Final Design Review

1. Final Design Review Fri aei ynCucfed Janine CrsohrO Mihe ernc T io MEMS-based Corrosion Health Monitoring Liaison Engineers: Pec uces Tr lw Faculty Coach: Jh .AboePD E

2. Introduction • Corrosion occurs on electronic chassis of aircraft • causes loss of integrity of EMI seal • Lockheed Martin technicians • responsible for avoiding critical corrosion damage • monitor the health of the chassis on a scheduled basis • the chassis is relatively inaccessible within the aircraft • in most cases, the chassis is corrosion free • time and money are wasted by this inefficiency

3. Aim • To reduce unnecessary corrosion related service activities with a stand alone system that can alert a technician of a needed inspection • Reliable measurement of the environmental corrosivity seen by the chassis • LED alert system • viewed from exterior of the chassis • 1-10 level of need for service activity

4. Business Case • Life cycle cost for the Apache Helicopter fleet* $14.3 billion • Percent Dedicated to Inspection** x 25% ------------------ • Inspection cost for the Apache Helicopter $3.575 billion • Percent inspections eliminated by SDX-4912 x 33% ------------------ • TOTAL PROGRAM SAVINGS $1.18 billion • Life cycle of Apache helicopter* ÷ 20 years ------------------ • TOTAL ANNUAL SAVINGS* $59 million • TOTAL LIFE CYCLE SAVINGS/helicopter*** $1.5 million *These estimates, in constant fiscal 1994 dollars, are provided in Annex D of the Longbow Apache Test and Evaluation Master Plan, which cites December 1993 estimates from the Longbow Program Office and the President’s fiscal 1995 budget as the original source. **Provided from the Military Analysis Network created by the FAS, Federation of American Scientists (non-profit, tax exempt, 501c3organization) ***Costs assuming that the SDX-4912 is installed in full apache fleet (assuming fleet size ≈ 800)

5. Elements of Chassis • Galvanic coupling of aluminum and nickel • Aluminum = anode • Nickel = cathode • Electrolyte provides driving force for corrosion

6. Galvanic Corrosion • As a result of nickel contact: • Corrosion potential of aluminum (M) increased • Corrosion rate of aluminum (M) is increased Nickel Aluminum Couple

7. Customer Requirements GENERAL NEEDS: Operate Under Harsh Conditions Non-Intrusive Feedback Long Life Span MEMS Based Light Weight Small Size

8. Hardware Design

9. Hardware Design Functional Diagram

10. Dimmed elements denote exploratory efforts not included in final design Hardware Design

11. Macroscopic System

12. Hardware Design Electrical Resistance Sensor Concept: • Near Linear Approximation • Module Expiration Detection • Manufacturability R = V / Iappl R = ρL / πr2

13. Sensor Sampling • Data sample taken hourly • All data stored on Flash • Light Emitting Diodes (LEDs) • 4 red, 3 yellow, 2 green • 1-10 level of corrosion damage • Relate to need for technician to perform service activity • Level 7 (1st Red LED) correlates to critical corrosion damage

14. DA Output Method • Corrosion will cause reduction in ER sensor’s cross-sectional area • At critical % area reduction critical voltage

15. Sensor Sampling Control Wire

16. Testing

17. Verification Testing • Hardware Unit Test • Sensor Proof of Concept • 5 days in Salt Spray Machine • Software Unit Test • Data Interface to software and LED display • Acceptance Testing • Functional Acceptance Test (Integration) • Environmental Acceptance Test (Survivability)

18. Proof of Sensor Concept • 48 hour test -24 hours immersed in salt bath -24 hours in atmosphere

19. Proof of Sensor Concept • Ground to 50% diameter along longitudinal plane and polished • Large cathode (Ni) to anode (Al) ratio Damage to nickel plating on aluminum wire

20. Testing • ASTM B117 Salt Fog Chamber • Constant corrosive vapor applied for 5 days • 5 Test coupons removed at daily intervals • Data samplings recorded as voltages • Recorded using a datalogger • Data sampling = once per minute Example of Salt Spray Chamber

21. Wireless - ZigBee • Proven feasible up to 6” thickness of casing • Due mainly to chamber reflections • Minimal aperture required • Wireless communication pursuit ended 2/7/05 given risk and manpower

22. Testing Results

23. Results

25. Results • ASTM D3359 Coating Adherence Test • Measures Amount of Undercut Nickel Plating • Designations: 5A (Least Corrosion)–0A (Most Corrosion) • 5 coupons tested • 24 hr: 5A • 48 hr: 4A • 71 hr: 2A • 139 hr (1): 1A • 139 hr (2): 2A Coupon 139 hr (1)

26. Measurement Correlation • Coupons • Minimal corrosion product for 24 & 48 hr coupons • Visible Al203 for 71 &139 hr coupons • Measurements • Rapid Increase in ER sensor at onset • Minimal Corrosion Product forming • Al+3 ions lost in aqueous solution • Resistance change levels off • Corrosion product protection

27. Sensor Lifespan • Electrical resistance sensor • Survived 5-day salt fog • Provided data throughout lifespan of operating board • Temperature • Survived 2-day salt fog • Humidity • Survived 1-day salt fog • Potentially a conformal coating problem on board

28. Environmental Survivability • Harshest of Possible Environments • Environmental Sensors • not conformally coated • survivable in constant spray for 1-2 days • Macroscopic System • conformal coating spot failures spot corrosion • emitted heat from conducting wires • survivable in constant spray for 4 days

29. Prototype Demonstration

30. LEVEL 7

31. 2 3 4 6 7 5 1

38. Conclusion

39. Recommendations • Wireless Link • Stand-Alone Custom GUI • Additional Low Power Research • Laser Etched Sensor Manufacturing

40. Acknowledgements • Thank You… • Lockheed Martin • eyunss • lew • ling • Kaara • University of Florida • ohnAoPE • ithanfillD, • an M • Marilyn Marlow

41. Questions