Location

Snowmass Village, CO

Start Date

1-1-1995 12:00 AM

Description

Eddy current nondestructive evaluation (NDE) is well known as an effective technique for detecting fatigue cracks in conducting materials [1]. Along with detection, it is also important to be able to size fatigue cracks. This sizing is difficult because eddy current phenomena do not in general allow a quantitative image to be obtained, rather, a characteristic signal is obtained from a test which is much like a defect fingerprint. Defect sizing is facilitated by calibration procedures, which utilize classification schemes. EDM notches are often used to produce reference signals which are then used in the classification schemes. There is, however, much discussion in the NDE community as to the accuracy of EDM notch reference standards for eddy current fatigue crack calibration [2–3]. In response to the need for accurate fatigue crack standards to be used for training a classification system for the NASA Space Shuttle main engine heat exchanger unit, a study was carried out comparing eddy current responses to EDM notches and fatigue cracks in stainless steel tubing.

Volume

14B

Chapter

Chapter 7: Materials' Degradation and Specific Applications

Section

Fatigue Damage and Crack Characterization

Pages

2043-2049

DOI

10.1007/978-1-4615-1987-4_261

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Eddy Current Calibration of Fatigue Cracks using EDM Notches

Snowmass Village, CO

Eddy current nondestructive evaluation (NDE) is well known as an effective technique for detecting fatigue cracks in conducting materials [1]. Along with detection, it is also important to be able to size fatigue cracks. This sizing is difficult because eddy current phenomena do not in general allow a quantitative image to be obtained, rather, a characteristic signal is obtained from a test which is much like a defect fingerprint. Defect sizing is facilitated by calibration procedures, which utilize classification schemes. EDM notches are often used to produce reference signals which are then used in the classification schemes. There is, however, much discussion in the NDE community as to the accuracy of EDM notch reference standards for eddy current fatigue crack calibration [2–3]. In response to the need for accurate fatigue crack standards to be used for training a classification system for the NASA Space Shuttle main engine heat exchanger unit, a study was carried out comparing eddy current responses to EDM notches and fatigue cracks in stainless steel tubing.