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Proceedings Paper

Porosity determination in thin graphite-epoxy composite laminates using histograms of ultrasonic C-scans
Author(s): Corinne Darvennes; Lance Lowe; Christopher Wilson
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Paper Abstract

Evidence of a direct correlation between attenuation and porosity in graphite-epoxy composites can be found during a literature review of ultrasonic research. This paper presents the possibility of detecting and quantifying porosity in thin laminates using amplitude histogram data obtained from ultrasonic C-scans in the pulse-echo mode. Seventeen composite panels were manufactured under various curing pressures to generate different levels of porosity. Multiple C-scans of these panels and their associated amplitude histograms were generated. Trends were calculated for quantifying porosity with respect to mean histogram amplitude data. The data indicate an effect of the material properties on the trendline which mean that different materials will need to be calibrated for this technique. Repeatability of the method was verified. Finally the sensitivity of the method was checked by zooming in on sections of the C-scans that displayed elevated levels of porosity. Comparing mean values for the zoomed histograms to mean values for the bulk histograms showed an ability to detect small local changes in the porosity levels. This method shows good potential for quantifying porosity levels larger than 1%. More data are still needed for a wider range of porosities to build more confidence in the porosity estimation.

Paper Details

Date Published: 20 July 2004
PDF: 8 pages
Proc. SPIE 5393, Nondestructive Evaluation and Health Monitoring of Aerospace Materials and Composites III, (20 July 2004); doi: 10.1117/12.540529
Show Author Affiliations
Corinne Darvennes, Tennessee Technological Univ. (United States)
Lance Lowe, Consulting Services (United States)
Christopher Wilson, Tennessee Technological Univ. (United States)

Published in SPIE Proceedings Vol. 5393:
Nondestructive Evaluation and Health Monitoring of Aerospace Materials and Composites III
Peter J. Shull; Andrew L. Gyekenyesi, Editor(s)

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