Features of changing the functional dependence of friction coefficients of feeds on the vertical load

As a rule, the numerical values of friction coefficients in reference literature are presented in fairly wide ranges. The researcher always faces the problem of unambiguous choice of their specific numerical value depending on a number of factors such as relative humidity, granulometric composition, vertical load, with the latter occupying the most prominent place among them. At the same time, at present, except for the assumptions about the functional dependence of the friction coefficients of feed ingredients and feed mixtures on the vertical load, nothing has been noted in the specialized literature. This article attempts to eliminate this significant gap. As a result of a fullscale experiment on an original installation for determining the numerical values of the coefficients of external and internal friction for summer and winter rations, polynomial dependencies of the second degree of the coefficients of the main ingredients (fodder beetroot, corn silage, green mass of grain legume mixture, barley meal) and typical feed mixtures for pigs were obtained depending on the vertical load. Based on the results of their structuring using the methodology that provides for the analysis of a step-by-step comparison of the change in the vertical load with the average hypothetical value over the entire interval of its transformation with a transition to the corresponding variations in the friction coefficients, there have been established some intervals when the friction coefficients significantly change at the corresponding intervals when changing in the vertical load (pressure). In particular, there has been revealed that stabilization of the coefficients for external friction on steel for the main ingredients of pig feed materials occurs within the pressure range of [8,54; 9,29] kPa, internal - [8,54; 9,22] kPa, and as for typical pig feed mixtures these intervals were, respectively, [9,29; 9,50] kPa and [9,50; 9,82] kPa.