Modeling and evaluation of product quality at conceptual design stage

Abstract

Quality of a product is a function of many variables. These have been identified, and modeled in terms of quality digraph. The nodes in the digraph represent the quality features and the edges represent the degree of influence among these. An equivalent matrix representation of the digraph is developed to define the product system quality function (PSQF). Quality index (QI) is defined as a ratio of the actual to the ideal values of PSQF. The designer may use this index to evaluate and compare alternative designs and choose the best among these from the perspective of quality. A high value of QI indicates that the product structure is closer to the ideal state. The presented model is illustrated with an example.