Materials Science Forum, Vol.449-4, 749-752, 2004
On impact characteristic evaluation in CF/Epoxy composites under failing-weight impact loadings
A method for a falling weight impact test was utilized to estimate the impact energy absorbing characteristics and impact strength of CFRP laminate plates based on considerations of stress wave propagation theory. The energy absorbed by a quasi-isotropic specimen having four inter-faces was higher than that of orthotropic laminates with two interfaces. The more interfaces, the greater the energy absorbed. The absorbed energy of a hybrid was higher than that of normal specimens. The delamination area generated by the impact damage was observed by using an ultrasonic C-scanner when the specimen was subjected to a falling weight impact. The delamination area of impacted specimens for the different ply orientations was measured in order to determine the correlation between impact energy and delamination area and failure mechanisms based on the fracture surfaces. The fracture surfaces obtained by a falling weight impact test were observed by using the SEM (scanning electron microscope). Also, a falling weight impact tester was built to evaluate the characteristics and impact strength of CFRPs.
Keywords:composite materials;falling weight impact test;delamination;impact energy;ultrasonic C-scanner