直线式振动筛横梁结构分析及优化改进

直线式振动筛横梁结构分析及优化改进

Abstract

Linearvibratingscreeniswidelyusedinindustriessuchasmining,

coal,metallurgy,buildingmaterials,andchemicals,butitsstructurecan

beimprovedforbetterperformance.Inthispaper,thestructural

analysisandoptimizationofthecrossbeamofthelinearvibrating

screenarestudied.Thefiniteelementmethodisusedtoanalyzethe

stressanddisplacementdistributionofthecrossbeam,andaseriesof

improvementsareproposed,includingchangingthecross-sectionshape,

increasingthestiffnessofthecrossbeam,andadjustingthepositionof

thebolts.Theoptimizeddesignimprovesthestructuralreliabilityand

reducesthefailurerateofthelinearvibratingscreen,whichhas

importantpracticalsignificance.

Introduction

Linearvibratingscreenisacommonlyusedscreeningequipment,

whichmainlyreliesonthevibrationmotortogeneratevibrationforce,

andthematerialonthescreensurfaceissubjectedtovibrationto

achievescreening.Intheprocessofusingthelinearvibratingscreen,

someproblemsareoftenencountered,suchasexcessivenoise,

unstableoperation,andfrequentfailureofcomponents.Amongthem,

thecrossbeamofthelinearvibratingscreenplaysanimportantrolein

supportingthescreenboxandtransmittingthevibrationforce.Dueto

thecomplexworkingconditionsandhighstress,thecrossbeamisprone

tofatiguefailure,whichseriouslyaffectsthescreeningefficiencyand

servicelifeoftheequipment.

Therefore,itisnecessarytocarryoutstructuralanalysisand

optimizationofthecrossbeamofthelinearvibratingscreen,inorderto

improveitsreliabilityandreducethefailurerate.Inthispaper,the

theoreticalcalculationandfiniteelementanalysismethodareusedto

analyzethestressanddisplacementdistributionofthecrossbeam,and

aseriesofimprovementsareproposed,includingchangingthecross­

sectionshape,increasingthestiffnessofthecrossbeam,andadjusting

thepositionofthebolts.

StructuralAnalysis

Thecrossbeamofthelinearvibratingscreenisusuallymadeof

twoparallelplatesandseveralribs,whichareconnectedbyboltsand

weldedtothescreenbox.Figure1showstheschematicdiagramofthe

crossbeamstructure.

Figure1.Schematicdiagramofthecrossbeamstructure.

Assumingthatthecrossbeamisfixedatbothendsandsubjected

totheloadofthescreenboxandthevibrationforceofthemotor,the

stressanddisplacementdistributionofthecrossbeamcanbecalculated

bytheoreticalanalysisandfiniteelementmethod.

Accordingtothebeamtheory,thebendingstressofthe

crossbeamcanbeexpressedas:

ob=M*y/I(1)

whereobisthebendingstress,Misthebendingmoment,yisthe

distancefromtheneutralaxistothepointinquestion,andIisthe

secondmomentofarea.Thebendingmomentcanbecalculatedby:

M=q*LA2/8(2)

whereqisthedistributedload,Listhelengthofthecrossbeam.

Thedeflectionofthecrossbeamcanbecalculatedby:

5=5*q*LA4/(384*E*I)(3)

whereEistheelasticmodulus.

Basedontheaboveequations,thestressanddisplacement

distributionofthecrossbeamcanbeobtainedforthegivenparameters.

However,inpracticalapplications,theparameterssuchastheload,the

stiffnessofthematerial,andtheconnectionmethodareoftenuncertain,

soitisdifficulttoaccuratelypredictthestressanddisplacementofthe

crossbeambytheoreticalanalysisalone.Therefore,thefiniteelement

methodisusedtosimulatetheworkingconditionsandanalyzethe

stressanddisplacementdistributionofthecrossbeam.

Thefiniteelementmodelofthecrossbeamisestablishedbyusing

theANSYSsoftware,asshowninFigure2,Thematerialpropertiesare

settobeconsistentwiththeactualsituation.Theloadisappliedtothe

nodeswheretheboltsareconnected,andtheboundaryconditionsare

settosimulateacantileverbeam.

Figure2.Finiteelementmodelofthecrossbeam.

Thestressanddisplacementdistributionofthecrossbeamunder

theworkingconditionscanbeobtainedbysolvingthefiniteelement

model,andtheresultsareshowninFigure3.

Figure3.Stressanddisplacementdistributionofthecrossbeam.

FromFigure3,itcanbeseenthatthemaximumstressofthe

crossbeamisconcentratedattheconnectionbetweentheplateandthe

rib,andthemaximumdisplacementislocatedinthemiddleofthe

crossbeam.Theactualstressanddisplacementvaluescanbecalculated

byreferringtothenumericalresultsofthefiniteelementanalysis.

OptimizationImprovement

Basedonthestructuralanalysisofthecrossbeam,several

improvementsareproposedtooptimizethedesignandimprovethe

structuralreliabilityofthelinearvibratingscreen.

1.Changingthecross-sectionshape

Thecross-sectionshapeofthecrossbeamhasasignificanteffect

onitsstiffnessandstressdistribution.Intheoriginaldesign,the

crossbeamisrectangularinshape,whichisnotconducivetothe

uniformdistributionofstress.Therefore,atrapezoidalcross-sectionis

proposedtoimprovethestressdistributionandincreasethestiffnessof

thecrossbeam.

Figure4.Comparisonofthestressdistributionofdifferentcross­

sectionshapes.

AsshowninFigure4,thestressdistributionofthetrapezoidal

cross-sectionismoreuniformthanthatoftherectangularcross-section,

andthemaximumstressvalueisreducedbyabout20%.Inaddition,

thetorsionalstiffnessofthetrapezoidalcross-sectionishigherthanthat

oftherectangularcross-section,whichcanreducethedeformationof

thecrossbeam.

2.Increasingthestiffnessofthecrossbeam

Thestiffnessofthecrossbeamisalsoanimportantfactoraffecting

theperformanceofthelinearvibratingscreen.Intheoriginaldesign,

thecrossbeamiscomposedoftwoparallelplatesandseveralribs,

whichresultsinlowstiffnessandpoorresistancetodeformation.

Therefore,anewstructureconsistingofabox-shapedcrossbeamand

diagonalribsisproposedtoincreasethestiffnessandreducethe

deformation.

Figure5.Comparisonofthedeformationofdifferentcrossbeam

structures.

AsshowninFigure5Zthebox-shapedcrossbeamanddiagonalribs

caneffectivelyimprovethestiffnessofthecrossbeamandreducethe

deformation.Thecalculationresultsshowthatthedeformationofthe

improvedcrossbeamisreducedbyabout50%comparedwiththe

originaldesign.

3.Adjustingthepositionofthebolts

Theconnectionmethodofthecrossbeamandthescreenboxis

alsoanimportantfactoraffectingthestressdistribution.Intheoriginal

design,theboltsarearrangedinastraightlinealongthecrossbeam,

whichresultsinunevenstressdistributionandeasyfatiguefailure.

Therefore,anewboltarrangementisproposedtoincreasethenumber

ofboltsandadjustthepositionoftheboltstoreducethestress

concentration.

Figure6.Comparisonofthestressdistributionofdifferentbolt

arrangements.

AsshowninFigure6,thenewboltarrangementcaneffectively

reducethestressconcentrationandimprovethestressdistribution.The

maximumstressvalueisreducedbyabout30%compared