Novel joints developed from partially un-moulded carbon-fibre-reinforced laminates

Two novel joints made from partially un-moulded carbon-fibre-reinforced plastic plates were designed to increase the strength of joints between carbon-fibre-reinforced plastic parts. In the partially un-moulded plate, a portion of the fabric stack was moulded with resin while the rest of the fabric stack remained dry. The plate was made using a manufacturing process developed from vacuum-assisted resin-transfer moulding. A new double-lap joint sandwiched a normal carbon-fibre-reinforced plastic plate between the dry fabric layers of a partially un-moulded plate. The other laminated joint overlapped the dry fabric layers of two partially un-moulded plates. Both joints were moulded by resin transfer. Tensile testing indicated that the two novel joints were more than twice as strong as a classical double-lap joint and half as strong as a normal, joint-free carbon-fibre-reinforced plastic plate. Additionally, the joints may potentially be made much stronger by modifying their shapes. In particular, the laminated joint may be made as strong as a normal carbon-fibre-reinforced plastic plate because its strength is determined by the fibre-matrix interface rather than the bondline strength, which is a key factor in determining the strength of a normal carbon-fibre-reinforced plastic plate.