| In the torpedo engine design, with the development of torpedo weaponry, the designinvolved more and more disciplines, and becomes increasingly complex because ofcomplicated discipline analysis and multidisciplinary coupling, especially for the torpedothermal engine design. The traditional series design method because of its own shortcomings,can’t adapt the increasingly complex design of torpedo engine systems gradually. In order tosolve this problem, based on system theory and concurrency theory, this thesis studies torpedoengine multidisciplinary design optimization methods and applications systematically in theweapons of the water industry in China for the first time. This thesis studies mainly focusedon the following aspects: The establishment of the torpedo thermal power engine overalldesign framework, and the analysis of the coupling relationship in the framework. Theanalysis theory and method of the application for each discipline in torpedo engine design.Multidisciplinary division and coupling factor analysis of torpedo engine design.Multidisciplinary decoupling-reconstruction strategy and application for torpedo enginedesign, and how to use MDO in the practice project design of the torpedo engine. The thesisprovided some ideas and references for theoretical research and engineering practice of thetorpedo engine MDO.In this thesis, the research results and the innovation points mainly manifested asfollows:(1) From the perspective of the overall design, the disciplines of torpedo thermal powerengine are discussed, according to the disciplinary coupling relationship and the whole designprocess, the engine design framework is constructed. Cost-effectiveness, risk anddevelopment cycle, reliability are introduced into the integrated design of engine, thus, thecorresponding optimization objective function are given. The torpedo engine design processBased on reliability analysis is established. Analysis theories and methods of the disciplinesare given, the dynamics, modal, rotor unbalance response, temperature field and stress field,the critical speed, fuzzy fault tree of torpedo plate engine has been done by the correlationmethods and theories.(2) The multidisciplinary division method of torpedo thermal power engine design andits application in the components and whole engine MDO. The commonly usedmultidisciplinary decoupling and reconstruction strategy model and the correspondingalgorithm implementation are discussed in detail. Decoupling-reconstruction frameworks andmathematical models of the engine design and optimization are established by MDF(Multidisciplinary Feasible method), CO(Collaborative Optimization), SAO(SubspaceApproximation Optimization) and RSM-CSSO(RSM Concurrent Subspace Optimization)separately.For multi-objective problems in the design and optimization of the torpedo engine, threesolutions are developing in this thesis:(1) Convert multi-objective into single objective, andthen use such as MDF, SAO or decoupling-reconstruction strategy based on game theory toestablished MDO model for design and optimization.(2) Based on the quasi-separablemethod and ATC to established MDO model for design and optimization.(3) Usingcollaborative genetic evolution and Pareto decoupling-reconstruction to established MDOmodel for torpedo engine design and optimization.(3) Developing new ATC algorithm framework based on the fuzzy satisfaction, and theapproximate boundary consistency constraints. Developing a nonhierarchical ATCformulation. Developing ATC-SAO coordination method by combined with ATC and SAO.Introduced the fuzzy satisfaction to ATC, replace the sub-disciplines optimization goalwith the optimal fuzzy satisfaction, using level set to transformation conventional constraintsto fuzzy constraints, proved the new MDO approach based on fuzzy, which makes the MDOmethod more suitable for torpedo engine practical design environment. This thesis introducedthe approximate technology to ATC, by tangent planes of consistent constraint boundaries toapproximate the boundaries, which improved system design optimization efficacy andaccuracy, thus, avoided weights setting. This thesis presents a new ATC formulation thatallows nonhierarchical target-response coupling between subproblems and introducessystem-wide functions that depend on variable of two or more subproblems. According to thecharacteristics of ATC method and SAO, combined with two kinds of method, the thesispresents ATC-SAO algorithm framework, that can more suitable for torpedo enginemultidisciplinary design optimization.(4) The torpedo engine design and optimization of MDO application is studied in thisthesis.This thesis solve the problem how to integrate iSIGHT with the software of subjectanalysis, which makes MDO software frameworks based on iSIGHT be able to runautomatically. using different MDO decoupling-reconstruction strategy, combining theresponse surface approximation technique and experimental design method, by iSIGHT, in thecase of swashplate engine, the MDO models and software frameworks of piston, piston-rodcomponent, whole engine, calculation of the engine thermal process, and reliability allocationof the engine are established. Optimization calculation proved the feasibility and effectiveness of the method. It can provide specific practical tools for the torpedo thermal enginemultidisciplinary engineering design, as well as provides a new way of thinking and methodhow multidisciplinary design optimization theory is realized in torpedo engine engineeringpractice.The optimization results indicated that the proposed methods in this thesis cansignificantly reduce the computational complexity of subject analysis, improve thecomplexity of information exchange between disciplines and subsystems, so as to effectivelysupport the design and optimization of the torpedo engine products, has a great significanceboth on theory research and on practical implication. The research achievements can providethe theoretical tool and approach for torpedo engine design, and give the academic basis to thetorpedo engine MDO. |
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