Research Of Economical Evolution And Strategic Decision-making Method In The Process Of Product Conceptual Design

About 70%-80% of the total cost is determined at the conceptual design stage, and the mistake at this stage will result in increasing of subsequent costs. Therefor, it has great significance to give out economic information as same as the principle scheme which based on function solving at the conceptual design. In addition, it only pursues the technical of products, the economy is to be considered after meeting the technical indicators. Economic evaluation lags behind the technical evaluation.In view of the above problems, a new method for economic modeling which bases on expansion cost unit is put forward. And expansion cost unit is used as a basic element in product economic design. The evolution of cost unit is realized at the conceptual design process. Information mapping, combined, the solution process are also researched to provide support for the economic evaluation of conceptual design. The main research efforts and achievements are as follows:1. Research on economy formation and evolution method of the product at the conceptual design stage. The concept of "expansion cost unit" was proposed, the expansion cost unit model was constructed. Combining with traditional characterization methods, a graphical multi-level expression method was used for expressing expansion cost unit. A function-behavior-virtual structure-expansion cost unit was established, the evolution of expansion cost unit was realized by inverse mapping method in the conceptual design process.2. Research on evaluation about economy of the product conceptual design scheme which based on expansion cost unit. The definition of the evaluation of knowledge element was given, and the model was also constructed. The economic evaluation design strategy at the conceptual design was explored, information mapping, combining, solution processbetween expansion cost unit were researched. Expansion cost unit was used to evaluate the principle of conceptual design scheme and virtual structure scheme.3. A prototype system for economic solution of product design process was developed,two typical complex electromechanical products were used as examples to validate the effectiveness of the above methods.