Case-based reasoning for developing initial aircraft concepts

To make use of the knowledge and experience embedded in previous aircraft concepts, as well as improve the quality and efficiency of design by using existed information, application of case-based reasoning has been investigated. In this paper, an adapted flow of applying this technique is firstly presented according to the process of conceptual design, and the traditional methods for two tasks in this flow, i.e., case representation and retrieval, have been improved. Considering the complexity of aircraft and dynamic increase of information during conceptual design, a hierarchy model was proposed to represent a concept as aggregation of sources, groups, segments and attributes. Based on this model, a hierarchy nearest-neighbor method and a method called distance criterion for calculating group similarity were proposed to retrieve the "best-matching" case. These methods have been implemented in a design system and an example is presented to validate their effectiveness.