| Recent research in function-based design includes the development of a vocabulary of functions, the Functional Basis, and a repository of products and their functions. Many design tools are being developed around this vocabulary and repository to support conceptual design. The usefulness of these tools, however, is dependent on the quality of the vocabulary and the information contained in the repository. In this research, both the vocabulary and the repository are empirically evaluated to understand their strengths and limitations. A statistical analysis is performed on function models in the repository to determine the frequency of usage of Functional Basis terms. It is determined from this analysis that many of the functions described in the repository are component-specific, contradicting the intent of function-based design, which is to remain solution-neutral. The hierarchical organization of the vocabulary is also analyzed by altering the level used within function structures. It is concluded that the hierarchy allows changes in the level of specificity of functions, but it is independent of function decomposition. A set of pruning rules is then presented that reduces the number of highly decomposed, component-specific functions from function structures. Pruned function structures are simpler, less component-specific, and provide a more consistent level of decomposition for repository tools to reason upon. Opportunities for future work identified through this research include extending and refining the existing vocabulary, developing a grammar for function structures, and developing a schema and similarity metric for a next-generation repository. |
