Identification of Aging Aircraft Electrical Wiring

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

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

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

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

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

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

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

8. 10x The Data Previous Cycle New Cycle

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

10. Aging Equipment • Kitchen Ovens • Can’t run continuously • Drying Ovens • Remove humidity • Incubators • Most don’t get hot enough • Environmental Chambers • Large temperature range • Humidity Control • Programmable • Too expensive (A Bluem Environmental Chamber) (Courtesy of www.lunaire.com)

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

12. Anticipated Results • Material characteristics should change • Texture • Coefficient of Friction • Capacitance • Resistance • Changes should be reflected in the triboelctric response, and are expected to follow a detectable pattern.

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

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

15. Anticipated Results Shaker/Wire Test Setup: • E = portion of energy output by shaker that is transmitted to wire through friction • E = σhoop(2πrL)µk|dx| • V = V(dE/dt, M1, M2) • where M1, M2 are material properties • We expect to find an empirical formula that describes how V changes with age L V dx Wire R Shaker

16. Anticipated Results • It’s expected that µk, M1, and M2 all change in a predictable manner as the wire deteriorates • At any particular time, the voltage induced in the wire can be described as a specific function of the excitation frequency • It is unclear whether or not this frequency response will change as the material properties of the wire (µk, M1, and M2 ) change

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

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

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

20. Identification of Aging Aircraft Electrical Wiring QUESTIONS ?