Abstract: A vacuum bag (18) is placed around the inner forming surface (IML) of an inner mandrel with radially retractable sectors (11a, 11b) having parallel longitudinal slots (17) with composite stringers (30) in the slots (17). An inner support (31) in each stringer is covered by an impermeable tubular bag (32). A composite skin (37) is laminated around the stringers (30), the coated supports (31, 32) and the inner forming surface (IML). An outer curing tool (50, 51) closes around the skin (37) defining an fuselage barrel outer forming surface (OML), leaving an annular gap (G) between the skin outer surface (37) and the outer forming surface (OML). Vacuum is applied between the vacuum bag (18) and the outer tool (50, 51), enlarges the uncured barrel diameter, releasing the barrel from the inner mandrel (10) and bringing the skin outer surface (37) into contact with the outer tool inner surface (IML).

Abstract: A method for producing a closed-section portion of an aircraft wherein a strain gauge is glued on a first face of a flat tape that, in turn, is fastened on a face of a tool comprising a rigid elongated body covered by an extensible sack. The tool supporting the tape is arranged in a cavity of an aircraft structure. A vacuum is then created to obtain the expansion of the vacuum sack and perform the pressure gluing of the tape onto a wall of said cavity. The tool is subsequently extracted from the cavity. Upon conclusion of these operations, the tape is integrally fastened onto a wall of the cavity so that any deformation applied to this wall is transmitted to said strain gauge.

Abstract: A straight threaded rod has three reference elements spaced apart from each other. A shoulder and a knob having a fourth reference element are screwed onto the rod. A spring is mounted on the rod between the knob and the shoulder. The rod is inserted through two axially aligned holes in two abutting pieces, with the shoulder bearing on a first surface of one of the two pieces. By adjusting the position of the shoulder and the knob along the rod it is possible to apply a calibrated clamping force to a pair of abutting pieces, regardless of the thickness of the pieces.

Abstract: A vacuum bag (18) is placed around the inner forming surface (IML) of an inner mandrel with radially retractable sectors (11a, 11b) having parallel longitudinal slots (17) with composite stringers (30) in the slots (17). An inner support (31) in each stringer is covered by an impermeable tubular bag (32). A composite skin (37) is laminated around the stringers (30), the coated supports (31, 32) and the inner forming surface (IML). An outer curing tool (50, 51) closes around the skin (37) defining an fuselage barrel outer forming surface (OML), leaving an annular gap (G) between the skin outer surface (37) and the outer forming surface (OML). Vacuum is applied between the vacuum bag (18) and the outer tool (50, 51), enlarges the uncured barrel diameter, releasing the barrel from the inner mandrel (10) and bringing the skin outer surface (37) into contact with the outer tool inner surface (IML).

Abstract: A method of manufacturing a wing structure includes laying a plurality of layers of preimpregnated material on a first mould half and on a second mold half so as to form a first fresh skin and a second fresh skin of the wing structure. A plurality of layers of preimpregnated material are laid in succession on a shaped apparatus to form a fresh leading edge skin of the wing structure. Fresh spars of preimpregnated material are formed. A wedgelike body of expanded plastics material is formed, this body being designed to be interposed between the first and second skins at the trailing edge of the wing structure. The fresh spars are positioned in a coordinated way on the first fresh skin, removable support members also positioned next to the spars. The second mold half is turned over on to the first mold half so as to position the second fresh skin on the spars and the supports, to produce a fresh wing structure. The fresh wing structure is subjected to a polymerization cycle, using a vacuum bag.

Abstract: A hollow manufactured body has at least one wall of non-ferromagnetic material with an outer surface and an inner surface facing a cavity of the body. Two mutually magnetically attracted sliders are positioned on the inner and outer surfaces. The outer slider is moved manually across the outer surface to a predetermined point where the wall thickness is to be detected; the inner slider on the inner surface follows the movements of the outer slider due to the effect of the magnetic attraction. A transducer on the outer slider is used to measure the force required to move a magnet away from the outer surface of the wall. The value of the thickness of the wall at the predetermined point is then derived from the measured force.

Abstract: A beam of fiber-reinforced curable thermosetting composite material is preliminarily assembled in an uncured condition. The beam is placed between two forming tools, namely a lower and an upper tool, shaped in such a way as to give the lower and upper flanges a predetermined shape, at least one of the flanges having a non-rectilinear profile viewed in a longitudinal vertical plane. Two longitudinally elongate rigid inserts are placed between the flanges at the sides of the web and are covered in respective airtight tubular bags. The spaces between the upper tool and the lower tool on the two opposite longitudinal sides are sealed. The open opposite ends of the tubular bags are also sealed in such a manner that the pressure applied in an autoclave during the step of curing causes the tubular bags to swell and presses them against the two opposite faces of the web and against the flanges of the beam. On completion of curing, the upper forming tool is removed and the inserts are extracted sideways.

Abstract: A method for producing a closed-section portion of an aircraft wherein a strain gauge is glued on a first face of a flat tape that, in turn, is fastened on a face of a tool comprising a rigid elongated body covered by an extensible sack. The tool supporting the tape is arranged in a cavity of an aircraft structure. A vacuum is then created to obtain the expansion of the vacuum sack and perform the pressure gluing of the tape onto a wall of said cavity. The tool is subsequently extracted from the cavity. Upon conclusion of these operations, the tape is integrally fastened onto a wall of the cavity so that any deformation applied to this wall is transmitted to said strain gauge.

Abstract: A method of manufacturing a curved structural element made of composite material has a complex, open cross-section the structural element is formed by the assembly of components made of composite material. A plurality of flat, fresh components are prepared, each component being constituted by a flat layer of curved fibres previously infused with resin, combined with a pre-impregnated layer with straight fibres. Hot-forming of the flat, raw components is then performed. The hot-formed, fresh components are then assembled in accordance with a predetermined sequence on a polymerization tool. The tool includes a shaped, inflatable device astride which a C-shaped raw component is deposited. Finally, the fresh components assembled on the tool are subjected to a polymerization cycle in an autoclave. The inflatable device is inflated by the pressure produced in the autoclave to apply a predetermined pressure from the inside of the C-shaped fresh component.

Abstract: For an arcuate structural member (10) of a fuselage frame, tapes of resin pre-impregnated unidirectional fibers are used. The member (10) includes a web (11) lying in a radial plane and a radially outer cylindrical flange (12). An elongate, arcuate forming mandrel (M1) having a flat radial surface (F) forming an angular edge (D) with a radially outer, convex cylindrical surface (S) is used and a series of promontories (P) radiating outwardly with respect to the cylindrical surface (S) are provided. Layers of pre-impregnated composite material are laid on the mandrel (M1) to form a first flat arcuate laminate (20?), with a part (20?) of the laminate projecting radially outwardly beyond the angular edge (D). The mandrel (M1), the laminate (20?) and the promontories (P) are covered with a membrane (E). A vacuum is then applied to urge the projecting part (20?) of the laminate against the cylindrical surface (S) and against the promontories (P).

Abstract: In order to manufacture beams of composite material with a J-shaped cross-section, a curing apparatus includes a bar supported parallel to a table by two end supports. A J-shaped beam of uncured composite material is prepared and arranged on the apparatus, positioning the bottom flange of the beam so that it faces the table and resting the web and the upper flange against two respective sides of the bar. The beam is covered with a vacuum bag and pressure and heat are applied inside an autoclave in order to cure the resin in the beam.

Abstract: A method of manufacturing a curved element made of composite material includes: preparing at least one dry, flat reinforcing layer with curved fibers. A resin film is combined with the dry, flat reinforcing layer, and heat and pressure are applied in controlled manner to bring about the infusion of the resin into the reinforcing layer and to obtain at least one layer of pre-infused material. At least one prepreg layer is prepared with straight fibers impregnated with resin compatible with the resin of the pre-infused material. The layer of pre-infused material and the prepreg layer are superimposed on one another to obtain a layered structure. The layered structure, arranged on a shaped support tool is subjected to a polymerization cycle to obtain the curved element.

Abstract: A method for manufacturing a recycled prepreg material in strip form, is composed of fiber sections embedded in a resin matrix. A charge of flat scraps from a prepreg starting material is supplied, recording the overall area of the scraps. Then the scraps are fragmented by cutting so as to obtain cut fragments of predetermined size. A strip of backing material and a strip of protective material are supplied. The cut fragments are then distributed in a random manner on the strip of backing material, the feeding speed of the strip of backing material being adjusted depending on the recorded area of the input scraps, so that the cut fragments form a substantially homogeneous layer. The strip of protective material is then arranged over the cut fragments distributed on the strip of backing material, and the whole assembly is then compacted so as to form a strip of recycled prepreg material.

Abstract: A straight threaded rod has three reference elements spaced apart from each other. A shoulder and a knob having a fourth reference element are screwed onto the rod. A spring is mounted on the rod between the knob and the shoulder. The rod is inserted through two axially aligned holes in two abutting pieces, with the shoulder bearing on a first surface of one of the two pieces. By adjusting the position of the shoulder and the knob along the rod it is possible to apply a calibrated clamping force to a pair of abutting pieces, regardless of the thickness of the pieces.

Abstract: A hollow manufactured body has at least one wall of non-ferromagnetic material with an outer surface and an inner surface facing a cavity of the body. Two mutually magnetically attracted sliders are positioned on the inner and outer surfaces. The outer slider is moved manually across the outer surface to a predetermined point where the wall thickness is to be detected; the inner slider on the inner surface follows the movements of the outer slider due to the effect of the magnetic attraction. A transducer on the outer slider is used to measure the force required to move a magnet away from the outer surface of the wall. The value of the thickness of the wall at the predetermined point is then derived from the measured force.

Abstract: A method of manufacturing a curved structural element made of composite material has a complex, open cross-section the structural element is formed by the assembly of components made of composite material. A plurality of flat, fresh components are prepared, each component being constituted by a flat layer of curved fibres previously infused with resin, combined with a pre-impregnated layer with straight fibres. Hot-forming of the flat, raw components is then performed. The hot-formed, fresh components are then assembled in accordance with a predetermined sequence on a polymerization tool. The tool includes a shaped, inflatable device astride which a C-shaped raw component is deposited. Finally, the fresh components assembled on the tool are subjected to a polymerization cycle in an autoclave. The inflatable device is inflated by the pressure produced in the autoclave to apply a predetermined pressure from the inside of the C-shaped fresh component.

Abstract: A beam of fibre-reinforced curable thermosetting composite material is preliminarily assembled in an uncured condition. The beam is placed between two forming tools, namely a lower and an upper tool, shaped in such a way as to give the lower and upper flanges a predetermined shape, at least one of the flanges having a non-rectilinear profile viewed in a longitudinal vertical plane. Two longitudinally elongate rigid inserts are placed between the flanges at the sides of the web and are covered in respective airtight tubular bags. The spaces between the upper tool and the lower tool on the two opposite longitudinal sides are sealed. The open opposite ends of the tubular bags are also sealed in such a manner that the pressure applied in an autoclave during the step of curing causes the tubular bags to swell and presses them against the two opposite faces of the web and against the flanges of the beam. On completion of curing, the upper forming tool is removed and the inserts are extracted sideways.

Abstract: For an arcuate structural member (10) of a fuselage frame, tapes of resin pre-impregnated unidirectional fibers are used. The member (10) includes a web (11) lying in a radial plane and a radially outer cylindrical flange (12). An elongate, arcuate forming mandrel (M1) having a flat radial surface (F) forming an angular edge (D) with a radially outer, convex cylindrical surface (S) is used and a series of promontories (P) radiating outwardly with respect to the cylindrical surface (S) are provided. Layers of pre-impregnated composite material are laid on the mandrel (M1) to form a first flat arcuate laminate (20?), with a part (20?) of the laminate projecting radially outwardly beyond the angular edge (D). The mandrel (M1), the laminate (20?) and the promontories (P) are covered with a membrane (E). A vacuum is then applied to urge the projecting part (20?) of the laminate against the cylindrical surface (S) and against the promontories (P).

Abstract: A method for manufacturing a recycled prepreg material in strip form, is composed of fibre sections embedded in a resin matrix. A charge of flat scraps from a prepreg starting material is supplied, recording the overall area of the scraps. Then the scraps are fragmented by cutting so as to obtain cut fragments of predetermined size. A strip of backing material and a strip of protective material are supplied. The cut fragments are then distributed in a random manner on the strip of backing material, the feeding speed of the strip of backing material being adjusted depending on the recorded area of the input scraps, so that the cut fragments form a substantially homogeneous layer. The strip of protective material is then arranged over the cut fragments distributed on the strip of backing material, and the whole assembly is then compacted so as to form a strip of recycled prepreg material.

Abstract: A method of manufacturing a curved element made of composite material includes: preparing at least one dry, flat reinforcing layer with curved fibres. A resin film is combined with the dry, flat reinforcing layer, and heat and pressure are applied in controlled manner to bring about the infusion of the resin into the reinforcing layer and to obtain at least one layer of pre-infused material. At least one prepreg layer is prepared with straight fibres impregnated with resin compatible with the resin of the pre-infused material. The layer of pre-infused material and the prepreg layer are superimposed on one another to obtain a layered structure. The layered structure, arranged on a shaped support tool is subjected to a polymerization cycle to obtain the curved element.