Enhanced Economic Order Quantity Framework for Reliability-Critical Industries: The EOQdsd Model

This chapter introduces the economic order quantity (EOQ) for demand-supply-downtime (EOQdsd) framework, extending classical inventory theory by systematically integrating reliability engineering parameters. Traditional EOQ models fail to address failure-driven demand patterns, extended lead times, and equipment downtime costs prevalent in reliability-critical industries. The EOQdsd framework progresses from a three-component basic formulation incorporating cycle stock, safety buffer, and downtime protection, through comprehensive implementations integrating warranty considerations, FMEA risk assessment, Weibull lifecycle analysis, and dynamic stocking indices. Mathematical development demonstrates dimensional consistency and reduction to classical EOQ under limiting conditions. Application to electric vehicle charging infrastructure using manufacturer data (SIRIEM, 2024–2025) shows a 61% total cost reduction compared to traditional EOQ while improving service levels from 87% to 97%. The framework’s scalability accommodates both high-volume operations and ultra-reliable systems where theoretical EOQ