A fuzzy multicriteria decision-making method for material selection

Human beings are always more comfortable making imprecise verbal statements rather than quantitative estimations for expressing preference, judgment, or prediction in an uncertain environment. Fuzzy set theory was developed based on the premise that the key elements in human thinking are not numbers, but linguistic terms or labels of fuzzy sets. Decision-making methods utilizing fuzzy set theory have gradually gained acceptance because of their capabilities in handling impreciseness, which commonly exists in system specifications, states, and alternatives ratings. Material selection problems possess such characteristics of impreciseness. This paper presents a fuzzy multicriteria decision-making method developed to support material selection decisions in engineering design applications. The methodology first asks the decision maker-the design engineer-to provide the necessary information on relevant material properties, their desired values, and their respective importance weights. Once obtained, the input is then automatically converted into trapezoidal fuzzy numbers. Through a series of fuzzy arithmetic operations, a fuzzy suitability index is calculated for each alternate material. Finally, the method of ranking fuzzy numbers with integral values is utilized to rank all of the suitable materials for the application. An example is used to illustrate the working of the proposed method.