Open Access
Differential equations of motion for combined flapwise bending, chordwise bending, and torsion of twisted nonuniform rotor blades
John C. Houbolt,George W Brooks +1 more
TLDR
In this article, the differential equations of motion for the lateral and torsional deformations of twisted rotating beams are developed for application to helicopter rotor and propeller blades, and the generality is such that previous theories involving various simplifications are contained as subcases to the theory presented in this paper.Abstract:
The differential equations of motion for the lateral and torsional deformations of twisted rotating beams are developed for application to helicopter rotor and propeller blades. No assumption is made regarding the coincidence of the neutral, elastic, and mass axes, and the generality is such that previous theories involving various simplifications are contained as subcases to the theory presented in this paper. Special attention is given the terms which are not included in previous theories. These terms are largely coupling-type terms associated with the centrifugal forces. Methods of solution of the equations of motion are indicated by selected examples.read more
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Dissertation
An Analytical Investigation of Flapping Wing Structures for Micro Air Vehicles
TL;DR: In this article, an analytical model of flapping wing structures for bio-inspired micro-air vehicles is presented, which includes bending and torsion degrees of freedom, and a flapping-wing stability diagram is developed as a function of the characteristic parameters.
Journal ArticleDOI
A Calculation of Rotor Impedance for Hovering Articulated-Rotor Helicopters
Kanichiro Kato,Takashi Yamane +1 more
TL;DR: In this article, a procedure is presented to calculate the loads transferred from an articulated rotor to the fuselage when the rotor hub is forced to oscillate sinusoidally in hover.
Sensitivity analysis of torsional vibration characteristics of helicopter rotor blades. Part 2: Aerodynamics and sensitivity analysis
T. Bratanow,A. Ecer +1 more
TL;DR: In this paper, a theoretical analysis of rotor blades was carried out with special emphasis on torsional degrees of freedom (DOF) and the sensitivity of overall blade vibration characteristics to torsion oscillations.
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Application of a Mixed Variational Approach to Aeroelastic Stability Analysis of a Nonuniform Blade
M. Natori,Sia Nemat-Nasser +1 more
TL;DR: In this paper, a mixed variational approach is used to investigate the coupled flap-lag-torsional aeroelastic stability of a non-uniform helicopter blade.
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Effect of mass and shear center offset on the dynamic response of a rotating blade
TL;DR: In this paper, a model that accounts for the extensional, chordwise, flapwise and torsional vibrations of a flexible rotating blade was developed, which also takes into consideration the offset offset.
References
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Book
Theory of elasticity
TL;DR: The theory of the slipline field is used in this article to solve the problem of stable and non-stressed problems in plane strains in a plane-strain scenario.
Simplified Procedures and Charts for the Rapid Estimation of Bending Frequencies of Rotating Beams
TL;DR: In this paper, a Rayleigh energy approach utilizing the bending mode of the nonrotating beam in the determination of the bending frequency of the rotating beam was presented, which is evaluated and is found to give good practical results for helicopter blades.