Modeling Inspectability for an Automated Eddy Current Measurement System

Abstract

The POD model we developed provides a measure of inspectability in the form of relative-operating-characteristic (ROC) curves and POD curves, demonstrating the ability of the model to quantitatively assess the crack-detection capability of our EG measurement station.

Eddy Current Corner Crack Inspection

“…The impedance measurements were carried out by using the automated EC measurement station reported earlier [4]. In the apparatus, a specimen is placed on a table which can be moved in two horizontal directions by stepper motors.…”

“…This year, the formulas presented there have been implemented into a numerical code, which now enables us to predict EC probe responses of corner cracks on a straight corner. We also wish to report on measurements taken with the automated EC measurement station [4]. Data were collected using both Al block and bolt hole specimens.…”

Probability of Detection (POD) for Nondestructive Evaluation (NDE)

“…Nakagawa, et al (1990) reported on their effort to develop a POD model for their automated eddy current measurement system. The heart of their automated system was a precision impedance analyzer capable of measuring impedance over a wide range of frequency (10 -10 Hz).…”

“…Data acquisition, processing, analysis, and display was via a personal computer, and a computercontrolled x-y positioning stage provided for either one or two dimensional scans of the specimen. (Nakagawa, et al 1990) …”