Process for the production of a panel of composite material with stiffening strips

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 to form an assembly, 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 improvement wherein the stiffening strip (3) is a cellular honeycomb 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), said non-adherent material preventing said plies from sinking into cells of said cellular honeycomb material.