Method of manufacturing a composite box beam with closed corners

Abstract

The present application belongs to the field of composite material manufacturing, and relates to a manufacturing method of a composite material box beam with a closed angle end. The present application can realize the manufacturing of a composite material cover plate of the composite material box beam, and the structure of the composite material cover plate can better act on the curing forming of the composite material box beam. The present application can realize the manufacturing of the composite material box beam, the inspection of the axial direction size, the inspection of the shape size and the like. The present application innovatively proposes a metal joint structure to replace the commonly used metal hinge support arm, and the metal joint structure has the function of measuring the shape precision of the inner shape of the rim strip of the composite material box beam. The present application innovatively proposes a split combination type forming tool and a measuring tool, and realizes a manufacturing process method of a composite material box beam with a closed angle end. The present application innovatively proposes a measuring tool, and the measuring tool can realize the measurement of the axial direction size of the composite material box beam, and the measurement range is larger.

Description

Technical Field

[0001] This invention belongs to the field of composite material manufacturing and relates to a method for manufacturing a composite material box beam with closed-angle ends. Background Technology

[0002] Unlike the general requirement of a draft angle >0° in the structural design of composite material parts, this invention addresses the design of composite box beams where at least one end has an angle of less than 90° with the web surface, i.e., a closed-angle design, considering structural design and functionality. For a composite box beam with a closed-angle end, the typical demolding process involves pushing and demolding from the narrower end (smaller end) towards the wider end (larger end). However, composite box beams have a recessed area with varying thickness, and the cured composite box beams have poor toughness. If the demolding method of pushing and demolding from the narrower end (smaller end) towards the wider end (larger end) is used, it is highly likely to damage or even render the composite box beam unusable.

[0003] Taking composite box-shaped beams as an example, if ordinary steel is chosen as the material for the molding tooling, the difference between the expansion coefficient of the molding tooling and that of the composite box-shaped beam needs to be considered. Certain process compensation is required along the axial direction of the composite box-shaped beam on the molding surface of the molding tooling, such as a slight inward reduction of the molding surface along the axial direction. If Invar 36 steel is chosen as the material for the molding tooling, the expansion coefficient of the molding tooling is close to that of the composite box-shaped beam, but differences still exist. For slender composite box-shaped beams, molding tooling manufactured according to the inner shape of the composite box-shaped beam will still result in dimensional deviations in the axial direction of the molded composite box-shaped beam. The curing process of composite parts is an extremely complex coupling process of time, temperature, and pressure. Whether using software simulation analysis or manufacturing based on experience, technicians need to rework the molding tooling based on the actual axial dimensions of the composite box-shaped beam. Especially during the development stage of composite box-shaped beams, repeated rework of the molding tooling is necessary to ensure that the actual axial dimensions of the composite box-shaped beam meet engineering requirements.

[0004] After the composite box beam has been cured and molded, its axial dimensions are measured using measuring tools such as steel rulers or calipers. However, due to the lack of a suitable measurement benchmark, the accuracy of the measured axial dimensions is low, and it is impossible to measure composite box beams with axial dimensions that are too large to exceed the measuring tool's range. If a molding fixture is used to measure the axial dimensions of the composite box beam, the composite box beam is positioned on the molding surface of the molding die according to its shape, and the gap between the composite box beam and the molding surface of the molding die is measured using a feeler gauge to indirectly obtain the axial dimensions of the composite box beam. This measurement method can only evaluate the axial dimensions of the composite box beam on the side of the composite box beam that is attached to the fixture, and cannot evaluate the axial dimensions of the composite box beam on the side that is attached to the bag. According to the general method for measuring the surface accuracy of composite parts after molding, after the composite box beam has been cured and molded, it is generally necessary to return to the molding fixture to check the gap between the mold and the surface. This is done by using a feeler gauge to measure the gap between the surface of the composite box beam and the molding fixture. However, the visibility of the feeler gauge is poor, meaning there is uncertainty in the inspection area and depth. Moreover, the feeler gauge can only measure the gap between the edge strip surface of the composite box beam and the molding fixture, and cannot measure the gap between the web surface of the composite box beam and the molding fixture. Obviously, the general method for measuring the surface accuracy of composite parts after molding cannot effectively and accurately measure the surface accuracy of the inner surface of the composite box beam.

[0005] In view of the above problems, this invention focuses on a manufacturing method for a composite box-shaped beam with closed-angle ends. It creatively proposes a molding fixture and its application method for the composite box-shaped beam. This fixture and method can solve the molding and demolding problems of composite box-shaped beams with closed-angle ends. The molding fixture features low rework difficulty and short rework cycle, making it suitable for manufacturing methods that require continuous correction of the axial dimensions of the composite box-shaped beam. Furthermore, it creatively proposes a measuring fixture and its application method for online measurement of the axial dimensions of the composite box-shaped beam on the bag-side surface. The measurement range is within -5 to 5 mm of the actual axial dimension relative to the axial dimension, with a measurement accuracy of 0.01 mm, fully meeting the manufacturing requirements of composite box-shaped beams. Finally, it creatively proposes a metal joint. This metal joint simplifies the main functions of the metal hinge arm, and the metal structure has the function of measuring the surface accuracy of the inner surface of the composite box-shaped beam's flange. Summary of the Invention

[0006] The purpose of this invention patent is to invent a method for manufacturing a composite material box beam with a closed end angle. The manufacturing method involves a composite material box beam forming fixture, a composite material cover plate forming fixture, a measuring fixture, and a method for using the fixture.

[0007] The technical solution of the present invention is as follows:

[0008] A method for manufacturing a composite box beam with closed-angle ends, the method involving a composite box beam forming fixture, a composite cover plate forming fixture, a measuring fixture, and a method for using the fixture.

[0009] 1) Composite material box beam forming fixture

[0010] The overall design of the composite box beam forming fixture adopts a positive mold frame structure. The fixture material is Invar36 steel, which has an expansion coefficient close to that of the composite parts. The forming surface of the fixture is extracted according to the theoretical inner shape of the composite box beam, and the thickness of the forming surface is 10-20mm.

[0011] The composite material box-shaped beam forming fixture adopts a combined structural design of a fixed jig, a detachable jig, and a detachable base. The detachable jig is combined with the fixed jig via the detachable base, and the mating surfaces mate. The detachable base is fixed to the fixture plate using a combination of screws and pins. The detachable jig and the detachable base use a surface-to-surface contact fit, such as the side of the detachable jig contacting the side of the detachable base, and the bottom surface of the detachable jig contacting the mating surface of the detachable base, to ensure the assembly accuracy of the fixed jig and the detachable jig.

[0012] The detachable base is designed with threaded holes for lifting rings and is equipped with lifting rings. The purpose of the lifting rings is to use the pulling force generated by the tractor on the production site to remove the detachable base from its initial position and cause lateral sliding after the composite box beam has been cured and formed. After the detachable base slides, it provides space for the detachable body to descend, that is, to remove the detachable body from the composite box beam, and then to realize the demolding of the composite box beam.

[0013] The allowance for the composite box beam forming tooling at the edge of the composite box beam is designed to be 40-60mm beyond the theoretical edge boundary.

[0014] 2) Composite cover plate forming tooling

[0015] The composite cover plate forming tooling is made of Invar36 steel with a coefficient of thermal expansion close to that of the composite cover plate. The forming surface of the tooling is made using the outer surface of the bag-attaching side of the composite box beam as the extraction surface. The composite cover plate forming tooling adopts a male mold frame structure design.

[0016] The composite cover plate forming fixture consists of two parts. One part is the closed-angle part of the composite cover plate, namely forming fixture 13-1, which takes into account that the composite cover plate and the composite box beam face the same demolding problem in the closed-angle part. The other part is the non-closed-angle part of the composite cover plate, namely forming fixture 13-2.

[0017] The composite cover plate forming fixture is manufactured and inspected with a negative tolerance of -0.1 to -0.2 mm on the outer surface of the bag-side of the composite box-shaped beam. This is to ensure that when the composite cover plate acts on the composite box-shaped beam, it can exert a certain compressive force on the beam blank, effectively eliminating air gaps trapped during the interlayer stacking process and guaranteeing the internal forming quality of the composite box-shaped beam, especially controlling the porosity in the R-corner area. Simultaneously, the composite cover plate forming fixture creates a boss working surface offset by H (5-10 mm) from the plane of the fixture support plate. The boss's length is the same as the composite cover plate's length, and its width is greater than the width L of the "skirt," giving it a "skirt-like" structural design. The "skirt" width L = 10-20 mm. The purpose of the "skirt" structure on the edge of the composite cover plate is twofold: firstly, the "skirt" can serve as a pry opening after the composite cover plate is demolded; secondly, when the composite box beam is cured and packaged, the vacuum nozzle is placed on the tooling tray, and the vacuum negative pressure under the vacuum bag packaging acts on the "skirt" of the composite cover plate, which in turn promotes the bonding effect between the composite cover plate and the composite box beam blank.

[0018] 3) Measuring fixtures

[0019] This measuring fixture consists of five main parts: the metal connector part, the positioning metal connector part, the adjustable end part, the fixed end part, and the flange outer surface clamping plate part.

[0020] The overall structure of the measuring fixture is as follows Figure 7 , Figure 8 It includes metal joint parts, platform, bracket, connecting components, column, jacking device support, jacking device, pin, connector, support, 0.1mm thick metal gasket, end face action end, spacer plate, beam end face adjustable end, end face action end, dial indicator, slotted screw, handle nut, T-key, sleeve, protrusion block, positioning pin, gauge base, beam end face fixed end, flange outer surface clamping plate, support plate, L-shaped support, and jacking device sleeve.

[0021] 3.1) The structural schematic diagram of the metal joint part is shown in Figure 6, which mainly consists of the working surface on the web side and the working surface on the flange side.

[0022] The metal joint section extracts the metal hinge arm from the composite rudder box segment used for docking with the aircraft fuselage structure. The metal hinge arm is simplified, retaining the central axis position of the intersection point and designing a diameter centered on this axis. The through-hole is provided. The metal joint is made of Invar steel, whose coefficient of thermal expansion is close to that of the composite box beam.

[0023] To reduce the self-weight of the metal joint section, the driven shaft of the metal hinge arm and unnecessary structures are removed. The metal joint section mainly retains the working surface, reinforcing ribs, and locating pin holes. The length of the working surface of the metal joint section along the axial direction of the composite box-shaped beam is designed to be 150-200mm. The working surface of the metal joint section on the web side of the composite box-shaped beam is offset by 2mm from its theoretical position towards the inner surface of the composite box-shaped beam, meaning there is a theoretical gap of 2mm between the working surface on the web side and the web surface of the composite box-shaped beam. The working surface of the metal joint section on the flange side of the composite box-shaped beam is offset by 0.5mm from its theoretical position towards the inner surface of the composite box-shaped beam, meaning there is a theoretical gap of 0.5mm between the working surface on the flange side and the flange surface of the composite box-shaped beam.

[0024] The working surfaces on the web and flange sides of the composite box girder are offset from their theoretical positions and manufactured. The purpose is to measure the flange surface deformation of the composite box girder using a feeler gauge between the working surfaces on the flange side and the flange side of the metal joint, where surface deformation is prone to occur.

[0025] 3.2) A partial structural diagram of the positioning metal connector portion is shown below. Figure 7 , Figure 8 , Figure 9 It is mainly composed of components such as platform and connecting components.

[0026] The platform height is between 1200mm and 1400mm, which is designed to facilitate assembly work while the operator is standing.

[0027] The connecting assembly mainly consists of components such as columns, clamping device supports, clamping devices, connectors, and supports.

[0028] The column is fixed to the platform by a mechanical connection of screws and pins, and the support is fixed to the column by a mechanical connection of screws and pins.

[0029] The connector is fixed to the support by a locating pin. The connector has two staggered pin holes. The connector can be connected and fixed to the metal joint part by the metal locating pin through the pin holes.

[0030] See the schematic diagram of the structure containing the clamping device. Figure 7 The main body of the jacking device support is cylindrical with an internal through-hole design. Both ends of the jacking device support have flange structures. One flange structure is fixed to the platform by a mechanical connection of screws and pins, while the other flange structure is connected and fixed to the jacking device sleeve by the same mechanical connection of screws and pins. The jacking device sleeve adopts a semi-circular annular groove design.

[0031] The handle nut features a boss structure on the outside and a threaded hole on the inside. The handle nut engages with the semi-circular annular groove of the clamping sleeve through its own boss structure. The handle nut and the clamping sleeve are fitted with a clearance to ensure that the handle nut can rotate around its own axis.

[0032] The handle nut features a threaded hole design. The main body of the clamping device is a threaded rod design. The clamping device and the handle nut are screwed together. Rotating the handle nut drives the clamping device to move along its own axis. The outer diameter of the clamping device is accommodated within the through hole of the clamping device support to ensure the range of motion of the clamping device. This allows the clamping device to act on the web surface of the composite material box beam to maintain a clamped state, and also to move away from the web surface of the composite material box beam to maintain a relaxed state, facilitating the loading and unloading of the composite material box beam.

[0033] 3.3) The structural schematic diagram of the adjustable end part is shown in Figure 10. The adjustable end of the beam end face is mainly composed of metal pin 28, end face action end, dial indicator, slotted screw, handle nut, T-key, sleeve, protrusion block, positioning pin, dial indicator base and other components.

[0034] The adjustable end of the beam is fixed to the column by a mechanical connection of screws and pins using a sleeve.

[0035] The socket has a through hole design inside, and one side of the socket has a semi-circular annular groove design. The top of the socket has a protrusion block, which is fixed to the top of the socket by welding. The working surface of the protrusion block is the working surface of the dial indicator's measuring head. The position of the working surface of the protrusion block should be perpendicular to the direction of movement of the dial indicator's measuring head. The top of the socket has a mating hole for cooperating with the T-key.

[0036] The handle nut features a boss structure on the outside and a threaded hole on the inside. The handle nut engages with the semi-circular annular groove of the socket through its own boss structure. The handle nut and the socket are fitted with a clearance fit to ensure that the handle nut can rotate around its own axis.

[0037] The outer diameter of the slotted lead screw is accommodated within the through hole of the sleeve to ensure that the slotted lead screw moves along its own axis. The sleeve supports the slotted lead screw. The handle nut is connected to the slotted lead screw by a screw connection.

[0038] One end of the T-key acts on the slotted lead screw, and the other end acts on the mating hole on the top of the sleeve that mates with the T-key. The purpose of the T-key is to ensure that the slotted lead screw does not deflect around its own axis when moving along its own axis.

[0039] The working surface of the end face is manufactured by extracting the shape of one end face of the composite material fitting beam, and the working surface of the end face is fixed to the slotted screw by means of metal positioning pin.

[0040] The dial indicator has a measuring range of 0-10mm and a graduation value of 0.01mm. The measuring rod and measuring head of the dial indicator are perpendicular to the working surface of the protrusion, and the direction of movement of the measuring rod and measuring head of the dial indicator should be parallel to the axis of the slotted lead screw.

[0041] The dial holder has a through-hole design, and the dial holder and the slotted lead screw are in an interference fit relationship to ensure that the dial holder is fixed on the slotted lead screw and moves along the direction of the slotted lead screw along its own axis.

[0042] The dial indicator base has a through-hole design, and the dial indicator base and the bushing of the dial indicator are in an interference fit relationship to ensure that the dial indicator is fixed on the base, and the measuring rod and measuring head of the dial indicator are in a relatively free extension and retraction state.

[0043] The rotation of the handle nut drives the slotted screw to move laterally, which in turn drives the end face action end to move laterally. A through hole is designed at the connection between the sleeve and the slotted screw. The diameter of the positioning pin is consistent with the diameter of the through hole. When the positioning pin is inserted into the through hole of the sleeve and the slotted screw, the theoretical distance between the action surface of the end face action end and the axial direction of one end face of the composite material box beam is 5mm. The measuring head of the dial indicator is at the position of 10mm elongation and acts on the action surface of the protrusion block.

[0044] With the end face in its theoretical position, pull out the positioning pin and rotate the handle nut to drive the slotted screw to move laterally. This will then drive the end face to move towards the end face axis of the composite material box beam until the end face of the end face is in contact with one end face of the composite material box beam. At this point, record the dial gauge reading 'a' on the end face of the protrusion. The actual axial dimension deviation of the composite material box beam is Δ = 5 - a. If Δ > 0, the actual axial dimension of the composite material box beam is larger than the theoretical dimension; if Δ < 0, the axial dimension of the composite material box beam is smaller than the theoretical dimension.

[0045] 3.4) The structural schematic diagram of the fixed end part is shown in Figure 12. The fixed end of the beam end face adopts a similar structural form, positioning and movement mode as the adjustable end of the beam end face. The fixed end of the beam end face is mainly composed of components such as the end face action end, slotted screw, handle nut, T-key, sleeve, and positioning pin.

[0046] The working surface of the end face is manufactured by extracting the shape of the other end face of the composite box beam. The end face has a slotted position designed at the position of the two side edge strips of the composite box beam. A placeholder is placed at the slotted position. The placeholder is extracted and manufactured according to the shape of the two side edge strips of the composite box beam. The purpose of the placeholder is to ensure that the composite box beam is in the center position of the end face. The end face is fixed to the slotted screw by a metal positioning pin.

[0047] The rotation of the handle nut drives the slotted screw to move laterally, which in turn drives the end face action end to move laterally. A through hole is designed at the connection between the sleeve and the slotted screw. The diameter of the positioning pin is consistent with the diameter of the through hole. When the positioning pin is inserted into the through hole of the sleeve and the slotted screw, the theoretical distance between the action surface of the end face action end and the axial direction of the other end face of the composite material box beam is 0mm, which is the theoretical position of the other end face of the composite material box beam.

[0048] 3.5) The structural schematic diagram of the flange outer surface clamping plate is shown in Figure 13. The working surface of the flange outer surface clamping plate is manufactured based on the flange outer surface extracted from the composite material box beam and offset outward by 2mm. The flange outer surface clamping plate is connected to the support plate by screws and positioning pins. The support plate is positioned and connected to the L-shaped support by screws and positioning pins. The L-shaped support is fixed to the platform by the mechanical connection of screws and positioning pins.

[0049] When measuring the outer surface of the flange of the composite box beam, a feeler gauge is used to measure the gap between the flange outer surface gauge plate and the outer surface of the composite box beam flange. The theoretical gap value is 2mm. The actual deviation of the outer surface of the composite box beam flange is calculated based on the gap value measured by the feeler gauge.

[0050] If the actual gap value measured by the feeler gauge is 3mm, then the actual deviation of the outer surface of the composite material box beam edge strip is -1mm.

[0051] If the actual gap value measured by the feeler gauge is 1mm, then the actual deviation of the outer surface of the composite material box beam edge strip is 1mm.

[0052] Advantages of the present invention

[0053] (1) This invention patent can realize the manufacturing of composite cover plates for composite box beams, and the structural form of the composite cover plate can better play the role of curing and molding of composite box beams.

[0054] (2) This invention patent can realize the manufacturing of composite material box beams, the inspection of axial dimensions, and the inspection of surface dimensions.

[0055] (3) This invention patent innovatively proposes a metal joint structure to replace the commonly used metal hinge arm. The metal joint structure has the function of measuring the surface accuracy of the inner surface of the composite material box beam edge strip.

[0056] (4) This invention patent innovatively proposes a split-combination molding fixture and a measuring fixture, realizing a manufacturing process method for a composite material box beam with closed end angle.

[0057] (5) This invention patent innovatively proposes a measuring fixture that can measure the axial dimension of a composite material box beam. The measuring fixture has a large measurement range, which is -5 to 5 mm relative to the theoretical axial dimension, and the measurement accuracy is 0.01 mm.

[0058] (6) This invention patent innovatively proposes a split-combination molding tooling, which has the characteristics of low rework difficulty and short rework cycle, and is suitable for manufacturing methods that require continuous correction of the axial dimension of composite material box beams. Attached Figure Description

[0059] Figure 1 Schematic diagram of tooling for forming composite material box beams;

[0060] Figure 2 Schematic diagram of composite cover plate forming tooling;

[0061] Figure 3 A schematic diagram of the molding structure of the composite cover plate;

[0062] Figure 4 A schematic diagram of the composite cover plate acting on the blank of the composite box beam and the butt joint of the composite cover plate;

[0063] Figure 5 Schematic diagram of a metal hinged support arm structure;

[0064] Figure 6(a) Schematic diagram of the metal joint structure;

[0065] Figure 6(b) Schematic diagram of the central axis of the intersection of the metal hinge arms;

[0066] Figure 7 Top view of the measuring fixture;

[0067] Figure 8 Partial front view of the measuring fixture;

[0068] Figure 9 Schematic diagram of the metal connector positioning part of the measuring fixture;

[0069] Figure 10(a) Three-dimensional view of the adjustable end portion;

[0070] Figure 10(b) Side view of the adjustable end portion;

[0071] Figure 11(a) Schematic diagram of the structure containing the clamping device;

[0072] Figure 11(b) Exploded view of the structure containing the clamping device;

[0073] Figure 12(a) Schematic diagram of the fixed end portion A;

[0074] Figure 12(b) Schematic diagram of the fixed end section;

[0075] Figure 13(a) Front view of the flange strip outer surface of the clamping plate;

[0076] Figure 13(b) Side view of the flange strip of the card plate.

[0077] In the diagram: 1. Composite material box beam forming fixture; 2. Fixed jig; 3. Removable jig; 4. Removable base; 5. Mating surface; 6. Fixture support plate; 7. Removable jig side; 8. Removable base side; 9. Removable jig bottom; 10. Removable base mating surface; 11. Lifting ring; 12. Allowance; 13. Composite cover plate forming fixture; 14. Composite cover plate; 15. "Skirt"; 16. Boss; 17. Metal hinge arm; 18. Central axis of the intersection of metal hinge arms; 19. Metal joint; 20. Working surface of web side; 21. Working surface of flange side; 22. Platform; 23. Bracket; 24. Connecting assembly; 25. Column; 26. Tensioner support; 27. Tensioner; 28. Pin; 29. ​​Connector; 30. Support; 31. 0.1mm thick metal gasket; 32 end face working end; 33 spacer plate; 34 beam end face adjustable end; 35 end face working end; 36 dial indicator; 37 slotted lead screw; 38 handle nut; 39 T-key; 40 sleeve; 41 protrusion block; 42 positioning pin; 43 indicator base; 44 beam end face fixed end; 45 flange outer surface retaining plate; 46 support plate; 47 L-shaped support; 48 tightening device sleeve. Detailed Implementation

[0078] Specifically, this includes the manufacturing of composite cover plates, the manufacturing of composite box beams, the measurement of the external dimensions of composite box beams, the repair of composite box beam forming fixtures, and the remanufacturing of composite box beams.

[0079] 1) Manufacturing of composite cover plates

[0080] 1.1) Based on composite cover plate forming tooling 13 (see Figure 2 ) Molded composite cover plate 14 (see Figure 3 The composite cover plate 14 adopts a hybrid form of rubber and plain weave fabric prepreg. The surface layer is rubber, with a single layer thickness of 1.59mm for the uncured airpad rubber. The plain weave fabric prepreg is arranged in the R-corner area and the "skirt" area. The thickness of a single layer of the plain weave fabric prepreg after curing is 0.2-0.3mm. The plain weave fabric prepreg is a high-temperature curing prepreg at 180±6℃. The composite cover plate 14 adopts a staggered layout of plain weave fabric prepreg in the R-corner area and the "skirt" area, with a total of 4 layers of plain weave fabric prepreg to increase the pressure transmission effect of the R-corner and the structural rigidity of the "skirt". The layers of plain weave fabric prepreg are staggered by 2mm.

[0081] 1.2) Curing parameters for composite cover plate: heat preservation temperature 180±6℃; heat preservation time 2-3h; full vacuum throughout the process, vacuum degree not lower than -0.092MPa; curing pressure 0.6-0.7MPa; heating and cooling rate 0.5-3℃ / min.

[0082] 1.3) A certain number of holes are drilled at the R-corner of the manufactured composite cover plate 14, with a hole diameter of... To facilitate ventilation.

[0083] 1.4) The composite cover plate forming tooling 13 is designed to consist of two parts, so there are at least two composite cover plates 14, namely composite cover plate 14-1 and composite cover plate 14-2. The edges of composite cover plate 14-1 and composite cover plate 14-2 are chamfered, and the chamfer angle is 20-40°.

[0084] 2) Manufacturing of composite material box beams

[0085] 2.1) Apply release agent to the molding surface of the composite box beam molding fixture 1, and lay up the composite box beam plywood layer by layer until all plywood plywood is laid up.

[0086] 2.2) Place composite cover plates 14-1 and 14-2 (see [reference]) on the outside of the already laid-out composite box beam blank. Figure 4 The composite cover plate 14-1 and composite cover plate 14-2 are then vacuum-sealed. A 0.1mm thick metal gasket 31 (see [reference]) is placed in the joint area between them. Figure 4 This is to prevent fiber wrinkles from appearing in the joint area between adjacent composite cover plates 14-1 and 14-2.

[0087] 2.3) Perform autoclave curing of composite box beam blanks. The curing parameters depend on the resin system of the prepreg. Generally, the entire process is vacuumed at a pressure of not less than -0.092 MPa, curing pressure of 0.6-0.8 MPa, temperature of 215±10℃, holding time of 180-240 min, and heating and cooling rate not exceeding 3℃ / min.

[0088] 2.4) After the composite box beam has been cured and formed, clean the vacuum bag, breathable felt and other auxiliary materials, and remove the composite cover plates 14-1 and 14-2.

[0089] 2.5) Using the pulling force generated by the production site tractor, the detachable base 13 is disengaged from its initial position and laterally slides. After the detachable base 13 slides, it provides space for the detachable body 12 to descend, thus removing the detachable body 12 from the composite material box beam and achieving demolding of the composite material box beam. (See...) Figure 1 )

[0090] 2.6) After the composite box beam is demolded, its shape is cut. The operator completes the shape cutting of the composite box beam along the imprint of the mold line.

[0091] 3) Dimensional measurement of composite material box beams

[0092] The external dimensional measurement of composite box beams mainly includes the measurement of the axial dimensions and the internal surface dimensions. (See...) Figures 7-1 3)

[0093] 3.1) Prepare composite material box beams.

[0094] 3.2) Remove the metal connector 19 from the measuring fixture, remove the side of the connector 29 that is connected to the support 30, and keep the connector 16 in the open state.

[0095] 3.3) The clamping device 27 is rotated to a low position, not higher than the working surface of the support plate 46, to ensure that when the composite material box beam is placed, the clamping device 14 does not interfere with the web surface of the composite material box beam.

[0096] 3.4) In the adjustable end section, i.e. the adjustable end 34 of the beam end face, the rotation of the handle nut 38 drives the slotted screw 37 to move laterally, which in turn drives the end face action end 35 to move laterally.

[0097] A through hole is designed at the connection between the sleeve 40 and the slotted lead screw 37, and the diameter of the positioning pin 42 is consistent with the diameter of the through hole. When the positioning pin 42 is inserted into the through hole, the initial axial distance between the working surface of the end face 35 and one end face of the composite material box beam is 5mm, and the measuring head of the dial indicator 36 is at the position of 10mm elongation and acts on the working surface of the protrusion 41.

[0098] 3.5) At the fixed end, i.e., the fixed end 44 of the beam end face, the rotation of the handle nut 38 drives the slotted screw 37 to move laterally, which in turn drives the end face action end 32 to move laterally. A through hole is designed at the connection between the sleeve 40 and the slotted screw 37. The diameter of the positioning pin 42 is consistent with the diameter of the through hole. When the positioning pin 42 is inserted into the through hole, the action surface of the end face action end 32 is located at the theoretical zero point position of one side end face of the composite material box beam. A placeholder piece 33 is placed in the slot of the end face action end 32.

[0099] 3.6) Place the composite material box beam on the measuring fixture.

[0100] 3.7) The metal connector 19 is connected to the connector 29 via a locating pin.

[0101] 3.8) Connect the open connector 29 to the support 30 via the positioning pin to keep the connector 29 in the closed working state.

[0102] 3.9) Insert a process compensation shim into the gap between the working surface 20 and the web surface on the web side of the metal joint portion 19. The process compensation shim is 2mm thick.

[0103] 3.10) Tighten the clamping device 27 outside the web surface of the composite box beam to ensure a tight fit between the web surface of the composite box beam, the metal joint part 19, and the process compensation shims. Because the working surface of the support plate 46 is 3mm lower than the theoretical web surface of the composite box beam, that is, the composite box beam with the near end face fixed end 34 is 3mm lower than the theoretical position, tightening the clamping device 27 will cause the end face of the composite box beam with the near end face fixed end 34 to rise continuously. It is possible that the end face of the composite box beam with the near end face fixed end 34 may not fit properly with the end face working end 32. It is necessary to use non-metallic tools such as rubber mallets to apply force to the end face of the composite box beam to ensure that the end face of the composite box beam fits properly with the end face working end 32, and finally reach a state where the clamping device 27 cannot be tightened.

[0104] 3.11) When the adjustable end part, i.e. the adjustable end 34 part of the beam end face, is positioned by the positioning pin 42, the initial distance in the axial direction between the working surface of the end face 35 and one side end face of the composite material box beam is 5mm.

[0105] Based on the comparison between the axial dimensional deviation L of the composite box beam and the initial spacing of 5mm, the rotation scale value a of the dial indicator 36 acting on the surface of the protrusion 41 is given, where a = 5 - L. The rotation of the handle nut 38 drives the slotted screw 37 to move laterally. The rotation of the handle nut 38 is unidirectional, meaning the unidirectional movement drives the end face acting end 35 to move towards the axial direction of the end face of the composite box beam. Simultaneously, the dial indicator 36 acting on the surface of the protrusion 41 rotates, with a rotation scale value a, until the surface of the end face acting end 35 is in contact with the other end face of the composite box beam.

[0106] If the rotation scale value 'a' is 3mm, then the axial dimension deviation L of the composite material box beam is 2mm.

[0107] If the rotation scale value a is 7mm, then the axial dimension deviation L of the composite material box beam is -2mm.

[0108] 3.12) Use a feeler gauge to measure the gap between the inner surface of the flange of the composite box beam and the working surface 21 of the flange of the metal joint, with a reserved gap value of 0.5mm. Calculate the actual deviation of the inner surface of the flange of the composite box beam based on the gap value measured by the feeler gauge.

[0109] If the actual gap value measured by the feeler gauge is 1mm, then the actual deviation of the inner surface of the composite material box beam edge strip is 0.5mm.

[0110] If the actual gap value measured by the feeler gauge is 0mm, then the actual deviation of the inner surface of the composite material box beam edge strip is -0.5mm.

[0111] 3.13) Remove the locating pin on the metal joint part 19, remove the clamping device 27, and disconnect the side of the connector 29 connected to the support 30, keeping the connector 29 in the open state. Pull out the locating pin 42 of the fixed end 44 of the beam end face, and rotate the handle nut 38 to make the end face action end 32 and end face action end 35 move laterally away from the composite material box beam, thereby removing the composite material box beam from the measuring fixture.

[0112] 4) Rework methods for composite material box beam forming fixtures

[0113] During the development stage of composite box-shaped beams, the relevant manufacturing technologies are relatively immature. The actual axial dimensions of the composite box-shaped beams, after being measured using measuring fixtures, may not match the engineering design dimensions. This necessitates rework of the composite box-shaped beam forming fixture 1, specifically involving material removal and addition processing on the end face of the composite box-shaped beam along its axial direction. Because it is a modular forming fixture, the rework difficulty of the forming fixture 1 of this invention will be reduced.

[0114] For the rework of the composite material box beam forming fixture 1, material removal and material addition are required. This rework involves removing and adding material to the detachable fixture 3 and detachable base 4. The detachable fixture 3 and detachable base 4 are small in size and light in weight, placing lower load-bearing and dimensional requirements on the CNC machine tool. If it is necessary to reduce the actual axial dimension of the composite material box beam after curing, the mating surface 5 of the detachable fixture 3 needs to be removed. The mating surface 5 is planar, making material removal relatively easy. The gap between the detachable fixture 3 and the restricting surface of the detachable base 4 created by material removal can be filled using a single layer of 0.1mm thick stainless steel sheet. Because stainless steel sheets have advantages such as conformability and economy, different numbers of stainless steel sheet layers are selected based on different gap values. If it is necessary to extend the actual axial dimension of the composite box beam after curing, it is necessary to add material to the mating surface 5 of the detachable jig 3. The mating surface is a planar design, and the addition of material is relatively easy. Either you can choose to weld invar36 raw material to the mating surface and then perform CNC milling, or you can choose to add several layers of 0.1mm thick stainless steel sheets to the mating surface 5 and then attach them to the molding surface of the mating surface 5 area of ​​the molding fixture. The single-layer 0.1mm single-sided adhesive release cloth gives the molding surface of the molding tooling a smooth feature. The corresponding restrictive surface of the detachable base 4, the detachable base side 8, and the detachable base mating surface 10 need to be dematerialized to avoid interference when the detachable base side 8 and the detachable base mating surface 10 of the detachable base 4 are combined with the detachable body 3.

[0115] 5) Reconstruction of composite material box beams

[0116] Based on the repaired composite material box beam molding tooling, the composite material box beam was remanufactured and its external dimensions were measured.

Claims

1. A method of manufacturing a composite box beam with closed corners at the ends, characterized in that, The steps are as follows: Step 1: Design of tooling for forming composite box beams The composite material box beam forming fixture adopts a combined structure design of a fixed jig (2), a detachable jig (3), and a detachable base (4). The detachable jig (3) is combined with the fixed jig (2) through the detachable base (4) and mated through mating surfaces (5). The detachable base (4) is fixed to the fixture pallet (6) by a combination of screws and pins. The detachable jig (3) and the detachable base (4) are mated by surface-to-surface contact. The allowance for the composite box beam forming tooling at the edge of the composite box beam is designed to be 40-60mm beyond the theoretical edge boundary; Step 2: Design of tooling for composite cover plate forming The forming surface of the composite cover plate forming fixture (13) is manufactured and inspected with a negative difference of -0.1~-0.2mm on the outer surface of the bag-side of the composite box beam. The composite cover plate forming fixture (13) is based on the plane of the fixture support plate (6) and offsets H to make the working surface of the boss (16). The length of the boss (16) is the same as the length of the composite cover plate (14), and the width of the boss (16) is greater than the width L of the "skirt" (15), L=10-20mm. Step 3: Measurement Fixture Design The measuring fixture includes a metal joint (19), a platform (22), a bracket (23), a connecting assembly (24), a column (25), a clamping device support (26), a clamping device (27), a pin (28), a connector (29), a support (30), a 0.1mm thick metal gasket (31), an end face action end (32), a spacer (33), an adjustable beam end face (34), an end face action end (35), a dial indicator (36), a slotted lead screw (37), a handle nut (38), a T-key (39), a sleeve (40), a protrusion (41), a positioning pin (42), a gauge base (43), a beam end face fixed end (44), a flange outer surface clamping plate (45), a support plate (46), an L-shaped support (47), and a clamping device sleeve (48). The metal joint portion (19) includes a working surface (20) on the web side and a working surface (21) on the flange side. The working surfaces (20) on the web side and (21) on the flange side of the composite box beam are offset from their theoretical positions and manufactured. The positioning metal joint consists of a platform and a connecting assembly (24); the connecting assembly (24) includes a column (25), a clamping device support (26), a clamping device (27), a connector (29), and a support (30); The column (25) is fixed to the platform (22) by a mechanical connection of screws and pins, and the support (30) is fixed to the column (25) by a mechanical connection of screws and pins. The connector (29) is fixed to the support (30) by a positioning pin. The connector (29) has two pin holes arranged in an alternating pattern. The connector (29) can be connected and fixed to the metal joint part (19) by the metal positioning pin through the pin holes. The adjustable end of the beam end face (34) includes a metal pin, an end face action end (35), a dial indicator (36), a slotted screw (37), a handle nut (38), a T-key (39), a sleeve (40), a protrusion (41), a positioning pin (42), and a gauge base (43). The adjustable end (34) of the beam end face includes a sleeve (40) which is fixed to the column (25) by a mechanical connection of screws and pins; the sleeve (40) has a through hole design inside, and one side of the sleeve (40) adopts a semi-circular annular groove design. The top of the sleeve (40) is designed with a protrusion (41), which is fixed to the top of the sleeve (40) by welding. The working surface of the protrusion (41) is the working surface of the measuring head of the dial indicator (36). The handle nut (38) adopts a boss structure design on the outside and a threaded hole design on the inside. The handle nut (38) is engaged with the semi-circular annular groove of the sleeve (40) through its own boss structure. The handle nut (38) and the sleeve (40) are in clearance fit to ensure that the handle nut (38) can rotate around its own axis. One end of the T-key (39) acts on the slotted lead screw (37), and the other end acts on the mating hole of the top of the sleeve (40) that mates with the T-key (39); The working surface of the end face (35) is manufactured by extracting the shape of one side end face of the composite material fitting beam. The end face (35) is fixed to the slotted screw (37) by means of metal positioning pin. The rotation of the handle nut (38) drives the slotted screw (37) to move laterally, which in turn drives the end face action end (35) to move laterally. A through hole is designed at the connection between the sleeve (40) and the slotted screw (37). The diameter of the positioning pin (42) is consistent with the diameter of the through hole. When the positioning pin (42) is inserted into the through hole of the sleeve (40) and the slotted screw (37), the theoretical distance between the action surface of the end face action end (35) and the axial direction of one end face of the composite material box beam is 5mm. The measuring head of the dial indicator (36) is at the position of 10mm elongation and acts on the action surface of the protrusion (41). The beam end face fixed end (44) includes the end face working end (32), slotted screw (37), handle screw nut (38), T-key (39), sleeve (40), and positioning pin (42); The end face function end (32) is designed with a slotted position on both sides of the relative composite material box beam. A spacer piece (33) is placed in the slotted position. The end face function end (32) is fixed to the slotted screw (37) by a metal positioning pin. The rotation of the handle nut (38) drives the slotted screw (37) to move laterally, which in turn drives the end face action end (32) to move laterally. A through hole is designed at the connection between the sleeve (40) and the slotted screw (37). The diameter of the positioning pin (42) is consistent with the diameter of the through hole. When the positioning pin (42) is inserted into the through hole of the sleeve (40) and the slotted screw (37), the theoretical distance between the action surface of the end face action end (32) and the axial direction of the other end face of the composite material box beam is 0mm, which is the theoretical position of the other end face of the composite material box beam. The working surface of the flange outer surface plate (45) is manufactured based on the flange outer surface extracted from the composite material box beam and offset outward by 2mm. The flange outer surface plate (45) is connected to the support plate (46) by screws and positioning pins. The support plate (46) is positioned and connected to the L-shaped support (47) by screws and positioning pins. The L-shaped support (47) is fixed on the platform (22) by the mechanical connection of screws and positioning pins.

2. A method of manufacturing a composite box beam with closed corner ends as defined in claim 1, wherein, The composite material box beam forming fixture (1) adopts a positive mold frame structure design as a whole. The fixture material is Invar36 steel with an expansion coefficient close to that of the composite material parts. The fixture forming surface is extracted according to the theoretical inner shape of the composite material box beam, and the thickness of the fixture forming surface is 10-20mm.

3. A method of manufacturing a composite box beam with closed corners as claimed in claim 1 or 2, wherein, The detachable base (4) is designed with threaded holes for lifting rings and is equipped with lifting rings (11). After the detachable base (4) slides, it provides space for the detachable body (3) to descend, that is, the detachable body (3) is removed from the composite material box beam, and then the demolding of the composite material box beam is realized.

4. A method for manufacturing a composite material box-shaped beam with closed-angle ends as described in claim 1 or 2, characterized in that, The metal joint part (19) extracts the metal hinge arm (17) in the composite material rudder box section for docking with the aircraft body structure. The metal hinge arm (17) is simplified, and the position of the central axis (18) of the intersection of the metal hinge arm is retained and a through hole with a diameter of φ6mm-φ10mm is designed with it as the center. The metal joint part (19) is made of Invar steel.

5. The method for manufacturing a composite material box beam with closed-angle ends as described in claim 3, characterized in that, The metal joint part (19) extracts the metal hinge arm (17) in the composite material rudder box section for docking with the aircraft body structure. The metal hinge arm (17) is simplified, and the position of the central axis (18) of the intersection of the metal hinge arm is retained and a through hole with a diameter of φ6mm-φ10mm is designed with it as the center. The metal joint part (19) is made of Invar steel.

6. The method for manufacturing a composite material box beam with closed-angle ends as described in claim 1, characterized in that, The working surface of the metal joint part (19) along the axial direction of the composite box beam is designed to be 150-200mm; the working surface (20) of the metal joint part (19) located on the web surface of the composite box beam is offset by 2mm from the inner surface of the composite box beam according to the theoretical position, that is, there is a theoretical gap of 2mm between the working surface (20) on the web surface and the web surface of the composite box beam; the working surface (21) of the metal joint part (19) located on the edge surface of the composite box beam is offset by 0.5mm from the inner surface of the composite box beam according to the theoretical position, that is, there is a theoretical gap of 0.5mm between the working surface (21) on the edge surface and the edge surface of the composite box beam.

7. The method for manufacturing a composite material box beam with closed-angle ends as described in claim 1, characterized in that, The main body of the clamping device support (26) is cylindrical with a through hole design. Both ends of the clamping device support (26) have flange structures. One flange structure is fixed to the platform (22) by a mechanical connection of screws and pins, and the other flange structure is connected and fixed to the clamping device sleeve (48) by a mechanical connection of screws and pins. The clamping device sleeve (48) adopts a semi-circular annular groove design.

8. The method for manufacturing a composite material box beam with closed-angle ends as described in claim 1, characterized in that, The handle nut (38) has a boss structure on the outside and a threaded hole on the inside. The handle nut (38) engages with the semi-circular annular groove of the tightening sleeve (48) through its own boss structure. The handle nut (38) and the tightening sleeve (48) are in clearance fit to ensure that the handle nut (38) can rotate around its own axis.

9. A method for manufacturing a composite material box beam with closed-angle ends as described in claim 1, characterized in that, The handle nut (38) has a threaded hole design inside; the main body of the clamping device (27) is a threaded rod design. The clamping device (27) and the handle nut (38) are screwed together. By rotating the handle nut (38), the clamping device (27) is driven to move along its own axis. The outer diameter of the clamping device (27) is accommodated within the through hole of the clamping device support (26) to ensure the range of motion of the clamping device (27). This allows the clamping device (27) to act on the web surface of the composite material box beam to maintain a clamped state, and to move away from the web surface of the composite material box beam to maintain a relaxed state, so as to facilitate the loading and unloading of the composite material box beam.

10. A method for manufacturing a composite material box beam with closed-angle ends as described in claim 1, characterized in that, The composite cover forming tooling (13) is made of Invar36 steel with an expansion coefficient close to that of the composite cover (14). The forming surface of the tooling is made using the outer surface of the bag-attached side of the composite box beam as the extraction surface. The composite cover forming tooling (13) adopts a positive mold frame structure design. The dial indicator (36) has a range of 0-10mm and a graduation value of 0.01mm. The measuring rod and measuring head of the dial indicator (36) are perpendicular to the working surface of the protrusion (41). The movement direction of the measuring rod and measuring head of the dial indicator (36) should be parallel to the slot. The axial direction of the screw (37); the base (43) has a through hole design, and the base (43) and the slotted screw (37) are in an interference fit relationship to ensure that the base (43) is fixed on the slotted screw (37) and moves along the axial direction of the slotted screw (37); the base (43) has a through hole design, and the base (43) and the bushing of the dial indicator (36) are in an interference fit relationship to ensure that the dial indicator (36) is fixed on the base (43), and the measuring rod and measuring head of the dial indicator (36) are in a relatively free extension and retraction state.

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