A single-vendor multiple-buyer inventory model with a multiple-shipment policy

This paper presents a new methodology to obtain the joint economic lot size in the case where multiple buyers are demanding one type of item from a single vendor. The shipment policy is found and a new model is proposed to minimise the joint total relevant cost (JTRC) for both vendor and buyer(s). Considering the two-buyer and the more-than-two-buyer cases, an analytical solution and numerical solution are obtained. A significant savings in joint total relevant cost is achieved when the total demand rate is close to the production rate. A sensitivity analysis is also conducted to test the robustness of the new model.