Characterisation of Carbon Fibre Reinforced Powder Epoxy Composites for Wind Energy Blades

Powder-epoxy resins have been shown to possess desirable properties making them suitable as a matrix for the production of composite wind blades. CFRP laminates manufactured using a powder-epoxy matrix were tested to determine mechanical properties. The laminates were manufactured using a noncrimp stitched unidirectional fabric and were compared to laminates manufactured from fibre tows with tension applied during the curing cycle. The tensioned case was investigated as a benchmark for superior fibre straightness mimicking the pultrusion process whereas the fabric was representative of materials used in industry. The materials were mechanically tested in the longitudinal and transverse directions in both tension and compression to determine strength and modulus. Results showed that the stitched case had a normalised tensile strength notably less than the tensioned tows in the longitudinal and transverse directions. While there was less of a drop in compressive properties in the longitudinal direction, the strength of the stitched case in the transverse direction was approximately 7% greater. No significant drop in modulus was observed due to stitching. It can be concluded that non-crimp carbon fabrics with powder epoxy matrices offer exceptional stiffness properties making them a suitable candidate for the production of spar caps in wind blades