<p>A crush test fixture for measuring energy absorption of flat plate
specimens from an earlier study was redesigned to eliminate the problem of
binding of the load transfer platen with the guide posts. Further
modifications were to increase the stroke, and combine the two scaled test
fixtures into one. This new crush test fixture was shown to produce load displacement
histories exhibiting well developed sustained crushing loads
over long strokes.</p>
<p>
An experimental study was conducted on two material systems:
AS4/3502 graphite/epoxy, and a hybrid AS4-Kevlar/3502 composite. The effect
of geometric scaling of specimen size, the effect of ply-level and
sublaminate-Ievel scaling of the stacking sequence of the full scale specimens,
and the effect of trigger mechanism on the energy absorption capability were
investigated.</p>
<p>
The new crush test fixture and flat plate specimens produced peak and
sustained crushing loads that were lower than obtained with the old crush
test fixture. The trigger mechanism used influenced the specific sustained
crushing stress (SSCS). The results of this study indicated that to avoid any
reduction in the SSCS when scaling from the 1/2 scale to full scale specimen
size, the sublaminate-level scaling approach should be used, in agreement
with experiments on tubes. The use of Kevlar in place of the graphite 45°
plies was not as effective a means for supporting and containing the 0°
graphite plies for crushing of flat plates and resulted in a drop in the SSCS.
This result did not correlate with that obtained for tubes.</p> / Master of Science
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/41649 |
| Date | 17 March 2010 |
| Creators | Lavoie, J. André |
| Contributors | Engineering Mechanics |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Master's project |
| Format | BTD, application/pdf |
| Relation | LD5655.V851_1993.L386.pdf |
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