Semi-Elliptical Surface Flaw EC Interaction and Inversion: Theory

Semi-Elliptical Surface Flaw EC Interaction and Inversion: Experiment

“…The objective of this study was to make a serjes of carefully controlled measurements of eddy current flaw signals for well characterized, semielliptical flaws in aluminum and titanium alloys to compare with flaw signals calculated using theoretical models described in a companion paper [5]. Both real fatigue cracks and EDM simulations were studied.…”

“…The present paper describes an extensive series of measurements of flaw signals for both fatigue cracks and semi-elliptical EDM notches in aluminum and titanium alloys. The measured flaw signals are compared with theoretical predictions and are also used to test the inversion procedure based on the theory [5]. …”

“…The following year brought development of a full inversion procedure for rectangular flaws [3], which was successfully demonstrated using flaw signals measured for a series of rectangular electrical-discharge machined (EDM) notches in aluminum [4]. This year, in a companion paper [5], the model for interaction of nonuniform probe fields with flaws has been extended to semi-elliptical flaws. The present paper describes an extensive series of measurements of flaw signals for both fatigue cracks and semi-elliptical EDM notches in aluminum and titanium alloys.…”

Uniform Field Eddy Current Probe: Experiments and Inversion for Realistic Flaws

“…âZ depends on frequency only through the skin depth 6 = {2/~wa. âZ depends strongly upon the flaw length, but depends on flaw depth only through IO and 1 1 • The I's appropriate to rect angular and semi-elliptical flaws were calculated numerically last year at Stanford University and published in reference [3]. This year it was discovered that the values for I O for …”

Pickup coil spacing effects on eddy current reflection probe sensitivity

“…The probes commonly used in a production shop for nondestructive testing (NDT) are invariably wound on ferrite cores because of the increased sensitivity that results from the use of high magnetic permeability core materials. However, recent advances in the theory of flawfield interactions have stimulated interest in the use of air core probes [4,5]. The use of air core coils in the detector helps to minimize the complexity of the calculations and leaves the experimenter with very adequate tools for verification studies.…”