Effects of Cutout Orientations on Natural Frequencies and Mode Shapes of Curved Rectangular Composite Panels.

Abstract

STAGSC-1, a finite element code, and holographic interferometry were used to analyze the effects of cutout orientation (O, +45, -45 and 90) on the first five natural frequencies and mode shapes of a curved Gr-Ep panel. The clamped-clamped panels had a quasi-isotropic layup 0, -45, 45, 90s and measured 12 inch high with a 12 inch chord. When the finite element code was compared to the time averaged holograms, the two techniques showed close correlation of both the natural frequencies and mode shapes. It was found that the 0 cutout orientation had a significant effect on the panel stiffness while the other cutout orientations did not adversely effect the stiffness. It was also found that if a large number of elements in the finite element mesh are oriented at an angle other than 0 or 90, then the STAGSC-1 model is artificially stiffened. The phenomenon of mode switching was investigated analytically and determined to be a function of the cutout dimensions. Keywords: Composites, Vibrations, Holography, Finite Elements, Natural Frequencies, Mode Shapes.

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1986
Accession Number
ADA178638

Entities

People

  • Garry J. Cyr

Organizations

  • Air Force Institute of Technology

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies
  • Space

DTIC Thesaurus Topics

  • Accuracy
  • Air Force
  • Classification
  • Composite Materials
  • Engineering
  • Fiberglass
  • Geometry
  • Holograms
  • Materials
  • Mechanical Properties
  • Orientation (Direction)
  • Physical Properties
  • Resonant Frequency
  • Stiffness
  • Test Fixtures
  • Vibration
  • Waves

Fields of Study

  • Physics

Readers

  • Structural Dynamics.
  • Structural Health Monitoring of Composite Structures.