Product Structure Regenerative Design And Feedback For Low-Carbon

Low-carbon design is a new topic of product design with the carbon emissions in its life cycle considered. Different measures can be taken in the design stage to reduce the carbon emission of products and this paper studies the method to realize product low-carbon design by structural design. The technologies and methodologies including multi-level modeling and product structure regenerative design technology, the quantitative feedback technology of carbon emissions in design processes and the scheme evaluation technology combined with low-carbon property are deeply studied. The theory and method are applied in the design processes of some complex products and the validity.and feasibility have been proved.The organization structure of the full thesis is as follows:Chapter1gives the reviews of product low-carbon design and product structural design.The shortage of present research for product low-carbon design and product structural design is proposed. Then the research content and architecture of the dissertation is presented.Chapter2proposes the method of constructing multilayer integrated model for product structure regenerative design. Product structure is an important factor which affects the carbon emissions in manufacture, assemble, and disassemble processes. Through the structure level classification designers can have a detail view of the whole structure, and appropriate choice for low-carbon can be made easily. Different ways to reduce the carbon emissions by optimizing the structure of each layer structure are analysed. An overall material selection technique is studied to make the product more recyclable, the thought of modular subdivision and rebuild is given out to improve the reusability of the components and the method of structure regenerateing for parts is studied to impove the disassemblability. Base on that the product multilayer integrated model is buit.Chapter3studies the product structure regenerative design technologies based on the multilayer integrated model. With the polychromatic graph relational model of product material and structure, the process to select material and generate the corresponding recycling strategy is carried out automatically. Then the algorithm for overall material selection for product based on polychromatic graph is given out. Using digraph and property list, the structure and attributes information of the product is expressed in a more fine level. Four basic rebuilding techniques are carried out based on the operational rules of digraph. With variation rules based on the structure variation units, connection structure variation unit and functional structure variation unit can be evolved respectively. Chapter4puts forward the method of quantitative feedback technology of carbon emissions in design processes. By analysing each structure unit and collecting the related information in its life cycle the carbon emissions can be mapped to the structure. With a novel method of evaluating the emissions factors relatively the carbon emission can be quantitatived. Basic components library of enterprises can be built by tracking the carbon emissions in life cycle of each part. Useing function-decomposition tree the basic components of products are divided hierarchically. Then the hierarchical expression for carbon emissions of complex products is constructed from bottom to top by constructing the structure and drawing the information of carbon emissions layer by layer. A feedback mechanism is given out for the quantitative feedback of carbon emissions in design processes.Chapter5studies the scheme evaluation technology combined with low-carbon property based on generalized logic analysis. AND/OR tree and matching proposition set are used to describe the design scheme of complex product. Independent matching proposition is evaluated respectively and then synthesized through which the evaluation process is detailed. Product performance indexes are divided into function correctness index and green rationality index and they are got with Fuzzy evaluation method for every independent matching proposition. Used the reasoning model integrated self-correlation and cross-correlation in generalized logic the two kinds of indexes are combined effectively. The overall evaluation value is calculated with the method of composite proposition generalized logic reasoning.Chapter6introduces the development of Structural Design for Low Carbon System and the application of theories and method in mechanical and electrical products. The cases study has proved the validity and feasibility of the proposed methods in this dissertation.Chapter7summarizes the dissertation and prospects the future research work.