Research On Design Knowledge Modeling Of Complex Products Based On The Living Systems Theory

The design of complex products is a creative activity involving multi-disciplinary,multi domain knowledge and a large number of designers working together.Thus a knowledge management method which can effectively organize the knowledge in different fields is required to realize the knowledge reuse in the design process.At present,some problems still exist in the study of complex product design knowledge management home and abroad.First,the use of existing abstract symbols or methods of functional modeling is either unable to fully express the interaction between subsystems,or too complicated to have too many rules with low versatility.Second,there are mainly two kinds of organization forms of existing design knowledge,of which one is based on product structure,and the other is based on design process.Consequently it cannot reflect the products' internal logic operation while taking into account the designer's thinking mode.Third,the existing design catalogue and design cases are focused on a certain product field without a method to effectively organize product design knowledge and design cases in different fields together.To solve these problems,the the Living Systems Theory is introduced into the complex product field,and the modeling of complex product design knowledge based on the Living Systems.The main contents are as follows:(1)Theory is carried out.First,the mapping model of Living Systems Theory and complex product is established by establishing the mapping relationship among hierarchy,key subsystems,subsystem process parameters and complex products.(2)The material flow,energy flow and information flow relationship among 20 key subsystems in living systems theory is analyzed.The method of product function expression based on living systems theory is put forward.This paper summarizes the current design knowledge representation methods based on(Function-behavior-stucture,FBS)model,and points out the existing problems.In functional decomposition,the living systems theory fails to summarize the general method to guide the designer to analyze the function of the existing products.Based on this problem,product function expression method is improved using the living systems theory and the design knowledge expression method is put forward based on living systems theory.Additionally,with a single cylinder diesel engine as an example,the design knowledge model based on the living systems theory is demonstrated as well.(3)Based on the hierarchical partition of the the Living Systems Theory and the mapping of 20 key subsystems in the complex product,this paper proposes a complex product design knowledge organization model based on the the Living Systems Theory combined with the design catalog and the example database.Finally,taking steam engine function modeling,tractor motor lectotype and single cylinder diesel engine design scheme modification as examples,the functions of the design knowledge modeling method in the design of complex products are verified based on the living systems theory.