Natural Frequencies in Coupled Bending and Torsion of Twisted Rotating and Nonrotating Blades

Abstract

A Holzer-Myklestad type of procedure, using a matrix formulation, is developed for the determination of the natural vibration characteristics of a pretwisted rotating blade in coupled bending and torsion. The nonrotating blade is considered as a special case. Results of a limited parametric study are presented. It is found that in the case of the rotating blade there can be an appreciable effect of centrifugal forces in coupling the bending and torsional vibrations. In order to investigate the effects of Coriolis forces and the nonlinear effects of large angular displacements, a study is made on the basis of a simple model. Numerical results indicate that the Coriolis forces may introduce substantial phase differences between bending and torsional vibration. Limited numerical results on the nonlinear effects indicate that these effects decrease slightly the frequency of the characteristic motions as determined from a linearized analysis and introduce some coupling between the characteristic motions.

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Document Details

Document Type
Technical Report
Publication Date
Jul 01, 1964
Accession Number
ADA397127

Entities

People

  • G. Isakson
  • J. G. Eisely

Organizations

  • University of Michigan

Tags

Communities of Interest

  • Air Platforms
  • C4I
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Bending Moments
  • Center Of Gravity
  • Centrifugal Force
  • Computers
  • Coordinate Systems
  • Differential Equations
  • Digital Computers
  • Energy
  • Equations
  • Equations Of Motion
  • Frequency
  • Gravity
  • Moment Of Inertia
  • Numerical Analysis
  • Resonant Frequency
  • Steady State
  • Vibration

Readers

  • Aerodynamics.
  • Structural Dynamics.