Dynamic Characteristics Of Three-deck Circular Vibrating Screen And Fatigue Life Analysis

With the steady progress of urbanization in China,the output of construction waste is increasing day by day.At the same time,the introduction of policies such as the "Interim Measures for the Management of Financial Subsidies for Renewable Energy Saving Building Materials" and the "Green Building Action Plan" has provided strong support for the resource utilization of construction waste by the government and society.Sorting construction waste is one of the important ways to achieve resource utilization of construction waste.At the same time,circular vibrating screen are important sorting equipment,and high-strength operation vibrating screen are prone to failure.Therefore,this article takes the three-deck circular vibrating screen as the research object,and uses dynamic analysis theory,finite element analysis theory,and fatigue life assessment theory to conduct research on it.The completed work and research conclusions are summarized as follows:Based on the force distribution of a single particle on a three-deck circular vibrating screen,the corresponding vibrating screen frequency of particles under different motion forms is explored;Combining the dynamic model of three-layer circular vibrating screen and and the Lagrange’s equation,the differential equation of motion of the vibrating screen was obtained.At the same time,the natural frequencies and vibration modes of each order of the vibrating screen were calculated based on the structural parameters of the vibrating screen;Using the state space method to solve the differential equation of motion of a three-deck circular vibrating screen,the time-domain response and spatial trajectory of the vibrating screen’s center of mass in the horizontal and vertical directions are obtained.The virtual prototype technology is used to carry out dynamic simulation on the three-deck circular vibrating screen,to obtain the movement of the vibrating screen in the actual working condition and the movement tracks of different points on the vibrating screen,and the kinematics parameters of the three-deck circular vibrating screen prototype are tested,according to the test results,to verify the accuracy of the dynamic theory results and simulation results;To explore the structural characteristics of a three-deck circular vibrating screen,modal and harmonic response analysis was conducted on its finite element model.Based on modal analysis,the natural frequencies and corresponding vibration modes of the vibrating screen and important components were obtained.The natural frequencies of each order were compared with the working frequency of the vibrating screen,and it was found that there would be no resonance phenomenon;Obtain the stress and deformation cloud map of the vibrating screen at a working frequency of 13 Hz through harmonic response analysis,and optimize the screen frame based on the harmonic response analysis results to improve the strength of the vibrating screen.According to the stress cloud map obtained from harmonic response analysis,it is found that the stress at the weld seam of the three-deck circular vibrating screen ear shaft is relatively high.Therefore,it is necessary to evaluate the fatigue life of the ear shaft weld seam.Based on this,the statics analysis of the trunnion assembly is carried out by using the sub model method,and the stress distribution of the trunnion is obtained;Then,a rigid flexible coupling model of a three-deck circular vibrating screen is established,and the load spectrum of the ear shaft is obtained through dynamic simulation;Finally,the FE-SAFE fatigue analysis software was used to set up the analysis object for the weld seam,and fatigue life analysis was conducted to obtain the fatigue life cloud map.At the same time,the response surface method was used to optimize the cross-section of the ear shaft weld seam.The optimized life of the vibrating screen was increased by nearly twice,providing a theoretical basis and method reference for improving the service life of the three-deck circular vibrating screen.This thesis has 71 figures,15 tables and 122 references.