Abstract: A method of manufacturing “T” shaped stringers for an aircraft whereby the “T” shaped stringers have a stringer web and a stringer foot, the method comprising: a first step of hot-forming a carbon fiber laminate in order to achieve semi-stringers with an “L” shaped cross-section, a second step of placing together two hot-formed “L” shaped semi-stringers in order to form a “T” shaped stringer, a third step of co-bonding the resulting “T” shaped stringer on a cured skin with an adhesive line between them, and a fourth step of curing the obtained “T” shaped stringer inside a vacuum bag using invar alloy angles as curing tools. The invar alloy angles are cut at a radius area eliminating a part of the invar alloy angles covering the stringer foot in order to define an invar alloy piece having no foot.

Abstract: Method of manufacturing “T” shaped stringers (1) with an angle different from 90° between the web (2) and the foot (3) whereby the “T” shaped stringers have a stringer web and a stringer foot. The method comprises, after placing together two hot-formed “L” shaped semi-stringers to form a “T” shaped stringer, placing the “T” shaped stringer inside an invar alloy angle leaving a gap between the stringer web and the invar alloy angle. Afterwards, a heating device (7) is moved over the stringer feet (3) surface and a roller (8) slides over said stringer feet (3) surface to adapt the geometry of the stringer feet to the geometry of the invar alloy angle. The resulting “T” shaped stringer is co-bonded on a cured skin with an adhesive line between the stringer and the cured skin, and finally the obtained “T” shaped stringer is cured.

Abstract: A re-usable retainer designed to be used in the curing process of co-bonding uncured stringers. The re-usable retainer is made of metal so it is not necessary to manufacture one retainer for each manufactured stringer. The metallic retainer is placed in direct contact with the uncured resin so the cured stringer has a very good surface quality. The re-usable retainer has a special shape that allows a mild transition of the vacuum bag that avoids vacuum bag breakages. The re-usable retainer is easy to install and to remove.

Abstract: Method of manufacturing “T” shaped stringers (1) with an angle different from 90° between the web (2) and the foot (3) whereby the “T” shaped stringers have a stringer web and a stringer foot. The method comprises, after placing together two hot-formed “L” shaped semi-stringers to form a “T” shaped stringer, placing the “T” shaped stringer inside an invar alloy angle leaving a gap between the stringer web and the invar alloy angle. Afterwards, a heating device (7) is moved over the stringer feet (3) surface and a roller (8) slides over said stringer feet (3) surface to adapt the geometry of the stringer feet to the geometry of the invar alloy angle. The resulting “T” shaped stringer is co-bonded on a cured skin with an adhesive line between the stringer and the cured skin, and finally the obtained “T” shaped stringer is cured.

Abstract: 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.

Abstract: A re-usable retainer designed to be used in the curing process of co-bonding uncured stringers. The re-usable retainer is made of metal so it is not necessary to manufacture one retainer for each manufactured stringer. The metallic retainer is placed in direct contact with the uncured resin so the cured stringer has a very good surface quality. The re-usable retainer has a special shape that allows a mild transition of the vacuum bag that avoids vacuum bag breakages. The re-usable retainer is easy to install and to remove.

Abstract: The system has special application in the manufacture of aircraft wing covers (10 made of carbon fiber and the stringers (3) cured jointly with the wing cover during the polymerization in autoclave. The tool pieces (4) being used are defined by angular elements (5, 6) copying the geometry of the stringers (3). The shape of these stringers corresponds to the “T” section. The angular elements (5, 6) comprise, in their upper part, a pair of battlements (7) in order to be caught by part of the clamps (9) of a head (10) linked to a robot (11) of the spherical type with articulated arm with six axes. The angular elements (5, 6) are made of INVAR material and they are used to keep in position the stringers during the curing cycle in the autoclave.

Abstract: Method of manufacturing “T” shaped stringers for an aircraft whereby the “T” shaped stringers have a stringer web and a stringer foot, the method comprising: a first step of hot-forming a carbon fiber laminate in order to achieve semi-stringers geometry with an “L” shaped cross-section, a second step of placing together two hot-formed “L” shaped semi-stringers in order to form a “T” shaped stringer, a third step of co-bonding the resulting “T” shaped stringer on a cured skin with an adhesive line between them, and a fourth step of curing the obtained “T” shaped stringer inside a vacuum bag using invar alloy angles as curing tools. The method characterised in that the invar alloy angles are cut at a radius area eliminating a part of the invar alloy angles covering the stringer foot in order to define an invar alloy piece having no foot.

Abstract: The invention proposes a forming process for forming geometrically complex laminates made of composite material which allows obtaining very complex folded geometries, reducing the area of influence of the formed areas and making its effect local, handling the geometry of the laminate near the area to he formed, replacing the formed geometries with folded geometries, this way forcing the area of influence of the forming to be local, such that the length of the reinforcing fibers affected by said forming is minimal. The present invention also relates to complex geometries of laminates made of composite material obtained by means of the previous forming process.

Abstract: The system has special application in the manufacture of aircraft wing covers (1) made of carbon fiber and the stringers (3) cured jointly with the wing cover during the polymerization in autoclave. The tool pieces (4) being used are defined by angular elements (5, 6) copying the geometry of the stringers (3). The shape of these stringers corresponds to the “T” section. The angular elements (5, 6) comprise, in their upper part, a pair of battlements (7) in order to be caught by part of the clamps (9) of a head (10) linked to a robot (11) of the spherical type with articulated arm with six axes. The angular elements (5, 6) are made of INVAR material and they are used to keep in position the stringers during the curing cycle in the autoclave.

Abstract: In the state of the art, a composite prepreg lamination (2) is obtained, arranged on a cutting table (1), the lamination being affix to the table (1) by means of applying a vacuum, and the cutting of the lamination (2) being done in longitudinal strips (3) between which remain wasting material strips (4), being manually removed in order to continue with the subsequent post-processing of the longitudinal strips (3) and obtain the longitudinal pieces. The aim of the invention is to automate the process of removing the wasting material strips (4) so that, prior to their removal, one end (4a) of the strips (4) is affix on a rolled up device (5) and the strips (4) are rolled up in the longitudinal direction of the lamination (2). The device basically comprises a roller (5) provided with means for affixing the ends (4a) of the strips (4) for carrying out the said automation.

Abstract: The invention relates to a quality control process for an adhesive joint of two sub-components of a structure comprising the following steps: a) Providing the structure of composite material to be controlled; b) Providing at least one premanufactured testing device (1) representative of one of the sub-components of the structure; c) Bonding the at least one premanufactured testing device (1) to the other sub-component (7) of the structure in conditions similar to those of the real adhesive joint of the sub-components; d) Carrying out at least one mechanical test on the at least one premanufactured testing device (1) which allows assessing the quality of the adhesive joint.

Abstract: 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.

Abstract: The invention proposes a forming process for forming geometrically complex laminates made of composite material which allows obtaining very complex folded geometries, reducing the area of influence of the formed areas and making its effect local, handling the geometry of the laminate near the area to be formed, replacing the formed geometries with folded geometries, this way forcing the area of influence of the forming to be local, such that the length of the reinforcing fibers affected by said forming is minimal. The present invention also relates to complex geometries of laminates made of composite material obtained by means of the previous forming process.

Abstract: The invention relates to a quality control process for an adhesive joint of two sub-components of a structure comprising the following steps: a) Providing the structure of composite material to be controlled; b) Providing at least one premanufactured testing device (1) representative of one of the sub-components of the structure; c) Bonding said at least one premanufactured testing device (1) to the other sub-component (7) of the structure in conditions similar to those of the real adhesive joint of said sub-components; d) Carrying out at least one mechanical test on said at least one premanufactured testing device (1) which allows assessing the quality of said adhesive joint.