ISSN: 0884-6804
CODEN: JCTRER
Page Count: 9

Low Velocity Impact Damage in Filament-Wound Composite Pressure Bottles
Highsmith, AL
Assistant professor, The University of Alabama, AL

Nettles, A
NASA Marshall Space Flight Center, Marshall Space Flight Center, AL

Ledbetter, FE
NASA Marshall Space Flight Center, Marshall Space Flight Center, AL

Russell, SS
NASA Marshall Space Flight Center, Marshall Space Flight Center, AL

Abstract

In an effort to better understand the damage that develops in filament-wound composite structures when they are subjected to low velocity impact loads, a series of low velocity impact experiments was performed on small (146 mm (5.75 in.) diameter) filament wound pressure bottles. Three different material systems, IM7/3501-6ATL, IM7/X8553-45, and IM7/977-2, were evaluated. Three impact energy levels, 4.07 J (3.0 ft-lb), 6.78 J (5.0 ft-lb), and 9.49 J (7.0 ft-lb), were applied. Dye penetrant enhanced X-ray radiography was used to assess the damage that resulted from the impact loading. The through-the-thickness location of damage was assessed by means of stereo radiography.

The two material systems with toughened epoxy matrices (X8553-45, 977-2) generally developed smaller damage zones than the system with a standard epoxy matrix (3501-6ATL). Two distinct types of fiber fracture were observed. All of the systems exhibited a tendency to develop fiber fracture in the interior helical layers, usually at locations removed from the impact site. Some of the specimens fabricated from the material systems with the toughened epoxy matrices also developed fiber fracture in the exterior hoop layers. This second fiber fracture mode appeared to originate at the point of contact between the impacting tup and the specimen.

Keywords:
composite material, filament-wound composite, impact, damage, delamination, matrix cracking, fiber fracture, X-ray radiography

Paper ID: CTR10522J
DOI: 10.1520/CTR10522J
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