DESIGN AND ANALYSIS OF COMPOSITE STRUCTURES WITH APPLICATIONS TO AEROSPACE STRUCTURES Christos Kassapoglou Delft University ofTechnology, The Netherlands DESIGN AND ANALYSIS OF COMPOSITE STRUCTURES Aerospace Series List CooperativePathPlanningofUnmanned Tsourdosetal November2010 AerialVehicles PrinciplesofFlightforPilots Swatton October2010 AirTravelandHealth:ASystems Seabridgeetal September2010 Perspective DesignandAnalysisofComposite Kassapoglou September2010 Structures:WithApplicationstoAerospace Structures UnmannedAircraftSystems:UAVS Austin April2010 Design,DevelopmentandDeployment IntroductiontoAntennaPlacement&Installations Macnamara April2010 PrinciplesofFlightSimulation Allerton October2009 AircraftFuelSystems Langtonetal May2009 TheGlobalAirlineIndustry Belobaba April2009 ComputationalModellingandSimulationof Diston April2009 AircraftandtheEnvironment:Volume1- PlatformKinematicsandSyntheticEnvironment HandbookofSpaceTechnology Ley,Wittmann April2009 Hallmann AircraftPerformanceTheoryand Swatton August2008 PracticeforPilots SurrogateModellinginEngineering Forrester,Sobester, August2008 Design:APracticalGuide Keane AircraftSystems,3rdEdition Moir&Seabridge March2008 IntroductiontoAircraftAeroelasticity AndLoads Wright&Cooper December2007 StabilityandControlofAircraftSystems Langton September2006 MilitaryAvionicsSystems Moir&Seabridge February2006 DesignandDevelopmentofAircraftSystems Moir&Seabridge June2004 AircraftLoadingandStructuralLayout Howe May2004 AircraftDisplaySystems Jukes December2003 CivilAvionicsSystems Moir&Seabridge December2002 DESIGN AND ANALYSIS OF COMPOSITE STRUCTURES WITH APPLICATIONS TO AEROSPACE STRUCTURES Christos Kassapoglou Delft University ofTechnology, The Netherlands Thiseditionfirstpublished2010 (cid:1)2010,JohnWiley&Sons,Ltd Registeredoffice JohnWiley&SonsLtd,TheAtrium,SouthernGate,Chichester,WestSussex,PO198SQ,UnitedKingdom Fordetailsofourglobaleditorialoffices,forcustomerservicesandforinformationabouthowtoapplyforpermission to reuse the copyright ma terial in this book please see our website at www.wiley.com. 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Contents About the Author ix Series Preface x Preface xi 1 Applications ofAdvanced Composites inAircraftStructures 1 References 7 2 Costof Composites:a QualitativeDiscussion 9 2.1 RecurringCost 10 2.2 Nonrecurring Cost 18 2.3 Technology Selection 20 2.4 Summary and Conclusions 27 Exercises 30 References 30 3 Review ofClassical Laminated Plate Theory 33 3.1 Composite Materials: Definitions, Symbols andTerminology 33 3.2 ConstitutiveEquations inThree Dimensions 35 3.2.1 Tensor Transformations 37 3.3 ConstitutiveEquations inTwoDimensions: Plane Stress 39 Exercises 52 References 53 4 Review ofLaminate Strengthand FailureCriteria 55 4.1 MaximumStressFailure Theory 57 4.2 MaximumStrainFailure Theory 58 4.3 Tsai–Hill Failure Theory 58 4.4 Tsai–Wu Failure Theory 59 4.5 Other Failure Theories 59 References 60 5 Composite Structural Components and MathematicalFormulation 63 5.1 Overview ofCompositeAirframe 63 5.1.1 The StructuralDesign Process:The Analyst’s Perspective 64 vi Contents 5.1.2 Basic Design Concept and Process/Material Considerations for AircraftParts 69 5.1.3 Sources ofUncertainty: Applied Loads, Usage and Material Scatter 72 5.1.4 Environmental Effects 75 5.1.5 EffectofDamage 76 5.1.6 Design Valuesand Allowables 78 5.1.7 AdditionalConsiderationsofthe Design Process 81 5.2 Governing Equations 82 5.2.1 EquilibriumEquations 82 5.2.2 Stress–StrainEquations 84 5.2.3 Strain-Displacement Equations 85 5.2.4 vonKarman Anisotropic Plate Equations for LargeDeflections 86 5.3 Reductions ofGoverningEquations: Applications toSpecificProblems 91 5.3.1 CompositePlateUnderLocalized in-Plane Load 92 5.3.2 CompositePlateUnderOut-of-Plane Point Load 103 5.4 EnergyMethods 106 5.4.1 Energy Expressionsfor Composite Plates 107 Exercises 113 References 116 6 Buckling ofComposite Plates 119 6.1 Bucklingof RectangularComposite Plate under Biaxial Loading 119 6.2 Bucklingof RectangularComposite Plate under Uniaxial Compression 122 6.2.1 Uniaxial Compression, Three Sides SimplySupported,One Side Free 124 6.3 Bucklingof RectangularComposite Plate under Shear 127 6.4 Bucklingof Long RectangularComposite Plates under Shear 129 6.5 Bucklingof RectangularComposite Plates under Combined Loads 132 6.6 Design Equations for Different Boundary Conditions andLoad Combinations 138 Exercises 141 References 143 7 Post-Buckling 145 7.1 Post-Buckling Analysis ofCompositePanelsunder Compression 149 7.1.1 Application: Post-BuckledPanel Under Compression 157 7.2 Post-Buckling Analysis ofCompositePlatesunder Shear 159 7.2.1 Post-bucklingof StiffenedComposite Panelsunder Shear 163 7.2.2 Post-bucklingof StiffenedComposite Panelsunder Combined Uniaxial andShearLoading 171 Exercises 174 References 177 8 Designand Analysisof CompositeBeams 179 8.1 Cross-section DefinitionBased on Design Guidelines 179 8.2 Cross-sectional Properties 182 8.3 ColumnBuckling 188 Contents vii 8.4 Beam onan Elastic Foundation under Compression 189 8.5 Crippling 194 8.5.1 One-Edge-Free (OEF) Crippling 196 8.5.2 No-Edge-Free (NEF) Crippling 200 8.5.3 Crippling under Bending Loads 202 8.5.4 Crippling ofClosed-Section Beams 207 8.6 Importance of Radius Regionsat Flange Intersections 207 8.7 Inter-rivetBuckling ofStiffener Flanges 210 8.8 Application: AnalysisofStiffeners in aStiffened Panel under Compression 215 Exercises 218 References 222 9 Skin-Stiffened Structure 223 9.1 Smearing ofStiffnessProperties (Equivalent Stiffness) 223 9.1.1 EquivalentMembrane Stiffnesses 223 9.1.2 EquivalentBending Stiffnesses 225 9.2 FailureModes of aStiffened Panel 227 9.2.1 Local Buckling (Between Stiffeners) Versus OverallPanel Buckling (the Panel Breaker Condition) 228 9.2.2 Skin–Stiffener Separation 236 9.3 Additional Considerations for Stiffened Panels 251 9.3.1 ‘Pinching’of Skin 251 9.3.2 Co-Curing Versus BondingVersus Fastening 251 Exercises 253 References 258 10 Sandwich Structure 259 10.1 Sandwich Bending Stiffnesses 260 10.2 Bucklingof Sandwich Structure 262 10.2.1 BucklingofSandwich Under Compression 262 10.2.2 BucklingofSan dwich Under Shear 264 10.2.3 BucklingofSandwich Under CombinedLoading 265 10.3 Sandwich Wrinkling 265 10.3.1 SandwichWrinkling Under Compression 265 10.3.2 SandwichWrinkling Under Shear 276 10.3.3 SandwichWrinkling Under Combined Loads 276 10.4 Sandwich Crimping 278 10.4.1 SandwichCrimpingUnderCompression 278 10.4.2 SandwichCrimpingUnderShear 278 10.5 Sandwich Intracellular Buckling (Dimpling) underCompression 278 10.6 Attaching Sandwich Structures 279 10.6.1 CoreRamp-Down Regions 280 10.6.2 Alternatives to Core Ramp-Down 282 Exercises 284 References 288 viii Contents 11 Good Design Practices and Design ‘Rules of Thumb’ 289 11.1 Lay up/StackingSequence-related 289 11.2 Loading andPerformance-related 290 11.3 Guidelines Related to EnvironmentalSensitivityand Manufacturing Constraints 292 11.4 Configurationand Layout-related 292 Exercises 294 References 295 Index 297
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