Evaluating design concepts using fuzzy arithmetic operations

A new method to evaluate the conceptual design of a mechanical system by means of a fuzzy distance measure is proposed. Firstly, all the factors that constrain the conceptual design are established, and the hierarchical relationship among them is set up in terms of usability, dynamic performance, and manufacturability. And then the evaluation criterions are proposed for all basic mechanical units. Secondly, the rating of various alternatives for each unit under different criteria and the weights of different criteria are represented, assessed and computed using standard fuzzy arithmetics. Based on the factor trees, a three-level fuzzy comprehensive evaluation model is set up, which is characterized by multi-factors, multi-hierarchy features, multi-experts involved as well as various constituent units. The concept of fuzzy distance measure is introduced to deckle the final ranking of alternatives using a proposed algorithm. Finally, an example is given to show the process of evaluation using distance measure