FCBS model for functional knowledge representation in conceptual design

Abstract

This paper proposes the function–cell–behaviour–structure (FCBS) model for better comprehending representation and reuse of design knowledge in conceptual design. Two knowledge representing layers, i.e. the principle layer and the physical layer are proposed in the FCBS model. In the principle layer, we focus on the underlying design principles in previous designs and FKC (functional knowledge cell; a kind of function–cell pair) is utilised to represent the principle knowledge. A functional sketch is proposed for recording and demonstrating working principles of design alternative on a functional basis. In the physical layer, case modelling is employed to integrate the structural information and behavioural performances of the existing devices which applies the design principles represented by FKCs. A case is composed of structure and its behaviour. A case-based method is adopted to substantiate functional cells into physical structures in embodiment design, in terms of case embodiment. The behavioural performances are taken as case attributes. A comparison between expected behaviour performances and behavioural performances of the existing artefacts is used to select structures for case adaptation and reuse. A prototype system called the conceptual design tool is developed to implement our approach and a simple example is illustrated with functional sketches.