Multi-objective mathematical models for risk assessment in the supply chain

In recent years, companies have tried to increase product quality, product variety, reduce cost and reduce product delivery time in order to keep up with increasing competition conditions and ensure their sustainability. To do this, the supply chain must be managed well. Risk management and evaluation are also an important issue in the management of the supply chain. In this study, an integrated model consisting of two stages is proposed for Supply Chain Risk Management (SCRM). In the first stage, a supply chain risk assessment was made for an international company in the automotive industry. As an initial phase, the ten most common risk criteria faced by the company where the application was made were determined and the risks were weighted using the Pythagorean Fuzzy Analytical Hierarchy Process (AHP) method. In the second phase, the weights obtained in the first phase were integrated into the Intuitive Fuzzy TOPSIS and Paksoy et al. (2019) approach. According to these two methods, the risk criteria weights of the five suppliers that the firm works with were obtained. In the second stage of the study, it is aimed to make the best possible combination of purchasing quantities among different suppliers. For this purpose, Multi-Objective Integer Linear Programming (MOILP) model including total cost minimization, supplier risk minimization and supplier distribution performance maximization has been proposed. This model is modeled as quantity discount, multi-product and multi-supplier. In addition, since the demand and delivery time constraints in this proposed model may have stochastic parameters, it has been rearranged as the Chance Constrained MOILP model. These two proposed deterministic and stochastic models were solved separately in the GAMS IDE 34/CPLEX program using Fuzzy MOILP, Goal Programming and Fuzzy Goal Programming methods and comparative analyzes were made. The results obtained have guided the company to prepare an order plan that shows which product to purchase from which supplier and in what quantity, in line with the objectives of the company.