1. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Yushi Sun - Innovative Materials Testing Technologies, Inc. John C. Brausch, Kenneth LaCivita, Lt William Sanders - U. S. Air Force Research Laboratory 1

2. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft Acknowledgements The authors would like to express their appreciation and great thanks to Jeff A. Register and Michael J, Fortman, Northwest Airlines[1], and Captain D. J. Butcher, Canadian Air Force, for their providing the test samples, test requirements and comments to IMTT.[1] The authors would like also to express their appreciation and great thanks to Dr. Ward D. Rummel, D&W Enterprises, LTD, for his careful view and valuable comments to this paper. [1][1] Jeff A. Register and Michael J, Fortman were with Northwest Airlines when they were involved in the work, Application No. 6, stated in this paper. Now they are working with Aerotechinics NDT, Inc.

3. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft 2 Introduction Current Tend of Utilizing Composite-Metal Structure in New & Old Airplanes New Demand to NDT – Inspection of Metals through Composite FG_RFEC Technique is Characterized by its Deep Penetration Purpose of This Paper: Introduce New Applications of FG_RFEC Technique in Inspection Metals Through Composite and others

4. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft 3 Six Examples 1.Detection of aluminum layer crack through 1.5” of polycarbonate 2.Detection of aluminum layer crack through 0.52” – 0.90” graphite epoxy composite 3.Detection of titanium layer crack through 0.25” – 0.50” graphite epoxy composite 4.Detection of cracks on titanium layer through graphite epoxy composite and suppression of sealant groove signals 5.Detection of crack 0.50” below aluminum structure surface (simulating CC130 Structure) 6.Detection of fine surface and subsurface cracking on curved steel surface (Airbus A-320 Landing Gear Structure)

5. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft 4 Probes

6. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft 5 SSEC System

7. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft 6 Example #1: Detection of aluminum layer crack through 1.5” of polycarbonate Three 7”×13” polycarbonate pieces with thicknesses: 567-007 – 0.567”; 483-007 – 0.483” 442-007 – 0.442” A 9.0”×1.25”×0.20” aluminum strip attached below Two layersOne layerThree layers Probe Aluminum Strip Probe Strip under inspection Probe

8. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft 7 T = 0.567”

9. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft 8

10. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft 9 Maximum Y = 0.1215v f = 200Hz Three Layers, T ~ 1.50”

11. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft 10 Example #2: Detection of aluminum layer crack through 0.52” – 0.90” graphite epoxy composite Specimens T = 0.520” or 0.896”

12. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft T = 0.520” Set #1 Set #2

13. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft T = 0.896” Set #1 Set #2

14. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft Example #3: Detection of titanium layer crack through 0.25” – 0.50” graphite epoxy composite Crack sizes: 0.250”, 0.500” and 0.750” Composite Thickness:0.250”, 0.333” and 0.500” Specimens

15. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft With Composite Sample #2 Thickness = 0.250” With Composite Sample #3 Thickness = 0.334” With Composite Sample #4 Thickness = 0.500” Summary of Test Results

16. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft Example #4: Detection of Ti layer crack through graphite epoxy composite and suppression of sealant groove signals Specimen

17. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft Rotational Probe RF4 ROT Scanning around Fastener

18. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft Case 1: Horizontal Groove is on top Case 2: Vertical Groove is on top Pickup

19. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft Example # 5: Detection of crack 0.50” below aluminum structure surface Using Rotational Probe (CC130)

20. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft Example #5: Detection of fine surface and subsurface cracking on curved steel surface (A-320 Landing Gear) 0.030”×0.030” upper EDM  0.080” hidden hole drilled from top cut section 0.030”×0.030” lower EDM Possible crack area

21. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft Rf2 V.3 Sliding Probe + Specially Designed Holder

22. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft Hidden hole F = 1.0 kHz Lower 0.030”×0.030” EDM F = 40.0 kHz Upper 0.030”×0.030” EDM F = 40.0 kHz

23. Innovative Materials Testing Technologies, Inc. Air Force Research Laboratory Session 27 - REMOTE FIELD EDDY CURRENT MILITARY AND COMMERCIAL PLATFORM APPLICATIONS Sun, Brausch, LaCivita and Sanders- 9 th Joint FAA/DoD/NASA Conference on Aging Aircraft Summary 1.Metallic layer cracks underneath thick composite layer are detectable using FG_RFEC technique – sliding probes or rotational probes; 2.Groove signal can be effectively suppressed using a band-pass filter; 3.FG_RFEC technique working with SSEC system is capable of detecting deeply hidden cracks and fine surface and subsurface cracking with high sensitivity. 4.The next step is to assess existing or new inspections, now available to our industry, to find the right fit and application of this advanced technology.