OPTIMUM MAINTENANCE POLICY FOR EQUIPMENT SUBJECT TO BREAKDOWN

Abstract

Equipment subject to random failure can be induced back by maintenance actions such as overhaul or replacement of worn out parts or repair and or complete replacement. To reduce the frequency of failure, preventive maintenance can be adopted; thus at various points in time the decision can be taken to overhaul, replacement of worn out parts, repair, or complete replacement of the equipment while it is still in an operating state. Equipment condition is judged by either GOOD or FAILED by thorough inspection at each decision point. It will be assumed that the decisions can only be made at discrete- points in time for that a maintenance policy has been developed in this work. It guides the manager for the action to be taken at each decision point to optimize the operating time of the system, subject to maintenance resources such as cost (overhaul cost, replacement of worn out parts cost, repair cost, complete replacement of equipment cost, labour cost of overhaul, labour cost of replacement of worn out parts, labour cost of repair, labour cost of complete replacement of equipment), labour (number of labour for overhaul, number of labour for replacement of worn out parts, number of labour for repair, and number of labour for complete replacement of equipment) and equipment age. It is considered that equipments are subjected to random failure and follow negative exponential distribution. A software programme is developed in C++, which gives the maintenance action to be taken at each decision point; average operating time of the system, system efficiency and maintenance cost of the system is also calculated. The software programme is tested for an example and a maintenance policy framed for the considered example.