This is an electronic version of the print textbook. Due to electronic rights restrictions, some third party content may be suppressed. Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. The publisher reserves the right to remove content from this title at any time if subsequent rights restrictions require it. For valuable information on pricing, previous editions, changes to current editions, and alternate formats, please visit www.cengage.com/highered to search by ISBN#, author, title, or keyword for materials in your areas of interest. Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 1019763_FM_VOL-I.qxp 9/17/07 4:22 PM Page viii 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 S 50 R 51 1st Pass Pages 1019763_FM_VOL-I.qxp 9/17/07 4:22 PM Page viii 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 S 50 R 51 1st Pass Pages AFirstCourseintheFiniteElementMethod, (cid:2)c 2012CengageLearning FifthEdition ALLRIGHTSRESERVED.Nopartofthisworkcoveredbythecopyright DarylL.Logan hereinmaybereproduced,transmitted,stored,orusedinanyformorby Publisher,GlobalEngineering: anymeansgraphic,electronic,ormechanical,includingbutnotlimitedto ChristopherM.Shortt photocopying,recording,scanning,digitizing,taping,Webdistribution, informationnetworks,informationstorageandretrievalsystems,exceptas SeniorAcquisitionsEditor:RandallAdams permittedunderSection107or108ofthe1976UnitedStatesCopyright SeniorDevelopmentalEditor: Act,withoutthepriorwrittenpermissionofthepublisher. 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Foryourcourseandlearningsolutions,visit www.cengage.com/engineering Purchaseanyofourproductsatyourlocalcollegestoreoratourpreferred onlinestorewww.cengagebrain.com PrintedintheUnitedStatesofAmerica 123456713121110 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. A F C IRST OURSE F IN THE INITE E M d LEMENT ETHOD Fifth Edition Daryl L. Logan University of Wisconsin–Platteville Australia • Brazil • Japan • Korea • Mexico • Singapore • Spain • United Kingdom • United States Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. d C ONTENTS Preface xi 1 Introduction 1 ChapterObjectives 1 Prologue 1 1.1 BriefHistory 2 1.2 IntroductiontoMatrixNotation 4 1.3 RoleoftheComputer 6 1.4 GeneralStepsoftheFiniteElementMethod 7 1.5 ApplicationsoftheFiniteElementMethod 15 1.6 AdvantagesoftheFiniteElementMethod 23 1.7 ComputerProgramsfortheFiniteElementMethod 25 References 27 Problems 29 2 Introduction to the Stiffness (Displacement) Method 31 ChapterObjectives 31 Introduction 31 2.1 DefinitionoftheSti¤nessMatrix 32 2.2 DerivationoftheSti¤nessMatrixforaSpringElement 32 2.3 ExampleofaSpringAssemblage 38 2.4 AssemblingtheTotalSti¤nessMatrixbySuperposition (DirectSti¤nessMethod) 40 2.5 BoundaryConditions 42 2.6 PotentialEnergyApproachtoDeriveSpringElementEquations 56 SummaryEquations 65 References 66 Problems 66 iii Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. iv d Contents 3 Development of Truss Equations 72 ChapterObjectives 72 Introduction 72 3.1 DerivationoftheSti¤nessMatrixforaBarElement inLocalCoordinates 73 3.2 SelectingApproximationFunctionsforDisplacements 79 3.3 TransformationofVectorsinTwoDimensions 82 3.4 GlobalSti¤nessMatrixforBarArbitrarilyOrientedinthePlane 85 3.5 ComputationofStressforaBarinthex-yPlane 90 3.6 SolutionofaPlaneTruss 92 3.7 TransformationMatrixandSti¤nessMatrixforaBar inThree-DimensionalSpace 100 3.8 UseofSymmetryinStructure 109 3.9 Inclined,orSkewed,Supports 112 3.10 PotentialEnergyApproachtoDeriveBarElementEquations 118 3.11 ComparisonofFiniteElementSolutiontoExactSolutionforBar 129 3.12 Galerkin’sResidualMethodandItsUsetoDerivetheOne-Dimensional BarElementEquations 133 3.13 OtherResidualMethodsandTheirApplicationtoaOne-Dimensional BarProblem 136 3.14 FlowchartforSolutionofThree-DimensionalTrussProblems 141 3.15 ComputerProgramAssistedStep-by-StepSolutionforTrussProblem 141 SummaryEquations 144 References 145 Problems 146 4 Development of Beam Equations 166 ChapterObjectives 166 Introduction 166 4.1 BeamSti¤ness 167 4.2 ExampleofAssemblageofBeamSti¤nessMatrices 177 4.3 ExamplesofBeamAnalysisUsingtheDirectSti¤nessMethod 179 4.4 DistributedLoading 192 4.5 ComparisonoftheFiniteElementSolutiontotheExactSolution foraBeam 205 4.6 BeamElementwithNodalHinge 211 Copyright 2010 Cengage Learning. 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Contents d v 4.7 PotentialEnergyApproachtoDeriveBeamElement Equations 218 4.8 Galerkin’sMethodforDerivingBeam ElementEquations 221 SummaryEquations 223 References 224 Problems 225 5 Frame and Grid Equations 235 ChapterObjectives 235 Introduction 235 5.1 Two-DimensionalArbitrarilyOrientedBeamElement 235 5.2 RigidPlaneFrameExamples 239 5.3 InclinedorSkewedSupports—FrameElement 258 5.4 GridEquations 259 5.5 BeamElementArbitrarilyOrientedinSpace 277 5.6 ConceptofSubstructureAnalysis 290 SummaryEquations 296 References 298 Problems 299 6 Development of the Plane Stress and Plane Strain Stiffness Equations 328 ChapterObjectives 328 Introduction 328 6.1 BasicConceptsofPlaneStressandPlaneStrain 329 6.2 DerivationoftheConstant-StrainTriangularElement Sti¤nessMatrixandEquations 334 6.3 TreatmentofBodyandSurfaceForces 349 6.4 ExplicitExpressionfortheConstant-Strain TriangleSti¤nessMatrix 354 6.5 FiniteElementSolutionofaPlaneStressProblem 356 6.6 RectangularPlaneElement(BilinearRectangle,Q4) 367 SummaryEquations 373 References 376 Problems 377 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. vi d Contents 7 Practical Considerations in Modeling; Interpreting Results; and Examples of Plane Stress–Strain Analysis 384 ChapterObjectives 384 Introduction 384 7.1 FiniteElementModeling 385 7.2 EquilibriumandCompatibilityofFiniteElementResults 398 7.3 ConvergenceofSolution 402 7.4 InterpretationofStresses 405 7.5 StaticCondensation 407 7.6 FlowchartfortheSolutionofPlaneStress–StrainProblems 411 7.7 ComputerProgram-AssistedStep-by-StepSolution,OtherModels, andResultsforPlaneStress–StrainProblems 411 References 417 Problems 420 8 Development of the Linear-Strain Triangle Equations 437 ChapterObjectives 437 Introduction 437 8.1 DerivationoftheLinear-StrainTriangularElement Sti¤nessMatrixandEquations 437 8.2 ExampleLSTSti¤nessDetermination 442 8.3 ComparisonofElements 445 SummaryEquations 448 References 448 Problems 449 9 Axisymmetric Elements 452 ChapterObjectives 452 Introduction 452 9.1 DerivationoftheSti¤nessMatrix 452 9.2 SolutionofanAxisymmetricPressureVessel 463 9.3 ApplicationsofAxisymmetricElements 469 SummaryEquations 474 References 476 Problems 476 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.