Table of Contents
ISRN Mechanical Engineering
Volume 2013, Article ID 686402, 15 pages
Research Article

A Functional Representation Model Facilitating Design Space Expansion

School of Electromechanical Engineering, Xidian University, Xi’an, Shaanxi 710071, China

Received 5 June 2013; Accepted 1 August 2013

Academic Editors: O. P. Gandhi and X.-J. Liu

Copyright © 2013 Wei Xu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This paper addresses the functional representation based on the event model. In the event model, the ontology is defined based on the theory of propositional logic to describe the connotation of the event, and the variant is defined based on the theories of domain relational calculus and set theory to express the variation range of the event, which is alterable part of the event under the constraints of the ontology. Function is an important concept in conceptual design and has its connotation and extension. The functional representation is proposed based on the event model. The ontology of event is used to describe the connotation of function and to reflect the stability of function. The variant of the event is used to represent the extension and to incarnate the variety of function. The extension of function is the change range of function under the constraints of the connotation. The proposed functional representation divides the function into the immutable part and the alterable part, facilitating the expansion of design space. A functional reasoning model is also put forward based on the event model to support the function reasoning on the computers. Finally, a simple case validates the feasibility of the model.