Reliability and Maintenance Scheduling Actions for Series - Parallel System

Abstract

The purpose of this work is to addresses some optimization models to process the performance of the series-parallel system. In it, system performance has been carried in the form of a reliability-cost optimization problem. The contradictory nature between the objectives is determined by establishing their fuzzy goals and consequently, the optimization problem under attention becomes a fuzzy programming problem. In a fuzzy multi-objective optimization problem, an optimal solution that concurrently optimizes all the goals is rarely possible. In such circumstances, one frequently measures to seek the most reliable potential solution in the appearance of rough, or imprecise erudition which is as close to the decision maker's (DM's) expectations. Exploration for such a pleasant solution necessitates working the multi-objective fuzzy optimization problem in an interactive way wherein the DM is originally required to define his or her choices. Based on given choices, the dilemma is answered and the DM is provided with a reasonable solution. If the DM is happy with this answer the problem stops there, unless, invited to alter their choices in the knowledge of the earlier received outcomes. This iterative procedure is resumed till a satisfying solution is arrived which is close to DM's expectations.

Apart from this, we also addressed some preventive maintenance (PM) schedule and their action namely (1a)-, (1b)- and (2p)- rather than only the replacement of the system. The optimal policy corresponding to each PM's actions is computed based on the optimal PM interval. For it, a multi-objective optimization model by considering the system availability and maintenance cost per unit time under the PM and corrective maintenance. Based on their optimal period, periodic PM scheduling is proposed and their corresponding PM actions, to save the money and increase the reliability of the system.

The objective of this work is to investigate the appearance of some series-parallel systems more firmly by expressing an optimization model.

The present dissertation is composed into four chapters which are concisely compiled as follows:

A concise description of the similar work of various authors in the evaluation of reliability and maintainability is exhibited in the first chapter. In Chapter 2, the basic and preliminaries linked to the reliability are furnished

Chapter 3 offers a new interactive multi-objective reliability-cost optimization model of a series-parallel system. The contradictory nature within the objectives is resolved by defining the fuzzy region of satisfaction. Further, by addressing the choices of the decision-maker towards the given objectives, the estimated bi-objective optimization model is molded into the single objective optimization model. Finally, the received problem is solved with the help of the PSO algorithm. Based on the reported parameters and the optimal cost and reliability of the system, a decision-maker can choose a good one according to his need to arrive at the desired goal.

In Chapter 4, we perform a periodic maintenance scheduling actions of a series-parallel system by examining the three main actions, namely (1a), (1b) and (2p)-maintenance for a multi-components system based on maintenance cost. The overall preventive maintenance (PM) interval of the system is considered as the minimum among them. Finally, the behavior of the system is scrutinized based on the reliability achievement and the effect of the PM actions is founded based on maximizing the maintenance-benefit analysis. The approach has been explained through a numerical case study.