2

Aircraft Structures By Megson

649 Pages · 2010 · 4.62 MB · English

  • Aircraft Structures By Megson

    An Introduction to Aircraft


    Structural Analysis


    T. H. G. Megson


    AMSTERDAM•BOSTON•HEIDELBERG•LONDON


    NEWYORK•OXFORD•PARIS•SANDIEGO


    SANFRANCISCO•SINGAPORE•SYDNEY•TOKYO



    Butterworth-HeinemannisanimprintofElsevier Butterworth-HeinemannisanimprintofElsevier


    30CorporateDrive,Suite400


    Burlington,MA01803,USA


    TheBoulevard,LangfordLane


    Kidlington,Oxford,OX51GB,UK


    Copyright©2010,T.H.G.Megson.PublishedbyElsevierLtd.Allrightsreserved.


    TherightofT.H.G.MegsontobeidentifiedastheauthorofthisworkhasbeenassertedinaccordancewiththeCopyright,Designsand


    PatentsAct1988.


    Nopartofthispublicationmaybereproducedortransmittedinanyformorbyanymeans,electronicormechanical,including


    photocopying,recording,oranyinformationstorageandretrievalsystem,withoutpermissioninwritingfromthepublisher.Detailson


    howtoseekpermission,furtherinformationaboutthePublisher’spermissionspoliciesandourarrangementswithorganizationssuchas


    theCopyrightClearanceCenterandtheCopyrightLicensingAgency,canbefoundatourWebsite:www.elsevier.com/permissions.


    ThisbookandtheindividualcontributionscontainedinitareprotectedundercopyrightbythePublisher(otherthanasmaybe


    notedherein).


    Notices


    Knowledgeandbestpracticeinthisfieldareconstantlychanging.Asnewresearchandexperiencebroadenourunderstanding,changes


    inresearchmethods,professionalpractices,ormedicaltreatmentmaybecomenecessary.


    Practitionersandresearchersmustalwaysrelyontheirownexperienceandknowledgeinevaluatingandusinganyinformation,


    methods,compounds,orexperimentsdescribedherein.Inusingsuchinformationormethods,theyshouldbemindfuloftheirown


    safetyandthesafetyofothers,includingpartiesforwhomtheyhaveaprofessionalresponsibility.


    Tothefullestextentofthelaw,neitherthePublishernortheauthors,contributors,oreditorsassumeanyliabilityforanyinjury


    and/ordamagetopersonsorpropertyasamatterofproductsliability,negligenceorotherwise,orfromanyuseoroperationofany


    methods,products,instructions,orideascontainedinthematerialherein.


    BritishLibraryCataloguinginPublicationData


    AcataloguerecordforthisbookisavailablefromtheBritishLibrary.


    LibraryofCongressCataloging-in-PublicationData


    Megson,T.H.G.(ThomasHenryGordon)


    Anintroductiontoaircraftstructuralanalysis/T.H.G.Megson.


    p.cm.


    Rev.ed.of:Aircraftstructuresforengineeringstudents/T.H.G.Megson.4thed.2007.


    Includesbibliographicalreferencesandindex.


    ISBN978-1-85617-932-4(alk.paper)


    1.Airframes.2.Structuralanalysis(Engineering)I.Title.


    TL671.6.M362010


    629.134’31–dc22


    2009050354


    ForinformationonallButterworth-Heinemannpublications


    visitourWebsiteatwww.elsevierdirect.com


    PrintedintheUnitedStatesofAmerica


    1011121314 10987654321 Contents


    Preface ............................................................................................. vii


    PART A FUNDAMENTALS OF STRUCTURAL ANALYSIS


    CHAPTER1 BasicElasticity........................................................................... 3


    1.1 Stress.................................................................................................. 3


    1.2 NotationforForcesandStresses................................................................... 5


    1.3 EquationsofEquilibrium ........................................................................... 7


    1.4 PlaneStress........................................................................................... 9


    1.5 BoundaryConditions................................................................................ 9


    1.6 DeterminationofStressesonInclinedPlanes.................................................... 10


    1.7 PrincipalStresses .................................................................................... 14


    1.8 Mohr’sCircleofStress.............................................................................. 16


    1.9 Strain.................................................................................................. 20


    1.10 CompatibilityEquations ............................................................................ 24


    1.11 PlaneStrain........................................................................................... 25


    1.12 DeterminationofStrainsonInclinedPlanes...................................................... 25


    1.13 PrincipalStrains...................................................................................... 27


    1.14 Mohr’sCircleofStrain.............................................................................. 28


    1.15 Stress–StrainRelationships......................................................................... 28


    1.16 ExperimentalMeasurementofSurfaceStrains................................................... 37


    Problems.............................................................................................. 41


    CHAPTER2 Two-DimensionalProblemsinElasticity.............................................. 45


    2.1 Two-DimensionalProblems........................................................................ 45


    2.2 StressFunctions...................................................................................... 47


    2.3 InverseandSemi-InverseMethods ................................................................ 48


    2.4 St.Venant’sPrinciple................................................................................ 53


    2.5 Displacements........................................................................................ 54


    2.6 BendingofanEnd-LoadedCantilever ............................................................ 55


    Problems.............................................................................................. 60


    CHAPTER3 TorsionofSolidSections............................................................... 65


    3.1 PrandtlStressFunctionSolution................................................................... 65


    3.2 St.VenantWarpingFunctionSolution ............................................................ 75


    3.3 TheMembraneAnalogy ............................................................................ 77


    3.4 TorsionofaNarrowRectangularStrip............................................................ 79


    Problems.............................................................................................. 82


    CHAPTER4 VirtualWorkandEnergyMethods..................................................... 85


    4.1 Work................................................................................................... 85


    4.2 PrincipleofVirtualWork ........................................................................... 86


    4.3 ApplicationsofthePrincipleofVirtualWork.................................................... 99


    Problems.............................................................................................. 107


    CHAPTER5 EnergyMethods.......................................................................... 111


    5.1 StrainEnergyandComplementaryEnergy....................................................... 111


    5.2 ThePrincipleoftheStationaryValueoftheTotalComplementaryEnergy.................. 113


    iii iv Contents


    5.3 ApplicationtoDeflectionProblems ............................................................... 114


    5.4 ApplicationtotheSolutionofStaticallyIndeterminateSystems............................... 122


    5.5 UnitLoadMethod ................................................................................... 138


    5.6 FlexibilityMethod................................................................................... 141


    5.7 TotalPotentialEnergy............................................................................... 147


    5.8 ThePrincipleoftheStationaryValueoftheTotalPotentialEnergy........................... 148


    5.9 PrincipleofSuperposition .......................................................................... 151


    5.10 TheReciprocalTheorem............................................................................ 151


    5.11 TemperatureEffects ................................................................................. 156


    Problems.............................................................................................. 158


    CHAPTER6 MatrixMethods........................................................................... 169


    6.1 Notation............................................................................................... 170


    6.2 StiffnessMatrixforanElasticSpring............................................................. 171


    6.3 StiffnessMatrixforTwoElasticSpringsinLine................................................. 172


    6.4 MatrixAnalysisofPin-jointedFrameworks...................................................... 176


    6.5 ApplicationtoStaticallyIndeterminateFrameworks............................................ 183


    6.6 MatrixAnalysisofSpaceFrames.................................................................. 183


    6.7 StiffnessMatrixforaUniformBeam.............................................................. 185


    6.8 FiniteElementMethodforContinuumStructures............................................... 193


    Problems.............................................................................................. 211


    CHAPTER7 BendingofThinPlates.................................................................. 219


    7.1 PureBendingofThinPlates........................................................................ 219


    7.2 PlatesSubjectedtoBendingandTwisting........................................................ 223


    7.3 PlatesSubjectedtoaDistributedTransverseLoad............................................... 227


    7.4 CombinedBendingandIn-PlaneLoadingofaThinRectangularPlate....................... 236


    7.5 BendingofThinPlatesHavingaSmallInitialCurvature....................................... 240


    7.6 EnergyMethodfortheBendingofThinPlates .................................................. 241


    Problems.............................................................................................. 250


    CHAPTER8 Columns................................................................................... 253


    8.1 EulerBucklingofColumns......................................................................... 253


    8.2 InelasticBuckling.................................................................................... 259


    8.3 EffectofInitialImperfections...................................................................... 263


    8.4 StabilityofBeamsunderTransverseandAxialLoads.......................................... 266


    8.5 EnergyMethodfortheCalculationofBucklingLoadsinColumns........................... 270


    8.6 Flexural–TorsionalBucklingofThin-WalledColumns......................................... 274


    Problems.............................................................................................. 287


    CHAPTER9 ThinPlates................................................................................ 293


    9.1 BucklingofThinPlates............................................................................. 293


    9.2 InelasticBucklingofPlates......................................................................... 296


    9.3 ExperimentalDeterminationofCriticalLoadforaFlatPlate.................................. 298


    9.4 LocalInstability...................................................................................... 299


    9.5 InstabilityofStiffenedPanels...................................................................... 300


    9.6 FailureStressinPlatesandStiffenedPanels...................................................... 302


    9.7 TensionFieldBeams ................................................................................ 304


    Problems.............................................................................................. 320 Contents v


    PART B ANALYSIS OF AIRCRAFT STRUCTURES


    CHAPTER10 Materials.................................................................................. 327


    10.1 AluminumAlloys.................................................................................... 327


    10.2 Steel ................................................................................................... 329


    10.3 Titanium............................................................................................... 330


    10.4 Plastics................................................................................................ 331


    10.5 Glass................................................................................................... 331


    10.6 CompositeMaterials................................................................................. 331


    10.7 PropertiesofMaterials.............................................................................. 333


    Problems.............................................................................................. 349


    CHAPTER11 StructuralComponentsofAircraft ..................................................... 351


    11.1 LoadsonStructuralComponents .................................................................. 351


    11.2 FunctionofStructuralComponents................................................................ 354


    11.3 FabricationofStructuralComponents............................................................. 359


    11.4 Connections........................................................................................... 363


    Problems.............................................................................................. 370


    CHAPTER12 Airworthiness............................................................................. 373


    12.1 FactorsofSafety-FlightEnvelope ................................................................. 373


    12.2 LoadFactorDetermination......................................................................... 375


    CHAPTER13 AirframeLoads........................................................................... 379


    13.1 AircraftInertiaLoads................................................................................ 379


    13.2 SymmetricManeuverLoads........................................................................ 386


    13.3 NormalAccelerationsAssociatedwithVariousTypesofManeuver .......................... 391


    13.4 GustLoads............................................................................................ 393


    Problems.............................................................................................. 399


    CHAPTER14 Fatigue .................................................................................... 403


    14.1 SafeLifeandFail-SafeStructures................................................................. 403


    14.2 DesigningAgainstFatigue.......................................................................... 404


    14.3 FatigueStrengthofComponents................................................................... 405


    14.4 PredictionofAircraftFatigueLife................................................................. 409


    14.5 CrackPropagation................................................................................... 414


    Problems.............................................................................................. 420


    CHAPTER15 BendingofOpenandClosed,Thin-WalledBeams................................... 423


    15.1 SymmetricalBending................................................................................ 424


    15.2 UnsymmetricalBending ............................................................................ 433


    15.3 DeflectionsduetoBending......................................................................... 441


    15.4 CalculationofSectionProperties.................................................................. 456


    15.5 ApplicabilityofBendingTheory................................................................... 466


    15.6 TemperatureEffects ................................................................................. 466


    Problems.............................................................................................. 471


    CHAPTER16 ShearofBeams .......................................................................... 479


    16.1 GeneralStress,Strain,andDisplacementRelationshipsforOpen


    andSingleCellClosedSectionThin-WalledBeams............................................ 479


    16.2 ShearofOpenSectionBeams...................................................................... 483 vi Contents


    16.3 ShearofClosedSectionBeams.................................................................... 488


    Problems.............................................................................................. 496


    CHAPTER17 TorsionofBeams ........................................................................ 503


    17.1 TorsionofClosedSectionBeams.................................................................. 503


    17.2 TorsionofOpenSectionBeams.................................................................... 514


    Problems.............................................................................................. 521


    CHAPTER18 CombinedOpenandClosedSectionBeams.......................................... 529


    18.1 Bending ............................................................................................... 529


    18.2 Shear................................................................................................... 529


    18.3 Torsion ................................................................................................ 533


    Problems.............................................................................................. 534


    CHAPTER19 StructuralIdealization .................................................................. 537


    19.1 Principle............................................................................................... 537


    19.2 IdealizationofaPanel............................................................................... 538


    19.3 EffectofIdealizationontheAnalysisofOpenandClosedSectionBeams................... 541


    19.4 DeflectionofOpenandClosedSectionBeams .................................................. 553


    Problems.............................................................................................. 556


    CHAPTER20 WingSparsandBoxBeams ............................................................ 561


    20.1 TaperedWingSpar................................................................................... 561


    20.2 OpenandClosedSectionBeams................................................................... 565


    20.3 BeamsHavingVariableStringerAreas............................................................ 571


    Problems.............................................................................................. 574


    CHAPTER21 Fuselages................................................................................. 577


    21.1 Bending ............................................................................................... 577


    21.2 Shear................................................................................................... 578


    21.3 Torsion ................................................................................................ 581


    21.4 CutoutsinFuselages................................................................................. 584


    Problems.............................................................................................. 585


    CHAPTER22 Wings...................................................................................... 587


    22.1 Three-BoomShell ................................................................................... 587


    22.2 Bending ............................................................................................... 588


    22.3 Torsion ................................................................................................ 590


    22.4 Shear................................................................................................... 594


    22.5 ShearCenter.......................................................................................... 599


    22.6 TaperedWings........................................................................................ 600


    22.7 Deflections............................................................................................ 603


    22.8 CutoutsinWings..................................................................................... 605


    Problems.............................................................................................. 613


    CHAPTER23 FuselageFramesandWingRibs....................................................... 619


    23.1 PrinciplesofStiffener/WebConstruction......................................................... 619


    23.2 FuselageFrames ..................................................................................... 625


    23.3 WingRibs............................................................................................. 626


    Problems.............................................................................................. 630


    Index.............................................................................................. 633 Preface


    Duringmyexperienceofteachingaircraftstructures,Ihavefelttheneedforatextbookwrittenspecif-


    icallyforstudentsofaeronauticalengineering.Althoughtherehavebeenanumberofexcellentbooks


    writtenonthesubject,theyarenoweitheroutofdateortoospecializedincontenttofulfilltherequire-


    ments of an undergraduate textbook. With that in mind, I wrote Aircraft Structures for Engineering


    Students,thetextonwhichthisoneisbased.Usersofthattexthavesuppliedmanyusefulcommentsto


    thepublisher,includingcommentsthatabrieferversionofthebookmightbedesirable,particularlyfor


    programsthatdonothavethetimetocoverallthematerialinthe“big”book.Thatfeedback,alongwith


    asurveydonebythepublisher,resultedinthisbook, AnIntroductiontoAircraftStructuralAnalysis,


    designedtomeettheneedsofmoretime-constrainedcourses.


    MuchofthecontentofthisbookissimilartothatofAircraftStructuresforEngineeringStudents,but


    thechapteron“VibrationofStructures”hasbeenremovedsincethisismostoftencoveredinaseparate


    standalonecourse.ThetopicofAeroelasticityhasalsobeenremoved,leavingdetailedtreatmenttothe


    graduate-levelcurriculum.Thesectionon“StructuralLoadingandDiscontinuities”remainsinthebig


    bookbutnotthis“intro”one.Whilethesetopicshelpdevelopadeeperunderstandingofloadtransfer


    andconstrainteffectsinaircraftstructures,theyareoftenoutsidethescopeofanundergraduatetext.


    Thereaderinterestedinlearningmoreonthosetopicsshouldrefertothe“big”book.Intheinterestof


    savingspace,theappendixon“DesignofaRearFuselage”isavailablefordownloadfromthebook’s


    companionWebsite.Pleasevisitwww.elsevierdirect.comandsearchon“Megson”tofindtheWebsite


    andthedownloadablecontent.


    Supplementarymaterials,includingsolutionstoend-of-chapterproblems,areavailableforregistered


    instructorswhoadoptthisbookasacoursetext.Pleasevisitwww.textbooks.elsevier.comforinformation


    andtoregisterforaccesstotheseresources.


    The help of Tom Lacy, Associate Professor of Mechanical and Aerospace Engineering at Missis-


    sippiStateUniversity,isgratefullyacknowledgedinthedevelopmentofthisbook.


    T.H.G.Megson


    Supportingmaterialaccompanyingthisbook


    Afullsetofworkedsolutionsforthisbookareavailableforteachingpurposes.


    Please visit www.textbooks.elsevier.com and follow the registration instructions to access this


    material,whichisintendedforusebylecturersandtutors.


    vii Thispageintentionallyleftblank PART


    A


    Fundamentals


    of Structural


    Analysis


    Please note: To fully download this free PDF,EBook files you need know All free.
    Found by internet command,site not saved pdf file
You May Also Like

Related PPT Template in the same category.