Abstract: A lay-up method of composite aircraft parts with an opening. Composite tows having an orientation of 0°, 90° or +/?45° are laid up forming plies which form a composite laminate. Each tow having an orientation of 0° and being within the perimeter of the opening comprises: a first gap located at approximately ? of the length of the first semi-major axis from the center, the first gap being configured as a first elongated gap longitudinally perpendicular to the orientation of the tow, and a second gap located at approximately ? of the length of the second semi-major axis from the center, the second gap being configured as a second elongated gap longitudinally perpendicular to the orientation of the tow.

Abstract: Method to make a T shaped stiffener form from a stiffener preform (100) having a foot (130) configured to be in contact with an aircraft panel, and a sole (120) with an edge (120a). The manufacturing method includes: obtaining laminates (110a, 110b) formed of layers of composite material, folding the laminates (110a, 110b) to be L shaped in cross section, joining the laminates to form a T shaped preform (100), molding the edge of the sole (120a) so that the edge is semicircular in cross section, applying to the edge (120a) a strip of semi-cured carbon fabric (L1) and a fresh strip of prepreg fiberglass (L2), and curing the preform (100) to obtain the stiffener.

Abstract: A composite part manufacturing method comprising the following consecutive steps: providing a manufacturing tooling, providing a composite laminate on the manufacturing tooling, providing a release film covering the composite laminate, providing a breather fabric covering the release film, providing a vacuum bag film covering the composite laminate, the release film and the breather fabric, sealing the vacuum bag film to the manufacturing tooling, curing the composite laminate, unsealing the vacuum bag film from the manufacturing tooling, removing the vacuum bag film, removing the breather fabric, inspecting the breather fabric to detect resin residues, removing any detected resin residues from the breather fabric, transporting the removed breather fabric to a manufacturing process of another composite part.

Abstract: A manufacturing method of structures formed co-bonding second structural components to a first structural component. The method comprises the following steps: a) preparing for each second structural component an ensemble wherein a preform of the second structural component, surrounded by a band of a suitable material to form a vacuum bag, is disposed between curing tools which are thus in contact with the bag and not with the preform; b) positioning the ensembles on the first structural component and forming the vacuum bag for the complete structure joining the bands and complementary pieces; c) applying to the resulting assembly an autoclave cycle.

Abstract: Inspection methods and systems for detecting leaks in a vacuum bag assembly used in the manufacture of a composite part based on spraying helium over the vacuum bag and detecting the helium drawn by the vacuum inside the vacuum bag through a leak. The inspection methods comprise creating a local helium atmosphere in a chamber over the vacuum bag assembly by zones, following a programmed zonal sequence, for a first leak detection test of each zone and a subsequent second leak detection test if the first test gives a positive result. The inspection systems comprise a helium spraying system and helium detecting equipment arranged to implement the inspection methods.

Abstract: A method of manufacturing T-shaped stringers made of composite material, including a second shaping step for shaping laminates into L-shaped preforms, which includes providing a set of tools formed by a fixed tool comprising a lower portion and an upper portion, and a moveable tool comprising a lower element and an upper element. It also includes the segment of the laminate intended for the foot of the preform being located between the lower portion and the upper portion of the fixed tool, and the segment of the laminate intended for the web of the preform being located between the lower element and the upper element of the moveable tool. It further includes vertically moving the moveable tool to progressively bend the web of the preform supporting it on a vertical wall of the fixed tool. The end of its web adopts a rounded shape.

Abstract: A manufacturing method is disclosed for manufacturing of a composite stiffening element, including: arranging composite laminates partially between caul plates and mold halves, and partially between a movable upper sandwich plate and a movable lower sandwich plate, moving the upper and lower sandwich plates together and moving the assembly formed by the first caul plate and the first mold half and the assembly formed by the second caul plate and the second mold half, and joining and co-curing the composite laminates to make up the composite stiffening element. A composite stiffening element is also disclosed.

Abstract: Inspection methods and systems for detecting leaks in a vacuum bag assembly used in the manufacture of a composite part based on spraying helium over the vacuum bag and detecting the helium drawn by the vacuum inside the vacuum bag through a leak. The inspection methods comprise creating a local helium atmosphere in a chamber over the vacuum bag assembly by zones, following a programmed zonal sequence, for a first leak detection test of each zone and a subsequent second leak detection test if the first test gives a positive result. The inspection systems comprise a helium spraying system and helium detecting equipment arranged to implement the inspection methods.

Abstract: A manufacturing method of structures formed co-bonding second structural components to a first structural component. The method comprises the following steps: a) preparing for each second structural component an ensemble wherein a preform of the second structural component, surrounded by a band of a suitable material to form a vacuum bag, is disposed between curing tools which are thus in contact with the bag and not with the preform; b) positioning the ensembles on the first structural component and forming the vacuum bag for the complete structure joining the bands and complementary pieces; c) applying to the resulting assembly an autoclave cycle.

Abstract: The present invention relates to a stringer, particularly to a stiffening and structural longitudinal element for skin of aircraft airfoil surfaces, characterized in that it incorporates two separate and independent reinforcement areas, one in the foot and the other at the end of the web (head) of the stringer, where the reinforcement areas are obtained by a widening of the section of the stringer, the widening being formed by a localized stack of reinforcing plies of composite material which are embedded within the stringer. The invention also relates to the method of manufacture and is particularly applicable to stringers having an L-shaped or T-shaped section.

Abstract: A manufacturing method is disclosed for manufacturing of a composite stiffening element, including: arranging composite laminates partially between caul plates and mold halves, and partially between a movable upper sandwich plate and a movable lower sandwich plate, moving the upper and lower sandwich plates together and moving the assembly formed by the first caul plate and the first mold half and the assembly formed by the second caul plate and the second mold half, and joining and co-curing the composite laminates to make up the composite stiffening element. A composite stiffening element is also disclosed.

Abstract: A method of manufacturing T-shaped stringers made of composite material, including a second shaping step for shaping laminates into L-shaped preforms, which includes providing a set of tools formed by a fixed tool comprising a lower portion and an upper portion, and a moveable tool comprising a lower element and an upper element. It also includes the segment of the laminate intended for the foot of the preform being located between the lower portion and the upper portion of the fixed tool, and the segment of the laminate intended for the web of the preform being located between the lower element and the upper element of the moveable tool. It further includes vertically moving the moveable tool to progressively bend the web of the preform supporting it on a vertical wall of the fixed tool. The end of its web adopts a rounded shape.

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 relates to a stringer, particularly to a stiffening and structural longitudinal element for skin of aircraft airfoil surfaces, characterized in that it incorporates two separate and independent reinforcement areas, one in the foot and the other at the end of the web (head) of the stringer, where the reinforcement areas are obtained by a widening of the section of the stringer, the widening being formed by a localized stack of reinforcing plies of composite material which are embedded within the stringer. The invention also relates to the method of manufacture and is particularly applicable to stringers having an L-shaped or T-shaped section.

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: A process for manufacturing stiffened structures (11) in composite materials formed by an outer coating (13) and a plurality of stiffeners (15) the cross-section of which has a closed form delimiting an inner opening (23), comprising the following steps: a) Providing a shaping tool (31); b) Providing auxiliary male tools (37) with an inert material inside them coated with membranes suitable for curing c) Providing stiffeners (15) in fresh or cured condition; d) Arranging the stiffeners (15) in the tool (31) and the auxiliary male tools (37) in their inner openings (23); e) Laminating the outer coating (13); f) Curing the stiffened structure (11) with high temperature and pressure; g) Removing the auxiliary male tools (37) after reducing their volume by withdrawing the inert material thereof; h) Separating the cured stiffened structure (11) from the tool (31). The invention also relates to the auxiliary male tools.

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.