Optimization And Evaluation Of Remanufacturing Disassembly Sequence Based On Carbon Emissions

Remanufacturing engineering is regarded as the significant measure and advanced technology to implement national outline of ‘Circular Economy'.The ‘Made in china 2025' plan calls for the full implementation of green remanufacturing,developing remanufacturing industry vigorously,and instituting advanced remanufacturing,intelligent remanufacturing as well as in-service remanufacturing.Disassembly is an essential step of remanufacturing.Reasonable and orderly disassembly can not only improve efficiency,but also reduce economic and environmental costs of disassembly.Moreover,under the guidance of the concept of green economy,it is necessary to carry out low-carbon research on the disassembly of decommissioned products.In this paper,disassembly modeling method,carbon emissions during disassembly process,optimization of disassembly sequence of remanufactured products and scheme evaluation are studied.The aim is to establish carbon emission evaluation index system and optimize disassembly sequence,so as to reduce carbon emissions during disassembly process.The main contents are as follows:(1)This paper researches the traditional methods for disassembly modeling.Analyzing the merits and drawbacks of undirected graph and directed graph in modeling.Using improved hybrid graph modeling method.Besides,achieving implement disassembly model reconstruction.The paper presents the concept of‘combinatorial element' and defines the disassembly priority level of combinatorial element.Establishing matter-element model of ‘composite element' according to extenics,and achieves the mapping from product to combinatorial element by combining with tree structure diagram.A plunger pump is taken as an example to generate the disassembly sequence.(2)Building And-Or graph model of cylinder based on combinatorial element.Through analysis of this model,obtaining better feasible disassembly sequence.Tracking carbon footprint of disassembly process from three aspects: energy consumption,material and waste.In this paper,some methods for calculating carbon emissions are proposed,such as partially destructive disassembly,parts removal,tool breakage,etc.Taking the cylinder as an example to calculate.Finally,building GERT model to analyze the uncertainty of disassembly process,quantifying the expectedcarbon emissions from different approaches.(3)Considering the strengths and weaknesses of genetic algorithm and simulated annealing algorithm.A genetic simulated annealing algorithm is proposed by combining the two and is used to optimize disassembly sequence.Designing carbon emission fitness function based on disassembly process and generating initial sequence randomly.Performing selection,crossover,mutation,disturbance and other operations to find better offspring.Keeping iterating and finally getting the optimal disassembly sequence that satisfies the constraints.At the same time,studing the convergence rate of the algorithm under various conditions,and comparing it with the traditional genetic algorithm.An example is given to verify the scientificity of the algorithm.(4)By considering three aspects: technicality,economy and environmental friendliness,designing eight evaluation indexes of disassembly schemes,such as disassembly time and disassembly accessibility.Combining the entropy weight method with AHP,a combination determining weights method is proposed to calculate the index weight in cylinder disassembly.Finally,useing the TOPSIS method and relative entropy to construct the expression of relative nearness degree,and judging the merits and demerits of the three disassembly schemes.