The Optimization of Multi-item Spare Parts Inventory System under(R,S) Policy

The optimization of multiple-item spare parts inventory structure was studied.To allocate the predetermined safety stock money reasonably and minimize the expected annual stock-out times under(R,S) policy,a nonlinear program is set up.Using the ratio of unit holding cost and cost per shortage occasion M as multiplier,Lagrange multiplier method is applied to solve the problem.The specific meaning of M is also given.Setting the safety stock money to different values and resolving the program, the total safety stock-service level exchange curve can be plotted which demonstrate the trade-off between safety stock and service level.