Ranking engineering design concepts using a fuzzy outranking preference model

The conceptual design evaluation is important, since the poor selection of a design concept can rarely be compensated at later design stages. Due to subjective and incomplete design information collected at the early design stage, it is difficult to select the "best" design concepts from a number of alternatives. To tackle this problem, an outranking preference model based on the possibility theory is developed in this paper. The fuzzy outranking relation is developed to model the imprecise preference relation between each pair of design concepts. A design concept outranked others if and only if there is sufficient evidence to support that the concept is superior or at least equal to the others. According to the fuzzy outranking relation identified between each pair of design concepts, three types of indices are developed to determine the non-dominated design concepts for continuous improvement or further development at later design stages. Moreover, the sensitivity analysis is used to examine the robustness of the result. The fuzzy outranking preference model developed is more suitable to be used for concept selection in the imprecise and uncertain design environment. (C) 2001 Elsevier Science B.V. All rights reserved.