Modelling Total Life Cycle Cost

Abstract

In this paper, the concept of terotechnology and the formulation of life cycle cost has been taken from the point of view of the user as against that of the manufacturer, and the stages of design, development of prototypes, manufacture and testing of the machine have not been considered. This is felt appropriate since terotechnology has to date found greater application (and will continue to do so, except for military systems and installations wherein it has possibly found the greatest application) in the case of large capital equipment and machines, for example for process plants, integrated iron and steelworks, power plants etc. The hazard curve provides the basis for the estimation of the time-dependent maintenance cost incurred over the life cycle of an equipment. Accordingly a system study of the hazard rate of power units of a thermal power plant was undertaken and has been presented. Using the modified ‘bath-tub’ curve obtained from the case study and the Weibull model, an equation of the total life cycle cost has been developed. Thus the model takes into account deterioration of components and system performance over time. The model brings out the efficacy of preventive maintenance action in the form of condition monitoring and shows that the total life cycle can be increased if appropriate preventive-maintenance actions are taken in the random failure and wear-out failure regions.