1. Identification of Aging Aircraft Electrical Wiring Woolrich Engineering Consulting Firm Group Members: Robert Beremand Chad Hanak Melissa Straubel Sponsors: Dr. R.O. Stearman Marcus Kruger (“Identification of Aging Aircraft Electrical Wiring,” December 2002)

2. History of the Problem b Solutions Visual inspectionVisual inspection –Impractical Triboelectric responseTriboelectric response –May indicate condition of wire (“Identification of Aging Aircraft Electrical Wiring,” December 2002) b Faulty electrical wiring Chafing and cracking insulationChafing and cracking insulation Electrical firesElectrical fires ArcingArcing

3. Overview b History of the Problem b Triboelectric Effect b Project Objective b Wire Specimen b Lab Aging b Age Analysis b Work to be Completed

4. Triboelectric Effect b Static Electricity b Frictional force causes charge imbalance b Induced current unwanted noise and interference b Magnitude is dependent on numerous factors (“Identification of Aging Aircraft Electrical Wiring,” December 2002)

5. Project Objectives b Age Analysis Does age influence triboelectric effect? Determine signal response to inputs Relate age to measured triboelectric response vibration  wire  current b Laboratory Aging Simulate aging through:Simulate aging through: –temperature & humidity –Hot and cold –Jet-A fuel –saltwater solution –Temperature cycling –combination of all Visual/Touch inspectionVisual/Touch inspection

6. Alpha Wire Specimen b Kapton too expensive hard to obtain b Alpha Wire 1632 Copper wire with rubber insulation 20 Gauge (thick) Stranded, Tinned Copper Rubber Insulation Low temperature tolerance -30 o to 90 o C b Alpha Wire 5825 28 Gauge (thin) Stranded, Silver-plated Copper Teflon insulation -60 o to 105 o C Low Friction High Chemical Resistances (Alpha 1632) (Alpha 5852)

7. Overview b History of the Problem b Triboelectric Effect b Project Objective b Wire Specimen b Lab Aging b Age Analysis b Work to be Completed

8. 10x The Data Remove 1 Sample at a Time Test Sample and Do Not Return it Aging Process Remove all 10 Samples Test Samples Return Samples to Aging Process Aging Process Previous CycleNew Cycle

9. Current Work Phase I: Laboratory Aging b Temperature and Humidity Previous success with heat alonePrevious success with heat alone –Go hotter Add Cold TestAdd Cold Test Temperature Cycles, Temperature ExtremesTemperature Cycles, Temperature Extremes Limited previous results from humidity aloneLimited previous results from humidity alone –Combine temperature and humidity exposure –Freezing and Thawing Tension test ?Tension test ? b Corrosives Jet-A fuel SoakJet-A fuel Soak –Visually obvious effects in previous work, swelling Saltwater SoakSaltwater Soak Residue Effects?Residue Effects? –Graphite lubricant b Combination Cycle

10. Aging Equipment b Kitchen Ovens Can’t run continuouslyCan’t run continuously b Drying Ovens Remove humidityRemove humidity b Incubators Most don’t get hot enoughMost don’t get hot enough b Environmental Chambers Large temperature rangeLarge temperature range Humidity ControlHumidity Control ProgrammableProgrammable Too expensiveToo expensive (A Bluem Environmental Chamber) (Courtesy of www.lunaire.com)

11. Aging Equipment b Zoology to the rescue! Old IncubatorOld Incubator –Humidity control –Adequate heat ? –Working condition –FREE ! Old FreezerOld Freezer –No humidity control –Needs cleaning –FREE ! (The Freezer) (The Zoology Building ( locked on Sundays )) (Courtesy of www.utexas.edu)

12. Anticipated Results b Material characteristics should change TextureTexture Coefficient of FrictionCoefficient of Friction CapacitanceCapacitance ResistanceResistance b Changes should be reflected in the triboelctric response, and are expected to follow a detectable pattern.

13. Overview b History of the Problem b Triboelectric Effect b Project Objective b Wire Specimen b Lab Aging b Age Analysis b Work to be Completed

14. Current Work Phase II: Age Analysis b Reconfigure test setup to reduce Electro- Magnetic Interference (EMI) Separate data acquisition unit and signal amplifierSeparate data acquisition unit and signal amplifier Connect cases of all units to common groundConnect cases of all units to common ground Encase units in grounded foil to shield from EMIEncase units in grounded foil to shield from EMI Test for presence of EMI using an EMF meter (to be acquired)Test for presence of EMI using an EMF meter (to be acquired) Make twisted pairs to partially cancel out magnetic inductanceMake twisted pairs to partially cancel out magnetic inductance –Tighter twists are more effective

15. Anticipated Results dx Shaker Wire V E = portion of energy output by shaker that is transmitted to wire through friction E = σ hoop (2πrL)µ k |dx| V = V(dE/dt, M 1, M 2 ) where M 1, M 2 are material properties We expect to find an empirical formula that describes how V changes with age L R Shaker/Wire Test Setup:

16. Anticipated Results b It’s expected that µ k, M 1, and M 2 all change in a predictable manner as the wire deteriorates b At any particular time, the voltage induced in the wire can be described as a specific function of the excitation frequency b It is unclear whether or not this frequency response will change as the material properties of the wire (µ k, M 1, and M 2 ) change

17. Work to be Completed b Acquire aging equipment Have freezer inspected by UTHave freezer inspected by UT Get technician from Labline to examine incubatorGet technician from Labline to examine incubator b Build new wire testing apparatus b Cut and twist wire samples b Construct EMF shielding

18. Work to be Completed b Buy EMF meter to verify that EMI has been eliminated b Verify test setup b Acquire used wire from aviation scrap yard in Dallas b Conduct age analysis on wire specimens

19. Conclusion b History of the Problem b Triboelectric Effect b Project Objectives b Wire Specimen b Lab Aging b Age Analysis b Work to be Completed

20. Identification of Aging Aircraft Electrical Wiring QUESTIONS ?