Study On Dynamic Characteristics Of Double-layer Circular Vibrating Relaxation Screen

Nowadays,coal is still the main energy source in China,occupying the main position of energy for a long time.The vibrating screen is an important equipment for coal sorting,mainly completing the screening and cleaning of raw coal through the principle of vibration.With the construction of modern coal bases,the development trend of relaxation screens is gradually moving towards large-scale,large processing capacity,and high efficiency.At present,the relaxation screen mainly consists of a single layer screen surface,and the positions of the vibration exciter and the reinforcing ribs at the side plate of the relaxation screen are arranged based on experience.There are few methods for optimizing the position of the exciter and strengthening the layout of the rib plate.This thesis takes the double-layer circular vibration relaxation screen as the research object,elaborates on its structure and working principle,establishes a three degree of freedom dynamic model,calculates the natural frequency and vibration mode of the screen body,and uses Simulink for simulation.Design a two factor four level experimental table,use the Runge Kutta method to numerically calculate the simulated values of the spatial trajectory deviation angle at the experimental points,and establish a mathematical model of the vibration exciter position on the amplitude curve of the key parts of the relaxation screen through experimental data.Use the genetic algorithm toolbox to find the optimal position of the vibration exciter.Establish a virtual prototype model of a double-layer circular vibration relaxation screen,and conduct dynamic simulation using Adams to verify the correctness of the established mathematical model.Perform finite element analysis on the double-layer circular vibration relaxation screen,obtain the natural frequency,natural vibration mode,and stress-strain situation of the screen structure,and analyze the deflection and stress distribution of the eccentric shaft.Through the fatigue analysis and topology optimization analysis of the side plate,the layout of the side plate stiffeners is optimized according to the analysis results,and the side plates before and after optimization are compared and analyzed.By calculating the mathematical model of the double-layer circular vibration relaxation screen,the third-order natural frequency was obtained and its third-order vibration mode diagram was drawn.The amplitude curve calculated by the relaxation screen theory was obtained through Simulink simulation.By analyzing the influence of the position of the exciter on the deviation angle of the feeding port,it is found that the optimal deviation angle of the feeding port is located at the center of mass.Through dynamic and finite element analysis,it has been verified that the doublelayer circular vibration relaxation screen meets the design requirements and meets the strength requirements of the material.The layout of stiffened plate is obtained through fatigue analysis and topology optimization analysis.Through comparative analysis,it is found that the optimized layout scheme effectively reduces the stress and strain,makes the natural frequency of the side plate avoid the working frequency,and increases the service life of the side plate.This provides a method for the design and optimization of a flip screen.This thesis contains 73 figures,17 tables and 104 references.