Mechanical Behavior of Materials

About our authors Norman E. Dowling earned his BS in civil engineering (structures) from Clemson University in Clemson, SC, and his MS and PhD in theoretical and applied mechanics from the University of Illinois in Urbana. He is a registered Professional Engineer. From 1972 to 1982, he was employed at Westinghouse Research Laboratories, Pittsburgh, PA. Since 1983, he has been at Virginia Polytechnic Institute and State University. In 2015, Professor Dowling retired from full employment and remains professionally active as Professor Emeritus. An ASTM International member since 1972, Dowling has served on several subcommittees and other activities of Committee E08 on Fatigue and Fracture. He has also been active in the Fatigue Design and Evaluation Committee of SAE International.Stephen L. Kampe received BS, MS and PhD degrees in Metallurgical Engineering from Michigan Technological University. He has held positions with Martin Marietta Corporation, and with Virginia Tech on the Materials Science and Engineering faculty. In 2008, he returned to Michigan Tech and is currently the St. John Professor and Chair of the Materials Science and Engineering Department. He is a member of TMS and ASEE, and a Fellow of ASM and Alpha Sigma Mu.Milo V. Kral earned his BE in mechanical engineering, and his MS and PhD in Materials Science & Engineering from Vanderbilt University. After an ASEE post-doctoral fellowship in 1996 to 1998 at the US Naval Research Laboratory in Washington, DC, Kral joined the engineering faculty at University of Canterbury in Christchurch New Zealand. He is a member of TMS, ASM, a fellow of Professional Engineers NZ and Alpha Sigma Mu.

• Introduction 1.1 Introduction1.2 Types of Material Failure1.3 Design and Materials Selection1.4 Technological Challenge1.5 Economic Importance of Fracture1.6 Summary ReferencesProblems and QuestionsStructure, Defects, and Deformation in Materials 2.1 Introduction2.2 Bonding in Solids2.3 Structure in Crystalline Materials2.4 Defects in Materials2.5 Elastic Deformation and Theoretical Strength2.6 Inelastic Deformation2.7 Summary ReferencesProblems and QuestionsMechanical Testing: Tension Test and Stress–Strain Mechanisms 3.1 Introduction3.2 Introduction to Tension Test3.3 Engineering Stress–Strain Properties3.4 Materials Science Description of Tensile Behavior3.5 Trends in Tensile Behavior3.6 True Stress–Strain Interpretation of Tension Test3.7 Materials Selection for Engineering Components3.8 Summary ReferencesProblems and QuestionsMechanical Testing: Additional Basic Tests 4.1 Introduction4.2 Compression Test4.3 Hardness Tests4.4 Notch-Impact Tests4.5 Bending and Torsion Tests4.6 Summary ReferencesProblems and QuestionsStress–Strain Relationships and Behavior 5.1 Introduction5.2 Models for Deformation Behavior5.3 Elastic Deformation5.4 Anisotropic Materials5.5 Summary ReferencesProblems and QuestionsReview of Complex and Principal States of Stress and Strain 6.1 Introduction6.2 Plane Stress6.3 Principal Stresses and the Maximum Shear Stress6.4 Three-Dimensional States of Stress6.5 Stresses on the Octahedral Planes6.6 Complex States of Strain6.7 Summary ReferencesProblems and QuestionsYielding and Fracture under Combined Stresses 7.1 Introduction7.2 General Form of Failure Criteria7.3 Maximum Normal Stress Fracture Criterion7.4 Maximum Shear Stress Yield Criterion7.5 Octahedral Shear Stress Yield Criterion7.6 Discussion of the Basic Failure Criteria7.7 Coulomb–Mohr Fracture Criterion7.8 Modified Mohr Fracture Criterion7.9 Additional Comments on Failure Criteria7.10 Summary ReferencesProblems and QuestionsFracture of Cracked Members 8.1 Introduction8.2 Preliminary Discussion8.3 Mathematical Concepts8.4 Application of K to Design and Analysis8.5 Additional Topics on Application of K8.6 Fracture Toughness Values and Trends8.7 Plastic Zone Size, and Plasticity Limitations on LEFM8.8 Discussion of Fracture Toughness Testing8.9 Extensions of Fracture Mechanics Beyond Linear Elasticity8.10 Summary ReferencesProblems and QuestionsFatigue of Materials: Introduction and Stress-Based Approach 9.1 Introduction9.2 Definitions and Concepts9.3 Sources of Cyclic Loading9.4 Fatigue Testing9.5 The Physical Nature of Fatigue Damage9.6 Trends in S-N Curves9.7 Mean Stresses9.8 Multiaxial Stresses9.9 Variable Amplitude Loading9.10 Summary ReferencesProblems and QuestionsStress-Based Approach to Fatigue: Notched Members 10.1 Introduction10.2 Notch Effects10.3 Notch Sensitivity and Empirical Estimates of kf10.4 Estimating Long-Life Fatigue Strengths (Fatigue Limits)10.5 Notch Effects at Intermediate and Short Lives10.6 Combined Effects of Notches and Mean Stress10.7 Estimating S-N Curves10.8 Use of Component S-N Data10.9 Designing to Avoid Fatigue Failure10.10 Discussion10.11 Summary ReferencesProblems and QuestionsFatigue Crack Growth 11.1 Introduction11.2 Preliminary Discussion11.3 Fatigue Crack Growth Rate Testing11.4 Effects of R = Smin/Smax on Fatigue Crack Growth11.5 Trends in Fatigue Crack Growth Behavior11.6 Life Estimates for Constant Amplitude Loading11.7 Life Estimates for Variable Amplitude Loading11.8 Design Considerations11.9 Plasticity Aspects and Limitations of LEFM for Fatigue Crack Growth11.10 Summary ReferencesProblems and QuestionsEnvironmentally Assisted Cracking 12.1 Introduction12.2 Definitions, Concepts, and Analysis12.3 EAC in Metals: Basic Mechanisms12.4 Hydrogen-Induced Embrittlement12.5 Liquid Metal Embrittlement12.6 EAC of Polymers12.7 EAC of Glasses and Ceramics12.8 Additional Comments and Preventative Measures ReferencesProblems and QuestionsPlastic Deformation Behavior and Models for Materials 13.1 Introduction13.2 Stress–Strain Curves13.3 Three-Dimensional Stress–Strain Relationships13.4 Unloading and Cyclic Loading Behavior from Rheological Models13.5 Cyclic Stress–Strain Behavior of Real Materials13.6 Summary ReferencesProblems and QuestionsStress–Strain Analysis of Plastically Deforming Members 14.1 Introduction14.2 Plasticity in Bending14.3 Residual Stresses and Strains for Bending14.4 Plasticity of Circular Shafts in Torsion14.5 Notched Members14.6 Cyclic Loading14.7 Summary ReferencesProblems and QuestionsStrain-Based Approach to Fatigue 15.1 Introduction15.2 Strain Versus Life Curves15.3 Mean Stress Effects15.4 Multiaxial Stress Effects15.5 Life Estimates for Structural Components15.6 Additional Discussion15.7 Summary ReferencesProblems and QuestionsTime-Dependent Behavior: Creep and Damping 16.1 Introduction16.2 Creep Testing16.3 Physical Mechanisms of Creep16.4 Time–Temperature Parameters and Life Estimates16.5 Creep Failure under Varying Stress16.6 Stress–Strain–Time Relationships16.7 Creep Deformation under Varying Stress16.8 Creep Deformation under Multiaxial Stress16.9 Component Stress–Strain Analysis16.10 Energy Dissipation (Damping) in Materials16.11 Summary ReferencesProblems and QuestionsAppendix A Review of Selected Topics from Mechanics of Materials A.1 IntroductionA.2 Basic Formulas for Stresses and DeflectionsA.3 Properties of AreasA.4 Shears, Moments, and Deflections in BeamsA.5 Stresses in Pressure Vessels, Tubes, and DiscsA.6 Elastic Stress Concentration Factors for NotchesA.7 Fully Plastic Yielding LoadsReferencesAppendix B Statistical Variation in Materials Properties B.1 IntroductionB.2 Mean and Standard DeviationB.3 Normal or Gaussian DistributionB.4 Typical Variation in Materials PropertiesB.5 One-Sided Tolerance LimitsB.6 DiscussionReferencesAppendix C A Survey of Engineering Materials C.1 IntroductionC.2 Alloying and Processing of MetalsC.3 Irons and SteelsC.4 Nonferrous MetalsC.5 PolymersC.6 Ceramics and GlassesC.7 Composite MaterialsC.8 Summary