OptimizationofanuclearfuelspacergridspringusinghomologyconstraintsOriginalResearchArticle

Thespringsinaspacergridsupportthefuelrodsinanuclearfuelsystem.Thespacergridispartofthefuelassembly.Sincethespringhasrepeatedcontactwiththefuelrod,frettingwearoccursonthesurfaceofthefuelrod.Designisusuallyperformedtoreducethewearwhilethefunctionsofthespringaremaintained.ThedesignprocessforthespringisdefinedbyusingtheIndependenceAxiomofaxiomaticdesignandthedesigniscarriedoutbasedonthedirectionthatthedesignmatrixindicates.Foradetaileddesign,anoptimizationproblemisformulated.Inoptimization,ahomologousdesignisemployedtoreducethefrettingwear.Thedeformationofastructureiscalledhomologousifagivengeometricalrelationshipholdsforacertainnumberofstructuralpointsbefore,during,andafterthedeformation.Inthiscase,thedeformedshapeofthespringshouldbethesameasthatofthefuelrod.Thisconditionistransformedtoafunctionandconsideredasaconstraintintheoptimizationprocess.Thefrettingwearisexpectedtobereducedduetothehomologyconstraint.Theobjectivefunctionisminimizingthemaximumstresstoallowlocalplasticdeformation.Optimizationresultsshowthatcontactoccursinawiderange.Theresultsareverifiedbynon-linearfiniteelementanalysis.