Extending the application of fuzzy COPRAS to optimal product design

Abstract

The availability of customized and multifunctional designs of a particular product in the market due to varieties in users’ requirement and demand necessitates that product design must be properly done before progressing to developmental stage. This implies that the importance of decision making in the selection of optimal conceptual design cannot be overstressed. The main contribution of this article is the implementation of Fuzzy COPRAS (COmplex PRoportional ASsessment) model as a decision tool for identification optimal design concept. The weights of the design features and sub-features were determined in the form linguistic terms generated from a triangular fuzzy number in order to avoid apportioning of crisp values in the decision process. An analytical approach was applied by creating a sub-aggregate matrix for each design feature, considering all the design alternatives in order to develop a sub-decision matrix. The relative significance or priorities of the design alternatives obtained from the maximization and minimization indices are defuzzified by applying the minimum degree of possibility in order to rank the design alternatives. The findings from the application of the Fuzzy COPRAS methodology to four design alternatives of pipe bending machines using eight design features and several sub-features indicates that the methodology can identify an optimal design concept from a set of alternative designs. The application of the methodology also shows that there are slight differences in the priority values of design alternatives next to the optimal design concept. The implication and recommendation from the application is that choosing any of the design alternatives other than the optimal design concept will provide the same risk