Analysis of Helicopter Aeroelastic Characteristics in High-Speed Flight

Gerstenberger, Walter; Wood, E. R.

doi:10.2514/3.2068

Cited by 13 publications

(4 citation statements)

References 3 publications

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“…Until the advent of high-speed computer methods, rotor trim was solved by hand using a graphical method based on Lissajous gures. 2 The new application of Lissajous gures presented here is based on the old helicopter rotor trim method. Instead of plotting calculated data as in the old method, actual ight test data form the Lissajous gures.…”

Section: Lissajous Figures For Flight Test Data Analysismentioning

confidence: 99%

Analysis of OH-6A Helicopter Flight Test Data Using Lissajous Figures

Sarigul‐Klijn

Sarigul-Klijn

1997

Journal of Aircraft

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This paper demonstrates that a new application of Lissajous gures to ight test data gives different capabilities to identify both the commensurateness and the relative phase between measured quantities. These are not available from either conventional time or frequency domain ight test data analysis. Fig. 1 Lissajous gures. Frequency ratios of 1:1 and 4:1 with initial phase differences of 0, 45, 90, 135, and 180 deg.

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Section: Lissajous Figures For Flight Test Data Analysismentioning

confidence: 99%

Analysis of OH-6A Helicopter Flight Test Data Using Lissajous Figures

Sarigul‐Klijn

Sarigul-Klijn

1997

Journal of Aircraft

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“…The aeroelastic response analysis of the rotor-fuselage coupled system of helicopters has been performed by many scholars. In early studies, [1][2][3][4] the 2 D aerodynamic force formula was used to calculate aerodynamic force, and the rigid body or beam models were used to simulate the fuselage structure. With the development of computer technology and the refined finite element modelling of structures, a refined 3 D FEM of the fuselage has gradually replaced the traditional simplified model and has become the most accurate structure model.…”

Section: Introductionmentioning

confidence: 99%

CFD-CSD method for coupled rotor-fuselage vibration analysis with free wake-panel coupled model

Wang

Jing

Yun

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part G:

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An efficient comprehensive vibration analysis method for a helicopter rotor–fuselage coupling system is presented. This loose computational fluid dynamics (CFD)/computational structural dynamics (CSD) coupling approach with a free wake–panel coupled model is used for system vibration response analysis. The CSD model of the helicopter consists of a fuselage model using a refined three dimensional (3 D) finite element model (FEM) and a rotor model consisting of nonlinear moderate deflection beam elements with 15 degrees of freedom. The unsteady Euler CFD solver is used for the flow field analysis of the entire vehicle. The induced inflow of the quasi-steady aerodynamic force is calculated with the free wake–panel coupled model, which is used to simulate rotor–fuselage aerodynamic interference. Using a full-scale helicopter as an example, the vibration responses of the typical fuselage position in hovering and level flights are analysed. When compared with the literature results and flight test data, the predictions of the proposed method are closer to the test data than those of the traditional method in hovering and low forward ratio flights, and the difference between the two methods is minimal in high forward ratio flight.

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“…Wood and Hilzinger (1963) developed the fully coupled equations of motion for aeroelastic response of rotor blades that is based on the superposition of separated harmonics of blade forced response. This method is an extension of the work done by Gerstenberger and Wood (1963) on the coupled equations of motion for flapwise and chordwise bending, which uses the method developed by for calculating the natural frequencies and mode shapes. Lee and Lin (1994) studied the vibration of non-uniform rotating beams by neglecting the Coriolis Effect.…”

Section: Introductionmentioning

confidence: 99%

Preparation of bi-polar membranes and their application to hypochlorite production

Kim¹,

Cho²,

Rhim³

et al. 2015

Membr. Water Treat.

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Flutter is a dangerous phenomenon encountered in flexible structures subjected to aerodynamic forces. This includes aircraft, helicopter blades, engine rotors, buildings and bridges. Flutter occurs as a result of interactions between aerodynamic, stiffness and inertia forces on a structure. The conventional method for designing a rotor blade to be free from flutter instability throughout the helicopter's flight regime is to design the blade so that the aerodynamic center (AC), elastic axis (EA) and center of gravity (CG) are coincident and located at the quarterchord. While this assures freedom from flutter, it adds constraints on rotor blade design which are not usually followed in fixed wing design. Periodic Structures have been in the focus of research for their useful characteristics and ability to attenuate vibration in frequency bands called "stop-bands". A periodic structure consists of cells which differ in material or geometry. As vibration waves travel along the structure and face the cell boundaries, some waves pass and some are reflected back, which may cause destructive interference with the succeeding waves. In this work, we analyze the flutter characteristics of a helicopter blades with a periodic change in their sandwich material using a finite element structural model. Results shows great improvements in the flutter forward speed of the rotating blade obtained by using periodic design and increasing the number of periodic cells.

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Analysis of Helicopter Aeroelastic Characteristics in High-Speed Flight

Cited by 13 publications

References 3 publications

Analysis of OH-6A Helicopter Flight Test Data Using Lissajous Figures

Analysis of OH-6A Helicopter Flight Test Data Using Lissajous Figures

CFD-CSD method for coupled rotor-fuselage vibration analysis with free wake-panel coupled model

Preparation of bi-polar membranes and their application to hypochlorite production

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