Crashworthiness of various random chopped carbon fiber reinforced epoxy composite materials and their strain rate dependence

The ACC (Automotive Composite Consortium) is interested in investigating the use of random chopped fiber reinforced composites as crash energy absorbers primarily because of the low costs involved in their manufacture thus making them cost effective for automotive applications. Although many scientists have investigated the energy absorption characteristics in various continuous fiber reinforced composite materials and their dependence on strain rate, there is very little literature available on the energy absorption and crushing characteristics of random chopped fiber reinforced composite materials and their strain rate dependence. Therefore, the primary goal was to determine the crashworthiness of various random chopped carbon fiber composite material systems. To meet this goal, first an experimental set up was developed for discerning the deformation behavior and damage mechanisms that oc cur during the progressive crushing of composite materials. The three different random chopped carbon reinforced epoxy composite material systems studied were P4, HexMC, and CCS100. Quasi-static progressive crush tests were then performed on these random chopped carbon fiber composite plates to determine their crashworthiness. In addition, an attempt was made to investigate and characterize the strain rate effects on the energy absorption of a random chopped carbon fiber P4 composite. The specific energy absorption was found to increase with increasing loading rate from 15.2 to 762 cm/min.