A Multistate Model of Reliability of Farming Machinery

Karol Durczak,Piotr Jurek,Jan Beba,Tomasz Żelaziński,Adam Ekielski,Anna Szeląg-Sikora

doi:10.1051/bioconf/20181002005

Abstract

The article describes a multistate model of reliability of farming machinery as a deductive stochastic model of the process of changes in the technical conditions observed during operation. These conditions determine the capacity of machinery to fulfil functions, simultaneously keeping safety and maintaining acceptable costs of possible repairs. The theory of semi-Markov processes was used to solve the problem. After detailed analysis of the symptoms of damage to exemplary groups of farming machinery (rotary mowers, rotary harrows and harvesting presses) we obligatorily and arbitrarily proposed an optimal four-state reliability model to describe changes in technical conditions. In contrast to the classic reliability theory, which allows only two states of technical usability (either a machine is fit to function or not), we also allowed intermediate states, because not all types of damage affect the functionality of machinery. This approach increases the probability of technical usability of machinery and rationally delays the moment of premature repair.

Highlights

Reliability is the ability of a technical device to perform its required functions under stated conditions for a specified time
The authors of this study proposed the graph method and the theory of semi-Markov processes to solve the problem of farming machinery passing from the complete usability (CU) through the intermediate states (IN) to the complete unusability (CUn) state
We used the system method of constructing deductive models and the theory of semi-Markov processes to make a four-state model of reliability of farming machinery

Summary

Introduction

Reliability is the ability of a technical device to perform its required functions under stated conditions for a specified time. According to the classic reliability theory, there are only two states of usability of a technical device, i.e. the state of being usable and the state of being unusable. A device is technically usable if it is able to perform its required functions at a specified moment or interval of time. The state of unusability is the opposite. The two-value approach to reliability, without intermediate states, simplifies reality, because there are repairable devices, composed of numerous parts, which form systems. Farming machinery is an example of such devices [1, 2, 3 and 4]

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