Forecasting the reliability of technical systems of agro-industrial production based on the results of statistical modeling

Abstract

In the offered article the problem of forecasting of indicators of reliability of the water ring vacuum pump which is a part of the unit of individual milking is considered. A feature of this pump is the use of an impeller, which is made of polypropylene. During operation, the blades of the impeller, which are under the influence of elevated temperature, are deformed by external loads. Given the tendency of polypropylene to creep, over time, the gap between the impeller blades and the pump housing gradually decreases until jamming. To a large extent, this process determines the amount of pump life.
In previous works, the issues of determining the parameters of the stress-strain state of the blades of a water ring vacuum pump were considered in detail, as well as an interval assessment of the durability of the impeller. But, to predict the reliability of the pump as a whole, it is necessary to develop a mathematical model that would allow the design parameters to determine its expected life.
To solve this problem, a statistical model was developed, which is based on the use of bootstrap modeling.
In contrast to the simulation of pseudo-random sample values, the statistical bootstrap model uses the real values of the resource components of individual structural elements, which were obtained by the results of resource tests. From them, randomly, the samples necessary for statistical analysis are formed. This approach to modeling samples, which determines the resource of the part, has a number of advantages over classical methods of forming pseudo-random samples, as it does not require determining the type and parameters of the distribution laws of the studied parameters, and allows the use of interconnected (vector) parameters, the resource of a single structural element.
Thus, the use of statistical bootstrap modeling allowed to obtain an interval estimate of the guaranteed average resource of polypropylene impeller, as well as to recommend a minimum gap that will provide the impeller resource for creep deformation not less than the normative resource of the milking parlor.