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Sikorsky PSU

Sikorsky PSU. Passive Vibration Isolation System. Catching Up…. Implement a Dynamic Anti-Resonant Vibration Isolator to isolate the blade passing frequency. Maintain system stiffness to minimize roll and vertical deflection.

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Sikorsky PSU

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  1. Sikorsky PSU Passive Vibration Isolation System

  2. Catching Up… Implement a Dynamic Anti-Resonant Vibration Isolator to isolate the blade passing frequency Maintain system stiffness to minimize roll and vertical deflection Add second accelerometer to measure the acceleration at the base and seat

  3. What we had to work with…

  4. History of the DAVI System First Patented by Michael Flannelly, an engineer at Kaman Aerospace in 1967 Continued research for 7 years by Robert Jones until 1974 Boeing sponsored research that was started to develop a DAVI System for their in-house research for a crew deck module The DAVI System concept is a basis for Bell’s LIVE vibration isolators as well as Lord’s Fluidlastic vibration isolators To our knowledge there was no attempt to apply the DAVI System to a crew seat or a pilot seat

  5. Theory of the DAVI System A passive vibration isolator that involves a moving mass and spring system interposed between the isolated body and the base A tuned anti-resonant frequency theoretically gives 100% isolation Anti-resonant frequency is independent of the mass of the isolated body.

  6. Claim 1: Achieve nearly 100% isolation at the tuned frequency Anti-resonant frequency is dependent on the spring rate of the system, ratio of R/r, the moment of inertia, and the weight of the auxiliary mass

  7. Claim 2: Isolation at its tuned frequency is independent of the isolated mass

  8. Claim 3: Isolation can be accomplished with a small static deflection Isolation can be achieved using a very stiff spring system allowing the seat to experience minimum deflection

  9. Claim 4: Achieve isolation using as little as 2% of the total isolated mass (seat + passenger) Robert Jones was able to isolate the rotor vibrations in a KAMAN UH-2 helicopter with low static deflection and with 2% of the design mass of the helicopter The KAMAN UH-2 helicopter weighed 4536 kg and the isolation system only weighed 93.44 kg! It only took Robert Jones 7 years to complete this task so 15 weeks should be plenty of time for us!

  10. The design of the DAVI System features several components DAVISystem Springs and Caps Lever Arm Brackets Weights Shafts and Couplers

  11. The design of the data acquisition system features several components SeatAccelerometer Mounting Bracket Wiring and soldering Adjusting the BASIC ATOM code

  12. Designing around the constraints and restrictions involved with a helicopter has been a real challenge System must be passive and light-weight Large deflections of the seat could cause the pilot to loose control of the aircraft Only a small area under the seat is available ( 4” x 15” x 15” ) Targeted frequency must be isolated for a variety of different pilot weights

  13. To account for unknown variables, the system has been designed to allow adjustment Using a threaded rod for the lever has allowed an easy adjustment of the R length Putting threads on the weight has made changing the effective mass simple To allow for different sized springs, spacers have been used under the bracket to raise or lower the bracket and DAVI bar

  14. The equations contained in the original patent were used to design the system as well as SolidWorks’ CosmosMotion

  15. Design for Manufacture played and important role in the development of our components The brackets and coupler links have been made from stock aluminum. All bolts used were common ¼ x 20, standardizing the previously used mix-match bolts. Bearings and threaded rod can be ordered from any industrial supplier

  16. To improve production times Design for Assembly was considered for all parts The bearings, shafts, and couplers are press-fit together in one motion

  17. The Manufacturing and Assembling process can be improved Using U-channel instead of bar stock will decrease the machining time Shortening the length of brackets will allow the entire DAVI System to be smaller

  18. A video of the working DAVI System shows the difference in G-Forces between the seat (.01g RMS) and the base (.24g RMS)

  19. Claim: The DAVI System can reduce vibrations at a targeted frequency by 100% Confirmation: The DAVI System reduced vibrations at 17Hz by 96%

  20. Claim: The DAVI System is independent of the isolated mass at the isolation frequency Confirmation: The DAVI System reached .01g (RMS) with varying masses

  21. Claim: Isolation can be accomplished with a small static deflection Confirmation: The DAVI System reached .01g (RMS) with 4120 lb/in spring system

  22. Claim: The DAVI System can achieve isolation using as little as 2% of the total isolated mass (seat + passenger) Confirmation: The DAVI System was 3.70% of the total mass The DAVI System weighed 7.5lbs Total isolated mass was 202 lbs (with 175lb passenger) Changes could be made to reduce unnecessary mass in the DAVI System A reduction of 3.5 lbs would reach the theoretical 2% mark

  23. The DAVI System drastically reduces the magnitude of visual impairment when compared to a non-isolated system (the base) Non-Isolated Isolated

  24. DAVI system could be implemented in multiple applications Implemented in a new Sikorsky BlackHawk helicopter Used as a low cost fix for an older helicopter with vibration problems Not limited to only helicopter use

  25. While preparing for the showcase, we encountered an electricity problem This is the plug we have Rating: 20A, 250V This is the HUB’s outlet Rating: 50A, 125/250V

  26. We also need to transport our box and seat system to the showcase Weight: 325 lbs Volume: 4’ x 3’ x 6’

  27. Questions?

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