Bowler Eddy-Current Nondestructive Evaluation

1. Auflage 2019
ISBN: 978-1-4939-9629-2
Verlag: Springer
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 232 Seiten

Reihe: Springer Series in Measurement Science and Technology

This book covers the topic of eddy current nondestructive evaluation, the most commonly practiced method of electromagnetic nondestructive evaluation (NDE). It emphasizes a clear presentation of the concepts, laws and relationships of electricity and magnetism upon which eddy current inspection methods are founded.  The chapters include material on signals obtained using many common eddy current probe types in various testing environments. Introductory mathematical and physical concepts in electromagnetism are introduced in sufficient detail and summarized in the Appendices for easy reference. Worked examples and simple calculations that can be done by hand are distributed throughout the text. These and more complex end-of-chapter examples and assignments are designed to impart a working knowledge of the connection between electromagnetic theory and the practical measurements described.  The book is intended to equip readers with sufficient knowledge to optimize routine eddy current NDE inspections, or design new ones. It is useful for graduate engineers and scientists seeking a deeper understanding of electromagnetic methods of NDE than can be found in a guide for practitioners.


Nicola was educated in physics at the University of Nottingham, UK, and conducted her PhD thesis research at the University of Surrey, UK, solving canonical problems of eddy-current nondestructive evaluation analytically using perturbation theory, the Wiener-Hopf method and an adapted form of the geometrical theory of diffraction. The latter piece of work was published in the Proceedings of the Royal Society.  Nicola moved to the USA in 1999 to join Iowa State University's Center for Nondestructive Evaluation as a research scientist, and joined the Department of Materials Science and Engineering at Iowa State University as an Associate Professor in 2006, obtaining tenure and promotion to the rank of Professor in 2012 and becoming a Fellow of the UK Institute of Physics in 2013.  
Nicola's research interests include nondestructive evaluation and materials characterization using eddy-current, four-point probe, capacitive and microwave sensors, and broadband dielectric spectroscopy applied, variously, to structural steels, metal powder, electrical insulation polymers and polymer-based composites.  Nicola enjoys teaching courses in electronic properties of materials and eddy current nondestructive evaluation to senior undergraduates and graduate research students in engineering, for whom she hopes that this book will be helpful.  She credits the late R. Bruce Thompson for supporting the writing of this book in its early stages, and her husband John R. Bowler for helping to envision it.

Autoren/Hrsg.

Bowler, Nicola

Inhaltsverzeichnis

1;Preface;8
2;Contents;12
3;1 Introduction;17
3.1;1.1 Introduction;17
3.2;1.2 Historical Background;18
3.2.1;1.2.1 Michael Faraday;18
3.2.2;1.2.2 Joseph Henry;20
3.2.3;1.2.3 David Hughes;20
3.2.4;1.2.4 Friedrich Förster;21
3.3;1.3 Electromagnetic Induction;21
3.4;1.4 Eddy-Current Nondestructive Evaluation;23
3.5;1.5 Air-Cored Coil;23
3.6;1.6 Summary;25
3.7;1.7 Exercises;25
3.8;References;26
4;2 Fields;27
4.1;2.1 Introduction;27
4.2;2.2 Current Density;28
4.3;2.3 Alternating Current and Phasor Representation;29
4.4;2.4 Conductivity and Resistivity;32
4.5;2.5 Electric Field;35
4.6;2.6 Magnetic Field;36
4.7;2.7 Poynting Vector;37
4.8;2.8 Permeability and Magnetic Induction;38
4.9;2.9 Electromagnetic Skin Effect;39
4.10;2.10 Polarization and Electric Displacement;43
4.11;2.11 Summary;44
4.12;2.12 Exercises;44
4.13;References;45
5;3 Ferromagnetic Materials;46
5.1;3.1 Introduction;46
5.2;3.2 Fundamental Source of the Magnetic Field;47
5.3;3.3 Magnetization;48
5.3.1;3.3.1 Rayleigh Law;50
5.4;3.4 Hysteresis;51
5.5;3.5 Permeability;52
5.6;3.6 Ferromagnetic Domains;54
5.6.1;3.6.1 Why do Domains Form?;54
5.6.2;3.6.2 Domain Walls;55
5.6.3;3.6.3 Domain Processes During Magnetization;56
5.6.4;3.6.4 Hard and Soft Ferromagnets;57
5.6.5;3.6.5 Evidence for the Existence of Domains;57
5.6.6;3.6.6 The Curie Temperature, TC;58
5.7;3.7 Demagnetization;59
5.8;3.8 Summary;61
5.9;3.9 Exercises;61
5.10;References;61
6;4 Circuits;62
6.1;4.1 Introduction;62
6.2;4.2 Electromotance and Potential Difference;62
6.3;4.3 Resistance;63
6.4;4.4 Capacitance;64
6.5;4.5 Discharge of a Capacitor Through a Resistor;65
6.6;4.6 Forced Oscillation of an RC Circuit by Alternating Electromotance;66
6.7;4.7 Inductance;67
6.8;4.8 Forced Oscillation of an LRC Circuit by Alternating Electromotance;68
6.9;4.9 Impedance;69
6.10;4.10 Frequency Response of an LRC Circuit;70
6.11;4.11 Equivalent Electrical Circuit for an Eddy-Current Probe;71
6.12;4.12 Summary;72
6.13;4.13 Exercises;72
6.14;References;73
7;5 Maxwell's Equations;74
7.1;5.1 Introduction;74
7.2;5.2 Faraday's Law;75
7.3;5.3 Maxwell–Ampère Law;77
7.3.1;5.3.1 Quasi-static Regime;78
7.4;5.4 Gauss' Law;79
7.5;5.5 Gauss' Law for Magnetic Fields;79
7.5.1;5.5.1 Magnetic Vector Potential;80
7.6;5.6 Interface Conditions on the Electromagnetic Field;80
7.7;5.7 Summary;83
7.8;5.8 Exercises;84
7.9;References;85
8;6 Signals and Coils;86
8.1;6.1 Introduction;86
8.2;6.2 Coil Impedance;88
8.2.1;6.2.1 Isolated Coil Impedance, Z0;88
8.2.2;6.2.2 Coil Impedance in the presence of a Conductor, Z, and the Impedance-Plane Plot;89
8.2.3;6.2.3 Coil Impedance Change Due to a Flaw, ?Z;92
8.3;6.3 Surface Coil;93
8.3.1;6.3.1 Excitation of a Half-Space Conductor by a Uniform Current Sheet;95
8.3.2;6.3.2 Circular Current Loop in Air;98
8.3.3;6.3.3 Circular Current Loop above a Half-Space Conductor;103
8.3.4;6.3.4 Coil above a Half-Space Conductor;108
8.3.5;6.3.5 Ferrite Core;112
8.3.6;6.3.6 Sources of Uncertainty;114
8.4;6.4 Tangent Coil;123
8.5;6.5 Encircling Coil;124
8.5.1;6.5.1 Circular Current Loop Encircling a Solid Cylindrical Conductor;127
8.5.2;6.5.2 Coil Encircling a Solid Cylindrical Conductor;131
8.5.3;6.5.3 Sources of Uncertainty;133
8.6;6.6 Bobbin Coil;133
8.6.1;6.6.1 Sources of Uncertainty;134
8.7;6.7 Summary;135
8.8;6.8 Exercises;136
8.9;References;138
9;7 Layered and Truncated Conductors;140
9.1;7.1 Introduction;140
9.2;7.2 Layered Conductors;141
9.2.1;7.2.1 Planar Conductor with an Arbitrary Number of Layers;141
9.2.2;7.2.2 Coated Half-Space Conductor;143
9.2.3;7.2.3 Plate Conductor;144
9.2.4;7.2.4 Cylindrical Conductor with an Arbitrary Number of Layers;144
9.2.5;7.2.5 Coated Cylindrical Conductor;146
9.2.6;7.2.6 Tube Conductor;148
9.3;7.3 Truncated Conductors;149
9.3.1;7.3.1 Truncated Region Eigenfunction Expansion Method;151
9.3.2;7.3.2 Wedge and Plate Edge;151
9.3.3;7.3.3 End Effects and Cylindrical Conductors;152
9.4;7.4 Summary;154
9.5;7.5 Examples;154
9.6;References;154
10;8 Probes;156
10.1;8.1 Introduction;156
10.2;8.2 Absolute Probe;157
10.3;8.3 Differential Probe;159
10.4;8.4 Driver Pick Up Probe;163
10.5;8.5 Plus-Point Probe;164
10.6;8.6 Array Probes;165
10.7;8.7 Flexible Probes;166
10.8;8.8 Hall Sensor Probes;167
10.8.1;8.8.1 The Hall Effect;167
10.8.2;8.8.2 Defect Detection with the Hall Sensor;170
10.8.3;8.8.3 Hall Sensors and Transient EC NDE;171
10.8.4;8.8.4 Hall Sensor Arrays;172
10.8.5;8.8.5 Conclusion;173
10.9;8.9 Giant Magnetoresistor (GMR) Probes;174
10.9.1;8.9.1 The Giant Magnetoresistive Effect;175
10.9.2;8.9.2 Defect Detection with the GMR Sensor;176
10.9.3;8.9.3 GMR Sensors and Transient EC NDE;177
10.9.4;8.9.4 GMR Arrays;177
10.9.5;8.9.5 Conclusion;178
10.10;8.10 Summary;178
10.11;8.11 Exercises;178
10.12;References;179
11;9 Flaw Models;182
11.1;9.1 Introduction;182
11.2;9.2 Reciprocity Theorem and ?Z;183
11.2.1;9.2.1 Coil and Flaw;184
11.2.2;9.2.2 Two Coils;185
11.3;9.3 The Dipole;186
11.3.1;9.3.1 Electric Dipole;186
11.3.2;9.3.2 Current Dipole;188
11.3.3;9.3.3 Magnetic Dipole;188
11.4;9.4 Small Flaws;188
11.4.1;9.4.1 Subsurface Sphere;190
11.4.2;9.4.2 Surface Defects;197
11.5;9.5 High-Frequency ``Thin-Skin'' Treatment of Surface Cracks;198
11.5.1;9.5.1 Poynting Vector and Z;199
11.5.2;9.5.2 Current-Sheet Excitation of an Unflawed Half-Space;199
11.5.3;9.5.3 Definition of an Ideal Crack;200
11.5.4;9.5.4 Long Crack in a Uniform Field;200
11.5.5;9.5.5 Semicircular Crack in a Uniform Field;204
11.5.6;9.5.6 Long Crack in a Coil Field;205
11.5.7;9.5.7 Rectangular Crack in a Coil Field;205
11.5.8;9.5.8 Semielliptical Crack in a Coil Field;208
11.5.9;9.5.9 Epicyclic Crack in a Coil Field;208
11.6;9.6 Other Regimes;211
11.7;9.7 Summary;211
11.8;9.8 Exercises;212
11.9;References;213
12;10 Appendices;214
12.1;10.1 Complex Numbers;214
12.2;10.2 Trigonometry;215
12.3;10.3 Vector Analysis;215
12.3.1;10.3.1 Continuity and Differentiability;216
12.3.2;10.3.2 Differential Operators;216
12.3.3;10.3.3 Circular–Cylindrical Coordinates;218
12.3.4;10.3.4 Spherical-Polar Coordinates;219
12.3.5;10.3.5 Differential Relationships;220
12.3.6;10.3.6 Integral Theorems;220
12.4;10.4 Bessel Functions;221
12.4.1;10.4.1 Separation of Variables;222
12.4.2;10.4.2 Higher Order Bessel Functions;224
12.5;10.5 Exercises;225
12.6;References;227
13;Index;228