简介：Toinvestigatethefeasibilityforahelicallinetobeusedasapulseformingline(PFL),thetransmissioncharacteristicsofthehelicaltransmissionlineisstudiedboththeoreticallyandexperimentally.Theresultsindicatethatitisfeasibletoemployahelicallineasalong-pulsePFL,andtheinfluenceofitsdispersionisnegligible.ComparedwithaconventionalcoaxialPFL,thehelicalPFLwiththesamesizecanproducealongerpulse.

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简介：Innormalfluvialprocessestheriverchannelisdeterminedbyriverflowswhilethemovementofriverflowsiscontainedbyriverchannels.Therelationshipbetweentherivermorphologyanditsbendcurvatureshowsthatriverswithlargebendcurvaturesalwayshavenarrowanddeepchannelsandthosewithshallowandwidechannelsarealwaysstraight.Theplanformofariverreachesisdeterminedbythecross-sectionalmorphology.Ameanderingriverreachmaybedevelopedundervariouswater-sedimentconditionsaslongasthenarrowanddeepchannelsareformed.

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

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简介：Thispaperpresentsanapproachwhichenablessurfacemodelling,meshgenerationandtheFiniteElement(FE)analysistobeintegratedtogethertosimulatesuperplasticformingprocessforcomplexshapedcomponents.TechniqueshavebeendevelopedtogenerateanFEmeshovernon-four-sidedsurfaceareas,theboundariesofwhichareBeziercurvesofarbitrarydegree,usingaconsistentexpression.TheoreticalevidenceisgiventodeterminethenumberofBeziertriangularpatchesrequiredforaccuratelyre-constructingdiesurfaceswithinacommercialFEsolver.Thedevelopedtechniqueshavebeensuccessfullyusedindeterminingtheprocessparametersforforminga3Drectangularbox.

简介：ThemetalsprayformingprocesswasexaminedusingmathematicalsimulationandverifiedthroughtheprototypingevaluationatBaosteel'stestanddevelopmentfacilities.Themathematicalmodelcomprisedoffoursections,includingjetgasflowinthedepositionchamber;singledropletbehavioralongitstrajectorypath;probabilityandstatisticalanalysisofdropletmassbehavior,andforecastoftheshapeandtemperaturedistributionofthebilletduringthesprayformingprocess.

简介：Onthebasesofhightemperaturecreepexperiments,theresearchonengineeringapplicationofrheologicalformingiscarriedoutontwokindsoflightmetalalloypartsnamedcylindricalshellofLc4aluminumalloyandvanediskwithcomplexcurvedsurfaceofTC11titaniumalloy.Moreover,themechanicalpropertytestsunderroomandhightemperaturesfortheworkpiecesproducedbythisnewtechniquearealsodone,theresultsshowedthattheyaremuchimprovedevidentlycomparedwiththoseproducedbytraditionalmethod.

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简介：Inthisstudy,theformabilityoftransformation-inducedplasticity(TRIP)steelisstudiedduringdeep-drawingprocesseswithpreforming.Theeffectsofpreformingontheminimumthicknessofcanareinvestigatedwithaconstitutivemodelaccompanyingstrain-inducedmartensitetransformationinprestraincondition.TheconstitutivemodelhasbeenimplementedintoABAQUS/UMATforanalysisofTRIPsteel-formingprocesses.TheresultsshowthatpreformingslightlyinfluencesthethicknessuniformityofTRIPsteel...

简介：TheformingtemperatureofClinkermeltunderdifferentburningconditionshasbeenstudiedbyappearanceexaminationandthermalshrinkerdetermination,andtheviscosityofmelthasbeendiscussedbystudyingthecoordinationnumberofAl3+andFe3+incementclinkerburnedbydifferentmethodwithx-rayfluorescenceanalysisandMoss-bauerspectroscopy.Theresultsshowthattheclin-kermeltunderrapidburningmaycomeintoexis-tenceatlowertemperatureandIt’sviscosityislower.Sotheformingprocessesofclinkermaybedifferentatrapidburningfromordinaryburning.Theyareprobablyanimportantfactortopromotetheformationofclinkerburnedatlowertemperaturewithrapidburningmethod.

简介：VolcanicrocksinseamountsoftheSouthChinaSeaconsistmainlyofalkalibasalt,tholeiiticbasalt,trachyandesiticpumice,dacite,etc.Inclusionsinthemineralsofthevolcanicrocksaremain-lyamorphorsmeltinclusions,whichreflectsthatthevolcanicrocksarecharacterizedbysubmarineeruptionandrapidcoolingontheseafloor.Furthermore,fluid-meltinclusionshavebeendiscoveredforthefirsttimeinalkalibasaltsandmantle-derivedxenoliths,indicatingaprocessofdifferentiationbetweenmagmaandfluidinthecourseofmantlepartialmelting.Alkalibasaltsandinclusionsmayhavebeenformedinthisnonhomogeneoussystem.Rock-formingtemperaturesoffourseamounsestimatedasfollows:theZhongnanseamountalkalibasalt1155-1185℃;theXianbeiseamountalkalibasalt960-1200℃;tholeiiticbasalt1040-1230℃;theDaimaoseamounttholeiiticbasalt1245-1280℃;andtheJianfengseamounttrachandesticprmice880-1140℃.EquilibriumpressuresofalkalibasaltsintheZhongnanandXianbeiseamountsare13.57and8.8×10^8Pa,respectively.Pyroxeneequilibriumtem-peraturesofmantlexenolithsfromtheXianbeiseamountwereestimatedat1073-1121℃,andpres-suresar(15.58-22.47)×10^8Pa,suggestingadeep-source(e.g.theasthenosphere)forthealkalibasalts.

简介：Numericalsimulationconcerningtheformingandweldingprocessofspiralweldedpipewasconducted,whichincludedthreesteps:thefirststepwasthestressanalysiswhenthespiralwasformed,andthenthestresswasregardedasinitialconditionofmeldingduringthetemperaturefieldanalysisintheprocessofwelding,thelaststepwasthethermalstressanalysisoftheweldseamaftertheweldingwasover.Moreover,whenthesteelstripwaspushed,thestresswasalsocalculatedbynon-linearitycontacttechnologyusingAbaqusSoftware.Byfiniteelementmodelingandcalculatingoftheformingandweldingprocessofthespiralweldedpipe,thekeypointsofthemulti-fieldssyntheticsimulatingwerestudiedanddiscussed.

简介：TheclucidationofconditionsoffVrmationofthelarge-scalemineraldepositsattractsattentionofanumberofresearchersdealingwiththedepositsofvariousgeneticgroupsformedinvariousgcodynamicenvironments’Suchsupcrlargedcpositsarewellknownamongthewidelysprcadgroupofhydrotber-maldepositsassociatcdwiththcstructurcsof

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简介：Lichensplayanunparalleledlyvitalroleinweatheringandsoil-formingprocessesinAntarcticregion,InthisstudysomerelatedchemicalcomponentsandmicromorphologicalanalyseshavebeencarriedoutonthesamplesoftheweatheredrocksandthelichensgrownonthemfromFilesPeninsula,Antarctic,Theresultsindicatiedthatthemajorchemicalcomponentsinthebioweatheringsurfacelayerofthesampledrockshavebeenobviouslyalteredandtheweatheringpotentialinthislayerhasgreatlydecreasedbyandaveragerangearound4.66percentin4samples,Intheweatheringsurfacelayerferruginiztionofsomemineralsinvaryingdegresswasseenbymeansofmicroscopicexaminationthroughthethinsectionoftheweatheredrocks,anditsproductsprovedtobedominatedbyhematitie,limonite,goethiteandfreeironoxidesMeanwhile,thestudysuggestedthatthedissolutionandabsorptionoflichensbytheirsecretionacceleratedtheprocessofcalcitizationofmineralsinthebio-weatheringsufacelayer,Eventually,theresultsalsoshowthatdifferentspeciesoflichensplaydifferentrolesinweatheringandsoil-formingproesses.

简介：Sprayformingisanewtypeofmetalmaterialformingprocess,whichcanproducemetalblankssuchasbillet,tube,plateetc.Amathematicalmodelhasbeendevelopedtoforecasttheshapeevolutionoftubebilletsduringthesprayformingprocess.Theatomizermassfluxas,radialdistributioncoefficientbs,drawvelocityanddiameterofmandrelwereconsideredinthismodelandtheinfluenceofdifferentparameterssuchasmetalflowrate,drawvelocityofmandrel,diameterofmandrelonthetube'sshapechangeweresimulatedandanalyzedinthispaper.Thesimulationresultsobtainedfromthismodelcanbeprovidedtoengineersasreference.

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简介：TakingTi-6Al-4Vspecimensintoconsideration,thecoupledthermal-electricalfiniteelementmodelhasbeendevelopedinAbaqus/ExplicittosimulatetheheatingprocessinGleeble3800andtostudythetemperaturehistoryanddistributioninthespecimen.Inordertoverifythefiniteelement(FE)results,thermaltestsarecarriedoutonGleeble3800foraTi-6Al-4Vspecimenwithaslottointhecentreofthespecimen.Theeffectsofthespecimensize,heatingrate,andairconvectiononthetemperaturedistributionoverthespecimenhavebeeninvestigated.Theconclusionscanbedrawnas:thetemperaturegradientofthespecimendecreasesasthespecimensize,heatingrate,andvacuumingdecrease.