A Hierarchical Material Flow Based Automated Functional Decomposition for Conceptual Design of Working Machines

Abstract

The purpose of conceptual design is to build the function structure and find the principle solution for fulfilling it. A formal functional representation is needed for decomposing the overall function to sub-functions with the computer-aid reasoning process. However, the existing functional representations lack of supporting the description of attributes and internal structures of input/output material flows. Material flow may be much more complicated than the other two kinds of flows (signal flow and energy flow) since its geometry and topology may be very complex, and which hinders the automated functional decomposition. In this paper, we propose a hierarchical material representation for the working machines which use material as the primary input/output flows. We combine input/output transformation model with “verb+noun” pairs, using the standard vocabulary of functional basis, to model function formally and objectively. Therefore, the functional effects can be inferred from the information contained in flows. Moreover, we propose the concept of action as an operation process that bridge what and how of one function to guide the further decomposition. Finally, a prototype tool is developed as a MagicDraw’s plug-in to implement the decomposition process.