The effect of strain rate on the compressive behavior of thick carbon/
epoxy composite materials was investigated. Falling weight impact and
split Hopkinson pressure bar systems were developed for dynamic charac
terization of composite materials in compression at strain rates up to
2000 s(-1) Strain rates below 10 s(-1) were generated using a servohy
draulic testing machine. Strain rates between 10 s(-1) and 500 s(-1) w
ere generated using the drop tower apparatus. Strain rates above 500 s
(-1) were generated using the split Hopkinson pressure bar. Unidirecti
onal carbon/epoxy laminates (IM6G/3501-6) loaded in the longitudinal a
nd transverse directions, and [(0(8)/90(8))(2)/(0) over bar(8)](s) cro
ss-ply laminates were characterized. The 90-deg properties, which are
governed by the matrix, show an increase in modulus and strength over
the static values but no significant change in ultimate strain. The 0-
deg and cross-ply laminates show higher strength and ultimate strain v
alues as the strain rate increases, whereas the modulus increases only
slightly over the static value. The increase in strength and ultimate
strain observed may be related to the shear behavior of the composite
and the change in failure modes. In all cases, the dynamic stress-str
ain curves stiffen as the strain rate increases. The stiffening is low
est in the longitudinal direction and highest in the transverse direct
ion.