Rotary-wing aeroelasticity with application to VTOL vehicles

This survey presents an assessment of the state of the art in rotary-wing aeroelasticity as applied to conventional helicopters as well as other VTOL vehicles such as tilting prop-rotors, the X-wing and a hybrid heavy lift vehicle. The objective is to enable the reader to develop an awareness of what has been accomplished, what remains to be done, and where to find more comprehensive treatments of the various topics discussed. The main topics discussed are: (1) structural modeling; (2) unsteady aerodynamic modeling; (3) formulation of the equations of motion and their solutions; (4) illustrative results for isolated blades in hover and forward flight; (5) illustrative results for coupled rotor/fuselage problems; (6) active control of aeromechanical and aeroelastic problems; (7) active controls for vibration reduction; (8) structural optimization with aeroelastic constraints; (9) gust response analysis of rotors; and (10) aeroelastic problems in special VTOL vehicles. These topics are reviewed with different levels of detail and some useful observation on potentially rewarding areas of future research are made.

[1]  E. R. Wood,et al.  ANALYSIS OF HELICOPTER AEROELASTIC CHARACTERISTICS IN HIGH-SPEED FLIGHT , 1963 .

[2]  R. Sopher,et al.  Development and application of a time-history analysis for rotorcraft dynamics based on a component approach , 1985 .

[3]  Marc Sheffler,et al.  Correlation of Test and Analysis for the 1/5-Scale V-22 Aeroelastic Model , 1987 .

[4]  Omri Rand,et al.  Influence of Interactional Aerodynamics on Helicopter Rotor/Fuselage Coupled Response in Hover and Forward Flight , 1989 .

[5]  Wayne Johnson,et al.  Influence of unsteady aerodynamics on hingeless rotor ground resonance , 1982 .

[6]  Y. K. Lin,et al.  Rotor Blade Flap-Lag Stability in Turbulent Flows , 1982 .

[7]  Peretz P. Friedmann,et al.  Numerical methods for determining the stability and response of periodic systems with applications to helicopter rotor dynamics and aeroelasticity , 1986 .

[8]  William Warmbrodt,et al.  Forward Flight Aeroelastic Stability from Symbolically Generated Equations , 1986 .

[9]  David A. Peters,et al.  Technical Note: Dynamic Inflow for Practical Applications , 1988 .

[10]  Gh Gaonkar,et al.  Gust Response of Rotor and Propeller Systems , 1981 .

[11]  W. Johnson,et al.  Recent developments in rotary-wing aerodynamic theory , 1986 .

[12]  Peretz P. Friedmann,et al.  APPLICATION OF THE FINITE ELEMENT METHOD TO ROTARY-WING AEROELASTICITY. , 1980 .

[13]  Kenneth F. Guinn.  Individual Blade Control Independent of a Swashplate , 1982 .

[14]  Santu T. Gangwani,et al.  Prediction of Dynamic Stall and Unsteady Airloads for Rotor Blades , 1981 .

[15]  Inderjit Chopra,et al.  Dynamic stability of hingeless and bearingless rotors in forward flight , 1986 .

[16]  J. E. Burkam,et al.  Exploration of Aeroelastic Stability Boundaries with a Soft-in-Plane Hingeless-Rotor Model , 1972 .

[17]  Kurt H. Hohenemser,et al.  Some Applications of the Method of Multiblade Coordinates , 1972 .

[18]  Victor Giurgiutiu.  Vibrations and dynamic stability of rotor blades , 1977 .

[19]  E. H. Mansfield,et al.  The Fibre Composite Helicopter Blade , 1979 .

[20]  T. N. Shiau,et al.  Rotor Blade Flap-Lag Stability and Response in Forward Flight in Turbulent Flows , 1984 .

[21]  R. E. Hansford,et al.  Torsion-Flap-Lag Coupling on Helicopter Rotor Blades , 1973 .

[22]  P. Friedmann,et al.  Structural dynamic modeling of advanced composite propellers by the finite element method , 1987 .

[23]  C. E. Hammond,et al.  An application of Floquet theory to prediction of mechanical instability. [for helicopter with inoperative blade damper] , 1974 .

[24]  Earl H. Dowell,et al.  An experimental-theoretical correlation study of non-linear bending and torsion deformations of a cantilever beam☆ , 1977 .

[25]  Raymond G. Kvaternik,et al.  Application of unsteady airfoil theory to rotary wings , 1981 .

[26]  John Dugundji,et al.  Experiments and analysis for structurally coupled composite blades under large deflections. II - Dynamic behavior , 1989 .

[27]  K. W. Shipman,et al.  A Two-Dimensional Theory for Rotor Blade Flutter in Forward Flight , 1971 .

[28]  Robert G. Loewy,et al.  Helicopter Vibrations: A Technological Perspective , 1984 .

[29]  W. Johnson,et al.  Development of a comprehensive analysis for rotorcraft. I - Rotor model and wake analysis , 1981 .

[30]  Peretz P. Friedmann,et al.  Unsteady aerodynamics in time and frequency domains for finite time arbitrary motion of rotary wings in hover and forward flight , 1984 .

[31]  Inderjit Chopra,et al.  Ground and Air Resonance of an Advanced Bearingless Rotor in Hover , 1988 .

[32]  Peretz P. Friedmann,et al.  A new look at arbitrary motion unsteady aerodynamics and its application to rotary-wing aeroelasticity , 1985 .

[33]  David A. Peters,et al.  Theoretical Flap-Lag Damping With Various Dynamic Inflow Models , 1980 .

[34]  Aviv Rosen,et al.  Nonlinear analysis of pretwisted rods using 'principal curvature transformation'. II - Numerical results , 1987 .

[35]  Peretz P. Friedmann,et al.  Optimum design of rotor blades for vibration reduction in forward flight , 1984 .

[36]  Kurt H. Hohenemser,et al.  Aeroelastic Instability of Torsionally Rigid Helicopter Blades , 1967 .

[37]  S. Lee,et al.  A new approach to the finite element modelling of beams with warping effect , 1987 .

[38]  Robert E. Hansford,et al.  Comparison of Predicted and Experimental Rotor Loads to Evaluate Flap-Lag Coupling with Blade Pitch , 1979 .

[39]  M. Borri,et al.  Helicopter rotor dynamics by finite element time approximation , 1986 .

[40]  Gloria K. Yamauchi,et al.  Correlation of SA349/2 helicopter flight-test data with a comprehensive rotorcraft model , 1988 .

[41]  Hughes Helicopters,et al.  On Developing and Flight Testing a Higher Harmonic Control System , 1983 .

[42]  David A. Peters,et al.  Use of Multiblade Coordinates for Helicopter Flap-Lag Stability with Dynamic Inflow , 1980 .

[43]  Robert A. Calico,et al.  Stabilization of Helicopter Blade Flapping , 1986 .

[44]  Alan D. Stemple,et al.  Finite-Element Model for Composite Beams with Arbitrary Cross-Sectional Warping , 1988 .

[45]  Peretz P. Friedmann,et al.  Rotor blade aeroelasticity in forward flight with an implicit aerodynamic formulation , 1988 .

[46]  Inderjit Chopra,et al.  Flap-Lag-Torsion Stability in Forward Flight , 1985 .

[47]  Robert G. Loewy,et al.  Review of rotary-wing V/STOL dynamic and aeroelastic problems , 1969 .

[48]  Dewey H. Hodges,et al.  Linear Flap-Lag Dynamics of Hingeless Helicopter Rotor Blades in Hover , 1972 .

[49]  R. H. Blackwell,et al.  Blade Design for Reduced Helicopter Vibration , 1983 .

[50]  Michael J. McNulty,et al.  Effects of blade-to-blade dissimilarities on rotor-body lead-lag dynamics , 1988 .

[51]  Todd R. Quackenbush.  Testing of a stall flutter suppression system for helicopter rotors using individual-blade-control , 1984 .

[52]  Peretz P. Friedmann,et al.  Time domain unsteady incompressible cascade airfoil theory for helicopter rotors in hover , 1989 .

[53]  J. G. Leishman,et al.  A Semi-Empirical Model for Dynamic Stall , 1989 .

[54]  Inderjit Chopra,et al.  Aeroelastic optimization of a helicopter rotor , 1989 .

[55]  Friedrich K. Straub,et al.  The use of active controls to augment rotor/fuselage stability , 1985 .

[56]  Earl H. Dowell,et al.  Influence of nonlinear blade damping on helicopter ground resonance instability , 1986 .

[57]  Olivier A. Bauchau,et al.  Nonlinear Composite Beam Theory , 1988 .

[58]  F. J. Tarzanin,et al.  Prediction of Control Loads Due to Blade Stall , 1972 .

[59]  David A. Peters,et al.  Flap-Lag Stability of Helicopter Rotor Blades in Forward Flight , 1975 .

[60]  Omri Rand,et al.  An Unsteady Prescribed Wake Model for a Helicopter Rotor in Forward Flight , 1985 .

[61]  Dewey H. Hodges,et al.  A review of composite rotor blade modeling , 1988 .

[62]  Jon P. Rogers,et al.  Applications of an Analytic Stall Model to Time-History and Eigenvalue Analysis of Rotor Blades , 1984 .

[63]  M. Silva,et al.  The role of computerized symbolic manipulation in rotorcraft dynamics analysis , 1986 .

[64]  G. Stein,et al.  Multivariable feedback design: Concepts for a classical/modern synthesis , 1981 .

[65]  J. A. Molusis.  The importance of nonlinearity on the higher harmonic control of helicopter vibration , 1984 .

[66]  Dewey H. Hodges,et al.  Nonlinear Beam Kinematics by Decomposition of the Rotation Tensor , 1987 .

[67]  Olivier A. Bauchau,et al.  Finite Element Approach to Rotor Blade Modeling , 1987 .

[68]  J. J. Traybar,et al.  An Experimental Study of the Nonlinear Stiffness of a Rotor Blade Undergoing Flap, Lag and Twist Deformations , 1975 .

[69]  Continuum Dynamics,et al.  Rotor Wake Modeling for High Speed Applications , 1987 .

[70]  P. Tong,et al.  Non-linear flap-lag dynamics of hingeless helicopter blades in hover and in forward flight , 1973 .

[71]  Inderjit Chopra,et al.  Aeroelastic stability of bearingless rotors in forward flight , 1988 .

[72]  Richard S. Teal,et al.  Higher Harmonic Control: Wind Tunnel Demonstration of Fully Effective Vibratory Hub Force Suppression , 1985 .

[73]  W. F. Hunter,et al.  Integrating-matrix method for determining the natural vibration characteristics of propeller blades , 1970 .

[74]  W. Johnson,et al.  Application of unsteady airfoil theory to rotary wings , 1980 .

[75]  Peretz P. Friedmann,et al.  Structural optimization with aeroelastic constraints of rotor bladeswith straight and swept tips , 1988 .

[76]  R. H. Miller,et al.  Computational methods for wake modeling and blade airload determination in hover and forward flight , 1986 .

[77]  Peretz P. Friedmann,et al.  Vibration analysis of composite turbopropellers using a nonlinear beam-type finite-element approach , 1989 .

[78]  J. M. Bilger,et al.  Results of Structural Dynamic Testing of the XV-15 Tilt Rotor Research Aircraft , 1981 .

[79]  Mark W. Nixon,et al.  Extension-twist coupling of composite circular tubes with application to tilt rotor blade design , 1987 .

[80]  M. W. Davis.  Development and evaluation of a generic active helicopter vibration controller , 1984 .

[81]  Khanh Nguyen,et al.  APPLICATION OF HIGHER HARMONIC CONTROL (HHC) TO HINGELESS ROTOR SYSTEMS , 1989 .

[82]  Peretz P. Friedmann,et al.  INFLUENCE OF UNSTEADY AERODYNAMIC MODELS ON AEROMECHANICAL STABILITY IN GROUND RESONANCE. , 1986 .

[83]  Murray S. Hirschbein,et al.  Open and Closed Loop Stability of Hingeless Rotor Helicopter Air and Ground Resonance , 1974 .

[84]  William Felton White.  Effect of compressibility on three-dimensional helicopter rotor blade flutter , 1973 .

[85]  M. Borri,et al.  Anisotropic beam theory and applications , 1983 .

[86]  W. R. Johnson,et al.  The Prediction of Transonic Flows on an Advancing Rotor , 1986 .

[87]  J. G. Leishman,et al.  Modeling Sweep Effects on Dynamic Stall , 1989 .

[88]  Aviv Rosen,et al.  Nonlinear analysis of pretwisted rods using 'principal curvature transformation'. I - Theoretical derivation , 1987 .

[89]  Pei Chi Chou,et al.  Pitch-Lag Instability of Helicopter Rotors , 1958 .

[90]  I. Chopra,et al.  Dynamic stability of a rotor blade using finite element analysis , 1981 .

[91]  Mark W. Davis,et al.  Wind Tunnel Tests of Helicopter Blade Designs Optimized for Minimum Vibration , 1989 .

[92]  W. J. McCroskey,et al.  Unsteady Aerodynamics of Helicopter Rotors , 1972 .

[93]  B. M. Rao,et al.  COMPRESSIBILITY EFFECTS ON OSCILLATING ROTOR BLADES IN HOVERING FLIGHT , 1970 .

[94]  R. Strawn,et al.  Conservative full-potential model for unsteady transonic rotor flows , 1987 .

[95]  Holt Ashley,et al.  On Making Things the Best-Aeronautical Uses of Optimization , 1982 .

[96]  Inderjit Chopra,et al.  Aeroelastic Stability Analysis of a Composite Rotor Blade , 1985 .

[97]  John L. McCloud,et al.  A Numerical Simulation Study of Open‐Loop, Closed‐Loop and Adaptive Multicyclic Control Systems , 1983 .

[98]  V. R. Murthy,et al.  Free vibration characteristics of multiple load path blades by the transfer matrix method , 1986 .

[99]  O. Bauchau.  A Beam Theory for Anisotropic Materials , 1985 .

[100]  C. E. Hammond,et al.  Wind Tunnel Results Showing Rotor Vibratory Loads Reduction Using Higher Harmonic Blade Pitch , 1980 .

[101]  Peretz P. Friedmann,et al.  Effect of modified aerodynamic strip theories on rotor blade aeroelastic stability , 1976 .

[102]  Peretz P. Friedmann,et al.  Formulation and solution of rotary-wing aeroelastic stability and response problems , 1983 .

[103]  J. Dugundji,et al.  Some analysis methods for rotating systems with periodic coefficients , 1983 .

[104]  Peretz P. Friedmann,et al.  Recent developments in rotary-wing aeroelasticity , 1977 .

[105]  J. G. Leishman,et al.  Two-dimensional model for airfoil unsteady drag below stall , 1988 .

[106]  M. Borri,et al.  A large displacement formulation for anisotropic beam analysis , 1986 .

[107]  Peretz P. Friedmann,et al.  Coupled flap-lag-torsional dynamics of hingeless rotor blades in forward flight , 1982 .

[108]  P. Friedmann,et al.  Aeroelastic stability of periodic systems with application to rotor blade flutter , 1974 .

[109]  Peretz P. Friedmann,et al.  Nonlinear equations of equilibrium for elastic helicopter or wind turbine blades undergoing moderate deformation , 1978 .

[110]  Peretz P. Friedmann,et al.  Coupled helicopter rotor/body aeromechanical stability comparison oftheoretical and experimental results , 1985 .

[111]  R. A. Ormiston,et al.  A Study of Stall-Induced Flap-Lag Instability of Hingeless Rotors , 1973 .

[112]  Omri Rand,et al.  A general model of the dynamics of moving and rotating rods , 1985 .

[113]  Inderjit Chopra,et al.  Finite Element Analysis for Bearingless Rotor Blade Aeroelasticity , 1984 .

[114]  R. Loewy.  A Two-Dimensional Approximation to the Unsteady Aerodynamics of Rotary Wings , 1957 .

[115]  R. B. Taylor,et al.  An active control system for helicopter vibration reduction by higher harmonic pitch , 1980 .

[116]  J. C. Biggers,et al.  Some Approximations to the Flapping Stability of Helicopter Rotors , 1974 .

[117]  D. H. Roberta. Hodges,et al.  Stability of elastic bending and torsion of uniform cantilever rotor blades in hover with variable structural coupling , 1976 .

[118]  W. F. White,et al.  A numerical method for determining the natural vibration characteristics of rotating nonuniform cantilever blades , 1975 .

[119]  Peretz P. Friedmann,et al.  New approach to finite-state modeling of unsteady aerodynamics , 1986 .

[120]  S. Atluri.  ALTERNATE STRESS AND CONJUGATE STRAIN MEASURES, AND MIXED VARIATIONAL FORMULATIONS INVOLVING RIGID ROTATIONS, FOR COMPUTATIONAL ANALYSES OF FINITELY DEFORMED SOLIDS, WITH APPLICATION TO PLATES AND SHELLS-I , 1984 .

[121]  W. Johnson,et al.  An assessment of the capability to calculate tilting prop-rotor aircraft performance, loads and stability , 1984 .

[122]  C. E. Hammond,et al.  Efficient numerical treatment of periodic systems with application to stability problems. [in linear systems and structural dynamics] , 1977 .

[123]  G. Stein,et al.  The LQG/LTR procedure for multivariable feedback control design , 1987 .

[124]  Dewey H. Hodges,et al.  Free-Vibration Analysis of Rotating Beams by a Variable-Order Finite-Element Method , 1981 .

[125]  David A. Peters,et al.  Toward a Unified Lift Model for Use in Rotor Blade Stability Analyses , 1985 .

[126]  Sikorsky Aircraft Division,et al.  Flight Demonstration of Higher Harmonic Control (HHC) on S-76 , 1986 .

[127]  Peretz P. Friedmann,et al.  Aeromechanical stability analysis of a hybrid heavy lift multirotor vehicle in hover , 1985 .

[128]  Robert Sopher,et al.  Effects of Analytical Modeling Assumptions on the Predicted Stability of a Model Hingeless Rotor , 1988 .

[129]  Aditi Chattopadhyay,et al.  Fully integrated aerodynamic/dynamic optimization of helicopter rotor blades , 1989 .

[130]  R. H. Miller,et al.  Rotor blade harmonic air loading , 1964 .

[131]  Peretz P. Friedmann,et al.  Application of time-domain unsteady aerodynamics to rotary-wing aeroelasticity , 1986 .

[132]  W. Mccroskey,et al.  Numerical simulations of unsteady airfoil-vortex interactions , 1987 .

[133]  David A. Peters,et al.  Finite-State Induced-Flow Model for Rotors in Hover and Forward Flight , 1989 .

[134]  Olivier A. Bauchau,et al.  Large displacement analysis of naturally curved and twisted composite beams , 1987 .

[135]  G. S. Bir,et al.  Gust Response of Hingeless Rotors , 1985 .

[136]  Peretz P. Friedmann,et al.  Influence of Modeling and Blade Parameters on the Aeroelastic Stability of a Cantilevered Rotor , 1977 .

[137]  A. Laub,et al.  Feedback properties of multivariable systems: The role and use of the return difference matrix , 1981 .

[138]  R. H. Miller,et al.  Helicopter Blade Vibration and Flutter , 1956 .

[139]  P. Friedmann,et al.  Aeroelastic stability of trimmed helicopter blades in forward flight , 1975 .

[140]  Olivier A. Bauchau,et al.  Composite Box Beam Analysis: Theory and Experiments , 1987 .

[141]  William G. Bousman,et al.  An Experimental Investigation of the Effects of Aeroelastic Couplings on Aeromechanical Stability of a Hingeless Rotor Helicopter , 1981 .

[142]  M. D. Takahashi,et al.  A model for active control of helicopter air resonance in hover and forward flight , 1988 .

[143]  Dewey H. Hodges,et al.  A Beam Theory for Large Global Rotation, Moderate Local Rotation, and Small Strain , 1988 .

[144]  H. Bergh,et al.  Comparison between measured and calculated stall-flutter behaviour of a one-bladed model rotor , 1985 .

[145]  Maurice I. Young,et al.  A Theory of Rotor Blade Motion Stability in Powered Flight , 1964 .

[146]  G. Alvin Pierce,et al.  Drag on an Oscillating Airfoil in a Fluctuating Free Stream , 1979 .

[147]  P. Friedmann,et al.  The Nonlinear Behavior of Elastic Slender Straight Beams Undergoing Small Strains and Moderate Rotations , 1979 .

[148]  W. Johnson,et al.  Analytical modeling requirements for tilting proprotor aircraft dynamics , 1975 .

[149]  F. K. Straub,et al.  A Galerkin type finite element method for rotary-wing aeroelasticity in hover and forward flight , 1980 .

[150]  J. Baeder,et al.  Aerodynamics of two-dimensional blade-vortex interaction , 1985 .

[151]  D. Peters,et al.  Effectiveness of Current Dynamic-Inflow Models in Hover and Forward Flight , 1986 .

[152]  Roberto Celi,et al.  AEROELASTIC MODELING OF SWEPT TIP ROTOR BLADES USING FINITE ELEMENTS. , 1988 .