الفهرس 
On Optimal Preventive Maintenance and Warranty Policies with Cost
AbstractOnly 14 pages are availabe for public view
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Abstract
In this thesis, a necessarily incomplete representative review of the events, people, and literature which have come to be associated with reliability. Also, some of the reliability rolls and applications are presented and followed by a definition to failure time and failure rate functions. Besides discussing their rolls on the lifetime of a product and their effects on establishing the preventive maintenance (PM) strategies. The thesis also uses mathematical statistical approaches, considers more than one type of warranty policies of arbitrary system whether it is a repairable or unrepairable, and considers preventive maintenance strategies for the repairable system.
Reliability is one among the most essential quality features of products in the marketplace. It is the probability that a product will function properly for a specified period of time under specified conditions. R(t)=P(T≥t)=1-F(t). Some reliability measures can be used as an indicator of the quality level. These measures are also called measures of performance. Mean time to failure (MTTF), Mean time between failure (MTBF), and mean residual time (MRT)…etc., are some of these measures. A product can fail early at the beginning of its life due to various production defects or late due to deterioration. Higher production costs and lower product quality are usually associated with item degradation.
The PM is one of some necessary actions that can be performed on a product to keep it out of failure as long as possible or restored it to an earlier functional state. Manufacturers adopt such maintenance to maximize their product’s reliability besides keeping production costs down while maintaining process.
A product’s warranty could be considered a good indicator of its reliability as well as a powerful resource for increasing sales and competing with other manufacturers. There are two types of warranties: one-dimensional (1D) and two-dimensional (2D) warranties. A one-dimensional warranty is defined by a calendar time, while a two-dimensional warranty is defined by item age and usage in a two-dimensional zone. There are many warranty policies to adopt but choosing an equilibrated one is very important to the manufacturer to either minimize the cost or maximize profit.
Copulas are tools by which a bivariate distribution of two random variables can be developed besides their dependence structures. In addition to the joint distribution function, copula can formulate the expected number of product failures across the warranty period to optimize the production process.
The main goals of this thesis are to
Find an optimal model to analyze the failure process of repairable system.
Establish an appropriate preventive maintenance strategy.
Discuss and perform one and two-dimensional warranty analysis.
Performing cost analysis to determine an appropriate two-dimensional warranty policy.