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
Citations
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Nonlinear flexure and torsion of rotating beams, with application to helicopter rotor blades. I - Formulation. II - Response and stability results
TL;DR: In this paper, the dynamic response and aero-elastic stability of rotating beams such as helicopter blades are investigated analytically, and the Hamilton principle is used to formulate the equations of motion for extensional and inextensional beams with precone angles and variable pitch angles.
Dissertation
Helicopter vibration suppression using simple pendulum absorbers on the rotor blade
G. A. Pierce,M. N. H. Hanouva +1 more
TL;DR: In this paper, a comprehensive anaytical design procedure for the installation of simple pendulums on the blades of a helicopter rotor to suppress the root reactions is presented, where a frequency response anaysis is conducted of typical rotor blades excited by a harmonic variation of spanwise airload distributions as well as a concentrated load at the tip.
Journal ArticleDOI
Testing coupled rotor blade–lag damper vibration using real-time dynamic substructuring
TL;DR: In this article, the authors present new results from laboratory tests of a helicopter rotor blade coupled with a lag damper from the EH101 helicopter, which reveal how the inclusion of a real damper produces a more realistic representation of the dynamic characteristics of the overall blade system than numerical modelling alone.
Proceedings ArticleDOI
Vibration and Flutter of Mistuned Bladed-Disk Assemblies
K. R. V. Kaza,Robert E. Kielb +1 more
TL;DR: In this article, an analytical model for investigating vibration and flutter of mistuned bladed disk assemblies is presented, which accounts for elastic, inertial and aerodynamic coupling between bending and torsional motions of each individual blade.
Proceedings ArticleDOI
Flutter Analysis of Mission-Adaptive Wing with Variable Camber Continuous Trailing Edge Flap
TL;DR: In this paper, an aeroelastic method for predicting flutter characteristics of a flexible wing transport aircraft is presented, which is referred to as an Elastically Shaped Aircraft Concept (ESAC) which is equipped with a new type of aerodynamic control surfaces for active wing shaping control for drag reduction.
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.