Structure for joining torsion boxes in an aircraft using a triform fitting made from non-metallic composite materials

A triform fitting made from non-metallic composite materials, for joining torsion boxes in an aircraft, comprising:

• two symmetrical flanges and a longitudinal flange converging at a central node, the two symmetrical flanges each having an external face opposite the longitudinal flange,
• the longitudinal flange being joined to an aircraft center rib by rivets, and
• a plurality of cross ribs that reinforce a joint between the symmetrical flanges and the longitudinal flange of the triform fitting, the cross ribs being oriented perpendicular to the longitudinal flange and the symmetric flanges,
• wherein skins of the torsion boxes are joined to the two symmetrical flanges by rivets, the torsion boxes having T-shaped internal stringers comprising feet joined to webs, the feet having a first faces opposite the webs and a second faces adjacent to the webs,
• wherein the first faces of the feet are joined to the skins of the torsion boxes,
• wherein at least a portion of the second faces are placed on the external faces of the symmetrical flanges such that the symmetrical flanges of the triform fitting are arranged inside the torsion boxes, and
• wherein the center rib of the aircraft comprises straight slots, the cross ribs of the triform fitting passing through the straight slots of the center rib.