Complex Product Disassemblability Analysis And Structure Design For Low-Carbon

With the development of human society production, the problems such as environmental pollution,resources exhaustion, climate change and so on have been a serious threat to human survival.Design for environment is one of the effective ways to alleviate these contradictions. While low carbon footprint and Disassemblability of product are important environmental performance in design for environment,the technology for complex product disassemblability analysis and structure design for low-carbon is put forward and studied based on the overview of the state of art of the technology. The technologies and methodologies including the construction and evolution of low-carbon and disassemblable structure unit map for products, disassembly process analysis model, disassembly sequence planning, multi-granularity and hierarchy disassemblability evaluation methodology and product structure design for low-carbon are deeply studied.The organization structure of the full thesis is as follows:Chapter 1 gives the reviews of product design for environment with the focus on design for low-carbon and disassembly.The shortage of present research for product design for disassembly and low-carbon is proposed. Then the research content and architecture of the dissertation is presented.Chapter 2 puts forward the method of construction and evolution for product low-carbon and disassemblable structure unit map.There are so many kinds of connection structures that the typical connection structure is extracted from the complex mechanical products.Based on matter-element and graph theory, the low-carbon and disassemblable structure unit graph(LCDSUG) is built. Furthermore,classifying and coding of connection type,composition and disassembly tool is performed to simplify the LCDSUG and thus to form the product low-carbon and disassemblable structure unit map(LCDSUM).In addition,LCDSUM evolution methods such as inheriting,combining and deriving operation are proposed to update the LCDSUM during the design process.Chapter 3 proposes the disassembly process information modelling and sequence planning for complex products.Disassembly hybrid graph and weighted disassembly hybrid graph are constructed to describe the disassembly information.Based on the graph,disassembly sequence planning is resolved fast using the particls swarm optimization (PSO) algorithm.In addition,cooperative disassembly sequence planning(CDSP) is presented and dealt with adaptively via branch-and bound method. Chapter 4 studies the product multi-granularity and hierarchy disassemblability evaluation model and methodology.Disassembly entropy is introduced in product's coarse granularity evaluation.And evaluation matrix is constructed by assigning time-based numeric indices to each design factor.In order to reduce the dimension of the evaluation matrix and eliminate the information redundancy of the evaluation indices,the comprehensive evaluation of disassemblability for design units is carried out by principal components analysis(PCA).Chapter 5 puts forward the method of product structure design for low-carbon. Through life cycle analysis, a product life-cycle greenhouse gas (GHG) emissions flow model is constructed. Focused on the connection characteristics between components, the basic low-carbon and disassemblable structure units are derived and the product can be considered as their organic combination, which is described by the product's greenhouse gas (GHG) emissions structure units mapping model. By analyzing the parts'connection characteristics, the GHG emissions of structure units are calculated by recursive calculus of approximation of unit structure's carbon footprint. After identifying the main sources of GHG emissions stages, the product structure is optimized under the low carbon constraints.Chapter 6 studies the application of the theories and method of complex product Disassemblability analysis and structure design for low carbon in mechanical and electrical products. The cases study has proved the validity and feasibility of the proposed methods in this dissertation.Chapter 7 summarizes the dissertation and prospects the future research work.