资源描述：
《7. Polymer Matrix Composites .pdf》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。
1、Chapter7PolymerMatrixCompositesManufacturingTechnologyforAerospaceStructuralMaterialsTheadvantagesofhighperformancecompositesaremany,includinglighterweight;theabilitytotailorlay-upsforoptimumstrengthandstiffness;improvedfatiguestrength;corrosionresistance;andwithgooddesig
2、npractice,reducedassemblycostsduetofewerdetailpartsandfasteners.Thespecificstrength(strength/density)andspecificmodulus(modulus/density)ofhighstrengthfibercomposites,especiallycarbon,arehigherthanothercomparableaerospacemetallicalloys.Thistranslatesintogreaterweightsaving
3、sresultinginimprovedperformance,greaterpayloads,longerrange,andfuelsavings.Acomparisonoftheoverallstructuralefficiencyofcarbon/epoxy,Ti-6Al-4V,and7075-T6aluminumisgiveninFig.7.1.Compositesdonotcorrodeandtheirfatigueresistanceisoutstanding.Corro-sionofaluminumalloysisamajo
4、rcost,andaconstantmaintenanceproblem,forbothcommercialandmilitaryaircraft.Thecorrosionresistanceofcompos-itescanresultinmajorsavingsinsupportabilitycosts.Thesuperiorfatigueresistanceofcomposites,comparedtohighstrengthmetals,isshowninFig.7.2.Aslongasreasonabledesignstrainl
5、evelsareused,fatigueofcarbonfibercompositesshouldnotbeaproblem.Assemblycostsusuallyaccountforabout50%ofthecostofanairframe.Compositesoffertheopportunitytosignificantlyreducetheamountofassemblylaborandfasteners.Detailpartscanbecombinedintoasinglecuredassembly,eitherduringi
6、nitialcureorbysecondarilyadhesivebonding.Disadvantagesofcompositesincludehighrawmaterialcostsandhighfabrica-tionandassemblycosts;compositesareadverselyaffectedbybothtemperatureandmoisture;compositesareweakintheout-of-planedirection,wherethematrixcarriestheprimaryload;comp
7、ositesaresusceptibletoimpactdamage3Carbon/Epoxy(AS/3501-6)Fatigue2StaticTitanium(Ti-6Al-4V)Aluminum(7075-T6)Static1StaticRelativeStructuralEfficiencyFatigueFatigue0Fig.7.1.RelativeStructuralEfficiencyofAircraftMaterials1274PolymerMatrixComposites800700Carbon/Epoxyin.(46%0
8、°/50%±45°/4%90°)360010×R=0.1UnloadedHole500Ti-6Al-4V4004340Steel(210ksi)3007075-T6AlFatigueStren
