3Ddesignandanalysisofthecrushingrollerofahigh-pressuregrindingrollerH.Gaoa,*,L.G.QubaSchoolofMechanicalEngineeringandAutomation,NortheasternUniversity,ShenYang110004,PRChinabDepartmentofMechanicalEngineering,ShenYangInstituteofAeronauticalEngineering,ShenYang110034,PRChinaAbstractThecrushingrollerisoneofthemainpartsofahigh-pressuregrindingroller,whichisatypeofhighlyefficientorecrushingequipment.Intheworkreportedinthispaper,akindofassembledroller,whichismoreconvenientintherenovationofwornsurfacebysimplyreplacingthesegmentedsurfaceoftheroller,wasdeveloped.Thestructuralmodelsoftheassembledrollerscomponentsweredesignedwithsolidworkssoftware,andthestressanddisplacementofthemainshaftandsurfacesegmentsintwodifferentworkingstateswereanalyzedquicklyusingCOSMOS/Workssoftware.Furthermore,anoptimumclearanceof1.02.0mmbetweentheconcaveconvexstuddedsegmentsisdeterminedtoprolongtheworkinglifeoftheassembledroller.Keywords:High-pressuregrindingroller；3Ddesign；Assembledroller；Finiteelementanalysis1.IntroductionHigh-pressuregrindingroller(HPGR)isatypeofnewhighlyefficientandenergy-savingequipment,whichisappliedtocrushinghardorebasedonthestatichigh-pressureprinciple13.TherolleristhemainworkingpartaccordingtotheHPGRsoperatingprinciple(seeFig.1).Inordertoimprovetheworkinglifeoftherollermuchefforthasbeenmadetoimprovetheanti-abrasionpropertiesoftherollersurface2.Theuseofasegmentedsurfaceoftheroller,whichisconvenientlymaintainedandreplaced,isanothereffectivetrial-and-errorprocess.Inthepaperanewkindofassembledroller,onwhichtungstencarbidecolumnsarestuddedtoimprovetheanti-abrasionofthesurface,hasbeendevelopedwitha3Ddesignmethodandthestrengthoftheshaftandthesegmentsanalyzedwiththefiniteelementmethodtoensureitsreliabilityunderheavyorecrushingconditions.2.3DvirtualassemblydesignofassembledrollerTheassembledrollerdesigniscomposedofamainshaft,surfacesegments,key,asideholdingblock,ascrewcon-nectingbar,andtungstencarbiderivets,etc.Therearesixcouplesofradialkeyholesandscreworientationholesinthemiddleofthemainshaft,and12axialconcavedgrooves,inwhichscrewconnectingbarsareputtofixthemainshaftandsurfacesegmentstightlyandsafelywithsideholdingblocks.Thesurfacesegmentisdesignasaconcavoconvexmatingstructuretopreventstressconcentrationatthematingedges.Thecomponentsmodelsarecreatedthroughsolidworks,whichisakindofcurrentlyapplied3Ddesignsoftware.Thebuiltmodelscanbeuseddirectlyforfiniteelementanalysisbywhichthedesignrationalityisensured.Theassembledmodelisthenorganizedwiththeassemblepatternofdowntotop,accordingtothematingandtherestraintrelationshipsoftheparts.Finally,theintervenesbetweenthepartsarecheckedwiththesoftwaretotestthevalidityoftheassemblestructure.Figs.2and3showtheflowdiagramofvirtualassemblydesignandthe3Dvirtualmodeloftheassembledmainshaft,respectively.3.Finiteelementanalysisofthemainshaft3.1.SolidandfiniteelementmodelThesolidandforce-loadingmodelofthemainshaftforGM1000C2200HPGRisshowninFig.4,whichiscreatedthrough3DCADsoftwaresolidworks.Therearesixcouplesofradialkeyholesinthemiddleofmainshaftand12axialJournalofMaterialsProcessingTechnology129(2002)649652*Correspondingauthor.Tel.:86-24-83684187；fax:86-24-23906969.E-mailaddress:(H.Gao).concavedgrooves.Thesedetailfeatureswillmakethestrengthanalysismoredifficultwiththetraditionalmethodbutiseasierwiththefiniteelementmethod4.ThusCOS-MOS/Workssoftware,whichisbasedonthefiniteelementprincipleandcantakeinthesolidmodelcreatedbysolidworkswithoutanydisfigurement,waschosentocalculatethestressanddeformationofthemainshaftandsegments,shownlater.FollowingistheprocesstocreatethefiniteelementmodelofthemainshaftwithCOSMOS/Workssoftware:(1)Appendthecharacteristicsofthematerial.Thematerialofthemainshaftis35CrMo,ofwhichtheelasticmodulusEis206MPa,thefrictioncoefficientmis0.3,thedensityris7.9kg/cm3andthelimitationstress(ss)is835MPa.(2)Loadingandrestraint.Theforcesenduredbythemainshaftcomefromthecrushingpressureaccordingtotheoperatingprinciple,itsterminalvalueFmaxbeing2500kN,theloadingareabeingintheformofanarcofangle608and200mmwidthonthesurfaceoftheshaft.Theboundaryconditionisrestrainedbyasupposedbearing.(3)Modelmeshing.Themeshingparametersareasfollow:38026nodes,24117elementsand114079degreeoffreedom(DOF).3.1.1.CalculatedresultsThestressdiagramthatiscalculatedthroughCOSMOS/WorksisshowninFig.5.Themaximumstresssmaxis296MPa,analyzedonVonMisestheory.ItstheoreticalequationissmaxC20ssn(1)wheresmaxisthemaximumstress,ssthelimitationstress,andnisthesafetycoefficient,usually,nis1.52.0.Thecalculatedresultsshowthattheshaftstrengthcansatisfythedesignrequirement.Furthermore,thesafetycoefficientncanachieve2.8accordingtotheVonMisestheory.4.Finiteelementanalysisofthesegment4.1.SolidandfiniteelementmodelThesolidandforce-loadingmodelsintwodifferentworkingstatesareshowninFig.5.ThesegmentisdesignFig.1.Principleofhigh-pressurerollermill.Fig.2.Flowdiagramofvirtualdesign.Fig.3.3Ddesignmodeloftheassembly.Fig.4.Loadingandrestrainofthemainshaft.Fig.5.Loadingandrestraintofasegment.650H.Gao,L.G.Qu/JournalofMaterialsProcessingTechnology129(2002)649652asaconcavoconvexmatingstructure.Alsotherearetra-peziumgroovesonbothofitssides.ThefollowingistheprocesstocreatethefiniteelementmodelofasurfacesegmentwithCOSMOS/Workssoftware:(1)Appendthecharacteristicsofthematerial.Thematerialofthesurfacesegmentis42CrMoV,withanelasticmodulusEof206MPa,theshearmodulusGis79.4MPa,thefrictioncoefficientmis0.3,thedensityris7.9kg/cm3andthelimitingstress(ss)is930MPa.(2)Loadingandrestraint.Twoworkingstatesareassumed.Firstistheidealandrationalstate,showninFig.5(a),forwhichtheloadingisFr2500,Ft10:56kN,theloadingareaisof200mmwidthand13mmarclengthonthesurfaceofsegment,andthefixedinternalsurfacebecomesitsrestraintcondi-tion.AnotherstateisshowninFig.5(b)inwhichonlytwoendsofthesegmentbottomarecontactedbytheshaftbecauseofanincorrectmanufacturingprocessorassembly.Forthisconditiontheforceenduredbythetwoendsisequal.Consequently,theothersurfaceandtheconcavogroovesarerestrained.(3)Modelmeshing.Themeshingparametersinthetwodifferentstatesarethesamebecauseofthesamesolidmodel,andtheyare:15367nodes,9792elementsand46101DOF.4.2.Calculatingresults(1)ThecalculationresultsareshowninFig.6.Accordingtothediagramin(a),themaximumnode(the8354th)stressis860MPaonthesurfaceofthesegmentinthefirstworkingstate；andthemaximumnode(the8295th)displacementis0.2mm.Inthesecondworkingstate,themaximumnode(the15361st)stressis5495MPa；andthemaximumnode(the417th)displacementis0.78mm.Therefore,thefirstworkingstateisrational,whilstincontrast,thestressofthesegmentinsecondstateexceedsthelimitingrange.(2)Accordingtothecalculations,thesegmentonlyendurestheworkingloadinginfirststateandthematingsegmentsdonotactoneachother,whileinthesecondstate,notonlydoesthesegmentendurestheworkingpressure,butalsoitenduresthestressfrommatingsegmentssynchronouslybecauseofitsdefor-mation.Thegreateristhestressandthedeformationbetweensegmentsandsideconnectingblocks,thelargeristhestressinthesegment.Thereforetheelasticdeformationandextensionofthematerialshouldbeconsideredinthesegmentdesign.Thematingclear-ancebetweenmatingsegmentsshouldbesuitable.Theoptimizedclearanceof1.02.0mmhasbeencalculatedwiththefiniteelementmethod.(3)Enoughstrengthandhighersurfacehardnessofthesegmentbasebodyarenecessary,orplasticdeforma-tionofthebodywilloccurandthecarbiderivetswillbepressedintothesegmentbodyundertheheavycrushingforce.Asanexample,steel45(ss300MPa)ischosentoexamineitsdeformationunderheavycrushingforceinthefirstworkingstate.ThecalculationresultisshowninFig.7.Itsmaximumstressis749MPa,andthesafetycoefficientis0.4,whichisbeyondthesafetylimitationofthematerialaccordingtoVonMisestheory.Heattreatedmaterialof42CrMoVwithHB240280hardnesshasmorethanthreetimesthestrengthcomparedwithsteel45.Thusitcanbechosentoproducethesurfacesegment.Inordertoimprovetheanti-abrasionabilityoftheroller,tungstencarbidecolumnsoff1020diameter,whichhavehardnessofHRC8593,arestuddedonthesegmentsurface.Anegativematingclearanceof0.040.08mmisnecessarytomakethecolumnsmatetightandfirmly7.5.Conclusions(1)AnewkindofassembledrollerforaGM1000C2200typeHPGR,inwhichtheworkingsurfaceiscomposedFig.6.Calculatedstressofasegment.Fig.7.Dangerouszoneofthesegment.H.Gao,L.G.Qu/JournalofMaterialsProcessingTechnology129(2002)649652651ofseveralsegments,hasbeendevelopedwith3DCADsoftwaresolidworks.Thiskindofsegmentedstructurecanmaketheworkinglifeoftherollerlongerandenablethewornsurfaceoftherollertobereplacedeasily.Thestressandthedeformationofthetwomainpartsoftheassembledroller:themainshaftandthesurfacesegment,havebeenanalyzedwit