Critical shear stresses in the sawdust-filled workspace between the die and the roller of a pellet mill machine
Determining the physical and mechanical properties of granular materials, in particular, critical shear stresses is a very important problem to be solved when studying the technical and economic parameters of the process of manufacturing wood pellets. There is a mathematical model of the stress state of semimanufactures in the granulator workspace that describes the technical and economic parameters of a feed pelleting machine. At the same time, the physical and mechanical properties of sawdust pellets are not studied, which makes it difficult to apply the developed mathematical model. The results of the experimental study of the stresses normal to the surface of the pressing roller of a pellet mill machine with an annular die were used to identify the mathematical model of the stress state of the sawdust in backward and forward creep zones of the wedge-shaped workspace of the pellet mill machine. The critical shear stress of the wood sawdust during pelleting is determined, which enables using the developed mathematical model for the parametric synthesis of the pressing mechanisms of sawdust pellet mill machines.