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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Estimation of blade airloads from rotor blade bending moments
TL;DR: In this article, a method is developed to estimate the rotor normal airloads by using measured flap bending moments; that is, the rotor blade is used as a force balance, and the airloads are then expressed as an algebraic sum of the mode shapes, modal amplitudes, mass distribution, and frequency properties.
Dissertation
Analysis, Validation, Prediction And Fundamental Understanding Of Rotor Blade Loads In An Unsteady Maneuver
TL;DR: Abhishek et al. as mentioned in this paper developed a comprehensive transient rotor analysis for predicting maneuver loads, including main rotor structural loads, control/pitch-link loads, and swashplate servo loads.
Dissertation
Simulation Framework Development for the Multidisciplinary Optimisation of Rotorcraft
TL;DR: In this paper, a series of individual modeling methods have been developed, each applicable to a dif-ferent aspect of helicopter flight dynamics and performance, including rotor blade modal analysis, aeroelasticity, flight dynamics trim solution, en-gine performance and three-dimensional flight path definition.
Journal ArticleDOI
Structural‐aeroelastic finite element modeling for advanced‐geometry rotor blades
TL;DR: In this paper, the structural dynamics model implemented is based on nonlinear, flap-lag-torsion, rotating beam equations that are valid for slender, homogeneous, isotropic, non-uniform, twisted blades undergoing moderate displacements.
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.