简介：Lightweightdesignisoneofthedevelopmenttrendsoftheautomobileindustry.AneffectivewaytoachievelightweightautobodiesistouseAHSS(advancedhighstrengthsteel)forthesafetycomponentsofautomobiles.ThisstudyhastakendoorsillreinforcementsmadeofmartensiteAHSSastheobject,andperformedresearchontheAHSSrollformingtechnologiesandprototypedevelopmentoftypicalasymmetricopencomponents.Bymeansoffiniteelementanalysis(FEA)andsimulation,studieshavebeencarriedoutonthespringbackandedgewavedefectsduringAHSSrollforming,andanoptimizedprocessdesignhasbeenachieved.Thegenerationmechanismsofverticalbows,horizontalcambers,twists,pre-punchedholedistortionandcutendflarehavebeenanalyzed,andsolutionstothesedefectshavebeengiven.Inaddition,tesingoftherollformingprocessforAHSShasbeenconductedandtypicalsampleswithrequireddimensionalaccuracyhavebeenmanufactured.Thisstudyhasprovidedtechnicalsupportforthelarge-scaleapplicationofAHSS.

简介：Inarecentarticle,theauthorsprovidedaneffectivealgorithmforbothcomputingtheglobalinfimumof/anddecidingwhetherornottheinfimumof/isattained,where/isamultivariatepolynomialoverthefieldRofrealnumbers.Asacomplement,theauthorsinvestigatethesemialgebraicallyconnectedcomponentsofminimumpointsofapolynomialfunctioninthispaper.Foragivenmultivariatepolynomial/overR,itisshownthattheabove-mentionedalgorithmcanfindatleastonepointineachsemi-algebraicallyconnectedcomponentofminimumpointsof/whenever/hasitsglobalminimum.

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