TRANSVERSE IMPACT BEHAVIOR OF KNITTED CARBON-FIBER FABRIC-REINFORCED THERMOPLASTIC COMPOSITE SHEETS

Instrumented falling weight impact (IFWI) properties of two-dimensiona l (2D) weft-knitted carbon-fiber (CF)-reinforced poly(ethyl methacryla te) (PEMA) and poly(ether ether ketone) (PEEK) composites with a reinf orcement content of V-f approximate to 35 and 51 vol. %, respectively, were studied under low-energy and perforation impact conditions. Resu lts indicated that the transverse impact response of these thermoplast ic composites strongly depends on the ductility of the matrix, on fibe r/matrix adhesion, and on the stitch (rib) structure (size, stretching of the fabrics) of the knitted fabric reinforcement. The highest thic kness-related perforation impact energy was found for the knitted CF-r einforced PEEK composite (approximate to 15 J/mm) due to its high rein forcement content, high matrix ductility, and good fiber/matrix bondin g.