简介:Theplowofthesubmarineplowingtrencherisoneofthemainfunctionalmechanisms,anditsoptimizationisveryimportant.Thedesignparametersplayaverysignificantroleindeterminingtherequirementsofthetowingforceofavessel.Amulti-objectivegeneticalgorithmbasedonanalyticalmodelsoftheplowsurfacehasbeenexaminedandappliedineffortstoobtainoptimaldesignoftheplow.Foraspecificsoilcondition,thedraftforceandmoldboardsurfaceareawhicharethekeyparametersintheworkingprocessoftheplowareoptimizedbyfindingthecorrespondingoptimalvaluesoftheplowbladepenetrationangleandtwosurfaceanglesofthemaincuttingbladeoftheplow.Parameterssuchasthemoldboardsideangleofdeviation,moldboardliftangle,angularvariationofthetangentline,andthespanninglengtharealsoanalyzedwithrespecttotheforceofthemoldboardsurfacealongsoilflowdirection.Resultsshowthattheoptimizedplowhasanimprovedplowperformance.Thedraftforcesofthemaincuttingbladeandthemoldboardare10.6%and7%,respectively,lessthantheoriginaldesign.ThestandarddeviationofGaussiancurvatureofmoldboardisloweredby64.5%,whichimpliesthatthesmoothnessoftheoptimizedmoldboardsurfaceismuchgreaterthantheoriginal.
简介:Inconsideringthetheoryofstructuraldynamicoptimizationdesign,adesignmethodofthestructuralstyleofshipcompositebracewithrigidvibrationisolationmasswasstudied.Twokindsofstructuraldynamicoptimizationformulationsminimizingthevibrationaccelerationofthenon-pressurehullontherestrainingconditionofthegrossweightoftheshipcabinwereestablished:1)dynamicoptimizationofthesectionaldimensionsoftherigidvibrationisolationmassinthecompositebrace;2)dynamicoptimizationofthearrangingpositionoftherigidvibrationisolationmass.Throughtheoptimizationresults,sectionaldimensionsandthearrangingpositionoftherigidvibrationisolationmasswithbetterperformanceinreducingvibrationweregained,andsomereferencewasprovidedforpracticalengineeringdesignsaswellasenrichmentofthedesignmethodofanovelshipvibration-isolationbrace.
简介:文章对影响柴油机NOX排放的因素进行分析,以某小型船用柴油机为例,通过对燃烧室结构及参数进行优化来控制其NOX排放,使其达到现阶段MARPOL公约附则Ⅵ修订案中对NOX排放的要求,同时保持较好的烟度和油耗。针对原来的燃烧室和改进后的燃烧室,在台架上作四种工况下的柴油机排放试验和外特性试验,并对试验结果进行分析研究,为小型船用柴油机排放控制提供一些思路。
简介:在对45901与44901两期海船船员适任统考试题进行对比分析的基础上,从提高命题质量、航海英语教学和教材要和考纲契合、利用语料库对学生进行错误分析、研制应用于航海英语写作或翻译的自动评分系统及优化航海英语测试题型结构等方面提出对航海英语测试体系进行优化的建议。