Patent ID: 7790082

Claim:
In a process for the production of a panel ( 7 ) of composite material with stiffening strips ( 3 ), in which a mold ( 1 ) having the shape and size of the panel to be produced, is draped with at least one first ply ( 2 ) of fibers pre-impregnated with resin, there is emplaced at desired positions on said ply ( 2 ) at least one stiffening strip ( 3 ), the stiffening strip ( 3 ) as well as at least a portion of the remaining surface of said first ply ( 2 ) is covered with at least one second ply ( 4 ) of fibers pre-impregnated with resin, then a bladder ( 6 ) is positioned to cover the above elements, a suitable vacuum is drawn in the space between the mold ( 1 ) and the bladder ( 6 ), the assembly is then disposed in an autoclave to subject it to a pre-established polymerization cycle for the resin, at temperatures and pressures suitable to said resin, and finally, the panel is demolded; the stiffening strip ( 3 ) being a foam structure, and prior to said emplacement of the stiffening strip ( 3 ) and/or of the second ply ( 4 ), there is interposed at least one layer ( 5 ) of a non-adherent material between at least a portion of the surface of the stiffening strip ( 3 ) and one and/or the other of said plies ( 2 , 4 ) for avoiding sinking of said fibers into said stiffening strips and wherein said foam structure is retained permanently within the panel after the resin is polymerized.