Elastomeric shimmy damper model and application thereof to helicopter system

A sway damper, helicopter technology, applied in aircraft parts, ground installations, transportation and packaging, etc., can solve problems such as error, helicopter dynamic stability deviation, etc.

Inactive Publication Date: 2014-03-12
BEIHANG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In the traditional viscoelastic damper analysis method, the vibration frequency can be used for analysis and calculation in the case of single-frequency action, but in the case of dual-frequency action, the system corresponds to two different frequency conditions of blade rotation frequency and disturbance frequency. At this time, two models need to be established to estimate the energy dissipation modulus of the shimmy absorber, but this method will cause a large error, and the resulting dynamic stability of the helicopter will also have a large deviation

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  • Elastomeric shimmy damper model and application thereof to helicopter system
  • Elastomeric shimmy damper model and application thereof to helicopter system
  • Elastomeric shimmy damper model and application thereof to helicopter system

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Embodiment

[0053] In order to verify the viscoelastic shimmy damper model under single-frequency or dual-frequency conditions proposed by the present invention, 4 rotor blades are used, the radius of the rotor blade is 5.965m, the mass of the blade is 42.3kg, and the chord length of the section is 0.385m. Airfoil NACA0012, the equivalent outrigger hinge is 0.23m, and the moment of inertia of the blade against the hinge is 456kgm 2 , the structural damping ratio of the blade shimmy surface is 0.52%, the distance from the viscoelastic shimmy damper to the shimmy hinge is 0.35m, and the stiffness of the shimmy surface of the flexible arm is 857500Nmrad -1 , elastic bearing shimmy surface constraint stiffness 500Nmrad -1 , the rolling and pitching moments of inertia of the airframe under no-load conditions are 2303kgm 2 and 12423kgm 2 , the rolling and pitching moments of inertia under full load are 3742kgm 2 and 13463kgm 2 .

[0054] The basic analysis model has a frequency ω, which is...

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Abstract

The invention discloses an elastomeric shimmy damper model and application thereof to a helicopter system and belongs to the field of helicopter dynamics design. The elastomeric shimmy damper model is applied to dynamic stability design of the helicopter system by the aid of an excitation frequency modifying formula, and the application specifically includes: firstly establishing a balance equation of a rotor and helicopter body coupling system of a helicopter with an elastomeric shimmy damper; then modifying a blade lagging natural frequency under the condition of single frequency; solving dynamic displacement of the elastomeric lag damper under the condition of forward flight and modifying an excitation frequency of the elastomeric lag damper and a blade shimmy natural frequency under the condition of double frequency; and finally solving modal damping of a rotor and helicopter body system under the condition of the double frequency so as to judge dynamic stability of a star flexible hub helicopter system. The excitation-frequency modified elastomeric shimmy damper model has high applicability, can be used under the condition of the single frequency or the double frequency and can be applied to design of hinged, hinge-less and bearing-less rotor helicopters with the elastomeric shimmy damper.

Description

technical field [0001] The invention belongs to the field of helicopter dynamics design, and specifically relates to a new viscoelastic shimmy model and its application in helicopter systems, which can be applied to various articulated, hingeless and non-hinged viscoelastic shimmy models. Bearing rotor helicopter. Background technique [0002] In 1907, the Frenchman Paul successfully developed the first full-size manned helicopter. Since then, the helicopter has been updated many times, and the technology has been continuously developed and improved. Due to the inherent characteristics of the helicopter structure, the vibration problem generated by the rotor is one of the important problems in the development process of the helicopter. The air resonance problem caused by this has attracted the attention of scholars and engineers. The methods to solve the dynamic instability caused by resonance include avoiding the resonance frequency by adjusting the system parameters of ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B64F5/00
Inventor 向锦武任毅如罗漳平李道春庄南剑张连鸿郭俊贤张亚军黄明其
Owner BEIHANG UNIV
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