| With the improvement of the economic level,people’s material consumption is increasingly stimulated,one of which is the purchase of new electronic products.The shortening of the update cycle of electronic products has further exacerbated the shortening of their service cycles,resulting in a large amount of electronic waste.How to turn electronic waste into treasure has become an urgent issue for the Chinese government and enterprises.Based on the government’s compensation and incentive policies for recycling waste products,some enterprises took the lead in establishing and improving the recycling mechanism of recycled products to achieve the recycling of valuable and high demand parts and components,thus reducing the cost of purchasing raw materials for enterprises and increasing revenue.In addition,this measure can not only alleviate resource consumption,but also reduce environmental pollution caused by improper disposal methods such as incineration and landfill.The most critical step in obtaining parts from waste products is disassembly.In the disassembly process,due to the unknown internal structure and quality of waste products,the diversity of disassembly tasks leads to different disassembly operation times.Some components may cause pollution or be highly dangerous and require special treatment to avoid damaging high demand parts.These factors will affect the disassembly sequence of parts.In view of this,from the perspective of economy and environmental protection,this paper considers the influence of different disassembly environments and different disassembly factors on the optimization results of disassembly sequence.Facing the complex internal structure of waste products,disassembly tools of different precisions are required,and the conversion of tools increases the time for disassembly.In addition,the change of disassembly direction also prolongs the time for disassembly of waste products.In order to shorten the disassembly cycle and reduce the disassembly cost,the disassembly sequence optimization problem is considered based on the disassembly time and cost.In which,a TAOG diagram is widely used to describe the sequence and process of disassembly tasks to construct a multi-objective dynamic programming model based on TAOG and design a forward recursive formula.In the recursive solution process,each stage of each state corresponds to several sub-strategies and the objective vector values.Based on the concept of Pareto,all Pareto optimal whole-process disassembly schemes in the obtained space and the Pareto optimal frontend corresponding to these schemes are finally obtained.The method proposed in this paper is a more accurate method,not only can quickly obtain the Pareto optimal front end of the problem,but also verifies the feasibility and effectiveness of the method to solve the multi-objective disassembly sequence optimization problem.In addition,the optimization results can provide more accurate information for decision makers and have good application prospects.Considering the disassembly of large-scale products,it is necessary to cooperate to achieve completely disassembly.Thence,disassembly line is the preferred mode of enterprises.How to reasonably allocate tasks and workstation configuration is the core issue that be attracted great attention of researchers and enterprises.In view of this,the multi-objective disassembly line balancing problem is studied,and a multi-objective dynamic programming model considering fixed cycle time is constructed.The model involves using piecewise functions to represent the evaluation metrics,which proves the monotonicity of the two objective functions.Using the concept of Pareto dominance,obtain all Pareto optimal solutions(disassemble task sequences)and Pareto front.Compared with existing algorithms,the results show that the MODP method is effective by solving cases of different scales.The diversity of Pareto optimal solutions enables decision makers to make informed decisions based on trade-off theory and utility theory.In the actual disassembly process,due to the instability of the quality of recycled waste products,the comprehensive value evaluation of disassembled parts is extremely important.The evaluation of multiple attributes of disassembled parts can not only obtain high-value parts,but also reduce unnecessary disassembly time.The rapid changes in the market make the decision-making process more and more complex,and the number of dismantled parts and evaluation criteria will directly affect the decisionmaking process.The multi-criteria decision-making(MCDM)method can deal with the subjective evaluation criteria of decision makers,and its performance will be significantly improved when it is mixed with fuzzy theory.The fuzzy MCDM method can deal with mixed problems that contain both qualitative and quantitative properties of disassembled parts.Therefore,a new AHP proposal is proposed consist of two parts:(1)a hierarchical structure model is constructed from the three aspects of environment,economy and recycled product quality;(2)a mixed MCDM method of SFS-AHP and SFS-MULTIMOORA is proposed,which is used to comprehensively evaluate the value of disassembled parts,and then sort them.The comprehensive value ranked first in the sequence is the largest,and so on.According to the order of value,under the condition that the order of disassembly is satisfied,the parts with high value can be dismantled first and reused to create profits for the enterprise.Finally,the multi-objective optimization problem of dismantling sequence with uncertain dismantling time is considered.The smaller the number of workstations opened on the disassembly line,the corresponding reduction in carbon emissions from electricity consumption,thereby reducing environmental pollution.To construct a stochastic low-carbon multi-objective mathematical model,the multi-objective problem is transformed into a constrained single-objective problem by using the main objective method.An improved flatworm algorithm is designed,in which the number of dismantling directions and the number of dismantling tool replacements are used as penalty functions.Penalty value parameters are introduced into the insertion point in the growth mechanism and mutation operations in order to find better solutions.The optimization research of the random stitch removal problem is helpful for the timely dynamic adjustment of stitch removal and timely stop loss,so as to avoid unbalanced stitch removal and lead to long-term suspension.The above research and results have a certain reference value for the decisionmaking of the demolition plan and the selection of the demolition site for the enterprise managers,and the proposed solution has a certain application value.Optimizing disassembly scheme can improve disassembly efficiency,reduce disassembly input cost,and create benefits for enterprises.In addition,the disassembly sequence optimization of carbon emissions is considered to reduce environmental pollution,improve the good image of enterprises and enhance market competitiveness. |
