Study On Vibration Of Biomass Ring Molding Machine During Compact Forming

Due to its high efficiency and low energy consumption,the ring die forming machine is currently widely used in the fields of feed and biomass energy.However,there is still a severe vibration problem during the working process.The material raw material is discrete and discontinuous,and the material undergoes elastic-plastic deformation after being subjected to the extrusion force.Therefore,the discrete element-multi-body dynamics coupling method is used to realize the simulation of the biomass compacting process.Different from the traditional method,Import the extrusion force curve obtained by EDEM into the finite element software workbench,analyze the force of the ring die,and conduct prestress modal and harmonic response analysis;conduct random vibration analysis on the ring die forming machine and predict its core component ring Vibration fatigue life of the die.The main research contents of this paper are as follows:(1)The virtual prototype model of the main body of the ring die forming machine is established according to the solid structure of the ring die forming machine.Considering the nonlinear mechanical behavior of a large number of contacts and collisions between the ring die,the pressing roller and the material during the working process of the forming machine,the multi-body dynamics and the discrete element two-way coupling are used.Methods The research on the process of biomass densification was realized.In the dynamics software Recurdyn,the FFlex method is used to flexibly process the ring die,and the rigid-flexible coupling model of the ring die forming machine is established.Based on the simulation of DEM-MBD bidirectional coupling of ring die forming machine,the effects of different spindle speed,particle size and particle shape on the extrusion force of the ring die are considered respectively.(2)Taking the maximum extrusion force of the ring die during the forming process as the loading condition,and using the method of unidirectional coupling of discrete element and finite element,the stress situation of the ring die during the working process is more accurately analyzed.The results show that the stress peaks of the ring die are mainly located at the entrance of the die hole and the bottom of the ring die.(3)According to the coupling results of discrete element and finite element method,the extrusion pressure on the ring die was applied to the ring die hole as the loading condition.The prestressed mode analysis was carried out on the ring die forming machine,and the vibration mode and natural frequency of the ring die forming machine were studied.It was found that the deformation forms of the ring die forming machine were mainly swing and torsion.By analyzing the harmonic response of the ring molding machine,the amplitude-frequency curves of the machine in the X,Y and Z directions were obtained.The results show that resonance is easy to occur at the first,third and fifth natural frequencies,and the work near the excitation frequency should be avoided.(4)The random vibration analysis of the ring die forming machine was carried out,and the acceleration power spectral density of the pressure roller obtained during the compact forming process was used as the excitation of random vibration,and the displacement response cloud map of the ring die forming machine was obtained,which was predicted by the three-interval method and the Miner fatigue cumulative damage criterion.Vibration fatigue life of ring die.