In-plane properties of CFRP laminates containing throughthickness reinforcing rods (Z-pins

SUMMARY: Delamination is a significant problem when composites are used for marine applications. One method of reducing delamination is to insert through-thickness reinforcement into the laminate. This paper will present results from the testing of z-pinned carbon-fibre reinforced epoxy laminates in direct compression using the Celanese testing apparatus. The results obtained in these tests will be discussed in relation to the microstructure of the samples, in particular the effect of fibre waviness induced by the insertion of the z-pins. It will be shown that fibre waviness is the governing factor controlling reduction in compressive strength due to the presence of z-pins, but that such fibre waviness may be mitigated by optimisation of the geometry of z-pin insertion