370 CHAPTER 11 Structural Components of Aircraft
a matter of research. Of these adhesives, epoxy resins are the most frequently used since they have
theadvantagesover,say,polyesterresins,ofgoodadhesiveproperties,lowshrinkageduringcureso
thatresidualstressesarereduced,goodmechanicalproperties,andthermalstability.Themodulusand
ultimate strength of epoxy resin are, typically, 5000 and 100N/mm^2. Epoxy resins are now found
extensivelyasthematrixcomponentinfibrouscomposites.
Reference
[1] Megson,T.H.G.,StructuralandStressAnalysis,2ndedition,Elsevier,2005.
Problems..............................................................................................
P.11.1 Examinepossibleusesofnewmaterialsinfutureaircraftmanufacture.
P.11.2 Describe the main features of a stressed skin structure. Discuss the structural functions of the various
componentswithparticularreferenceeithertothefuselageortothewingofamedium-sizedtransportaircraft.
P.11.3 Thedouble-rivetedbuttjointshowninFig.P.11.3connectstwoplateswhichareeach2.5mmthick,and
the rivets have a diameter of 3mm. If the failure strength of the rivets in shear is 370N/mm^2 and the ultimate
tensilestrengthoftheplateis465N/mm^2 ,determinethenecessaryrivetpitchifthejointistobedesignedsothat
failureduetoshearintherivetsandfailureduetotensionintheplateoccursimultaneously.Calculatealsothejoint
efficiency.
Fig. P.11.3Ans. Rivetpitchis12mm,jointefficiencyis75percent.P.11.4 TherivetgroupshowninFig.P.11.4connectstwonarrowlengthsofplate,oneofwhichcarriesa15kNload
positionedasshown.Iftheultimateshearstrengthofarivetis350N/mm^2 anditsfailurestrengthincompression
is600N/mm^2 ,determinetheminimumallowablevaluesofrivetdiameterandplatethickness.