Impact perforation of thin stiffened CFRP panels

Static indentation and dropweight impact tests have been performed on thin CFRP panels stiffened with three T-blade stiffeners and comparisons made with similar tests on plain panels. The impact perforation threshold energy may be estimated from the work done by the indentor during a static indentation test for both plain and stiffened panels. For impacts conducted in-line with the stiffener the perforation energy is significantly increased and the maximum damage levels occur at higher energies than for other panel loading conditions.