CFRP laminates impacted at low velocity: Influence of the matrix and temperature

Abstract

Carbon fibre composite laminates in vinyl ester and epoxy resin were dynamically loaded by a falling weight machine, by using a cylindrical impactor with a hemispherical nose. The same woven fabric was immersed in epoxy and vinylester resin in the same stacking sequence to obtain the same thickness at the aim to compare the dynamic response of the different matrix, at room and extreme conditions. The tests, in fact, were performed at room and at the low temperature of -25°C. Impact tests were carried out at penetration to obtain the complete load-displacement curve and to measure the penetration energy, and at different energy levels, 5J, 10J and 20J, to investigate the influence of the matrix on the damage start and propagation. After the impact tests, the specimens were non destructively investigated by Ultra Sound technique to measure the delamination. A general better behavior of vinyl ester resin was noted. The latter was of Naval interest where this resin is largely applied mainly due to the low absorption of humidity.