Product sustainability assessment for product life cycle

The product sustainability assessment is a progress to evaluate sustainability with indicators for product sustainability in the whole product life cycle. However, the current approaches could not deal with the relationships of those closed-loop indicators. This paper is devoted to a graph theory-based product sustainability assessment approach to avoid those closed loops of the evaluation indicators. The hierarchical evaluation system for mechanical product sustainability assessment with energy, environmental, resource, technical, and economic indicators is proposed. The product sustainability assessment approach is proposed with five steps: rationalization of the directed graph of the evaluation system, construction of the hierarchical structure, transformation from reachability matrix to judgment matrix, consistency check and adjustment of judgment matrix, and indicator weight determination and comprehensive assessment of evaluation system. The product sustainability assessment of an underactuated exoskeleton robot is given as an example to demonstrate the proposed methodology.