack on lateral board and beams. The strength problem is much more serious for large-scale vibrating screen. Therefore, it has a great significance to research on vibrating screen system and structural dynamics, ensure the motion meeting the requirements, eliminate stress concentration of vibrating screen, reduce stress and avoid sympathetic vibration for improving its working reliability and extending the life.This thesis established the mathematic model of linear vibrating screen by Lagrange method, made motion and system dynamics analysis, deduced the expression of natural frequencies and response, and analyzed the effects of the change of spring supports'location on kinetic characteristics of vibrating screen, put forward a plan for screen frame optimization by changing the location of screen frame support.The finite element analysis software was applied to establish the finite element model of vibrating screen frame, the first ten frequencies and modal shapes were got, and dynamic evaluation of the vibrating screen frame design was made. The result shows that the structure after alternation doesn't have sympathetic vibration under steady state.Harmonic analysis was done to get the stress distribution under steady state. The result shows that the structure modification makes the dynamic stress distribution more uniform and makes the entire stress lower under steady state.Dynamic transient analysis was made to get the stress changing with time in the process of starting. The result shows that the stress distribution is more uniform and the stress is significantly reduced in the process of starting. The acting force of foundation was analyzed to provide reference to the installation of vibrating screen.This research provides a new structure modification program for solving vibrating screen strength problem, and is meaningful for the design and use of vibrating screens.