Impact perforation behavior of CFRPs using high-velocity steel sphere

In order to investigate impact perforation behavior of Carbon Fiber Reinforced Plastics (CFRPs), a steel sphere having a velocity of 500–1230 m/s was impacted to several kinds of CFRP laminate specimens consisting of different carbon fibers, interlaminate sequence, configuration; cross-ply or woven cloths, or thickness. The perforation behaviors were evaluated by absorbed energies during perforation, morphological in situ observations using high-speed framing cameras and postmortem observations. Spheres penetrated specimens in a fluid manner on the front surface, and perforated them in an extrusive manner on the rear surface in case of thick specimens. In case of thin specimens, on the contrary, spheres perforated specimens in fluid manner on the rear surface. In the fluid manner energy absorption was independent of the static mechanical properties of the fibers. In extrusion the energy absorption depended on the static tensile fracture energy of the fiber: high fracture energy resulted in large energy-absorption. The boundary velocities in changing failure modes depended on the tensile moduli of the reinforced fibers. Failure modes were significantly affected by the mechanical properties of the fiber: with low strength or fracture strain of reinforced carbon fiber, the specimens showed plugging fractures on the rear surfaces. With high strength and fracture strain, the specimens showed larger delamination on both surfaces.