| Ship accessibility reflects the relationship among the merits of the general layout of ships and the efficiency of flow of persons and materials,and has important influence on the ship's combat capability,support capacity and survivability.In China,with development of large-scale naval ships,the general layout of ships is becoming increasingly complex.Also,requirements for the efficiency of flow of persons and materials are increasing.In recent correlation research and existing standards,there are little systematic researchs and certain definitions of ship accessibility,in addition to the lack of effective assessment indicators and methods.At preliminary design stage,according to the ship accessibility,this thesis analyses and presents the definition,elements and main research objects of ship accessibility.In addition,the multi-objective optimization of elements of ship cabin layout and multi-attribute decision-making problems of limited layout scheme related to accessibility are studied,in order to establish an accessibility-based system and method,which applies to overall design,optimization,evaluation and decision-making of large ships.The evaluation index system of ship accessibility is established based on representative scenario,which takes the indicators of layout,process,timing,environment under each scenario as the framework,and obstructive factors of the efficiency of persons and materials as specific assessment indicators.In the calculation problem of the persons flow and materials flow,calculation model of personnel flow based on dynamically network flow is proposed,as well as the time-estimated model of materials flow based on stochastic Petri nets,which provide a convenient algorithm to assessment model of ship accessibility at the stage of preliminary design.A multi-objective optimization model of ship cabin layout is established,which seeks balanced result from three aspects,namely,the cost of the flow between people and supplies cabin,the requirements of adjacent or distant compartments,the ship-environmental impact on people.The method of grid-based flat decks and cabins is presented.Simplified parameter calculation model for optimization model is designed to achieve fast calculation of multi-objective optimization model of ship cabin layout.The algorithm strategy of ship cabin layout is established based on hierarchical evolutionary multi-objective optimization model.In addition,according to the characteristic of ship cabin layout,matrix coding and the generation of the initial plan and the scheme of genetic crossover and genetic mutation are designed and algorithms of block-chamber arrangement within the chamber is proposed,numerical examples of single and multi-deck cabin layout are calculate to verify the feasibility validity of the algorithm,respectively.The research of Multiple Attributive Decision Making based on multi-objective optimization results in multi-deck cabin layout program is conducted.To minimize the impact of subjective factors of assessment experts,considering the weight of a representative scenario,five objectives Multiple Attributive Decision Making are selected:Information Entropy Evaluation,Least Squares Gray Correlation Analysis Method,the Relative Entropy Sort,Maximizing Deviation Method and Opened the Grade method,among which the adaptive research are carried out respectively.The results show that there exsists inconsistency among the evaluation conclusions drawn by different evaluation methods even subjective factors are ignored.So combination assessment methods based on method set are adopted for evaluation of different kind methods,and for seeking the most satisfied combined assessment conclusion as the final order for decision-making. |
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