Otomotiv endüstrisinde bütünleşik bulanık karar verme ve çok amaçlı optimizasyon methoduyla sürdürülebilir tedarikçi seçimi ve sipariş miktarının belirlenmesi

Along with the increasing factors influencing global markets, companies become more motivated to seek an optimum strategy for achieving competitive advantage covering the whole supply chain. Also, due to the excessive use of natural resources and increasing consumers' awareness, the regulations have become stricter and the pressure of stakeholders' has increased. This has stimulated companies to incorporate environmental and social aspects into their strategy in addition to economical aspect in order to achieve long-term competitiveness. This study aims to develop an integrated two-phase sustainable supplier selection and order allocation model considering the experiences and observations of decision makers, corrective and preventive actions and product development rate. In the first phase, the weight of each alternative supplier is obtained through interval-valued intuitionistic fuzzy analytical hierarchy process method based on the economic, environmental, and social dimensions of sustainability. In the second phase, these weights are incorporated into a multi-product and multi-objective mixed integer linear programming model to obtain optimum number of suppliers and order quantities. Lastly, the model is empirically tested on an original equipment manufacturer parts supplier company in automotive industry. As a result, it was ensured that all factors originating from the supplier and product in the company and the experiences and observations of experts who faced with the problems of the system were included in the decision making process and optimum number of suppliers and ordering quantity is determined for each product types.