SOME SIMPLE APPROACHES TO PLANNING THE INVENTORY OF SPARE COMPONENTS OF AN INDUSTRIAL SYSTEM

Abstract

Two variants of a simple stochastic model for planning the inventory of spare components supporting maintenance of an industrial system are developed. In both variants, the aim is to determine how many spare components are needed at the beginning of a planning interval to fulfil demand for corrective replacements during this interval. Under the first variant, the acceptable probability of spare shortage during the planning interval is chosen as a decision variable while in the second variant, the adequate spare inventory level is assessed taking into account the expected number of component failures within the planning interval. Calculation of the number of spare components needed depends on the form of the probability density function of component failure times. Different statistical density functions that are useful to describe this function are presented. Advantages and disadvantages of using a particular density function in our model are discussed. The applicability of the model is given through illustrative numerical examples.

Keywords

• industrial system
• maintenance
• corrective replacement
• spare components
• inventory planning
• stochastic modelling