Prognosis and Diagnosis of Farm Tractors Reliability and Availability for Maintenance Policies Using Markov – Chain Model

Omran Musa Abbas,Hassan Ibrahim Mohammed

doi:10.13189/ujar.2015.030401

Abstract

A sound maintenance planning is of crucial importance for farm power systems. There is a large potential in cost savings by optimizing maintenance decisions to make utilization of farm tractors more cost-efficient. Reliability and availability are fundamental attributes of organization, scheduling and operation of fleet of tractors in agricultural project of multi-farms. This paper utilizes recursive Markov chain closed-form analytical solution and condition-based maintenance model to evaluate performance of degraded multi-state system. First state of system failure is inspected, analyzed, and classified into partial, or combined or complete failure of estimating the transition matrix for the failure state. At each inspection of failure status a preventive maintenance (minor repair by replacement of parts) or corrective maintenance (major replacement of parts by complete overhaul) is performed to restore the system to good as new. The development of condition-based maintenance is used to signify the monitoring of machines for the purpose of diagnostics and prognostics. Diagnostics are used to determine the current status of a machine's frequency of failure (useful life) and prognostics are used to predict its dependability, availability (utility).Hence, the system of evaluation is quantified by six distinct indicators (maximum time before failure, tractor dependability, availability, frequency of failure and operating time between preventive and corrective maintenance) such that appropriate actions can be planned and taken in order to minimize the impact of equipment failure to operation. Simulation results for a dataset of three tractors (T120, C225 and B250) from two workshops of sugar plantation (Gunied and Sennar factories in Sudan) is investigated to assert the magnitude of variation between the tested variables that justify changing current maintenance policy using analysis of variation. The results indicate the applicability of Markov where comparison with condition-based maintenance is the optimal maintenance strategy for tractor high failure rate.

Highlights

Worldwide agricultural projects with smallholder farms are assumed to be effective instrument to develop rural areas.Tractors which is the main source of power in these farms, if properly and given the necessary field maintenance will operate for long period and do a great deal of work before major repairs are required.[8]Sudan has three distinct farming systems, these are: irrigated, mechanized rain-fed and traditional rain-fed sub-sectors
Performance of existing maintenance system: The main indicators used in this study to evaluate level of performance of executed maintenance and the need of the studied tractors for either preventive or corrective maintenance is planned to be made by evaluating three parameters: maximum time before failure, tractor dependability, and frequency of occurrence of failure
Conclusions and Recommendations other tractors in descending manner is that B250 tractor of

Summary

Introduction

Worldwide agricultural projects with smallholder farms are assumed to be effective instrument to develop rural areas. Sudan has three distinct farming systems, these are: irrigated, mechanized rain-fed and traditional rain-fed sub-sectors. The irrigated agriculture accounted for an average of about 21% of the value of total agricultural, irrigated farming has been one of the pillars of agricultural development strategy. This sector is dominated by large national schemes like Gezira, New Halfa, Rahad and Sugar schemes. The Mechanized Rain-fed Sub-Sector concentrated in Gadara, White Nile, Sinnar, and Southern Kordofan states

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Conclusion