Abstract
KEYWORDS
low-velocity impact, carbon/epoxy vinyl ester composite, failure energy/force, indentation, BVID.
ABSTRACT
In this paper the authors present an experimental investigation about low velocity impact behavior of composite fiber reinforced plastics materials. The objectives of investigations are to measure the failure energy/force which determine a complete penetration and the level of energy/force for which the damages are not visible with naked eye (BVID level). It is identified the relation between force and identation on the impact point and it is noted the external aspects of the damage/failure modes of the specimens. It was used coupon specimens made from carbon/epoxy vinyl ester composite laminate cut from flat plate, with dimensions 100x150x2.5mm3. The plate had 8 laminae with [0/-45/45/90]s stacking sequence. The test set-up included instrumented drop weight tower equipment with a 16mm diameter hemispherical-shaped impactor made from hardened steel and data acquisition system. The indentation in the impact point was measured after 24 hours when test had placed using a steel ball with the same diameter with hemispherical-tip impactor. The relation between contact force and indent in the impact point and impact force related to the initial kinetic energy of the projectile are presented.