Research On Complex Product Disassembly Sequence Planning Method For Maintenance Of Ships

Disassembly sequence planning is the important section of maintenance.Due to complex structure and the large quantity of parts,complex product disassembly sequence planning for ship maintenance has many problems,such as modeling,solving and evaluating.Aiming at these problems,this thesis studies the key technologies of the disassembly sequence planning of complex products,including disassembly modeling,evaluation indicator,optimization algorithm and module partition.This thesis includes the following aspects:Firstly,the product parts are divided into fasteners and general parts.After analyzing the disassembly rules of fasteners and their constraints on parts,the concealed priority relationship of parts based on fasteners is found and the relationship table of fasteners(RTF)is established.Then synthesizing the RTF and the interference matrix(IM)of parts,the new modeling method-the constraint interference matrix considering the influence of fasteners(CIM)is established.Based on this modeling method,parts removability rules and fastener disassembly rules are proposed.The product example shows the effectiveness and superiority of this method.Compared with the common modeling methods,the CIM has the advantages of small amount of data,complete expression information,easy construction and easy solution.Secondly,the evaluation indicator system of ship maintenance is proposed and the disassembly sequence planning method based on immune algorithm is established.The indicator system includes time index,operational index and economic index.Then,by establishing the mathematical model of disassembly sequence planning and analyzing the process of immune algorithm planning,the disassembly sequence planning is completed by improving the algorithm adaptively according to the disassembly problem.Finally,an example is given to illustrate the effectiveness of this method,and by comparing with genetic algorithm the superiority of immune algorithm in disassembly problem is demonstrated.Then,in order to solve the combination explosion problem of complex product,a modular disassembly planning method is proposed.After establishing the module partition rule and the calculation method of part association degree,the module partition is completed by hierarchical clustering analysis.Then a module-based disassembly sequence planning method is proposed,and the prototype system development is completed.The example shows that modular disassembly can effectively reduce the difficulty of disassembly planning.Compared with the common modular partition method which is partitioned based on typical parts,this method is more practical and accurate.Finally,this thesis summarizes the research contents and innovations of the full text,and looks forward to the direction of further research in the future.