A total of 28 graphite/epoxy nat-plate specimens and six graphite/epox
y tube specimens ere crushed under quasi-static conditions to provide
a basis far comparison of the measured energy absorbency of these two
geometries. The energy absorbency of each specimen was measured, and t
he specific sustained crushing stress (SSCS) was determined. All plate
and tube specimens were manufactured from AS4/3501-6 graphite/epoxy w
ith the same layup and thickness. thus providing a common laminate for
comparison. Flat-plate specimens of two different widths were tested
to determine the effect of the testing fixture on the observed energy
absorbency. The flat-plate results indicate that the specific energy a
bsorbency per unit thickness is nearly independent of the specimen wid
th, with a small contribution to the energy absorbency by the testing
fixture. However, this calculated value of measured energy absorption
due to the test fixture is within the scatter of the data. The results
also indicate that specimen geometry affects specimen stability and t
herefore the failure modes exhibited by the specimen during crushing.
Similar failure modes were observed in the tube and flat-plate specime
ns with the flat plates absorbing 12% less energy per unit mass. Conse
quently, flat-plate specimens can be used as a lower-cost alternative
to tube specimens or in test programs requiring simpler geometries.