简介:介绍了FGB法曲面外板高效焊接工艺的来源和应用现状,阐述了该焊接工艺的应用价值.针对国内船舶制造企业在曲面板焊接时遇到的反变形值和余量加放控制的问题,运用有限元方法对FGB法焊接进行数值模拟,计算分析该焊接方法可能引起的变形.设计并完成了FGB法焊接试验,将实验结果与理论计算结果相对比,验证了FGB法具有较小的焊后变形.通过生产现场的应用试验,详细分析了FGB法焊接工艺在实际应用中的现场适用性和实用性.并通过与原先曲面板CO2气体保护焊的对比研究发现:FGB法焊接工艺具有焊后变形小、焊接效率高等优点,可以完全不需要通过调整胎架的方式加放反变形.在曲面外板拼板焊接时使用FGB工艺可以提升焊接自动化水平,焊接效率提升明显,节约辅助材料.
简介:Theplowofthesubmarineplowingtrencherisoneofthemainfunctionalmechanisms,anditsoptimizationisveryimportant.Thedesignparametersplayaverysignificantroleindeterminingtherequirementsofthetowingforceofavessel.Amulti-objectivegeneticalgorithmbasedonanalyticalmodelsoftheplowsurfacehasbeenexaminedandappliedineffortstoobtainoptimaldesignoftheplow.Foraspecificsoilcondition,thedraftforceandmoldboardsurfaceareawhicharethekeyparametersintheworkingprocessoftheplowareoptimizedbyfindingthecorrespondingoptimalvaluesoftheplowbladepenetrationangleandtwosurfaceanglesofthemaincuttingbladeoftheplow.Parameterssuchasthemoldboardsideangleofdeviation,moldboardliftangle,angularvariationofthetangentline,andthespanninglengtharealsoanalyzedwithrespecttotheforceofthemoldboardsurfacealongsoilflowdirection.Resultsshowthattheoptimizedplowhasanimprovedplowperformance.Thedraftforcesofthemaincuttingbladeandthemoldboardare10.6%and7%,respectively,lessthantheoriginaldesign.ThestandarddeviationofGaussiancurvatureofmoldboardisloweredby64.5%,whichimpliesthatthesmoothnessoftheoptimizedmoldboardsurfaceismuchgreaterthantheoriginal.