Composite material structure for aircraft fuselage and process for manufacturing it
The present invention provides a closed composite material structure for aircraft fuselage shaped on a male jig from which it can be separated in a certain direction, said structure comprising a single outer panel and a plurality of inner longitudinal stiffeners integrated in said panel, such that the expansion coefficient of the male jig is greater than the expansion coefficient of the composite material of the structure, thus being able to remove the already manufactured structure, formed by the panel and the integrated inner stiffeners, in a single operation. The present invention further provides a process for manufacturing such a closed structure.
1 . A closed composite material structure ( 1 ) for aircraft fuselage shaped on a male jig ( 2 ), said structure ( 1 ) comprising an outer panel ( 3 ) and a plurality of longitudinal stiffeners ( 4 ) inside said outer panel ( 3 ), characterized in that the expansion coefficient of the male jig ( 2 ) is greater than the expansion coefficient of the composite material of the structure ( 1 ), a clearance ( 10 ) which allows separating the structure ( 1 ) from the male jig ( 2 ) being generated between the outer panel ( 3 ) and the male jig ( 2 ) in the process for curing the composite material of the structure ( 1 ).
2 . A closed structure ( 1 ) according to claim 1 , characterized in that the male jig ( 2 ) comprises a leak-tight tubular element ( 81 ) on which a plurality of detachable elements ( 82 ) are placed.
3 . A closed structure ( 3 ) according to claim 1 , characterized in that the outer panel ( 3 ) comprises in its inner surface at least one element ( 14 ) with a size smaller than the clearance ( 10 ) generated in the process for curing the composite material of the structure ( 1 ).
4 . A closed structure ( 3 ) according to claim 1 , characterized in that the stiffeners ( 4 ) comprise webs ( 5 ) separated from the panel ( 3 ) and legs ( 6 ) joined to the panel ( 3 ).
5 . A closed structure ( 3 ) according to claim 1 , characterized in that the stiffeners ( 4 ) have a honeycomb shape.
6 . A closed structure ( 3 ) according to claim 1 , characterized in that the stiffeners ( 4 ) have an omega (Ω) shape.
7 . A closed structure ( 3 ) according to claim 1 , characterized in that the structure ( 1 ) has a shape such as a cylindrical shape.
8 . A closed structure ( 3 ) according to claim 1 , characterized in that the structure ( 1 ) has a shape such as a frustoconical shape.
9 . A process for manufacturing a closed composite material structure ( 1 ) for aircraft fuselage comprising the following steps:
a) sequentially arranging the stiffeners ( 4 ) on the male jig ( 2 );
b) laminating the composite material on the surface formed by the male jig ( 2 ) and the stiffeners ( 4 ) to form the outer panel ( 3 ) of the closed structure 1 ;
c) placing a hold-down plate ( 9 ) on the outer surface of the outer panel ( 3 );
d) placing the necessary remaining auxiliary elements ( 13 ) for the autoclave curing of the composite materials used;
e) curing the closed structure ( 1 ) inside the autoclave in high pressure and temperature conditions;
f) separating the closed structure ( 1 ) from the male jig ( 2 ) according to a separation direction ( 11 ) and direction ( 12 ).