Rotary-wing aeroelasticity - Current status and future trends

39th Aerospace Sciences Meeting and Exhibit

Volumn , Issue , 2001, Pages

  Friedmann, Peretz P ^a  

^a UNIVERSITY OF MICHIGAN   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

AERODYNAMIC STALLING; AEROSPACE ENGINEERING; ELASTIC WAVES; TURBOMACHINE BLADES; VIBRATION ANALYSIS; WINGS;

BEARINGLESS ROTOR; COMPOSITE ROTOR BLADE; CURRENT STATUS; ELASTOMERIC LAG DAMPER; RESEARCH ACTIVITIES; STATE OF THE ART; UNSTEADY AERODYNAMICS; VIBRATION REDUCTIONS;

AEROELASTICITY;

EID: 85088760916     PISSN: None     EISSN: None     Source Type: Conference Proceeding    
DOI: 10.2514/6.2001-427     Document Type: Conference Paper

References (124)

1. Anon., 2GCHAS Theory Manual, U.S. Aeroflightdynamics Directorate, ATCOM, TM 93-A-004, 1993.
2. Atilgan, A. R and Hodges, D.H., "Unified Nonlinear Analysis for Nonhomogeneous Anisotropic Beams with Closed Cross-Section, " AIAA Journal, Vol. 29, No. 11, November 1991, pp. 1990-1999.
3. Bagai, A., and Leishman, J.G., "Rotor Free-Wake Modeling Using a Pseudo-Implicit Technique-Including Comparisons with Experimental Data, " Journal of the American Helicopter Society, Vol. 40, No. 3, July 1995, pp. 29-41.
4. Barkai, S.M., and Rand, O., "The Influence of Composite Induced Couplings on Tiltrotor Whirl Flutter Stability, " Journal of The American Helicopter Society, Vol. 43, No. 2, April 1998, pp. 133-145.
5. Barwey, D., Gaonkar, G.H., and Ormiston, R.A., "Investigation of Dynamic Stall Effects on Isolated Rotor Flap-Lag Stability with Experimental Correlation, " Journal of the American Helicopter Society, Vol. 36, No. 4, October 1991, pp. 12-24.
6. Bauchau, O.A., and Chiang, W., "Dynamic Analysis of Rotor Flexbeams Based on Nonlinear Anisotropic Shell Models, " Journal of The American Helicopter Society, Vol. 38, No. 1, January 1993, pp. 55-61.
7. Bauchau, O.A., and Rang, N.K., "A Multibody Formulation for Helicopter Structural Dynamic Analysis, " Journal of the American Helicopter Society, Vol. 38, No. 2, April 1993, pp. 3-14.
8. Bielawa, R.L., Rotary-Wing Aeroelasticity and Structural Dynamics, AIAA Education Series, AIAA, 1992.
9. Brackbill, C.R., Lesieutre, G.A., Smith, E.G., and Ruhl, L.E., "Characterization and Modeling of Low Strain Amplitude and Frequency Dependent Behavior of Elastomeric Damper Materials, " Journal of The American Helicopter Society, Vol. 45, No. 1, January 2000, pp. 34-42.
10. Celi, R., "Stabilization of a Blade with a Severed Pitch Link Using a Trailing Edge Flap, " Paper G.18, Proceedings of the 25th European Rotorcraft Forum, Rome, Italy, September 14-16 1999.
11. Celi, R. and Friedmann, P.P., "Rotor Blade Aeroelasticity in Forward Flight With an Implicit Aerodynamic Formulation, " AIAA Journal, Vol. 26, No. 5, May 1988, pp. 1425-1433.
12. Cesnik, C.E.S., and Hodges, D.H., "VABS: A New Concept for Composite Rotor Blade Cross-Sectional Modeling, " Journal of the American Helicopter Society, Vol. 42, No. 1, January 1997, pp. 27-38.
13. Cesnik, C.E.S., Shin, S., Wilbur, M.L., and Wilkie, W.K., "Design and Testing of the NASA/Army/MIT Active Twist Prototype Blade, " Proceedings of the 26th European Rotorcraft Forum, The Hague, The Netherlands, September 26-29 2000, pp. 17.1-17.11.
14. Cesnik, C.E.S., Sutyrin, V.G., and Hodges, D.H., "Refined Theory of Twisted and Curved Composite Beams: The Role of Short-Wavelength Extrapolation, " International Journal of Solids and Structures, Vol. 33, No. 10, No. 10, 1996, pp. 1387-1408.
15. Cesnik, C.E.S., Sutyrin, Y.G., and Hodges, D.H., "A Refined Composite Beam Theory Based on the Variational-Asymptotical Method, " AIAA Paper 93-1616, 34th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, April 19-22 1993, pp. 2710-2720, La Jolla, CA.
16. Chopra, I., "Perspectives in Aeromechanical Stability of Helicopter Rotors, " Vertica, Vol. 14, No. 4, No. 4, 1990, pp. 457-508.
17. Chopra, I., "Status of Application of Smart Structures Technology to Rotorcraft Systems, " Journal of The American Helicopter Society, Vol. 45, No. 4, October 2000, pp. 228-252.
18. Chopra, I., and Bir, G., "University of Maryland Advanced Rotor Code:UMARC, " Proceedings of AHS Aeromechanics Specialists Conference on Aerodynamics, Acoustics and Dynamics, San Francisco, CA, Jan. 19-21 1994.
19. Chunduru, S.J., Subramanian, S., and Gaonkar, G.H., "Dynamic Stall and Wake Effects on Trim and Stability of Hingeless Rotors With Experimental Correlation, " Journal of The American Helicopter Society, Vol. 42, No. 4, October 1997, pp. 370-382.
20. Corrigan, J.J., "Computational of Loads During Maneuvering Flight Using a Comprehensive Rotorcraft Code, " Proceedings of 2nd International Aeromechanics Specialists7 Conference, Bridgeport, CT, October 11-13 1995, pp. 2.44-2.64.
21. Cribbs, R. and Friedmann, P.P., "Vibration Reduction in Rotorcraft Using an Enhanced ACSR Model, " AIAA Paper No. 2000-1687, Proceedings of the AIAA/ASME/ASCE/AHS/ASC 41st Structures, Structural Dynamics and Materials Conference, Atlanta, GA, April 3-6 2000.
22. Dat, R., Aeroelasticity of Rotary Wing Aircraft in Helicopter Aerodynamics and Dynamics, Vol. 63, Agard Lecture Series, 1973, Ch. 4.
23. de Terlizzi, M. and Friedmann, P.P., "Aeroelastic Response of Swept-Tip Rotors Including the Effects of BVI, " Proceedings of the 54th Annual Form of the American Helicopter Society, Washington, DC, May 1998. pp. 644-663.
24. de Terlizzi, M. and Friedmann, P.P., "Active Control of BVI Induced Vibrations Using a Refined Aerodynamic Model and Experimental Correlation, " Proceedings of the 55th Annual Forum of the American Helicopter Society, Montreal, Quebec, Canada, May 25-27 1999.
25. de Terlizzi, M. and Friedmann, P.P., "Active Control of Vibrations due to BVI and Experimental Correlation, " Proceedings of the 25th European Rotorcraft Forum, Rome, Italy, September 14-16 1999, pp. G6.1-G6.16.
26. Epps, J.J., and Chandra, R., "The Natural Frequencies of Rotating Beams with Tip Sweep, " Journal of The American Helicopter Society, Vol. 41, No. 1, January 1996, pp. 29-36.
27. Fink, D. A, Hawkey, T.J., Gadreau, P.J., Wellman, B., and Ormiston, R.A., "An Electromagnetic Actuator for Individual Blade Control, " Proceedings of the 56th Annual Forum of the American Helicopter Society, Virginia Beach, VA, May 2-4 2000.
28. Friedmann, P.P., "Recent Development in Rotary-Wing Aeroelasticity, " Journal of Aircraft, Vol. 14, No. 11, No. 11, 1977, pp. 1027-1041.
29. Friedmann, P.P., "Formulation and Solution of Rotary-Wing Aeroelastic Stability and Response Problems, " Vertica, Vol. 7, No. 2, No. 2, 1983, pp. 101-141.
30. Friedmann, P.P., "Recent Trends in Rotary-Wing Aeroelasticity, " Vertica, Vol. 11, No. 1/2, No. 1/2, 1987, pp. 139-170.
31. Friedmann, P.P., "Helicopter Rotor Dynamics and Aeroelasticity: Some Key Ideas and Insights, " Vertica, Vol. 14, No. 1, No. 1, 1990, pp. 101-121.
32. Friedmann, P. P, "Renaissance of Aeroelasticity and Its Future, " Journal of Aircraft, Vol. 36, No. 1, January-February 1999, pp. 105-121.
33. Friedmann, P.P., and Hodges, D.A., "Rotary-Wing Aeroelasticity with Application to VTOL Vehicles, " Flight Vehicles, Materials, Structures, and Dynamics-Assessment and Future Directions, Noor, A.K. and Venneri, S.L., Eds., Vol. 5, New York, ASME, 1993, Ch. 6, pp. 299-391.
34. Friedmann, P.P., and Millott, T.A., "Vibration Reduction in Rotorcraft Using Active Control: A Comparison of Various Approaches, " AIAA Journal of Guidance, Control and Dynamics, Vol. 18, No. 4, July-August 1995, pp. 664-673.
35. Fulton, M. and Ormiston, R.A., "Small-Scale Rotor Experiments with On-Blade Elevens to Reduce Blade Vibratory Loads in Forward Flight, " Proceedings of the 54th Annual Forum of the American Helicopter Society, Washington, DC, May 20-22 1998, pp. 433-451.
36. Fulton, M.V., and Hodges, D.H., "Aeroelastic Stability of Composite Hingeless Rotor Blades in Hover: Part I: Theory, " Mathematical and Computer Modeling, Vol. 18, No. 3/4, August 1993, pp. 1-18.
37. Fulton, M.V., and Hodges, D.H., "Aeroelastic Stability of Composite Hingeless Rotor Blades in Hover: Part I: Results, " Mathematical and Computer Modeling, Vol. 18, No. 3/4, August 1993, pp. 19-36.
38. Gandhi, F., and Chopra, I., "An Analytical Model for a Nonlinear Elastomeric Lag Damper and Its Effect on Aeromechanical Stability in Hover, " Journal of the American Helicopter Society, Vol. 39, No. 4, October 1994, pp. 59-69.
39. Gandhi, F., and Chopra, I., "Analysis of Bearingless Main Rotor Aeroelasticity Using an Improved Time Domain Nonlinear Elastomeric Damper Model, " Journal of the American Helicopter Society, Vol. 41, No. 3, July 1996, pp. 267-277.
40. Gandhi, F., and Chopra, I., "An Aeroelastic Analysis Methodology for Bearingless Main Rotor Helicopters, " Journal of The American Helicopter Society, VoL 43, No. 1, January 1998, pp. 66-75.
41. Hodges, D.H., "A Review of Composite Rotor Blade Modeling, " AIAA Journal, Vol. 28, No. 3, No. 3, 1990, pp. 561-565.
42. Hodges, D.H., Atilgan, A.R., Fulton, M.V., and Rehfield, L.W., "Free-Vibration Analysis of Composite Beams, " Journal of The American Helicopter Society, VoL 36, No. 3, July 1991, pp. 36-47.
43. Hodges, D. H, Shang, X, and Cesnik, C.E.S., "Finite Element Solution of Nonlinear Intrinsic Equations for Curved Composite Beams, " Journal of the American Helicopter Society, VoL 41, No. 4, October 1996, pp. 313-321.
44. Hopkins, S.A., Ruzicka, G.C., and Ormiston, R.A., "Analytical Investigations of Coupled Rotorcraft/Engine/Drive Train Dynamics, " Proceedings of 2nd International Aeromechanics Specialists' Conference, Bridgeport, CT, October 11-13 1995, pp. 2.1-2.23.
45. Le, C.A. and Kosmatka, J.B., "Formulation of a Nonlinear Theory for Spinning Anisotropic Beams, " Recent Advances in Structural Dynamic Modeling of Composite Rotor Blades and Thick Composites, Vol. AD-Vol. 30, Winter Annual Meeting of ASME, (Friedmann, P.P. and Kosmatka, J.B., Editors), Anaheim, CA, November 8-13 1992, pp. 41-57.
46. Johnson, W., Helicopter Theory, Princeton University Press, 1980.
47. Johnson, W., "Recent Developments in Dynamics of Advanced Rotor Systems-Part I, " Vertica, Vol. 10, No. 1, No. 1, 1986, pp. 73-107.
48. Johnson, W., "Recent Developments in Dynamics of Advanced Rotor Systems-Part II, " Vertica, Vol. 10, No. 2, No. 2, 1986, pp. 109-150.
49. Johnson, W., A Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics, Vol. I: Theory Manual, Johnson Aeronautics, Palo Alto, CA, 1988.
50. Johnson, W., CAMR AD II, Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics, Johnson Aeronautics, Palo Alto, CA, 1992-1997.
51. Johnson, W., "Technology Drivers in the Development of CAMRAD II, " Presented at AHS Aeromechanics Specialists Conference on Aerodynamics, Acoustics and Dynamics, San Francisco, CA, Jan. 19-21 1994.
52. Jung, S.N., Nagaraj, V.T., and Chopra, L, "Assessment of Composite Rotor Blade Modeling Techniques, " Journal of The American Helicopter Society, Vol. 44, No. 3, July 1999, pp. 188-205.
53. Kampa, K., Enenkl, B., Polz, G., and Roth, G., "Aeromechanic Aspects in the Design of the EC135, " Journal of The American Helicopter Society, Vol. 44, No. 2, April 1999, pp. 83-93.
54. Kim, K., and Chopra, L, "Aeroelastic Analysis of Swept, Anhedral, and Tapered Tip Rotor Blades, " Journal of the American Helicopter Society, Vol. 37, No. 1, Jan. 1992, pp. 15-30.
55. Kosmatka, J.B. and Friedmann, P.P., "Vibration Analysis of Composite Turbopropellers Using a Nonlinear Beam-Type Finite Element Approach, " AIAA Journal, Vol. 27, No. 11, November 1989, pp. 1606-1614.
56. Kunz, D.L., "Influence of Elastomeric Lag Damper Modeling on the Predicted Dynamic Response of Helicopter Rotor Systems, " AIAA Paper 96-1219-CP, AIAA Dynamics Specialists' Conference, Salt Lake City, UT, April 18-19 1996, pp. 154-164.
57. Leishman, J.G., Principles of Helicopter Aerodynamics, Cambridge University Press, 2000.
58. Leishman, J.G. and Beddoes, T.S., "A Generalized Model for Unsteady Aerodynamic Behavior and Dynamic Stall Using Indicial Method, " Journal of The American Helicopter Society, Vol. 34, No. 3, July 1989, pp. 3-17.
59. Lim, J.W., and Anastassiades, T., "Correlation of 2GCHAS Analysis with Experimental Data, " Journal of the American Helicopter Society, Vol. 40, No. 4, October 1995, pp. 18-33.
60. Lim, J.W., Panda, B., Sopher, R., Cassarino, S.J., and Lee, C.S., "Current Status of U.S. Army Comprehensive Helicopter Analysis System, " Proceedings of the 56th Annual Forum of the American Helicopter Society, Virginia Beach, VA, May 2-4 2000.
61. Loewy, R.G., "Review of Rotary-Wing V/STOL Dynamic and Aeroelastic Problems, " Journal of The American Helicopter Society, Vol. 14, No. 3, July 1969, pp. 3-23.
62. Loewy, R.G., "Helicopter Vibrations: A Technological Perspective, " Journal of The American Helicopter Society, Vol. 29, No. 4, October 1984, pp. 4-30.
63. Maier, H.T. and Abrego, A.L., "Analytical Model Sensitivity Study for Aeroelastic Stability of Straight and Swept-Tip Rotor Blades, " Proceedings of the 26th European Rotorcraft Forum, The Hague, The Netherlands, September 26-29 2000.
64. Maier, T.H., Sharpe, D.L., and Abrego, A.L., "Aeroelastic Stability for Straight and Swept-Tip Rotor Blades in Hover and Forward Flight, " Proceedings of the 55th Annual Forum of the American Helicopter Society, Montreal, Quebec, Canada, May 25-27 1999.
65. Milgram, J., and Chopra, L, "A Parametric Design Study for Actively Controlled Trailing Edge Flaps, " Journal of The American Helicopter Society, Vol. 43, No. 2, April 1998, pp. 110-119.
66. Milgram, J., Chopra, L, and Straub, F.K., "A Comprehensive Rotorcraft Aeroelastic Analysis with Trailing Edge Flap Model: Validation with Experimental Data, " 52nd Annuual Forum of the American Helicopter Society, Washington, DC, June 4-6 1996, pp. 715-725.
67. Milgram, J.H., and Chopra, L, "Air Resonance of Hingeless Rotor Helicopters in Trimmed Forward Flight, " Journal of The American Helicopter Society, Vol. 39, No. 4, October 1994, pp. 46-58.
68. Millot, T.A., Friedmann, P.P., and Yuan, K., "Correlation Studies for Hingeless Rotors in Forward Flight Using 2GCHAS, " Journal of The American Helicopter Society, Vol. 43, No. 3, July 1998, pp. 257-262.
69. Millott, T., and Friedmann, P.P., "The Practical Implementation of an Actively Controlled Flap to Reduce Vibrations in Helicopter Rotors, " Proceedings of the 49th Annual Forum of the American Helicopter Society, St. Louis, MO, may 1993, pp. 1079-1092.
70. Millott, T.A., and Friedmann, P.P., "Vibration Reduction in Helicopter Rotors Using an Active Control Surface Located on the Blade, " AIAA Paper 92-2451, Proceedings of 33rd Structures, Structural Dynamics, and Materials Conference, Dallas, TX, April 1992, pp. 1974-1988.
71. Millott, T.A., and Friedmann, P.P., "Vibration and Reduction in Hingeless Rotor Using an Actively Controlled Trailing Edge Flap: Implementation and Time Domain Simulation, " AIAA Paper 94-1306, Proceedings of 35th AIAA/ASME/ASCE/AHS/ASC Structures, Structual Dynamics and Materials Conference, Hilton Head, SC, April 18-20 1994, pp. 9-22.
72. Millott, T.A., and Friedmann, P.P., "Vibration Reduction in Helicopter Rotors Using an Actively Controlled Partial Span Trailing Edge Flap Located on the Blade, " NASA, CR 4611, June 1994.
73. Myrtle, T.F., "Development of an Improved Aeroelastic Model for the Investigation of Vibration Reduction in Helicopter Rotors Using Trailing Edge Flaps, " Ph.D. Dissertation, Mechanical and Aerospace Engineering Dept., University of California, Los Angeles, CA, June 1998.
74. Myrtle, T.F., and Friedmann, P.P., "Unsteady Compressible Aerodynamics of a Flapped Airfoil with Application to Helicopter Vibration Reduction, " AIAA Paper 97-1083-CP, Proceedings of the 38th AIAA/ASME/ASCE/AHS Structures, Structural Dynamics and Materials Conference, Kissimmee, FL, April, 7-10 1997, pp. 224-240.
75. Myrtle, T.F., and Friedmann, P.P., "Vibration Reduction in Rotorcraft Using the Actively Controlled Trailing Edge Flap and Issues Related to Practical Implementation, " Proceedings of the 54th Annual Forum of the American Helicopter Society, Washington, DC, May, 20-22 1998.
76. Myrtle, T.R. and Friedmann, P.P., "Application of a New Compressible Time Domain Aerodynamic Model to Vibration Reduction in Helicopters Using An Actively Controlled Flap, " Journal of The American Helicopter Society, Vol. 46, No. 1, January 2001.
77. Nagabhushanam, J., and Gaonkar, G.H., "Hingeless-Rotor Aeromechanical Stability in Axial and Forward Flight With Wake Dynamics, " Journal of The American Helicopter Society, Vol. 44, No. 3, July 1999, pp. 222-233.
78. Nixon, M.W., "Aeroelastic Response and Stability of Tiltrotors with Elastically-Coupled Composite Rotor Blades, " Ph.D. Dissertation, Dept. of Aerospace Engineering, University of Maryland, 1993.
79. Ormiston, R.A., "Investigation of Hingeless Rotor Stability, " Vertica, Vol. 7, No. 2, No. 2, 1983, pp. 143-181.
80. Ormiston, R.A., "Rotor-Fuselage Dynamics of Helicopter Air and Ground Resonance, " Journal of The American Helicopter Society, Vol. 36, No. 2, April 1991, pp. 3-20.
81. Ormiston, R.A., Saberi, H., and Anastaniades, T., "Application of 2 GCHAS to the Investigation of Aeromechanical Stability of Hingeless and Bearingless Rotor Helicopters, " 51st Annual Forum of the American Helicopter Society, Fort Worth, TX, May 9-11 1995, pp. 1132-1155.
82. Ormiston, R.A., Warmbrodt, W.G., Hodges, D.H., and Peters, D.A., "Survey of Army/NASA Rotorcraft Aeroelastic Stability Research, " NASA, TM 101026, October 1971.
83. Panda, B., and Mychalowycz, E., "Aeroelastic Stability Wind Tunnel Testing with Analytical Correlation of the Comanche Bearingless Main Rotor, " Journal of The American Helicopter Society, Vol. 42, No. 3, July 1997, pp. 207-217.
84. Peters, D.A., Boyd, D.D., and He, C.J., "Finite-State Induced-Flow Model for Rotors in Hover and Forward Flight, " Journal of The American Helicopter Society, Vol. 34, No. 4, October 1989.
85. Peters, D.A. and He, C.H., "A Closed-Form Unsteady Aerodynamic Theory for Lifting Rotors in Hover and Forward Flight, " Proceedings of the 43rd Annual Forum of the American Helicopter Society, St. Louis, MO, May 18-20 1987.
86. Peters, D.A., and He, C.J., "Finite State Induced Flow Models Part II: Three Dimensional Rotor Disk, " Journal of Aircraft, Vol. 32, No. 2, March-April 1995, pp. 323-333.
87. Peters, D.A., Karunamoorthy, S., and Cao, W., "Finite State Induced Flow Models Part I: Two Dimensional Thin Airfoil, " Journal of Aircraft, Vol. 32, No. 2, March-April 1995, pp. 313-322.
88. Petot, D., "Differential Equation Modeling of Dynamic Stall, " La Reserche Aerospatiale, Vol. 5, 1989, pp. 59-71.
89. Petot, D., Arnaud, G., Harrison, R., Stevens, J., Dieterich, O., van der Wall, B.C., Young, C., and Szechenyi, E., "Stall Effects and Blade Torsion-An Evaluation of Predictive Tools, " Journal of The American Helicopter Society, Vol. 44, No. 4, October 1999, pp. 320-331.
90. Pitt, D.M. and Peters, D.A., "Theoretical Prediction of Dynamic Inflow Derivatives, " Vertica, Vol. 5, No. 1, No. 1, 1981, pp. 21-34.
91. Rand, O., "Periodic Response of Thin-Walled Composite Helicopter Rotor Blades, " Journal of The American Helicopter Society, Vol. 36, No. 4, October 1991, pp. 3-11.
92. Reichert, G., "Helicopter Vibration Control-A Survey, " Vertica, Vol. 5, No. 1, No. 1, 1981, pp. 1-20.
93. Rutkowski, M.J. et al, "Comprehensive Aeromechanics Analysis of Complex Rotorcraft Using 2GCHAS, " Journal of the American Helicopter Society, Vol. 40, No. 4, October 1995, pp. 3-17.
94. Saberi, H., Jung, Y.C., and Anastassiades, T., "Finite Element and Modal Method in Multibody Dynamic Code, " Proceedings of 2nd International Aeromechanics Specialists' Conference, Bridgeport, CT, October 11-13 1995, pp. 8.1-8.16.
95. Shang, X., Hodges, D.H., and Peters, D.A., "Aeroelastic Stability of Composite Hingeless Rotors in Hover with Finite-State Unsteady Aerodynamics, " Journal of The American Helicopter Society, Vol. 44, No. 3, July 1999, pp. 206-221.
96. Silverthorn, L.J., Anand, V.R., and Lauzon, D.M., "FAA Certification of the MD 900 Dynamic Systems, " Presented at the 6th International Workshop on Dynamics and Aeroelastic Stability Modeling of Rotorcraft Systems, University of California, Los Angeles, November 1995.
97. Smith, E. et al, "Aeroelastic Response and Stability of Helicopters with Elastomeric Lag Dampers, " Journal of the American Helicopter Society, Vol. 41, No. 3, July 1996, pp. 257-266.
98. Smith, E. et al, "Formulation, Validation and Application of a Finite Element Model for Elastomeric Lag Dampers, " Journal of the American Helicopter Society, Vol. 41, No. 3, July 1996, pp. 247-256.
99. Smith, E.G., "Aeroelastic Response and Aeromechanical Stability of Helicopters with Elasticity Coupled Composite Rotor Blades, " Ph.D. Dissertation, Dept. of Aerospace Engineering, University of Maryland, July 1992.
100. Smith, E.G., and Chopra, I., "Formulation and Evaluation of an Analytical Model for Composite Box-Beams, " Journal of The American Helicopter Society, Vol. 36, No. 3, July 1991, pp. 23-35.
101. Smith, E.G. and Chopra, L, "Air and Ground Resonance With Elastically Tailored Composite Rotor Blades, " Journal of The American Helicopter Society, Vol. 38, No. 4, October 1993. pp. 50-61.
102. Song, O., and Librescu, L., "Structural Modeling and Free Vibration Analysis of Rotating Composite Thin-Walled Beams, " Journal of The American Helicopter Society, Vol. 42, No. 4, October 1997, pp. 358-369.
103. Sopher, R. and Hallock, D., "Time History Analysis of Rotorcraft Dynamics Based on a Component Approach, " Journal of The American Helicopter Society, Vol. 31, No. 1, January 1986, pp. 43-51.
104. Srinivas, V., and Chopra, L, "Validation of a Comprehensive Aeroelastic Analysis for Tiltrotor Aircraft, " Journal of The American Helicopter Society, Vol. 43, No. 3, July 1998.
105. Srinivas, V., Chopra, L, and Nixon, M.W., "Aeroelastic Analysis of Advanced Geometry Tiltrotor Aircraft, " Journal of The American Helicopter Society, Vol. 43, No. 3, July 1998, pp. 212-221.
106. Straub, F.K., "Active Flap Control for Vibration Reduction and Performance Improvement, " Proceedings of the 51st American Helicopter Society Forum, Fort Worth, TX, 1995, pp. 381-392.
107. Straub, F.K. and Charles, B.D., "Comprehensive Modeling of Rotors with Trailing Edge Flaps, " Proceedings of the 55th Annual Forum of the American Helicopter Society, Montreal, Canada, May 25-27 1999.
108. Straub, F.K., Sangha, K.B., and Panda, B., "Advanced Finite Element Modeling of Rotor Blade Aeroelasticity, " Journal of the American Helicopter Society, Vol. 39, No. 2, April 1994. pp. 56-68.
109. Takahashi, M.D., and Friedmann, P.P., "Helicopter Air Resonance Modeling and Suppression Using Active Control, " Journal of Guidance, Control and Dynamics, Vol. 14, No. 6, Nov./Dec. 1991, pp. 1294-1300.
110. Tang, D., Dowell, E.H., and Peters, D.A., "Reduced Order Aerodynamic Models Based Upon Inflow Eigenmodes, " Journal of The American Helicopter Society, Vol. 43, No. 4, October 1998, pp. 342-351.
111. Torok, M.S., and Berezin, C.R., "Aerodynamic and Wake Methodology Evaluation Using Model UH-60A Experimental Data, " Journal of the American Helicopter Society, Vol. 39, No. 2, April 1994, pp. 21-29.
112. Torok, M.S., and Chopra, L, "Hingeless Rotor Aeroelastic Stability Analysis with Refined Aerodynamic Modeling, " Journal of the American Helicopter Society, Vol. 36, No. 4, October 1991, pp. 48-56.
113. Toulmay, F., Arnaud, G., Falchero, D., and Villat, V., "Analytical Prediction of Rotor Dynamics for Advanced Geometry Blades, " 52nd Annuual Forum of the American Helicopter Society, Washington, DC, June 4-6 1996, pp. 685-703.
114. Tracy, A.L., and Chopra, L, "Aeroelastic Analysis of a Composite Bearingless Rotor in Forward Flight Using an Improved Warping Model, " Journal of the American Helicopter Society, Vol. 40, No. 3, July 1995, pp. 80-91.
115. Truong, V.K., "Prediction of Helicopter Rotor Airloads Based on Physical Modeling of 3-D Unsteady Aerodynamics, " Paper No. 96, Proceedings 22nd European Rotorcraft Forum, Brighton, UK, September 17-19 1996, pp. 96.1-96.14.
116. Tyler, J.C., and Leishman, J.G., "Analysis of Pitch and Plunge Effects on Unsteady Airfoil Behavior, " Journal of The American Helicopter Society, Vol. 37, No. 3, July 1992, pp. 69-82.
117. Weller, W.H., "Relative Aeromechanical Stability Characteristics for Hingeless and Bearingless Rotors, " Journal of The American Helicopter Society, Vol. 35, No. 3, July 1990, pp. 68-77.
118. Weller, W.H., "Variation in Hover Aeromechanical Stability Trends with Bearingless Main Rotor Design, " Journal of The American Helicopter Society, Vol. 39, No. 1, January 1994, pp. 70-80.
119. Weller, W.H., "Fuselage State Feedback for Aeromechanical Stability Augmentation of a Bearingless Main Rotor, " Journal of The American Helicopter Society, Vol. 41, No. 2, April 1996, pp. 85-93.
120. Wilkie, W.K., Wilbur, W. M, Mirick, P.H., Cesnik, C.E.S., and Shin, S., "Aeroelastic Analysis of the NASA/Army/MIT Active Twist Rotor, " Proceedings of the 55th Annual Forum of the American Helicopter Society, Montreal, Canada, May 25-27 1999.
121. Yuan, K., Friedmann, P.P., and Venkatesan, C., "Aeroelastic Behavior of Composite Rotor Blades with Swept Tips, " Proceedings of the 48th Annual Forum of American Helicopter Society, Washington, DC, June 1992, pp. 1039-1059.
122. Yuan, K., Friedmann, P.P., and Venkatesan, C., "A New Aeroelastic Model for Composite Rotor Blades with Straight and Swept Tips, " AIAA Paper 92-2259, 33rd AIAA/ASME/AHS/ASC Structures, Structural Dynamics and Materials Conference, Dallas, TX, April 13-15 1992, pp. 1371-1390.
123. Yuan, K., Friedmann, PP., and Venkatesan, C., "Aeroelastic Stability, Response and Loads of Swept Tip Composite Rotor Blades in Forward Flight, " Proceedings 35th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, Hilton Head, SC, April 18-20 1994, pp. 23-42.
124. Yuan, K.A., and Friedmann, P.P., "Aeroelasticity and Structural Optimization of Composite Helicopter Rotor Blades with Swept Tips, " NASA, CR 4665, May 1995.