Research On Ring Die Life Of Biomass Molding Machine Based On Discrete Element Finite Element Coupling

Ring die forming machine has the characteristics of high output,high efficiency and low energy consumption.It is widely used in biomass energy and other fields,but there are still shortcomings in the working process,mainly manifested in high manufacturing cost,poor forming quality,short service life,etc.aspect.In this paper,the force analysis is carried out through the actual grabbing situation of the ring die forming machine.Considering the nonlinear mechanical behavior of a large number of contacts and collisions between the ring die and the pressing roller when they are working,the FFlex method is used to establish a flexible body dynamic model.The simulation of the DEM-MFBD bidirectional coupling of the ring die forming machine is carried out,and the results are analyzed.The main work of the paper is as follows:(1)The orthogonal test method was used to analyze the influence of three factors,such as the rotational speed of the ring die,the gap between the die rolls and the particle size,on the maximum pressure of the Salix twigs.The minimum die-roll gap,particle size,and ring die rotation speed were determined to be the optimal solution as the minimum die-roll gap of 2mm,the particle size of 2.4mm,and the ring die rotation speed of 8rad/s.(2)The influence of the parameters of ring die speed,particle size and minimum die roll gap on the maximum pressure of the granule and the maximum torque of the ring die was analyzed,and the relationship between the speed of the ring die,the particle diameter,the minimum die roll gap and the maximum pressure of the granule and the maximum torque of the ring die were found.relation.(3)The influence of particle size on the wear of the inner wall of the ring die was analyzed,and the relationship between the particle size and the average wear depth of the ring die was obtained.The results show that with the increase of particle size,the average wear depth of the ring die also increases,and with the increase of time,the average wear depth also increases.(4)When the ring die forming machine is working,the pressure roller is rotated by the friction force between the material and the pressure roller.When the rotational speed of the ring die is 8rad/s,the movement change of the pressure roller is analyzed.The motion state of Salix twig particles in the simulation process is analyzed.(5)On the premise of the optimal parameters,the stress analysis of the ring die and the pressure roller is carried out,and the equivalent stress cloud diagram of the ring die and the pressure roller is obtained.The results show that the maximum stress value of the ring die is 55.8MPa,and the maximum stress value of the pressure roller is 40.3MPa,both of which occur at the minimum gap between the ring die and the pressure roller.The S-N curve is established by using the Durability module,the dynamic load spectrum of the ring die and the pressure roller is extracted,the fatigue life of the ring die and the pressure roller is studied,and the limitation of the traditional method for analyzing the ring die forming machine is discussed.The results show that the minimum fatigue life of the ring die is 3.12×10~6 times,and the minimum fatigue life of the pressing roller is 6.11×10~6 times.