Impact force analysis during low-velocity impact of woven carbon/vinylester

This study is focused on the impact force response of two woven plain weave composites consisting of carbon fibers (T700) in vinylester 510A and 8084 matrices. Quasi-static loading was conducted to establish the indentation and bending responses and the threshold force where damage is initiated. The quasi-static tests verified that the indentation response followed the Willis formula for contact between a rigid sphere and a transversely isotropic half-space. The C/VE510A system displayed a lower impact force threshold for damage initiation than the C/VE8084 system, which is attributed to a more brittle VE510A matrix. With the contact and bending stiffnesses determined in the quasi-static tests, a mass-spring model of the impact configuration was solved numerically to determine the magnitude of force produced by hard-object impact with a given impact velocity. Falling weight impact tests were conducted over a range of drop heights to obtain velocity and impact force data. The spring-mass model predictions of impact force magnitude were in reasonable agreement with experimental results, although the model tends to under-predict the force, except at the highest impact energy.