USE OF MODAL ACOUSTIC EMISSION TO MONITOR DAMAGE PROGRESSION IN CARBON FIBER/EPOXY COMPOSITES.

Autor: Waller, J. M., Nichols, C. T., Wentzel, D. J., Saulsberry, R. L.
Předmět:
Zdroj: AIP Conference Proceedings; 6/23/2011, Vol. 1335 Issue 1, p919-926, 8p, 1 Diagram, 3 Charts, 4 Graphs
Abstrakt: Broad-band modal acoustic emission (AE) was used to characterize micromechanical damage progression in uniaxial IM7 and T1000 carbon fiber-epoxy (C/Ep) tows, and a helical and hoop-wrapped IM7 composite overwrapped pressure vessel (COPV). To expedite analysis, tows and the COPV were subjected to an intermittent load hold tensile stress profile. Damage progression in tow specimens was followed by analyzing the Fast Fourier Transforms (FFTs) associated with AE events. FFT analysis showed that damage was usually cooperative, consisting of several failure modes occurring at once, and was dominated by fiber breakage throughout the duration of the stress profile. Evidence was found for the existence of a universal damage parameter, referred to here as the critical Felicity ratio, or Felicity ratio at rupture (FR*), which had a value close to 0.96 for the tows and the COPV tested. The use of FR* to predict the burst pressure of the COPV is demonstrated. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index