Optimal order policy based on three-item inventory models with Weibull distribution deterioration and price-dependent demand

We construct three one-item inventory models with Weibull distribution deterioration, corresponding to three different dependences of the item's demand rate on its selling price: linear, quadratic, and exponential. We combine the three models to obtain five different three-item inventory models, corresponding to the existing five different order policies: the individual order policy, the three semi-joint order policies, and the joint order policy. We carry out a computational analysis of these models, which reveals that the joint order policy - that of ordering the three items simultaneously - gives the highest total profit, and that under this policy, the total profit depends most sensitively on the constant coefficient of the quadratic demand-rate function, i.e., the second item's demand rate in the case of zero selling price.