Availability based spare optimization using renewal process

In this article, we develop mathematical models for spare components with exponential, gamma, normal and Weibull time to failure distribution using a renewal process. The models can be used to predict the number of spares required for a component or system to achieve specified inherent availability. The paper also presents optimization models for systems with components in series where the time to failure distribution of the components follow any general distribution. The objective of the optimization problem is to maximize the availability of the system satisfying constraints on cost and weight. The optimization model developed in the paper can be solved using many general purpose software like LINDO, SOLVER of EXCEL etc. An efficient branch and bound procedure which can be used to solve the optimization problem is also presented in the article.