Conceptual Design, Functional Decomposition, Mathematical Modelling, and Perturbation Analysis

The Functional Decomposition method provides a hierarchically structured approach in the conceptual design of technical systems. It not only helps to find a good technical solution for a give problem but also reflects the "problem structure" as well as the design history, if it is properly documented. Its documentation even for moderately complex systems needs computer support. Data bank system are well suited for this purpose. Mathematical models of different complexity should convene the design process. At the rather abstract level of functional solution concepts so called Essential Mathematical Models help to evaluate the diverse concepts. For the qualitative evaluation the application of Suh's independence axiom is recommended. The refined mathematical models used at later, more detailed stages of design should be in reasonable neighbourhood of the results of the Essential Models. A concept for defining this neighbourhood is regular perturbation with respect to the Functional Requirements and the Design Parameters.