A dual supplier repairable supply chain with δ-shock <i>via</i> phase type geometric process

This study presents a δ-shock model for dual-source suppliers of a degenerative repairable supply chain with non-negligible repair times. Suppliers of the supply chain (system) are affected by random shocks due to disasters, and the system thus fails if the interarrival time between shocks is below a random threshold. The supply chain comprises of two suppliers, namely supplier 1 (chief source) and supplier 2 (alternative source). The supply chain shall be restored to its working condition by supplier 2 whenever supplier 1 is under repair. The shock arrivals, repair times of the suppliers, and the random threshold time of shocks are governed by the phase type geometric process. Employing <i>N</i> policy, the long-run average cost rate and optimal reengineering policy N∗ are obtained analytically. Numerical examples and sensitivity analysis are presented to substantiate the analytical results.