Sustainability assessment of products based on fuzzy multi-criteria decision analysis

Sustainable product design is one of the key challenges for manufacturers to achieve sustainability, whereas it is not clear what products mean sustainability due to subjectivity of concept. This paper proposes a novel assessment methodology for evaluating product sustainability performance based on quantitative and qualitative information. Product sustainability performance index (PSPI) is defined to assist designers and engineers to evaluate and compare the relative sustainability performance of different product. An evaluation model is established based on six dimension sustainability elements (Environment, Economy, Society, Functionality, Manufacturability, and Reusability) in order to provide a new comprehensive sustainability assessment framework in a closed-loop life cycle system. Furthermore, the multi-level hierarchical structure based on criteria and corresponding sub-criteria is utilized in order to conduct more effective analysis. The improved fuzzy multi-criteria decision method is employed incorporating subjective judgment and objective information to determine weights of criteria and related sub-criteria in real decision-making situation. The positive-ideal and negative-ideal solutions are employed to satisfy the designers' desire to be as close as possible from the positive-ideal solutions. Sustainability performances of different manufactured products are assessed by integrating different levels sub-criteria into criteria. Illustrative example involving Bridgeport manual mill and Mori Seiki DuraVertical 5060 in three use environments is discussed to demonstrate the feasibility of the proposed methodology.