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Trans-Ply Crack Density Detection by Acousto-Ultrasonics

  • John H. Hemann
  • Paul Cavano
  • Harold Kautz
  • Ken Bowles

Abstract

The use of advanced composite materials, particularly for aerospace use, requires dimensional stability and the absence of cracks. The presence of cracks reduces mechanical characteristics and exposes the fibers and interfaces to environmental (moisture) effects. Graphite/PMR polyimide composites are candidate materials to replace metals in moderate high temperature zones (up to 316°C) in jet engines. These types of applications will introduce thermal cycling which in turn will produce trans-ply cracking unless tougher matrix materials are developed. Because these trans-ply cracks are very undesirable, NDE techniques are needed to detect the presence of trans-ply cracks. This paper will demonstrate that acousto-ultrasonics can be used to detect trans-ply cracks in graphite/PMR polyimide cross-ply and woven fabric laminates.

Keywords

Crack Density Fabric Laminate NASA Lewis Research Pyromellitic Dianhydride Advanced Composite Material 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    D. S. Adams, D. E. Bowles, and C. T. Herakovich, Thermally Induced Transverse Cracking in Graphite-Epoxy Cross-ply Laminates, J of Rein Plas & Comp. 5:152 (1986).CrossRefGoogle Scholar
  2. 2.
    T. Ishikawa and T. W. Chou, In-Plane Thermal Expansion and Thermal Bending Coefficients of Fabric Composites, J of Comp Matls. 17:92 (1983).CrossRefGoogle Scholar
  3. 3.
    H. E. Kautz, “Acousto-Ultrasonic Verification of the Strength of Filament Wound Composite Material, TM-88827,” NASA, Cleveland (1986).Google Scholar

Copyright information

© Springer Science+Business Media New York 1988

Authors and Affiliations

  • John H. Hemann
    • 1
  • Paul Cavano
    • 1
  • Harold Kautz
    • 2
  • Ken Bowles
    • 2
  1. 1.Cleveland State UniversityClevelandUSA
  2. 2.NASA Lewis Research CenterClevelandUSA

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