Box-shaped composite material structure for aircrafts

A box-shaped structure for aircrafts made of a fiber-reinforced polymer matrix prepreg composite material, said box-shaped structure extending along a longitudinal direction between a first longitudinal end and a second longitudinal end, and comprising:

• a first longitudinal wall;
• a second longitudinal wall facing the first longitudinal wall and arranged spaced from the first longitudinal wall by a non-zero amount;
• a plurality of spars extending longitudinally and between said first longitudinal wall and second longitudinal wall, connected to these latter and delimiting with the first longitudinal wall and the second longitudinal wall respective longitudinal cavities;
• and
• at least one reinforcing rib arranged transversal to the spars at a transversal sector of said box-shaped structure interposed between said first longitudinal end and second longitudinal end;
• each spar comprising two profiles having a longitudinal axis, a C-shaped cross section, each including a central flange and two longitudinal winglets projecting transversally from the central flange, and joined at the respective central flanges, so that each spar has a double-T cross section defined by a central web and two opposite end wings;
• wherein the central flange of each profile has:
• a first portion extending from an axial end of the profile up to a predetermined axial coordinate of the profile, axially interposed between said one axial end and the other end axial of the profile, said first portion being full in the longitudinal direction and in the transversal direction with respect to the relative longitudinal axis and between the relative winglets;
• and
• a second portion extending from said axial coordinate up to said other axial end and comprising a through slot extending longitudinally from the axial coordinate up to said other axial end and laterally open at said other axial end by means of a relative lateral opening, so as to define a lack of material on the relative flange in the longitudinal direction, so that each spar has, in turn, a longitudinal spar cavity open laterally and determined by the union of the relative slots;
• wherein the spars are oriented in such a way that the relative spar cavities all face each other transversally to the longitudinal direction of the box-shaped structure and are all arranged at said first end longitudinal of the box-shaped structure;
• wherein the lateral openings of the slots are arranged at said first longitudinal end;
• and
• wherein the at least one reinforcing rib is inserted transversally between the first longitudinal wall and the second longitudinal wall through the lateral openings of the slots, so as to engage the spar cavities.