Patent ID: 8623159

Claim:
A method for producing a continuous, three-dimensional, closed semi-finished product made of fiber composite from a planar, fibrous preform, comprising the steps of: a) providing a planar, fibrous preform having a first thickness, a width, a length, a first end extending along the length and a second end extending along the length and spaced the width from the first end, and laying the planar, fibrous preform flat; b) aligning the planar, fibrous preform to ensure optimum load bearing orientation of the fibers in the planar fibrous preform, and compacting the fibrous preform to a final thickness, the final thickness being less than the first thickness, the compacted preform, after being compacted to the final thickness, being sufficiently flexible to enable the compacted preform to be manipulated into a three-dimensional structure; c) forming the compacted planar, fibrous preform into a three-dimensional structure by contacting the first end with the second end to form a four-sided polygonal tube; d) closing the four-sided polygonal tube by sewing together the ends of the compacted preform along the length of the preform with a stretchable and meltable thread material to form a flexible closed four-sided polygonal tube that is flexible along its length.