Damage to thickness-reinforced C/C laminates by low-energy impact

The damage behavior caused by the low-energy impact on thickness-reinforced carbon/carbon (C/C) laminates was investigated. The C/C laminates were fabricated using isothermal chemical vapor infiltration (CVI) processes under vacuum. A drop weight impact testing was carried out on the laminates. The damages on the C/C laminates were examined using radiography, scanning electron microscopy, optical microscopy and strain analysis. The compressive strength of C/C laminates was observed to increase both before and after impact due to stitching reinforcement in the thickness direction. Through-thickness stitching interrupted delamination propagation and increased the damage tolerance of laminates more than a factor of two.