Integration of Reliability Design, Installed Base, and After-Sales Services for System Availability

Abstract

System availability is a fundamental measure to evaluate the reliability performance of capital goods. Traditional approaches to availability management, such as reliability-redundancy allocation, preventive maintenance, and spare parts logistics, usually focus on a particular phase of system life. This paper discusses a holistic lifetime approach to sustaining system availability in an integrated product-service framework. Our approach seamlessly incorporates reliability, redundancy, maintenance, repairable inventory, and installed base information into a unified availability measure. A superimposed renewal process is adopted to characterize spare part demands considering the effect of installed base and proactive replacements. Extensive simulations are conducted to analyze the spares demand profile in terms of maintenance time, lifetime distribution, inventory lead time, and repair and renewing capacity. The study reveals that: (1) system availability is jointly determined by ten performance drivers across the product design, manufacturing, and after-sales market; (2) Poisson spare parts demand assumption is valid provided the item lifetime is much longer than the inventory replenishment time; and (3) installed base information provides a causal approach for spares demand forecasting during the new product introduction phase.