Introduction to Impact Dynamics

Fundamental guidance--including concepts, models, and methodology--for better understanding the dynamic behavior of materials and for designing for objects and structures under impact or intensive dynamic loading

This book introduces readers to the dynamic response of structures with important emphasis on the material behavior under dynamic loadings. It utilizes theoretical modelling and analytical methods in order to provide readers with insight into the various phenomena. The content of the book is an introduction to the fundamental aspects, which underpin many important industrial areas. These areas include the safety of various transportation systems and a range of different structures when subjected to various impact and dynamic loadings, including terrorist attacks.

Presented in three parts--Stress Waves in Solids, Dynamic Behaviors of Materials Under High Strain Rate, and Dynamic Response of Structures to Impact and Pulse Loading--Introduction to Impact Dynamics covers elastic waves, rate dependent behaviors of materials, effects of tensile force, inertial effects, and more. The book also features numerous case studies to aid in facilitating learning. The strength of the book is its clarity, balanced coverage, and practical examples, which allow students to learn the overall knowledge of impact dynamics in a limited time whilst directing them to explore more advanced technical knowledge and skills.

• Considers both the dynamic behavior of materials and stress waves, and the dynamic structural response and energy absorption, emphasizing the interaction between material behavior and the structural response

• Provides a comprehensive description of the phenomenon of impact of structures, containing both fundamental issues of wave propagation and constitutive relation of materials, and the dynamic response of structures under impact loads

• Based on the authors' research and teaching experience as well as updated developments in the field

Introduction to Impact Dynamics is the perfect textbook for graduate and postgraduate students, and will work as a reference for engineers in the fields of solid mechanics, automotive design, aerospace, mechanical, nuclear, marine, and defense.

Auteur

T.X. Yu, PhD, is Professor Emeritus at the Department of Mechanical Engineering, The Hong Kong University of Science and Technology, Hong Kong. XinMing Qiu, PhD, is Professor at the School of Aerospace Engineering, Tsinghua University, Beijing, China.

Résumé
Fundamental guidanceincluding concepts, models, and methodologyfor better understanding the dynamic behavior of materials and for designing for objects and structures under impact or intensive dynamic loading

This book introduces readers to the dynamic response of structures with important emphasis on the material behavior under dynamic loadings. It utilizes theoretical modelling and analytical methods in order to provide readers with insight into the various phenomena. The content of the book is an introduction to the fundamental aspects, which underpin many important industrial areas. These areas include the safety of various transportation systems and a range of different structures when subjected to various impact and dynamic loadings, including terrorist attacks.

Presented in three partsStress Waves in Solids, Dynamic Behaviors of Materials Under High Strain Rate, and Dynamic Response of Structures to Impact and Pulse LoadingIntroduction to Impact Dynamics covers elastic waves, rate dependent behaviors of materials, effects of tensile force, inertial effects, and more. The book also features numerous case studies to aid in facilitating learning. The strength of the book is its clarity, balanced coverage, and practical examples, which allow students to learn the overall knowledge of impact dynamics in a limited time whilst directing them to explore more advanced technical knowledge and skills.

• Considers both the dynamic behavior of materials and stress waves, and the dynamic structural response and energy absorption, emphasizing the interaction between material behavior and the structural response
• Provides a comprehensive description of the phenomenon of impact of structures, containing both fundamental issues of wave propagation and constitutive relation of materials, and the dynamic response of structures under impact loads
• Based on the authors' research and teaching experience as well as updated developments in the field
  Introduction to Impact Dynamics is the perfect textbook for graduate and postgraduate students, and will work as a reference for engineers in the fields of solid mechanics, automotive design, aerospace, mechanical, nuclear, marine, and defense.

Contenu

Preface xi

Introduction to Impact Dynamics xiii

Part 1 Stress Waves in Solids 1

1 Elastic Waves 3

1.1 Elastic Wave in a Uniform Circular Bar 3

1.1.1 The Propagation of a Compressive Elastic Wave 3

1.2 Types of Elastic Wave 6

1.2.1 Longitudinal Waves 6

1.2.2 Transverse Waves 7

1.2.3 Surface Wave (Rayleigh Wave) 7

1.2.4 Interfacial Waves 8

1.2.5 Waves in Layered Media (Love Waves) 8

1.2.6 Bending (Flexural) Waves 8

1.3 Reflection and Interaction of Waves 9

1.3.1 Mechanical Impedance 9

1.3.2 Waves When they Encounter a Boundary 10

1.3.3 Reflection and Transmission of 1D Longitudinal Waves 11

Questions 1 17

Problems 1 18

2 Elastic-Plastic Waves 19

2.1 One-Dimensional Elastic-Plastic Stress Wave in Bars 19

2.1.1 A Semi-Infinite Bar Made of Linear Strain-Hardening Material Subjected to a Step Load at its Free End 21

2.1.2 A Semi-Infinite Bar Made of Decreasingly Strain-Hardening Material Subjected to a Monotonically Increasing Load at its Free End 22

2.1.3 A Semi-Infinite Bar Made of Increasingly Strain-Hardening Material Subjected to a Monotonically Increasing Load at its Free End 23

2.1.4 Unloading Waves 25

2.1.5 Relationship Between Stress and Particle Velocity 26

2.1.6 Impact of a Finite-Length Uniform Bar Made of Elastic-Linear Strain-Hardening Material on a Rigid Flat Anvil 28

2.2 High-Speed Impact of a Bar of Finite Length on a Rigid Anvil (Mushrooming) 31

2.2.1 Taylor's Approach 31

2.2.2 Hawkyard's Energy Approach 36

Questions 2 38

Problems 2 38

Part 2 Dynamic Behavior of Materials under High Strain Rate 39

3 Rate-Dependent Behavior of Materials 41

3.1 Materials' Behavior under High Strain Rates 41

3.2 High-Strain-Rate Mechanical Properties of Materials 44

3.2.1 Strain Rate Effect of Materials under Compression 44

3.2.2 Strain Rate Effect of Materials under Tension 44

3.2.3 Strain Rate Effect of Materials under Shear 47

3.3 High-Strain-Rate Mechanical Testing 48

3.3.1 Intermediate-Strain-Rate Machines 48

3.3.2 Split Hopkinson Pressure Bar (SHPB) 53

3.3.3 Expanding-Ring Technique 61

3.4 Explosively Driven Devices 62

3.4.1 Line-Wave and Plane-Wave Generators 63

3.4.2 Flyer Plate Accelerating 65

3.4.3 Pressure-Shear Impact Configuration 66

3.5 Gun Systems 67

3.5.1 One-Stage Gas Gun 67

3.5.2 Two-Stage Gas Gun 68

3.5.3 Electric Rail Gun 69

Problems 3 69

4 Constitutive Equations at High Strain Rates 71

4.1 Introduction to Constitutive Relations 71

4.2 Empirical Constitutive Equations 72

4.3 Relationship between Dislocation Velocity and Applied Stress 76

4.3.1 Dislocation Dynamics 76

4.3.2 Thermally Activated Dislocation Motion 81

4.3.3 Dislocation Drag Mechanisms 85

4.3.4 Relativistic Effects on Dislocation Motion 85

4.3.5 Synopsis 86

4.4 Physically Based Constitutive Relations 87

4.5 Experimental Validation of Constitutive Equations 90

Problems 4 90

Part 3 Dynamic Response of Structures to Impact and Pulse Loading 91

5 Inertia Effects and Plastic Hinges 93

5.1 Relationship between Wave Propagation and Glob…