DEVELOPMENT OF AN OPTIMAL PREVENTIVE MAINTENANCE MODEL BASED ON THE RELIABILITY ASSESSMENT FOR A SYSTEM OF BHEL

Abstract

Equipment subjected to random failure can be induced back by maintenance actions such as overhaul, replacement of worn out parts, repair or complete replacement. To reduce the failure frequency, Preventive maintenance (PM) can be adopted as an effective approach for reliability enhancement. Time-based and condition-based maintenance are two major approaches for PM. In-contrast, condition-based maintenance can be a better and more cost-effective type of maintenance than time-based maintenance. Irrespective of the approach adopted for PM, the key point is whether a failure can be detected early or even predicted. This study describes the probability process for detecting the fault well before the failure takes place and proposes the optimal inspection period of condition-based preventive maintenance as a preventive maintenance policy to improve reliability of system. A simulation model is presented to analyze condition-based preventive maintenance through a fixed period maintenance inspection by maintenance personnel conducted to detect failure occurring. Based on this simulation model, the effect of the preventive maintenance factors such as the inspection frequency, the calculated MTBF, the fault occurrence period, the diagnosis time, to affect the reliability improvement of system is investigated by a sensitivity analysis and the effect of the calculated MTBF and the inspection frequency to affect the expected profit was grasped. To analyze the proposed method a case of a system of BHEL is under taken. From the results it is observed that the proposed method help to seek the optimal inspection period for the assemblies of the system. In - addition, prediction of fault occurrence period, diagnosis time for the assembly (investigated with the help of sensitivity analysis) may help the organization to plan the PM schedule