Patent ID: 8287790

Claim:
A method for manufacturing a hollow load-bearing beam structure of fiber-reinforced composite material, wherein the load-bearing beam structure includes at least a first and a second plurality of laminated layers shaped by a rigid mandrel having an outer surface that corresponds to an inner surface of the load-bearing beam structure, the method comprising: preparing, on substantially flat supporting surface, a flat first lay-up of the first plurality of laminated layers, one on top of another, with respective side edges of the plurality of laminated layers arranged offset with respect to each other, preparing, on a substantially flat supporting surface, a flat second lay-up of the second plurality of laminated layers, one on top of another, with respective side edges of the plurality of laminated layers arranged offset with respect to each other, positioning a surface of the first lay-up on a first side of the rigid mandrel, positioning a surface of the second lay-up on a second side of the rigid mandrel, forming the first and second lay-ups to the shape of the beam structure by bending the lay-ups against sides of the mandrel adjacent the first and second sides of the mandrel, such that the offset side edges of respective laminated layers of the first and second lay-ups overlap and are arranged as offset butt joints in a circumferential direction around the formed beam structure, curing the beam structure after forming the first lay-up and second lay-ups to the shape of the beam structure, and removing the cured beam structure from the mandrel.