Damage Assessment by Acousto-Ultrasonic Techniques in Composites,

Abstract

This paper addresses the non-destructive evaluation of cross-ply 0/90 subscript 2S and 90/0 subscript 25 S-2 G1/DER 332 laminates using acousto-ultrasonic and acoustic emission techniques. Acoustic emission and acousto-ultrasonic measurements gave early warnings of damage initiation before transverse cracks became visible. AU parameters such as peak amplitude, energy and stress wave factor were equally sensitive to damage initiation but peak amplitude and energy were more sensitive to damage accumulation. Variations of peak amplitude, event duration, ringdown counts, and rise time in AU tests were analyzed to show that internal damage not only increased the apparent attenuation but also affected the wave envelope. The same effect was also present AE tests. Acousto-ultrasonic tests of an undamaged cross-ply laminate showed that the apparent attenuation coefficients were almost independent of the wave propagation direction. The strongest wave was found along the fibers in the ply in contact with the transducers and the weakest wave traveled at an angle of 45 deg to the fibers. (Keywords: Glass/epoxy; and Ply cracking).

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Document Details

Document Type
Technical Report
Publication Date
Apr 01, 1986
Accession Number
ADA168097

Entities

People

  • H. T. Hahn
  • Luis Lorenzo

Organizations

  • University of Washington

Tags

Communities of Interest

  • Sensors

DTIC Thesaurus Topics

  • Acoustic Emissions
  • Amplitude
  • Composite Materials
  • Damage Assessment
  • Epoxy Laminates
  • Failure Mode And Effect Analysis
  • Frequency
  • Laminates
  • Materials
  • Materials Testing
  • Measurement
  • Orientation (Direction)
  • Repetition Rate
  • Stress Waves
  • Test Methods
  • Ultrasonic Tests
  • Wave Propagation

Readers

  • Materials Science and Engineering.
  • Seismology
  • Structural Health Monitoring of Composite Structures.