Dynamic Characteristics Analysis And Optimized Design Of 3080 Circular Vibration Flip-Flow Screen

Coal is the basic energy and important raw materials of China,and the coal industry is an foundational industry that is related to the country's economic lifeline and energy security.Coal preparation is the most economical and effective way to clean and efficiently use coal.Vibrating screening equipment is one of the main screening equipment for classification,dehydration,de-mudging and de-packing of raw coal.However,at present,the mining of coal generally adopts fully mechanized mining technology,which results in the high degree of broken coal.Moreover,due to the use of hydraulic coal mining,downhole water spray and other measures,the rock components and moisture content of the fine-grained coal in the raw coal are eventually increased.When the conventional linear vibrating screen is used for dry screening of such moist fine coal,the pores and plugging of the screen plate are serious,and the screening efficiency is significantly reduced.In recent years,in the deep screening of wet fine-grain coal,the flip-flow screen has the comparative advantages of high screening efficiency,large processing capacity and not easy to block,which means it has broad application prospects and market potential.However,the existing flip-flow screen adopts a statically-determined structure.Under the combined action of the exciting force,the inertial force and the material impact force,the stability is lowered,the rigidity and the strength are easily insufficient,which leads to the deformation of screen body,the tube beam fracture,the cracking of side plate and other issues.In view of the problems existing in the process of the depth screening of wet fine-grain coal,the hyperstatic theory is applied to the structural development of flip-flow screen in this paper.A 3080 circular vibration flip-flow screen with a hyperstatic net-beam excitation system was designed.Taking it as the research object,theoretical analysis,numerical simulation,finite element analysis and structural optimization design are carried out.The research results are as follows:According to the mechanical model of 3080 circular vibration flip-flow screen established,the three-degree-of-freedom vibration differential equation of the sieve box is derived based on the influence coefficient method.The amplitude and phase frequency characteristics of the vibration system are determined by the complex method.Through the MATLAB/Simulink dynamic system modeling simulation,the time domain characteristics of the relaxation screen are known.Finally,based on the theoretical calculation results,the structural design of the 3080 circular vibration relaxation sieve was carried out.The Mooney-Rivilin model was used to simulate the mechanical properties of polyurethane elastic materials during deformation,and the model material constants were determined to lay the foundation for subsequent simulation analysis.Mechanism analysis of the polyurethane screen surface of the flip-flow's overcoming the problem of plugging and screen paste adhesion is carried out.Then the mechanical model of elastic pressure bar for polyurethane screen surface is established,and the displacement,velocity and acceleration of different positions of the polyurethane screen surface are determined by theoretical derivation calculation.Finally,the finite element analysis method is used and the screen surface is simulated and analyzed to determine the stress and deformation of the screen surface during the working process.Finite element analysis was carried out on the model of 3080 circular vibration flip-flow screen established by ANSYS Workbench software.Through the modal analysis,the first 16 natural frequencies of the structure are obtained.It is determined by analysis that at the operating frequency of 14.1 Hz,the screen box structure will not generate resonance and the harm caused by resonance to the structure can be avoided.Through the harmonic response analysis of the key components such as the total screen body,the side plate and the hperstatic net-beam excitation system,we can know the deformation and stress distribution of different parts of the flip-flow screen,which lays a foundation for the subsequent optimization and improvement of the 3080 circular vibration relaxation screen structure.Finally,the prototype is manufactured according to the structural similarity theory,and the kinematic parameters of the prototype are tested to verify the correctness of the theoretical calculation and simulation results.According to the engineering structure optimization design theory,the mathematical model of the position optimization design of the 3080 circular vibration relaxation screen support beam is established.Based on the linear static structural analysis,the position of the four support beams on the screen box was optimized using the Design Exploration Rapid Optimization Toolbox of ANSYS Workbench.The core design variables and optimal schemes of the support beam optimization are determined by solving the analysis.The scheme improves the deformation and stress distribution of the 3080 circular vibration flip-flow screen.