PROCESS AND JIG FOR MANUFACTURING COMPOSITE MATERIAL STRUCTURES

The invention relates to a method for producing stiffened structures (1) made from composite materials, formed by an exterior covering (2) and a plur ality of stiffeners (3) having a closed cross-section defining an interior o pening (6), which method comprises the following steps: a) providing a mould ing tool (34); b) providing auxiliary male tools (36) having interior caviti es (32) reinforced (33) along the length thereof, said tools being covered b y membranes (37) suitable for curing; c) providing stiffeners (3); d) arrang ing the stiffeners (3) in the tool (34) and the auxiliary male tools (36) in the interior openings (6); e) laminating the exterior coating (2); f) curin g the stiffened structure (1) at a high temperature and pressure; g) removin g the auxiliary male tools (36) after the section (41) thereof has been redu ced; h) and separating the cured, stiffened structure (1) from the tool (34) . The invention also relates to the auxiliary male tools (36), including the design of the interior cavities (32), the reinforcement (33) thereof and th e fact that the section of same can be maintained or reduced with the applic ation of overpressure or underpressure respectively.