Hostname: page-component-78c5997874-dh8gc Total loading time: 0 Render date: 2024-11-13T05:03:04.214Z Has data issue: false hasContentIssue false
  • English
  • Français

Flap-wise loads reduction of rotor blades by embedded flap-wise absorbers

Published online by Cambridge University Press:  31 May 2016

D. Han
D. Han*
Affiliation:
National Key Laboratory of Science and Technology on Rotorcraft Aeromechanics, Nanjing University of Aeronautics and Astronautics, Nanjing, China
*
donghan@nuaa.edu.cn
Get access Rights & Permissions [Opens in a new window]

Abstract

Elastomeric and Fluidlastic® absorbers are proposed to be embedded in blade cavity to reduce troublesome second harmonic flap-wise blade loads of rigid rotors. A simple model of a blade with a flap-wise dynamic absorber is derived to investigate centrifugal force effects on the absorber's rotating frequency. The system's dynamic equations of motion indicate that centrifugal force has no effect on absorber's frequency under rotation. Aeroelastic simulation of the coupled rotor and absorber system based on an elastic beam model in generalised force formulation is used to explore load reduction extent and dynamic absorber behaviour. At a forward speed of 200 km/h, the elastomeric absorber reduces the second harmonic flap-wise root-bending moment by 88.8% for unacceptably large stroke; the Fluidlastic® absorber reduces the moment by 78.5% with a stroke 4.26% of blade chord length. Results indicate that placing an embedded Fluidlastic® absorber in the blade's flap-wise direction has potential for reducing load in different flight states with relatively small strokes. Increasing tuning port area ratio or Fluidlastic® absorber mass can distinctly decrease strokes without increasing loads. However, deviation from normal rotor speed significantly lowers Fluidlastic® absorber performance.

Keywords

Rotorflap-wise loadsreductionelastomeric absorberFluidlastic absorber
Type
Research Article
Information
The Aeronautical Journal , Volume 120 , Issue 1230 , August 2016 , pp. 1215 - 1229
Copyright
Copyright © Royal Aeronautical Society 2016 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Abbe, J.T.L., Blackwell, R.H. and Jenny, D.S. Advancing blade concept (ABC)™ dynamics, American Helicopter Society 33rd Annual Forum Proceedings, May 1977, Washington, DC, US.Google Scholar
2. Blackwell, R. and Millott, T. Dynamics design of the sikorsky X2 technology™ demonstrator aircraft, American Helicopter Society 64th Annual Forum Proceedings, 29 April-1 May 2008, Montreal, Canada.Google Scholar
3. Johnson, W. Helicopter Theory, 1980, Princeton University Press, Princeton, New Jersey, US.Google Scholar
4. Nitzsche, F. A comparative study on different techniques to control rotary wing vibration using smart structures, Aeronautical J., 1999, 103, (1027), pp 429–434.CrossRefGoogle Scholar
5. Milgram, J. and Chopra, I. Helicopter vibration reduction with trailing edge flaps, 36th AIAA/ASME/ASCE/AHS Structures, Structural Dynamics, and Materials Conference, 10-12 April 1995, New Orleans, Louisiana, US.Google Scholar
6. Fulton, M.V. and Ormiston, R.A. Small-scale rotor experiments with on-blade elevons to reduce blade vibratory loads in forward flight, American Helicopter Society 54th Annual Forum Proceedings, 20-22 May 1998, Washington, DC, US.Google Scholar
7. Kim, J.-S., Smith, E.C. and Wang, K.W. Active load control of an articulated composite rotor blade via dual trailing edge flaps, 44th AIAA/ASME/ASCE/AHS Structures, Structural Dynamics, and Materials Conference, 7-10 April 2003, Norfolk, Virginia, US.Google Scholar
8. Viswamurthy, S.R. and Ganguli, R. Using the complete authority of multiple active trailing-edge flaps for helicopter vibration control, J. Vibration and Control, 2008, 14, (8), pp 1175–1199, doi: 10.1177/1077546307081323.Google Scholar
9. Nguyen, K. and Chopra, I. Effects of higher harmonic control on rotor performance and control loads, J. Aircraft, 1992, 29, (3), pp 336–342.CrossRefGoogle Scholar
10. Norman, T.R., Theodore, C., Shinoda, P., Fuerst, D., Arnold, U.T.P., Makinen, S., Lorber, P. and O'Neill, J. Full-scale wind tunnel test of a UH-60 individual blade control system for performance improvement and vibration, loads, and noise control, American Helicopter Society 65th Annual Forum Proceedings, 27-29 May 2009, Grapevine, Texas, US.Google Scholar
11. Nitzsche, F., Zimcik, D.G., Wickramasinghe, V.K. and Yong, C. Control laws for an active tunable vibration absorber designed for rotor blade damping augmentation, Aeronautical J., 2004, 108, (1079), pp 35–42.Google Scholar
12. Ganguli, R. and Chopra, I. Aeroelastic optimization of a helicopter rotor with composite coupling, J. Aircraft, 1995, 32, (6), pp 1326–1334.Google Scholar
13. Murugan, M.S., Ganguli, R. and Harursampath, D. Surrogate based design optimization of composite aerofoil cross-section for helicopter vibration reduction, Aeronautical J., 2012, 116, (1181), pp 709–725.Google Scholar
14. Chiu, T. and Friedmann, P.P. An analytical model for ACSR approach to vibration reduction in a helicopter rotor-flexible fuselage system, Aeronautical J., 1997, 101, (1009), pp 399–408.Google Scholar
15. Han, D. and Smith, E.C. Lagwise loads analysis of a rotor blade with an embedded chordwise absorber, J. Aircraft, 2009, 46, (4), pp 1280–1290, doi: 10.2514/1.40569.CrossRefGoogle Scholar
16. McGuire, D.P. Fluidlastic® dampers and isolators for vibration control in helicopters, American Helicopter Society 50th Annual Forum Proceedings, 11-13 May 1994, Washington, DC, US.Google Scholar
17. Panda, B., Mychalowycz, E. and Tarzanin, F.J. Application of passive dampers to modern helicopters, Smart Materials and Structures, 1996, 5, (5), pp 509–516, doi: 10.1088/0964-1726/5/5/001.Google Scholar
18. Han, D., Wang, J., Smith, E.C. and Lesieutre, G.A. Transient loads control of a variable speed rotor during resonance crossing, AIAA J., 2013, 51, (1), pp 20–29, doi: 10.2514/1.J050598.CrossRefGoogle Scholar
19. Petrie, J.S., Lesieutre, G.A. and Smith, E.C. Helicopter blade lag damping using embedded fluid elastic chordwise inertial dampers, AIAA Paper 2004-1950, April 2004.Google Scholar
20. Hodges, D.H. and Dowell, E.H. Nonlinear equations of motion for the elastic bending and torsion of twisted non-uniform blades, NASA TND-7818, December 1974.Google Scholar
21. Straub, F.K., Sangha, K.B. and Panda, B. Advanced finite element modeling of rotor blade aeroelasticity, J. American Helicopter Society, 1994, 39, (2), pp 56–68.Google Scholar
22. Zheng, Z.C., Ren, G. and Cheng, Y.M. Aeroelastic response of a coupled rotor/fuselage system in hovering and forward flight, Archives of Applied Mechanics, 1999, 69, (1), pp 68–82, doi: 10.1007/s004190050205.Google Scholar
23. Leishman, J.G. and Beddoes, T.S. A semi-empirical model for dynamic stall, J. American Helicopter Society, 1989, 34, (3), pp 3–17.Google Scholar
24. Peters, D.A. and HaQuang, N. Dynamic Inflow for practical application, J. American Helicopter Society, 1988, 33, (4), pp 64–68.Google Scholar
25. Leishman, J.G. Principles of Helicopter Aerodynamics, 2nd ed., 2006, Cambridge University Press, New York, New York, US.Google Scholar