Inversemethodfortemperatureandstressmonitoringincomplex-shapedbodiesOriginalResearchArticle

Thepurposeofthisworkistoformulateaspacemarchingmethod,whichcanbeusedtosolveinversemultidimensionalheatconductionproblems.Themethodisdesignedtoreconstructthetransienttemperaturedistributioninawholeconstructionelementbasedonmeasuredtemperaturestakenatselectedpointsontheoutersurfaceoftheconstructionelement.Next,theFiniteElementMethodisusedtocalculatethermalstressesandstressescausedbyotherloadssuchas,forinstance,internalpressure.Thedevelopedmethodforsolvingtemperatureandtotalstressdistributionistestedusingthemeasuredtemperaturesgeneratedfromadirectsolution.Transienttemperatureandtotalstressdistributionsobtainedfromthemethodpresentedbelowarecomparedwiththevaluesobtainedfromthedirectsolution.Finally,thepresentedmethodisexperimentallyverifiedduringthecoolingofathick-walledcylindricalelement.Themodelofapressurevesselwaspreheatedat300°Candthencooledbycoldwaterinjection.Thecomparisonofresultsobtainedfromtheinversemethodwithexperimentaldatashowsthehighaccuracyofthedevelopedmethod.Thepresentedmethodallowstooptimizethepowerblock’sstart-upandshut-downoperations,contributestothereductionofheatlossduringtheseoperationsandtotheextensionofpowerblock’slife.Thefatigueandcreepusagefactorcanbecomputedinanon-linemode.Thepresentedmethodhereincanbeappliedtomonitoringsystemsthatworkinconventionalaswellasinnuclearpowerplants.