Managing Functional Coupling Sequence to Decrease Complexity and Increase Modularity in Conceptual Design

Abstract

Conceptual design is the stage where the upstream objectives and downstream constraints meet, so both the ideality and practicality are important in conceptual design. Modularity supports designing complex system while the design can take advantages from the downstream resources. According to Axiomatic Design Theory (ADT), the design with the least complexity is the ideal design, and managing functional coupling sequence can lead to the minimal complexity of design concepts. In this paper, Design Coupling Sequence (DCS) was introduced to bridge the ADT and the modular design. The ‘precedence’ and ‘functional sets’ were defined in DCS to manage the coupled design concepts in order to support the modularity of the design concepts. The ‘precedence’ identified by the level of functional coupling helps realize the sequencing order. The two ‘functional sets’ were defined as the independent U-set: the collection of functionally dependent concepts, and the coupled C-set: the collection of the strongly coupled concepts. The faucet design case study shows how the DCS method and its strategy to decrease relative complexity and increase modularity, and the results between design by extra coupling elimination and design by the existing modules are compared. The DCS method bridges the design theory to design practice.