材料导论课后习题七章

Module7 7-1Understandthefollowingterms:(a)composites;(b)nanocomposites;(纳米复合材料）(c)environmentalcomposites.（环保复合材料） (a)ausefulcomplexsolidmaterialcomposedoftwoormorematerialsthatarecombinedonamacroscopicscale（宏观尺寸）byphysicalmeansanddonotlosetheiridentity（特性）. (b)anewsubset(子集)ofCMC,MMCorPMC,arecompositeswithasubstrate（基板）thatisreinforced（加强）withnanometersizeparticles（微粒）thatenhance（提高）thesubstrates’physicalproperties. (c)acompositeconsistingof80%advancedpolymerand20%aluminum,developedforautomotiveapplication，andeasilyrecycledandaremadeusinglowenergyandacleanmanufacturing（制造）system. 7-5WhatdotheabbreviationsCMC,PMCandMMCstandfor,respectively? MMC:Metallicmatrixcomposites金属基复合材料 PMC:Polymermatrixcomposites聚合物基复合材料 CMC:Ceramicmatrixcomposites陶瓷基复合材料 7-6Definethefollowingterms:(a)fiber-reinforcedcomposite;(b)fiber;(c)whisker（晶须）;(d)continuousfiber(连续纤维);(e)discontinuousfiber（间断纤维）;(f)criticallengthofafiber（纤维临界长度） (a)amaterialssystemmadeprimarilyofvarying（不同）amountsofaparticularfiberreinforcementembedded（嵌入）inaprotectivematerialcalledamatrix;acouplingagentisappliedtothefibertoimprovetheadhesionofthefibertothematrixmaterial. (b)thebasicindividualfilament(个别纤维)ofrawmaterialfromwhichthreadsorfabrics(线程或面料)aremade. (c)areformedfromextremelythinsinglecrystals(单晶)ofhighperfection(完善)withalargelength-to-diameterratioforreinforcingcompositematerials. (d)areessentially（基本上）infinite（无限）inlengthandextendcontinuouslythroughoutthematrixinacompositematerial. (e)arenotlessthan3mminlengthandtendtoorient（方向）themselvesinthedirectionofresinflowasacompositematerialisprocessed. (f)Thelengthlimitforafibertohaveaload-carryingandreinforcingabilities(P332) 7-8Listthefunctionsofamatrixandacouplingagentinacomposite. Thefunctionsofamatrixaretosupportandprotectthefibers,theprincipalload-carryingagent（传递受力）,andtoprovideameansofdistributingtheloadamongandbetweenthefiberswithoutitselffracturing.基体未破坏可分散均匀受力 Acouplingagentprovidesaflexiblelayer（层）attheinterface（界面）betweenfiberandmatrixthatwillimprovetheiradhesionandreducethenumberofvoidstrappedin（空隙被困在）thematerial.7-12Whenspeakingofinterfaceandinterphase,whichtermrepresentsthelargerareaorvolumeinacompositematerial?Recallthedifferencebetweenthetwotermsinterfaceandinterphase.Interphase界面相 Interfaceisasurfacethatformsacommonareaorboundarysimilarinmanyrespectstograinboundariesbetweenanytwoconstituents(成分)inamonolithic(单片)material. Interphasesistheregionformedbetweentwointerfaces.Itisthereforeadistinctphaseinitselfwithitsownidentity(特性),formingaregioncontiguoustotwophases. 7-13Sketchatypicalfiber-reinforcedcompositeandlabelthefollowing:matrix,reinforcingfiber,interface,interphase.P335 Afiber-reinforcedcompositeisamaterialssystemmadeprimarilyofvaryingamountsofaparticularfiberreinforcementembeddedinaprotectivematerialcalledamatrix,acouplingagentisappliedtothefibertoimprovetheadhesionofthefibertothematrixmaterial.7-14Understandthedefinitionsoftheterms:(a)preimpregnation预浸渍;(b)prepreg预浸料;(c)preforms（型坯）;(d)lamina（薄板）;(e)laminate;(f)bulkmoldingcompound(BMCs){块（团）状模塑料};(g)sheetmoldingcompounds(SMCs)（片状模塑料）. (a)Fibercanbesaturatedwithresinousmaterial（纤维饱和树脂）throughaprocesscalledpreimpregnation; (b)Thepreimpregnatedfibersarecalledprepregs; (c)Preformsarecustom-shaped定制成型,resin-bondedmats树脂结合剂垫forreinforcementofmoldedpartswithcomplexshapes.Inotherwords,apreformisabundle纤维束offibershavingthedesiredvolumeandarchitecture量和结构tofillamoldcavity模具型腔foraone-shotmolding注射成型; (d)aflatarrangementofunidirectionalfibersorwovenfibersinamatrix平面布置的单向纤维或无纺布纤维基体; (e)astackoflamina（一叠薄板）withvariousorientations（不同方向ofthedirectionsoftheprincipalmaterials（主体材料）inthelamina; (f)apremixedmaterialofshortfiberspreimpregnatedwithresinandvariousadditives预混材料的短纤维预浸树脂及各种添加剂 (g)sheetmoldingcompoundsareimpregnated,continuoussheetsofcompositematerial.片状模塑料浸渍，复合材料的连续的片 7-16Nametwotypesofglassfiber.Comparethemintermsoftheircompositions,propertiesandapplications.E-glass无碱玻璃纤维S-glass高强玻璃纤维 E-glassiscomposedof55%silica,20%calciumoxide,15%aluminumoxide,and10%boronoxide.Itisthestandardgradeofglassusedinfiberglassandhasatensilestrengthofabout3.45Gpaandhighresistivity.Fiberdiametersrangebetween3and20μm.55％的二氧化硅，氧化钙20％，15％的三氧化二铝，10％氧化硼无碱玻璃纤维组成。它是在玻璃纤维用玻璃的 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等级，并拥有约3.45GPa和高电阻率的拉伸强度。纤维直径介于3至20微米 S-glasswasdevelopedforhigh-tensile-strengthapplicationsintheaerospaceindustry.Itisaboutone-thirdstrongerthanE-glassandiscomposedof65%silicondioxide,25%aluminumoxide,and10%magnesiumoxide.拉伸强度高，在航空航天工业应用开发的S-玻璃。这是约三分之一比E玻璃和二氧化硅65％，25％的三氧化二铝，氧化镁10％组成。7-17Whatisthestructureofaboronfiber?Whatistheproblemwhenboronfibersareusedasreinforcementinanaluminummatrix?Listoneapproachtoovercomethisproblem.课件 Problemswithchemicalreactionsbetweenboronandothermetalscontinuetobeasourceofconcerntomaterialstechnologists. OneapproachtothisproblemwasthecoatingoftheBORSICfiberwithsiliconcarbide,whichprovidesafiberthatismorecompatiblewith（兼容性）metal-matrixmaterials,particularlyathighoperatingtemperatures. 7-18Comparecarbonandgraphitefibersintermsofmodulus,carboncontentandpyrolyzing（裂解）temperature.Whichfibermaterialhasthegreaterspecificmodulus? Carbonfiberusuallyhasamodulusoflessthan344Gpaandacarboncontentbetween80%and95%.Graphitefibershaveamodulusofover344Gpaandacarboncontentof99%orgreater.Forcarbon,thistemperatureisaround1315°C,andforgraphite,itisaround1900°Cto2480°C. Graphite  7-19Listatleasttwoprecursorsusedtoproducecarbonfibers.生产碳纤维的前体好像是SiC(Siliconcarbide)and TiC(Titaniumcarbide)  7-26Whatarethefactorsinfluencingthestrengthofanindividual(单独)fiber? Theabsenceofsurfacedefects;Thepresenceofmicrocracksanywhereinthesmallfibercauseslocalizedstressandloadconcentrationsandeventualfailureoftheindividualfiber.任何地方在小纤维的 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面缺陷的情况下，裂纹的存在导致局部构造应力和负载浓度和个别纤维的最终失败。 7-27Definiethefiber-aspectratio.Howdoesthestrengthofthecompositechangewithincreasingtheratio? Fiber-aspectratioisaratiooflength（L）todiameter（D)Theoptimumreinforcingfiberforacompositematerialhasaratiooflengthtodiameterofabout150.（最佳）Thisratioincreasesthestrengthofthecompositeincreases. 7-28Definethetermsspecifictensilestrengthandspecificstiffness.1. Specifictensilestrength:TheratioofthetensilestrengthofafibermaterialtoitsweighdensityinKN/m3 2.Specificstiffness:Specificstiffness(orspecificmodulus)isaratioofthemodulusofelasticity(ortensileelasticity)totheweightdensityofthefiber. 7-30Whatdoesfiberloadingreferto?Whatistherelationbetweenthestrengthofthecompositesandthefiberloading? Fiberloading（填充量）:theamountofreinforcementinacompositematerial. Thestrengthofthecompositeisdirectlyproportional（按比例）tothevolumeoffiber. 7-32UseequationstoexpresstheROMintermsofmodulusfortheisostrainsituationandtheinverseROMintermsofmodulusfortheisostresssituation.Givetwoassumingconditionsforisostrainloading.举两个isostrain加载的假设条件课件 1:E(C)=E(f)V(f)+E(m)V(m) 2.e(c)=e(f)+e(m)  7-34Listsomefatigue-failurecharacteristicsofFRP. 1.Agradualdecrease（逐渐减少）intheslopeofthestress-straincurveoccursduringcyclicloading. 2.Elevatedtemperatures（高温）normallyreducetheperformanceofmatrix-dominated（基体为主）composites.Fiberfatiguepropertiesarebetterthanthoseofthepolymermatrix. 3.Moistureandchemicalexposure（水分和化学物质影响）cangreatlyaffectthepolymermatrix. 4.Notch（缺口）sensitivityinhigh-cycletensile-fatigueconditionsislessthanformetals. 5.Thereareconsiderablyfewer（相当少）matrix-dominatedpropertiesthanfiber-dominatedproperties.Hence（因此）tensile,compressive（抗压）,andshearstressesintheinterlaminardirection（层间方向）,beingmatrixdominated（基体为主）,shouldbekepttoaminimum（最低限度）. 7-35Whatdoesfracturetoughness（断裂韧性）referto? Inunitsofstresstimesthesquarerootofacracklength,isanindicatorof（指标）amaterial’sresistancetotheextension（延伸）ofapreexisting（先前存在）crack, 7-37Classifythecompositesbasedonmatrixandthegeometry（几何形状）ofreinforcement. Fiber（纤维）,laminated（叠层），sandwich（夹层）,particulate（颗粒）,flake（片状），filled（填补），hybrid（混杂），foam（泡沫）. 7-38WhatdoesGRPstandfor?ListsomeoftheadvantagesandapplicationsofGRPs. GRP:glass-reinforcedplastics玻璃增强塑料 Goodbalanceofproperties;highcorrosionresistance;lowincost;amultitude（大量）ofusesinstructural,industrialandconsumer-relatedproducts;ranginginsizefromminutecircuitboardstoboathulls（船体）可用作fiberand汽车玻璃  7-39Whataretheadvantagesanddisadvantagesofcarbon/carboncomposites?Listsomeapplicationsofcarbon/carboncomposites.  1.Lightweight(density:1.3g/cm3)2.Strongerathightemps.thanatlowtemps.3.Highspecificstrength比强度4.Goodresistancetothermalshock耐热冲击性5.Self-lubricating自润滑6.Electricalproperties7.Limitation:oxidation,limitsthehightemperatureapplications•Solution:SiCcoating{氧化高温使用限制解决 方案 气瓶 现场处置方案 .pdf气瓶 现场处置方案 .doc见习基地管理方案.doc关于群访事件的化解方案建筑工地扬尘治理专项方案下载 SiC涂层}  7-45Whatisalaminarcomposite?Giveseveralexamplesoflaminarcomposites. Laminarcomposite:consistoflayersofatleasttwodifferentsolidmaterialsbondedtogethersothatthefiberorientation（方向）runsatdifferentangles. Cladmetals,safetyglass,graftskin,rigidlaminates.包钢金属，安全玻璃，皮肤移植，刚性层压板  7-47Sandwichcompositesusuallyhavefacingmaterialsandcoresofvariousconfigurations.Pleaselistseveralfacingmaterialsandsomecoreforms. Facingmaterials:面材aluminum,wood,vinyl,paper,glass-reinforcedplastics,andstainlesssteel. Corematerials:芯材cellularinformandtakeontheconfigurationsknowashoneycomb蜂窝状,waffle华夫饼状,corrugated波纹状,tubeandcone管状和锥状. 7-51Whydocarbonblackshavereinforcingeffectwhenusedasinexpensivereinforcingfillersintires? WhenusedforreinforcingfillersItires,carbonblackenhancesthetensilestrength,toughnessandwearresistance.Itsreinforcingeffectonsuchpropertiesistheresultofitsparticularlygoodadhesivebonding.(P367) 7-52Whatisahybridcomposite?Listthefourbasictypesofhybrids. Hybridcomposites:differentfibersinacommonmatrix,greatlyexpandtherangeofpropertiesthatcanbeachievedwithadvancedcomposites. interply层间混杂,intraply层内混杂,interply/intraply层间/层内混杂,superhybrids超混杂   7-59Understandthethreekindsofclosedmoldingmethods:compressingmolding,injectionmolding;resintransfermolding. Compressionmolding模压成型:useTSresinsplacedinacavityofamatchedmoldintheopenposition. Injectionmolding注射模塑:isusedtoformmoltenthermoplasticandthermosettingmatrixinaclosedmold,wheretheyarehelduntilthematerialssolidify. 转移模塑ResinTransfermolding:differsfromRIMinthatareinforcementismoldedwiththeresin,however,theequipmentisbasicallythesame. 7-66Understandthecompositefabrication制作methodofpultrusion拉挤. Acompositefabricationmethodbywhichanextremelylong,fiber-reinforced,polymer-matrixmaterialcanbeproducedbypullingafiberorabundleofcontinuousfilamentsthrougharesinsystemforimpregnationandthenthroughaheatedcuringdie. 附加题1.Howistheorientationoffiberrelatedtofiberloadingandprocessingmethodsofcomposites？1.Maximumloadofabout85%•allfibersplacedparalleltoeachother最大负荷的85％左右•所有纤维平行放置彼此2.Between50and75%loadrange•halfofthefibersarrangedatrightanglestoeachother50至75％负载范围•一半安排在合适的纤维对对方的角度3.Arangeofonly15to50%•arandomarrangement(choppedstrands）一个只有15至50％范围内•随机安排（短切原丝）2.TheabbreviationsandtheChinesenamesofthecommoncomposites，prepregsandmoldingmethodsofcomposites？1.Glassfiber玻璃纤维2.Boronfiber硼纤维3.Carbonandgraphitefiber碳和石墨纤维4.Ceramicfiber陶瓷纤维5.High-performancemanufacturedpolymericfiber高性能合成聚合物纤维Bulkmoldingcompounds(BMCs)块(团)状模塑料Sheetmoldingcompounds(SMCs)片状模塑料 A.Contactmolding,openingmolding,andlaminationmoldingprocesses（接触成型敞口成型，层压成型工艺）：Handlayup（手糊成型）Spray-up（喷射成型）B.Closedmoldingprocesses（闭式模压成型）：Compressionmolding（模压成型）Injectionmolding（注射模塑）Reactioninjectionmolding(RIM)（反应注射成型）{ReinforcedReactionInjectionMolding(RRIM)（增强反应注射成型）StructuralReactionInjectionMolding(SRIM)结构反应注射成型}C.Resintransfermolding(RTM)转移模塑（High-speedresintransfermolding(HSRTM)高速树脂转移成型Flexibleresintransfermolding(FRTM)柔性树脂转移成型Continuousresintransfermolding(CRTM)连续树脂转移成型.Vacuumresintransfermolding(VRTM）真空树脂转移成型）3.Understandthetermsoflaminatesandparticulate(颗粒)composites.Layers(lamina薄层)ofatleasttwodifferentsolidmaterialsbondedtogetherParticulate(颗粒)compositesmaterialscontainreinforcingparticlesofoneormorematerialssuspendedin(悬浮在)amatrixofadifferentmaterials.4.Whatistheprocessingmethodforthecompositepartswithroundoroval（圆形或椭圆）innersurfaces？？？？？？？5.