Nonlinear Large Amplitude Vibration of Composite Helicopter Rotor Blade at Large Static Deflection

Abstract

The nonlinear, large amplitude free vibration of compo site helicopter blades under large static deflection is investigated analytically. A new model capable of handling large amplitudes as well as large deflections was developed, based on the work in a previous report by Minguet. The model can deal with large displacements and rotations by use of Euler angles and can account for structural couplings such as bending-twist and extension-twist. The reduction of this large deflection model to a commonly used moderate deflection model is also shown. A Newton-Raphson type iterative solution technique based on numerical integration of the basic large deflection equations is seen effective for the present analysis. It is found that both large static deflection and large amplitudes can affect the fore-and-aft and torsion modes significantly, but bending modes are not influenced much by the geometrical nonlinearities. (js)

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Document Details

Document Type
Technical Report
Publication Date
Jul 25, 1990
Accession Number
ADA227933

Entities

People

  • John Dugundji
  • Taehyoun Kim

Organizations

  • Massachusetts Institute of Technology

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Angular Acceleration
  • Boundaries
  • Classification
  • Composite Materials
  • Contracts
  • Differential Equations
  • Epoxy Composites
  • Equations
  • Equations Of Motion
  • Euler Angles
  • Frequency
  • Helicopter Rotors
  • Modal Analysis
  • Nonlinear Differential Equations
  • Numerical Analysis
  • Numerical Integration
  • Resonant Frequency

Fields of Study

  • Physics

Readers

  • Aerodynamics.
  • Finite Element Method (FEM) for solving Partial Differential Equations (PDEs)
  • Structural Dynamics.