Functional design is a process in engineering design that dominates the key features of the result to be developed. Designing good functions that both satisfies the requirements and leads to better results is a challenge due to uncertainties on the consequences of the selected functions, and the lack of analysis methods for identifying the properties of function structures. Therefore, extensive experiences are usually required for functional design. This research argues that the physical relationships among the resulting components of a design are the consequences of functional dependencies developed during the functional design process. Therefore based on the understanding of functions and functional dependencies, a reasoning procedure can be developed to predict the performance properties of the design so that the effectiveness of the functional design can be evaluated at an early design stage. This paper proposes a dependency-based function modeling and analysis method that can be applied to represent and assess functions and function structures at the functional design stage. Designers can predict the properties of the functions they designed without having to have similar design experiences. An application software is also developed to implement the method and demonstrate its effectiveness.

In collaborative engineering, the dependencies of engineering problems determine with whom and how designers should coordinate. Based on the directed dependency framework introduced in this research, we argue that the reciprocal and cyclic dependencies cause design iterations and inefficiencies, and should be avoided if possible. By studying the patterns of engineering dependencies and design decomposition, this paper provides an approach to manage the dependencies in order to avoid reciprocal and cyclic dependencies both in the early conceptual design stage and in design task arrangement stage, to make collaborative design more efficient. The long-term goal of this research is to develop a dependency-based coordination framework that consists of a formal model of engineering dependencies, and coordination methods, and guidelines for dependency-based engineering design and management. This paper describes our current dependency modeling framework and dependency management methods for collaborative design.

Collaborative engineering design involves coordination among designers. While coordination in most cases entails explicit communication between designers, the real reason for designers to coordinate with each other is not for communication but for resolving engineering dependencies. In the field of collaborative engineering research, various computer models and tools have been developed to facilitate communication among designers aiming to improve their communication efficiency for coordination. We argue that in order to provide effective and purposeful coordination support, one must understand how engineering dependencies evolve and propagate in different phases, of design, from problem definition, conceptual design, to detail design. In our research on collaborative design, we take a dependency-based approach, i.e., to explicitly capture and manipulate dependencies and create design processes and support tools based on explicit understanding of underlying dependencies. The long term goal of our research is to develop a dependency-based coordination framework that consists of a formal model of engineering dependencies and coordination mechanisms, mapping between the dependencies and coordination methods, and guidelines and procedures for dependency-based work process design and management. This paper describes our current status of developing a formal model of engineering dependencies.