Electrical and Magnetic Methods of Non-destructive Testing

1 Introduction.- 1.1 General considerations.- 1.2 Methods of non-destructive testing.- 1.3 Electrical and magnetic methods.- 1.4 Choosing a method.- 1.5 Automation in non-destructive testing.- 1.6 Conclusion.- 1.7 Further reading.- 2 Fundamental theory.- 2.1 General considerations.- 2.2 Electrical conductivity and resistivity.- 2.3 Dielectric materials.- 2.4 Electromagnetism.- 2.5 Alternating currents.- 2.6 Circuit networks.- 2.7 Ferromagnetic materials.- 2.8 Electromagnetic radiation.- 3 Magnetic methods.- 3.1 Introduction.- 3.2 Flux leakage methods.- 3.3 Magnetic particle inspection (MPI).- 3.4 Magnetic tape inspection (magnetography).- 3.5 Quantitative flux leakage detectors.- 3.6 Quantitative flux leakage applications.- 3.7 Magnetization and hysteresis methods.- 3.8 Less common magnetic techniques.- 4 Eddy current principles.- 4.1 Introduction.- 4.2 Coils encircling defect-free metal rods.- 4.3 Coils encircling defect-free metal tubes.- 4.4 Internal coaxial coils in defect-free metal tubes.- 4.5 Coils scanning the surfaces of defect-free conductors.- 4.6 Defect modelling.- 5 Eddy current methods.- 5.1 General considerations.- 5.2 Fundamental measurements.- 5.3 Probe design.- 5.4 Requirements for eddy current measurements.- 5.5 Basic eddy current tests: measurements.- 5.6 Basic eddy current defect detection and sizing.- 6 More advanced eddy current testing methods.- 6.1 Automatic testing.- 6.2 Multifrequency testing.- 6.3 Remote field testing.- 6.4 Lift-off flaw detection.- 6.5 Pulsed eddy current testing.- 6.6 Microwave eddy current testing.- 6.7 Fibre-reinforced plastics.- 6.8 Neural networks.- 6.9 Defect imaging.- 7 Microwave methods.- 7.1 Introduction.- 7.2 Microwave radiation.- 7.3 Microwave instrumentation.- 7.4 Microwave measurements.- 8 Miscellaneous methods.- 8.1 General considerations.- 8.2 Potential drop methods.- 8.3 Resistance strain gauges.- 8.4 Electrified particle testing.- 8.5 Direct measurement of resistance or capacitance.- Appendices.- A Notes on units.- B Standards.- C Bessel functions.- D BASIC programs for predicting impedence components.- D.1 Coils encircling electrically conducting cylindrical rods.- D.2 Coils encircling electrically conducting cylindrical tubes.- D.3 Air-cored: scanning the surfaces of electrical conductors.- References.