The Calculation of the Spare Parts in the Auto-service Enterprise on the Base of Real Demand

Abstract

The main goal of the work is the development of a methodology for calculating the spare parts of cars in a service center for the period of replenishment of spare parts, tools, accessories, the English version - spare parts, instruments, accessories - SPIA on the basis of analysis of statistical information on the failures of the details of each standard. This information should be accumulated on daily information about the replacement of spare parts of failed parts in vehicles that arrived during the entire period of replenishment for maintenance at this service station. Previously, from the totality of a finite number of competing hypotheses about a possible theoretical parametric distribution of failures (including diffusion distributions), the distribution function most consistent with the empirical distribution function is chosen by Kolmogorov-Smirnov's agreement criterion. When calculating the failure distribution function in the theory of system reliability, information is usually used about the main characteristic of failures-the time between failures, and in the absence of such information, they use the number of failures at certain points in time. To this end, the relationship between the expressions for the distribution function of the operating time to a fixed number of failures and the function of the distribution of the number of failures for a fixed operating time to failure is established in this paper. This makes it possible to calculate the planned need for spare parts on the basis of the available statistics of failure of parts (and replacement of their corresponding spare parts) in previous planning periods. Given that fatigue wear of one part, even before its complete failure, can diffusively affect the performance of other car parts, in the aggregate of competing functions for the distribution of failures of parts included diffusion monotonic (DM) and diffusion no monotonic (DM). The proposed methodology is approved for the calculation of spare parts for individual component sizes and, in general, for any car parts by the example of a particular auto service company in the replenishment period of the SPIA equal to one calendar month.