A multi-objective programming model for selection third-party logistics companies and suppliers in a closed-loop supply chain

Due to globalisation and increasing competition in markets, the manufacturers and service organisations tend to outsource their logistics activities. On behalf of manufacturers and service organisations, an outer firm which called third party logistics (3PLs) company manages, controls and performs the logistics activities. In this paper, a general closed-loop supply chain network is designed that includes manufacturers, 3PLs, supplier, evaluation, disassembly, refurbishing and disposal sites. The proposed model of this paper has two phases. First phase determines 3PL and external supplier by using fuzzy sets theory. Namely, the preferences of decision makers for selecting 3PLs and suppliers are expressed by triangular fuzzy numbers and then, the weights of 3PLs and suppliers are determined. In the second phase, a multi-objective mixed integer linear programming model is proposed to determine the product optimum quantity assigned to the 3PL and parts purchased from supplier. The proposed model considers 3PL and supplier selection, simultaneously. To illustrate the capability of the suggested model, a numerical example is solved and the results are analysed.