involving网易yeah
网易yeah 时间:2021-02-16 阅读:(
)
APFIS2017-6thAsia-PacificConferenceonFRPinStructuresSingapore,19-21stJuly20171HaiFang,HuiyuanShi,WeiqingLiu,YujunQi,andRuiliHuoENHANCEMENTEFFECTANALYSISOFLATTICE-WEBSTOGFRP-WOODSANDWICHBEAMSINFLATWISEANDSIDEWISEBENDINGHaiFang1*,HuiyuanShi2,WeiqingLiu3,YujunQi4,RuiliHuo51Correspondingauthor,CollegeofCivilEngineering,NanjingTechUniversity,Nanjing,ChinaEmail:fanghainjut@njtech.
edu.
cn,WebPage:http://cce.
njtech.
edu.
cn/view.
aspid=527&class=2212SchoolofCivilEngineering,SoutheastUniversity,Nanjing,ChinaEmail:hyshiseu@yeah.
net3AdvancedEngineeringCompositesResearchCenter,NanjingTechUniversity,Nanjing,ChinaEmail:wqliu@njtech.
edu.
cn,WebPage:http://cce.
njtech.
edu.
cn/view.
aspid=485&class=2404CollegeofCivilEngineering,NanjingTechUniversity,Nanjing,ChinaEmail:qiyujun11@163.
com,WebPage:http://cce.
njtech.
edu.
cn/view.
aspid=1385&class=2215CollegeofCivilEngineering,NanjingTechUniversity,Nanjing,ChinaEmail:ruilihuo@njtech.
edu.
cnKeywords:GFRP-woodsandwichbeams,lattice-webreinforced,flexural,flatwise,sidewiseAbstractThispaperinvestigatestheflexuralbehaviorinflatwiseandsidewisepositionsofnovelgenerationcompositesandwichbeamswithPaulowniaandsouthernpinewoodcoreandglass-fiberreinforcedpolymer(GFRP)facesheetandlattice-webs.
Avacuumassistedresininfusionprocess(VARI)wasemployedtoformsandwichbeamswithdifferentnumbersofwebs.
Twocontrolwoodenbeamsandeighteenlattice-webreinforcedsandwichbeamsweresubjectedtofour-pointbendingteststodeterminetheirstiffness,capacity,andfailuremechanismsintheflatwiseandsidewisepositions.
Theexperimentalresultsrevealedthatthecompositesandwichbeamsfailedinflatwisebendingtestsunderlowerloadbutproducedagreaterdeflectioncomparedtothebeamsinsidewisebendingtests.
Withtheincreaseinthenumberoflattice-webs,ductilitywasfoundtoincreaseinflatwisepositionswhiledecreasinginsidewisepositions.
Analyticalformulasforcalculatingthebendingstiffness,capacity,andductilityoftheGFRP-woodsandwichbeamswereprovided,andtheanalysisresultsformechanicalperformanceshowedgoodagreementwiththeexperimentalresults.
1.
IntroductionComparedtotraditionalconstructionmaterials,themainbenefitsofGFRPcompositematerialinstructuralcomponentsareitshighstrength,excellentcorrosionresistance,easeofhandingandapplication,andflexibilityofdesign[1].
Inthispaperwepresentanewgenerationofcompositesandwichbeamsintendedforuseasloading-bearingcomponents.
Thecompositesandwichisintegrallyformedinthemoldbyavacuum-assistedresininfusionprocessinvolvingcompositeface-skins,webs,andcorematerials,asshowninFigure1.
Onenovelfeatureisthebundlingofthecorematerials,mainlycharacterizedbyhighstrength,intoinbothwebs.
Thesandwichbeams,thatclearlyenhancetheantistrippingandcooperativeperformancebetweensurfacelayerandcore,areconstructedbycloselywrappingwoodcorematerialstogetherusinglattice-websandface-skinsthatcangivefullplaytothepropertiesofthebendingandshearcapacityofthesandwichbeams.
Whenthesurfacelayerofthecompositesandwichbeamisundernormalload,themainfunctionofthewoodcoreistoimproveshapingandbearingandtoprovideelasticsupportsforthesandwichbeams.
Thecompositesandwichbeamavoidstheoccurrenceoflocalbucklinganddebonding,becausethecorematerialimprovesthedistributionofsectionstress,APFIS2017-6thAsia-PacificConferenceonFRPinStructuresSingapore,19-21stJuly20172HaiFang,HuiyuanShi,WeiqingLiu,YujunQi,andRuiliHuoeffectivelyreducingthestressconcentrationattheintersectionofthesurfacelayerandlattice-webs,significantlydelayingsplittingfailure.
Meanwhile,theGFRPlattice-webscaneffectivelyincreasethecapacityofshear,compression,andstripping,bothintheflatwise(horizontal)orinthesidewise(vertical)position.
Inthispaper,theultimatefailuremechanisms,initialbendingstiffness,load-deflectionbehaviorandstress-strainbehaviorofGFRP-woodsandwichbeamsunderfour-pointstaticbendingintheflatwiseandsidewisepositionsarereportedanddiscussed.
Thetheoreticaloutcomesforthestiffnessandstrengthofthecompositesandwichbeamsarealsopredictedandcomparedwiththeexperimentalresults.
(a)(b)(c)Figure1.
Lattice-webreinforcedcompositesandwichbeams(a)flatwise,(b)sidewise,and(c)cross-sectionalviewofrealobject.
2.
ExperimentalProgram2.
1.
TestSpecimensandMaterialsThestructuralsandwichbeamstestedinthisstudywereemployedusingGFRPskinsandlattice-webscomposedofbi-axial[0/90]glassfiberlaminates(800g/m2)andHS-2101-G100unsaturatedpolyesterresintowrapthecorematerialstogether.
High-classPaulowniaorsouthernpinewood,weighing280kg/m3and500kg/m3respectively,werefilledascorematerialsinthesespecimens.
Theoveralldensityofthecompositesandwichbeamswasmuchlessthanthatofconcreteandsteel,withdensitiesof2400kg/m3and7850kg/m3respectively.
Table1summariestheultimatestrengthandYoung'smodulusoftheGFRPface-skins,lattice-webs,andcorematerials.
Table1.
Effectivemechanicalpropertiesoftheglassfiberskinsandcorematerials.
PropertiesSkinsandwebsPaulowniawoodSouthernpinewoodCompressionUltimatestrength(MPa)223.
7426.
5332.
76Young'smodulus(GPa)16.
011.
863.
57TensionUltimatestrength(MPa)305.
00——Young'smodulus(GPa)20.
95——ShearUltimatestrength(MPa)16.
273.
346.
55Young'smodulus(GPa)7.
680.
420.
68Twentysandwichbeamswithidenticaldimensions(1400mm*120mm*120mm),including2woodenbeams,2compositesandwichbeamswithoutlattice-webs,and16sandwichbeamswithlattice-webs,werefabricatedandmanufacturedintheAdvancedCompositeStructuresResearchInstituteatNanjingTechUniversity.
DetailsofeachspecimenaresummarizedinTable2.
Horizontallattice-websVerticallattice-websAPFIS2017-6thAsia-PacificConferenceonFRPinStructuresSingapore,19-21stJuly20173HaiFang,HuiyuanShi,WeiqingLiu,YujunQi,andRuiliHuoTable2.
Descriptionofspecimens.
SpecimensSizeofspecimenSizeofcoreOrientationoftestingl(mm)B(mm)H(mm)b(mm)h(mm)PA/SP-CON-F/S1400120120120120FlatwiseandsidewisePA/SP-0-F/S1400120120110110FlatwiseandsidewisePA/SP-1-F140012012011053.
0FlatwisePA/SP-2-F140012012011034.
0FlatwisePA/SP-3-F140012012011024.
5FlatwisePA/SP-4-F140012012011018.
8FlatwisePA/SP-1-S140012012053.
0110SidewisePA/SP-2-S140012012034.
0110SidewisePA/SP-3-S140012012024.
5110SidewisePA/SP-4-S140012012018.
8110Sidewise2.
2.
TestSet-upandInstrumentationThespecimenswereloadedunderstaticfour-pointbendinginaccordancewiththeASTMC393standard[2]byauniversaltestingmachine.
Theloadingexperimentalsetupemployedinthetestswassimplysupportedandthenetspanwas1200mmbetweenthetworollersupports.
Averticalmonotonicloadingwassetbya300kNcapacityhydraulicjack,whichwasequallysplituptotwocentralpointsonthespecimensbyasteeltransferbeamandmovedataloadingrateof2mm/min,asshowninFigure2.
Duringtesting,straincollectionwasperformedbyaDH3816staticstraintestsystem.
TheverticaldisplacementwasmeasuredbyaLVDT(linearvariabledeflectiontransducer)arrangedatthebottomofmid-spanandthetopofsupport.
Twolongitudinalstraingaugestoobservetherelationoftheloadandthestrainoftheface-skinwereattachedtothetopandbottomface-skinsofthemid-span.
Figure2.
Experimentalsetupofflexuralbehaviorofthebeam:(a)pictureofflexuraltestsetup,(b)schematicplot,and(c)straingaugearrangement.
3.
ExperimentalResultsandDiscussionControlspecimensPA-CON-F/SandSP-CON-F/Sfailedinabrittlemanner,asshowninFigure3a.
Theappearanceofsheartensilecrackswasfirstobserved.
Owingtothemaximumshearstrainofthewoodexceedsitscrushingstrain,thesecracks,thatsuddenlyproducedaloudnoise,rapidlyextendedupwardandcausedimmediatefailurewiththeincreaseofslowloadandquickdeflection.
InthecompositesandwichspecimensPA-0-F/SandSP-0-F/S,withoutlatticewebs,brittlefailuredidnotoccurbecausethefibercompositeexternalskinsonthetensilefaceofthespecimensbridgedthecrackedcorecomponentstogethertopreventfailure.
Whenthemaximumcompressivestrainoftheexternalsurfaceexceededitscompressivestrain,toplocalindentationoccurredaswellascompressivecracksonthelateralface-skin,asshowninFigure3b.
Specimenswith1,2,3,and4websintheAPFIS2017-6thAsia-PacificConferenceonFRPinStructuresSingapore,19-21stJuly20174HaiFang,HuiyuanShi,WeiqingLiu,YujunQi,andRuiliHuoflatwisepositionsmainlyfailedbycrushingofthefibercompositeskinsattheloadingpointfollowedbytheoccurrenceofsplittingofthebottomglassfibercausedbyalargedeformationatthebottomofthebeam,asshowninFigure3c.
Compressivewrinklingwasobservedinthesidewisepositions,asshowninFigure3d,andcontinuousapplicationofloadcausedcrackspreadingextendingfromtheuppermosttotheundersection,followedbycompressivefailure.
(a)(b)(c)(d)Figure3.
FailuremodesofGFRP-woodsandwichbeams.
Fromtheexperimentaldataitcanbeseenthattheload-deflectionbehaviorofthespecimenschangesfromlineartononlinearwiththeincreaseinappliedload.
AsshowninFigure4aand4b,whenthecoreisPaulownia,theultimatebendingstrengthofspecimensPA-(1~4)-SisbasicallygreaterthanthatofspecimensPA-(1~4)-F,amongwhichPA-3isthemostobvious.
ThesetrendsinFigure4cand4dcanalsobefoundwithsouthernpinecore.
Meanwhile,theultimatebearingcapacityofthebeamswithsouthernpinewoodisslighterhigherthanthatofbeamswithPaulownia.
Itcanbeconcludedthattheuseofverticalwebsandtheapplicationofhigh-strengthcorematerialwillobtaingreaterbendingstiffnessofthebeam.
(a)(b)(c)(d)Figure4.
Load-deflectioncurvesforsandwichbeam.
4.
ConclusionsInvestigationoftheflexuralbehaviorofinnovativecompositesandwichbeamsreinforcedbylattice-websunderfour-pointstaticbendingtestintheflatwiseandsidewisepositionswasundertakenexperimentallyinthispaper.
WiththisstudyoftheseGFRPsandwichbeams,onegoalistomaximallyincreasethevalueofthesespecimens;theothergoalistoseekastructuretosubstitutefortraditionalbeamsthatwereeasilysubjecttobrittlefailureanddelamination.
Itwasfoundthat,toimprovethecapacityofstiffness,strength,andmonolithicstability,settingupappropriatelaminationandorientationofthelatticewebsforthesandwichbeamsisnecessary.
TheapplicationoffiberinsertionswasfoundtobeviableinthereinforcementandrecoveryofGFRP-woodbeams.
Thistechniqueisnotonlyeasybutalsoconfersgreaterstrengthandstiffnessofreinforcedstructuralelements.
Italsorendersthesystemmorereliable,reducingthepossibilityoftensilefailurecausedbydefects.
APFIS2017-6thAsia-PacificConferenceonFRPinStructuresSingapore,19-21stJuly20175HaiFang,HuiyuanShi,WeiqingLiu,YujunQi,andRuiliHuoAcknowledgmentsTheresearchdescribedherewassupportedbytheNationalNaturalScienceFoundationofChina(GrantNo.
51578285)andfundedbythePriorityAcademicProgramDevelopmentofJiangsuHigherEducationInstitutionsPAPD(GrantNo.
CE02-1-11).
References[1]ZamanA,GutubSA,WafaMA.
AreviewonFRPcompositesapplicationsanddurabilityconcernsintheconstructionsector.
JReinfPlastCompos,2013,32(24):1966-1988.
[2]ASTMC393/C393M-16,Standardtestmethodforcoreshearpropertiesofsandwichconstructionsbybeamflexure,ASTMInternational,WestConshohocken,PA,2016.
最近主机参考拿到了一台恒创科技的美国VPS云服务器测试机器,那具体恒创科技美国云服务器性能到底怎么样呢?主机参考进行了一番VPS测评,大家可以参考一下,总体来说还是非常不错的,是值得购买的。非常适用于稳定建站业务需求。恒创科技服务器怎么样?恒创科技服务器好不好?henghost怎么样?henghost值不值得购买?SonderCloud服务器好不好?恒创科技henghost值不值得购买?恒创科技是...
硅云怎么样?硅云是一家专业的云服务商,硅云的主营产品包括域名和服务器,其中香港云服务器、香港云虚拟主机是非常受欢迎的产品。硅云香港可用区接入了中国电信CN2 GIA、中国联通直连、中国移动直连、HGC、NTT、COGENT、PCCW在内的数十家优质的全球顶级运营商,是为数不多的多线香港云服务商之一。目前,硅云香港云服务器,CN2+BGP线路,1核1G香港云主机仅188元/年起,域名无需备案,支持个...
已经有一段时间没有分享阿里云服务商的促销活动,主要原因在于他们以前的促销都仅限新用户,而且我们大部分人都已经有过账户基本上促销活动和我们无缘。即便老用户可选新产品购买,也是比较配置较高的,所以就懒得分享。这不看到有阿里云金秋活动,有不错的促销活动可以允许产品新购。即便我们是老用户,但是比如你没有购买过他们轻量服务器,也是可以享受优惠活动的。这次轻量服务器在金秋活动中力度折扣比较大,2G5M配置年付...
网易yeah为你推荐
操作http大学生创新实验计划sns平台社交网站是啥意思?http500http 500是什么意思?重庆杨家坪猪肉摊主杀人重庆九龙坡区治安好么www.topit.mehttp://www.topit.me/ 中自己上传的照片如何删除台北市cuteftp小型汽车网上自主编号申请成都新车上牌办理流程和办理条件是如何的curl扩展如何增加mysqli扩展zhuo爱timi什么意思
怎么注册域名 欧洲欧洲vps 汉邦高科域名申请 google电话 gitcafe 美国php主机 admit的用法 微软服务器操作系统 免费网页空间 电信托管 路由跟踪 工信部网站备案查询 域名转入 登陆qq空间 免费网络空间 带宽测试 九零网络 美国主机侦探 塔式服务器 泥瓦工 更多