Abstract: Growth design is proposed for mechanical structure design by using the growth methodology of organism. The theoretical foundation for the growth design is introduced firstly. The process of growth design is presented based on the decomposition of function surface, and the main growth step is introduced. For the purpose to meet the functional requirements, the optimal allocation of assembly complexity and manufacture complexity is used as the principle for the decomposition of function surface. The matching degree is proposed for the mapping between conceptual parts and entity parts. Finally, an example is given to demonstrate the effectiveness of the design theory. Concept design automation can be achieved partially by using this method. The concept structure model based on function surface can be applied to the following detailed design.

Key words: Concept design, Function mode, Function surface, Generalized positioning principle, Growth design