Composite tubular structure

A method of manufacturing a tubular structure, the method comprising:

• locating a plurality of inner, circumferentially continuous braided tubes of fibre reinforced plastics material around a respective bladder;
• locating an outer, circumferentially continuous braided tube of fibre reinforced plastics material onto the plurality of inner tubes;
• expanding each of the bladders around which the inner tubes are located whilst the inner tubes are within the outer tube such the inner tubes are urged against one another and against the outer tube and adjacent parts of the inner and outer tubes are compressed together;
• and
• bonding the outer and inner tubes together to form an outer shell having a pair of laminated layers of fibre reinforced plastics material and at least one internal web with a pair of laminated layers of fibre reinforced plastics material.

A system for manufacturing a tubular structure, the system comprising:

• a plurality of inner circumferentially continuous braided tubes of fibre reinforced plastics material
• a plurality of bladders for receipt within a respective one of the inner tubes;
• an outer circumferentially continuous braided tube of fibre reinforced plastics material;
• and
• a mould tool defining a cavity therein for receiving the outer tube and the inner tubes;
• wherein the system is configured to expand, in use, the plurality of bladders when the inner tubes are located therearound whilst the inner tubes are within the outer tube and the outer tube is within the mould tool such the inner tubes are urged against one another and against the outer tube, the outer tube is compressed against the mould tool, adjacent parts of the inner and outer tubes are compressed together and the outer and inner tubes are bonded together to form an outer shell having a pair of laminated layers of fibre reinforced plastics material and at least one internal web with a pair of laminated layers of fibre reinforced plastics material.