Research findings on physical and mechanical properties of multicomponent grain mixtures of different moisture content

Abstract

When designing machines, hoppers and other equipment intended for working with grain mixtures, the knowledge of the physical and mechanical properties of these mixtures is required, since they affect the choice of material (friction coefficient), the size and shape of the hopper (volume weight, angles of natural slope and collapse, tendency to arch formation), etc. In the reference literature, the values of physical and mechanical properties are given only for individual grain crops at a moisture content level of 10-14%. In this regard, the research goal is to obtain mathematical models of the composition and properties that make it possible to calculate the basic physical and mechanical properties of multicomponent grain mixtures depending on their composition and moisture content. To achieve this goal, Scheffe's Simplex Lattice Model was used. Eventually, regression equations describing the physical and mechanical properties of the grain mixture were obtained in an arbitrary range of varying its composition at moisture content of 10%, 25% and 35%. It was determined that the main physical and mechanical properties of the grain mixture were influenced by its porosity which depended on the crop and crop percentage in the mixture. Thus, larger percentage of wheat and peas in the mixture lowers its porosity, and larger percentage of oats and barley increases the porosity of the mixture. Increasing mixture porosity leads to decreasing values of volume weight, angle of natural slope, angle of collapse, coefficients of internal and external friction, but increases the values of maximum width of arch-forming slot.