Surface Profiling and Core Evaluation of Aluminum Honeycomb Sandwich Aircraft Panels Using Multi-Frequency Eddy Current Testing

Surface damage on honeycomb aircraft panels is often measured manually, and is therefore subject to variation based on inspection personnel. Eddy current testing (ECT) is sensitive to variations in probe-to-specimen spacing, or lift-off, and is thus promising for high-resolution profiling of surface...

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Main Authors: Tyler Reyno, P. Ross Underhill, Thomas W. Krause, Catharine Marsden, Diane Wowk
Format: Article
Language:English
Published: MDPI AG 2017-09-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/17/9/2114
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spelling doaj-03b53e58dfe84eceb140ad423ae72e332020-11-24T21:58:37ZengMDPI AGSensors1424-82202017-09-01179211410.3390/s17092114s17092114Surface Profiling and Core Evaluation of Aluminum Honeycomb Sandwich Aircraft Panels Using Multi-Frequency Eddy Current TestingTyler Reyno0P. Ross Underhill1Thomas W. Krause2Catharine Marsden3Diane Wowk4Department of Mechanical and Aerospace Engineering, Royal Military College of Canada, Kingston, ON K7K 7B4, CanadaDepartment of Physics, Royal Military College of Canada, Kingston, ON K7K 7B4, CanadaDepartment of Physics, Royal Military College of Canada, Kingston, ON K7K 7B4, CanadaFaculty of Engineering and Computer Science, Concordia University, Montreal, QC H3G 1M8, CanadaDepartment of Mechanical and Aerospace Engineering, Royal Military College of Canada, Kingston, ON K7K 7B4, CanadaSurface damage on honeycomb aircraft panels is often measured manually, and is therefore subject to variation based on inspection personnel. Eddy current testing (ECT) is sensitive to variations in probe-to-specimen spacing, or lift-off, and is thus promising for high-resolution profiling of surface damage on aluminum panels. Lower frequency testing also allows inspection through the face sheet, an advantage over optical 3D scanning methods. This paper presents results from the ECT inspection of surface damage on an approximately flat aluminum honeycomb aircraft panel, and compares the measurements to those taken using optical 3D scanning technology. An ECT C-Scan of the dented panel surface was obtained by attaching the probe to a robotic scanning apparatus. Data was taken simultaneously at four frequencies of 25, 100, 400 and 1600 kHz. A reference surface was then defined that approximated the original, undamaged panel surface, which also compensated for the effects of specimen tilt and thermal drift within the ECT instrument. Data was converted to lift-off using height calibration curves developed for each probe frequency. A damage region of 22,550 mm2 area with dents ranging in depth from 0.13–1.01 mm was analyzed. The method was accurate at 1600 kHz to within 0.05 mm (2σ) when compared with 231 measurements taken via optical 3D scanning. Testing at 25 kHz revealed a 3.2 mm cell size within the honeycomb core, which was confirmed via destructive evaluation. As a result, ECT demonstrates potential for implementation as a method for rapid in-field aircraft panel surface damage assessment.https://www.mdpi.com/1424-8220/17/9/2114eddy currentmulti-frequency eddy currentsurface profilingsurface damagehoneycomb paneling
collection DOAJ
language English
format Article
sources DOAJ
author Tyler Reyno
P. Ross Underhill
Thomas W. Krause
Catharine Marsden
Diane Wowk
spellingShingle Tyler Reyno
P. Ross Underhill
Thomas W. Krause
Catharine Marsden
Diane Wowk
Surface Profiling and Core Evaluation of Aluminum Honeycomb Sandwich Aircraft Panels Using Multi-Frequency Eddy Current Testing
Sensors
eddy current
multi-frequency eddy current
surface profiling
surface damage
honeycomb paneling
author_facet Tyler Reyno
P. Ross Underhill
Thomas W. Krause
Catharine Marsden
Diane Wowk
author_sort Tyler Reyno
title Surface Profiling and Core Evaluation of Aluminum Honeycomb Sandwich Aircraft Panels Using Multi-Frequency Eddy Current Testing
title_short Surface Profiling and Core Evaluation of Aluminum Honeycomb Sandwich Aircraft Panels Using Multi-Frequency Eddy Current Testing
title_full Surface Profiling and Core Evaluation of Aluminum Honeycomb Sandwich Aircraft Panels Using Multi-Frequency Eddy Current Testing
title_fullStr Surface Profiling and Core Evaluation of Aluminum Honeycomb Sandwich Aircraft Panels Using Multi-Frequency Eddy Current Testing
title_full_unstemmed Surface Profiling and Core Evaluation of Aluminum Honeycomb Sandwich Aircraft Panels Using Multi-Frequency Eddy Current Testing
title_sort surface profiling and core evaluation of aluminum honeycomb sandwich aircraft panels using multi-frequency eddy current testing
publisher MDPI AG
series Sensors
issn 1424-8220
publishDate 2017-09-01
description Surface damage on honeycomb aircraft panels is often measured manually, and is therefore subject to variation based on inspection personnel. Eddy current testing (ECT) is sensitive to variations in probe-to-specimen spacing, or lift-off, and is thus promising for high-resolution profiling of surface damage on aluminum panels. Lower frequency testing also allows inspection through the face sheet, an advantage over optical 3D scanning methods. This paper presents results from the ECT inspection of surface damage on an approximately flat aluminum honeycomb aircraft panel, and compares the measurements to those taken using optical 3D scanning technology. An ECT C-Scan of the dented panel surface was obtained by attaching the probe to a robotic scanning apparatus. Data was taken simultaneously at four frequencies of 25, 100, 400 and 1600 kHz. A reference surface was then defined that approximated the original, undamaged panel surface, which also compensated for the effects of specimen tilt and thermal drift within the ECT instrument. Data was converted to lift-off using height calibration curves developed for each probe frequency. A damage region of 22,550 mm2 area with dents ranging in depth from 0.13–1.01 mm was analyzed. The method was accurate at 1600 kHz to within 0.05 mm (2σ) when compared with 231 measurements taken via optical 3D scanning. Testing at 25 kHz revealed a 3.2 mm cell size within the honeycomb core, which was confirmed via destructive evaluation. As a result, ECT demonstrates potential for implementation as a method for rapid in-field aircraft panel surface damage assessment.
topic eddy current
multi-frequency eddy current
surface profiling
surface damage
honeycomb paneling
url https://www.mdpi.com/1424-8220/17/9/2114
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