COMPARISON OF ENERGY-ABSORPTION OF CARBON EPOXY AND CARBON PEEK COMPOSITE TUBES

Axial compressive tests have been carried out on carbon fibre/epoxy and carbon fibre/PEEK tubes made from unidirectional prepreg materials. Three fibre architectures were investigated: unidirectional fibres parallel (0-degrees) to the axis of the tube, +/-30-degrees and +/-45-degrees. One set of tubes was machined with a 45-degrees chamfer at one end in an attempt to trigger progressive crushing and the other set had square ends to determine the compressive strength of the material. Stable progressive crushing occurred in +/-45-degrees carbon fibre/epoxy tubes and 0-degrees carbon fibre/PEEK tubes where the crush stress was significantly lower than the compressive fracture strength. The 0-degrees carbon fibre/PEEK tubes had a specific energy absorption of 180 kJ kg-1, which is the highest value recorded for any material. This high value is interpreted in terms of the high interlaminar toughness of PEEK-matrix composites.