Braided tubular Structure for a composite part its construction and its applications

A braided tubular structure (11) including longitudinal elongate elements (9) distributed on a plurality of collars coaxial with structure and helical braiding threads (8) forming two grids of directions oblique in relation to said longitudinal elongate elements and wound around and interlaced with said longitudinal elongate elements, said longitudinal elongate elements being selected from among the elements of a group consisting of threads, thread rovings, cables, rods and tubes, said helical braiding threads following paths which cause them to pass between said longitudinal elongate elements, wherein, in projection orthogonal to said longitudinal elongate elements (9), said paths of said helical braiding threads are constituted by:

• first elementary paths (t1) having a direction parallel to the thickness of the wall of the tubular structure (11) and orthogonal to the coaxial collars of elongate elements (9);
• second elementary paths (t2) having a direction circumferential in relation to said coaxial collars of elongate elements (9);
• and
• third elementary paths (r) connecting first elementary paths (t1) to second elementary paths (t2),
• in such a way that said helical braiding threads (8) of each one of said grids form an assembly of superposed layers in the direction of the thickness of the wall of said tubular structure 11, in which layers said helical braiding threads (8) are parallel from one layer to the next, wherein the braiding threads are all circumferential in relation to the braid and so that each of the braiding threads does not pass completely through the thickness of the wall of the tubular structure.