CN115675824A - Processing technology of hard cover plate at stringer end and hat-shaped stringer stiffened co-cured wallboard - Google Patents
Processing technology of hard cover plate at stringer end and hat-shaped stringer stiffened co-cured wallboard Download PDFInfo
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- CN115675824A CN115675824A CN202211215628.4A CN202211215628A CN115675824A CN 115675824 A CN115675824 A CN 115675824A CN 202211215628 A CN202211215628 A CN 202211215628A CN 115675824 A CN115675824 A CN 115675824A
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Abstract
The invention relates to the technical field of preparation of a stringer stiffened co-cured wallboard, in particular to a processing technology of a rigid cover plate at a stringer end and a hat-shaped stringer stiffened co-cured wallboard. The stringer end hard cover plate comprises a rubber core die attaching portion, the rubber core die attaching portion comprises a first attaching portion and a second attaching portion which are connected, retaining portions are further arranged on two sides of the rubber core die attaching portion respectively, and retaining holes are formed in each retaining portion respectively; each retainer is connected with the rubber core die joint part through a cover plate R region; the thicknesses of the first attaching parts are equal; the thickness of the second attaching portion is gradually reduced. According to the rigid cover plate for the stringer end, the surface quality of the skin and the hat bottom area of the stringer end can be guaranteed to be good, the thickness is uniform, the forming quality is stable and reliable, and the rigid cover plate for the stringer end is also suitable for forming the co-curing stiffened wall plate with the multi-rib structure.
Description
Technical Field
The invention relates to the technical field of preparation of a stringer stiffened co-cured wallboard, in particular to a processing technology of a rigid cover plate at a stringer end and a hat-shaped stringer stiffened co-cured wallboard.
Background
The carbon fiber reinforced composite material has the advantages of high specific modulus and specific strength, corrosion resistance, high temperature resistance, fatigue resistance, good damping and shock absorption, strong designability, good dimensional stability and the like, and is widely applied to the fields of aviation, aerospace and the like. The use of composite materials in the civil aviation field has been increasing, with the weight percentage increasing from 4.5% for a300 to 53% for a350 and from 10% for B777 to 50% for B787. The reinforced structure has better torsion-resistant and bending-resistant rigidity cap and can be widely applied to the mechanism design. Carbon fiber reinforced M21 epoxy uni-directional tape prepreg of HEXCEL may be used as the body material for the stringers and skin. In addition, there may be a plurality of stringers on the skin, and the skin is generally wider and longer than the stringers for assembly with other components, so that there is skin at the lengthwise edges of the stringers.
The problems of poor quality of the inner surface of the skin at the end of the stringer, fiber wrinkles, unqualified thickness and the like are encountered in the process of developing the hat-shaped stringer stiffened wallboard.
Disclosure of Invention
In view of the above-mentioned shortcomings of the prior art, it is an object of the present invention to provide a stringer end rigid decking which addresses the problems of the prior art.
In order to achieve the above and other related objects, the present invention provides a stringer end rigid cover plate, including a rubber core fitting portion, where the rubber core fitting portion includes a first fitting portion and a second fitting portion that are connected, two sides of the rubber core fitting portion are respectively provided with a retaining portion, and each retaining portion is respectively provided with a retaining hole; each retaining part is connected with the rubber core die attaching part through a cover plate R region; the thicknesses of the first attaching parts are equal; the thickness of the second attaching portion is gradually reduced.
In some embodiments of the present invention, the thickness of the second bonded portion gradually decreases in a direction away from the first bonded portion, and an angle α of a tip portion of the second bonded portion is 5 ° to 30 °; the tail end of the sharp corner part is provided with a boss.
In some embodiments of the invention, the thickness of the retainer is greater than the thickness of the rubber core fit.
In some embodiments of the present invention, the first attached portion has a thickness of 1mm to 5mm.
In some embodiments of the invention, the retainer has a thickness of 3mm to 8mm.
In some embodiments of the invention, the stiff stringer end cover sheet is selected from materials having a coefficient of thermal expansion similar to that of the stringer.
In some embodiments of the invention, the stringer thermal expansion coefficient is 0.5 x10 -6 /℃～1.5×10 -6 /℃。
In some embodiments of the present invention, the stringer end hard cover plate is made of a metal material; preferably, the material of the rigid cover plate at the end of the stringer is steel, and more preferably, the material is Invar steel.
In some embodiments of the invention, the stringer end rigid decking has a coefficient of thermal expansion of 0.5 x10 -6 /℃～2×10 -6 /℃。
In another aspect, the invention provides the use of a rigid stringer end cover according to the invention in the manufacture of a hat stringer stiffened co-cured panel.
The invention provides a processing technology of a hat-shaped stringer stiffened co-cured wallboard, which is characterized by comprising the following steps:
1) Assembling the inner core mold and the flexible rubber core mold to obtain an inner core mold and flexible rubber core mold assembly;
2) Turning the net-size stringer into a female die forming tool; the net-size stringer comprises a stringer crown, two symmetrically distributed stringer waists, and two symmetrically distributed stringer flanges;
3) Placing the inner core mould and the flexible rubber core mould assembly in the step 1) into an inner cavity of the net-size stringer;
4) Filling the twill strips into the residual gaps of the inner cavity of the stringer by utilizing laser projection positioning, sleeving a temporary vacuum bag on the outer surface of the stringer and compacting, wherein the assembled cap bottom of the rubber core die, the twill strips, the stringer flanges and the skin paving area of the female die forming tool are parallel and level;
5) The end part of the net-size stringer is provided with the stringer end hard cover plate; a cover plate groove matched with the hard cover plate at the end of the stringer is formed in the female die forming tool; arranging the rigid cover plate at the end of the stringer in the cover plate groove; the second laminating portion of stringer end stereoplasm apron is the inclined plane, laminates with the rubber mandrel.
6) Skin spreading silks are carried out on a skin spreading area of the female die forming tool, a stringer area and a cap bottom area of the flexible rubber core die, skin is formed after silks are spread, and the inner core die is taken out;
7) Fixing a pneumatic outer surface cover plate on the outer surface of the skin, wherein a pneumatic outer surface vacuum bag is arranged on the pneumatic outer surface cover plate, the pneumatic outer surface vacuum bag and the pneumatic outer surface cover plate are sealed through a first sealing rubber strip, and the tubular vacuum bag is communicated with the pneumatic outer surface vacuum bag;
8) And demolding after curing.
In some embodiments of the invention, the stringer tape has a slope of 40 ° to 50 °.
In some embodiments of the invention, the stringer ends are at right angles to the direction of elongation of the stringer crown in cross section.
Compared with the prior art, the invention has the following beneficial effects:
according to the rigid stringer end cover plate provided by the invention, the rigid stringer end cover plate is assembled, so that the surface quality of the skin and the bottom area of the stringer end cover plate is good, the thickness is uniform, the forming quality is stable and reliable, and the rigid stringer end cover plate is also suitable for forming the co-cured stiffened wallboard with the multi-rib structure.
Drawings
FIG. 1 is a schematic perspective view of a rigid stringer end cover according to the present invention.
FIG. 2 is a schematic cross-sectional view of the rubber core bonded portion of the rigid cover plate for stringer ends according to the present invention.
Fig. 3 is a partially enlarged schematic view of fig. 2.
FIG. 4 is a schematic front view of a rigid stringer end cover according to the present invention.
FIG. 5 is a schematic view of the stringer end cover plate and tooling provided in the present invention.
FIG. 6 is a schematic view of the mating of a rigid cover plate at the stringer end of the present invention with a rubber core.
FIG. 7 is a stringer configuration view provided by the present invention.
FIG. 8 is a schematic illustration of the problem of wrinkling at the end regions of the skin hat stringers to be solved by the present invention.
FIG. 9 is a cross-sectional view of a hat stringer stiffened co-cured panel of the present invention.
Fig. 10 is a schematic view of a female die forming tool provided by the present invention.
FIG. 11 is a schematic view of the final envelope provided by the present invention.
FIG. 12 is a pictorial view of a hat stringer stiffened co-cured wallboard stringer end skin made by the method of example 1 of the present invention.
FIG. 13 is a pictorial view of a hat stringer stiffened co-cured wallboard stringer end skin made using the method of comparative example 1.
FIG. 14 is a pictorial view of a hat stringer stiffened co-cured wallboard stringer end skin made using the method of comparative example 2.
FIG. 15 is a graph of stringer end thickness measurements in hat stringer stiffened co-cured panels made according to example 1.
Fig. 16 is a schematic view of the thickness measurement points of the siding prepared in example 1.
FIG. 17 is a graph of the results of ultrasonic testing of the siding panels prepared in example 1.
FIG. 18 is a diagram of the locations of the aerodynamic profile face mold inspection points of the panel after the hat-shaped stringer stiffened co-cured panel is prepared.
FIG. 19 is a diagram of a pneumatic profile inspection sandbag layout of panels made in example 1.
Fig. 20 is a numerical scattergram of the aerodynamic profile contour detection values of the cross sections 2 to 6.
FIG. 21 is a graphical representation of the location of the edge of the stringer of example 1 where wrinkles are likely to occur.
FIG. 22 is a skin state view of the stringer at the end of example 1, sectioned for microscopic observation, marked with fold locations.
Description of the drawings: 1-female die tooling hat top region, 2-female die tooling stringer hat top R-corner region, 3-female die tooling hat waist region, 4-female die tooling bead region, 5-skin lay-up region, 6-coverplate groove, 7-forming tooling stringer outer rubber core mold groove, 8-forming tooling bead region groove, 9-stringer end hard coverplate, 91-rubber core mold fit, 911-first fit, 912-second fit, 9121-boss, 92-fit, 93-coverplate R region, 94-retention hole, 10-female die forming tooling, 11-stringer hat top, 12-stringer hat waist, 13-stringer, 14-skin, 15-twister strip, 16-flexible rubber core mold, 17-aerodynamic profile, 18-first sealant strip, 19-tubular vacuum bag, 20-aerodynamic profile, 21-forming tooling stringer bevel region, 22-skin stringer end region, 22-forming tooling stringer end region
Detailed Description
In the description of the present invention, it should be noted that the structures, the proportions, the sizes, and the like shown in the drawings attached to the present specification are only used for matching with the contents disclosed in the specification, so as to be understood and read by those skilled in the art, and are not used for limiting the conditions under which the present invention can be implemented, so that the present invention has no technical significance, and any modifications of the structures, changes of the proportion relation, or adjustments of the sizes, can still fall within the range covered by the technical contents disclosed in the present invention without affecting the efficacy and the achievable purpose of the present invention. While the terms "central," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for convenience in describing the invention and to simplify the description, it is not intended to indicate or imply that the device or element so referred to must have a particular orientation, be constructed in a particular orientation and be operated in a particular manner, and is not to be construed as limiting the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In addition, in the description of the present invention, "a plurality" means two or more unless otherwise specified.
Referring to FIG. 8, it is common in the art to have the problem of wrinkling at the end regions of the skin hat stringers. Through a large number of tests, the invention discovers the hard cover plate at the stringer end, and the hard cover plate is applied to the processing technology of the hat-shaped stringer stiffened co-cured wallboard, so that the surface quality of the skin 14 at the stringer end and the hat bottom area is good, the thickness is uniform, the forming quality is stable and reliable, and the cover plate is also suitable for forming the stiffened co-cured wallboard with a multi-rib structure. On this basis, the present application has been completed.
According to one aspect of the present invention, as shown in fig. 1 to 4, the stringer end hard cover plate 9 includes a rubber core mold attaching portion 91, the rubber core mold attaching portion includes a first attaching portion 911 and a second attaching portion 912 which are connected, two sides of the rubber core mold attaching portion are further respectively provided with a retaining portion 92, and each retaining portion is respectively provided with a retaining hole 94; each of the retainers 92 is connected to the rubber core attaching portion 91 via a cover R region 93; the thicknesses of the first bonding portions 911 are equal; the thickness of the second attaching portion 912 is gradually reduced. In application, as shown in fig. 6, the thickness of the second attaching portion 912 of the rigid cover plate 9 at the end of the stringer tends to be gradually reduced toward the stringer, and the mating end of the stringer is in a wedge-shaped structure, which can ensure that the inner cavity of the stringer has no fiber wrinkles when the stringer is mated with the rubber core mold.
In the stringer end rigid cover plate provided by the invention, the thickness of the second bonding part 912 is gradually reduced along the direction far away from the first bonding part 911, and the angle alpha of the tip part of the second bonding part 912 is 5-60 degrees. In some embodiments, the angle α is 5 ° to 30 °,5 ° to 10 °,10 ° to 15 °,15 ° to 20 °,20 ° to 25 °, or 25 ° to 30 °, or the like. The end of the sharp corner is a boss 9121. Preventing scratching in the using process. The boss 9121 means that the longitudinal section of the end of the sharp corner is rectangular. The height of the projection 9121 may be, for example, 0 to 1mm, preferably 0 to 0.3mm, or 0.3mm to 1mm. More preferably 0.3mm.
In the hard cover plate for the stringer end provided by the invention, the thickness of the retainer part is greater than that of the rubber core die joint part. In some embodiments, the thickness of the first bonded portion 911 may be, for example, 1mm to 5mm, 1mm to 2mm, 2mm to 4mm, or 4mm to 5mm. The thickness of the first bonded portion 911 is preferably 2mm. The thickness of the retainer 92 may be, for example, 3mm to 5mm, or 5mm to 8mm. The thickness of the retainer 92 is preferably 5mm.
In the rigid cover plate for the stringer end provided by the invention, the material of the rigid cover plate 9 for the stringer end is selected from materials with the thermal expansion coefficient similar to that of the stringer. In some embodiments, the stringer coefficient of thermal expansion may be 0.5 x10 -6 /℃～1.5×10 -6 /℃、 0.5×10 -6 /℃～1.0×10 -6 /° C, or 1.0 × 10 -6 /℃～1.5×10 -6 /° c, etc. So that the contact surface of the stringer end hard cover plate 9 and the skin 14 can beEnsuring the surface quality of the stringer end skin 14.
In the stringer end hard cover plate provided by the invention, the stringer end hard cover plate 9 is made of a metal material. In some embodiments, the rigid stringer end cover plates 9 are made of steel. More specifically, the material may be Invar steel, for example. The stringer end rigid decking may have a coefficient of thermal expansion of, for example, 0.5 x10 -6 /℃～2×10 -6 /℃、 0.5×10 -6 /℃～1.0×10 -6 /℃、1.0×10 -6 /℃～1.5×10 -6 /. Degree.C., or 1.5X 10 -6 /℃～2×10 -6 /° c, etc.
The invention also provides a preparation method of the stringer end hard cover plate, which comprises the step of processing the material mentioned in the first aspect of the invention into the shape of the stringer end hard cover plate 9. The processing method belongs to the prior art.
In another aspect, the invention provides the use of a rigid stringer-terminated cover sheet according to the invention in the preparation of a hat stringer stiffened co-cured panel.
The invention also provides a processing technology of the hat-shaped stringer stiffened co-cured wallboard, which comprises the following steps:
1) Assembling the inner core mold and the flexible rubber core mold 16 to obtain an inner core mold and flexible rubber core mold assembly;
2) Turning the net-size stringer into a female die forming tool 10; the net stringer comprises a stringer crown 11, two stringer waists 12 symmetrically distributed, and two stringer flanges 13 symmetrically distributed;
3) Placing the assembly of the inner core mold and the flexible rubber core mold 16 in the step 1) into the inner cavity of the net-size stringer;
4) Utilizing laser projection positioning to fill the twill strip 15 into the residual gap of the inner cavity of the stringer, sleeving a temporary vacuum bag on the outer surface of the stringer and compacting, wherein the cap bottom of the assembled rubber core mold, the twill strip 15, the stringer flange strip 13 and the skin paving area 5 of the female mold forming tool 10 are flush;
5) The end of the net stringer is provided with a stringer end rigid cover plate 9 according to the first aspect of the invention; a cover plate groove 6 matched with a stringer end hard cover plate 9 is arranged on the female die forming tool 10; arranging the rigid cover plate 9 at the end of the stringer in the cover plate groove 6; the second attaching part 912 of the stringer end hard cover plate 9 is an inclined plane and is attached to the rubber core mold.
6) Carrying out skin 14 thread laying on a skin laying and pasting region 5 of the female die forming tool 10, a stringer region and a cap bottom region of a flexible rubber core die 16, forming a skin 14 after thread laying is finished, and taking out the inner core die;
7) Fixing a pneumatic outer surface cover plate 17 on the outer surface of the skin 14, arranging a pneumatic outer surface vacuum bag 20 on the pneumatic outer surface cover plate 17, sealing the pneumatic outer surface vacuum bag 20 and the pneumatic outer surface cover plate 17 through a first sealing rubber strip 18, and communicating a tubular vacuum bag 19 with the pneumatic outer surface vacuum bag 20;
8) And demolding after curing.
In the processing technology of the hat-shaped stringer stiffened co-cured wallboard provided by the invention, step 1) is to assemble an inner core mould and a flexible rubber core mould 16 to obtain an inner core mould, a flexible rubber inner core mould and a flexible rubber core mould assembly. The preparation method of the flexible rubber inner core mold and the flexible rubber core mold component comprises the following steps: placing the inner core mould inside a tubular vacuum bag 19; the tubular vacuum bag 19 is placed into the rubber cavity of the flexible rubber core mold 16 to obtain an inner core mold and flexible rubber core mold assembly, as shown in fig. 11.
In the preparation method of the inner core mold and flexible rubber core mold assembly, the inner core mold is filled with liquid rubber which is mixed according to the proportion requirement, and a metal chain is added in the liquid rubber to enhance the rigidity of the inner core mold.
In the processing technology of the hat-shaped stringer stiffened co-cured wallboard provided by the invention, step 2) is to turn the net-size stringer into a female die forming tool 10. Wherein the net stringer is obtained by laying and cutting the stringer. Specifically, the preparation of the net-size stringer is accomplished by hand lay-up of the stringer and ultrasonic automated cutting. Further, as shown in FIG. 9, the net stringer includes a top stringer 11, two symmetrically disposed waist stringers 12, and two symmetrically disposed stringer flanges 13. Two stringer waists 12 are respectively connected to both side edges of the stringer tops 11. Stringer tape 13 is connected to stringer waists 12 to form a stringer that is hat-shaped in cross-section. In particular, a stringer crown 11 and two stringer waists 12 enclose an interior cavity of the stringer. As shown in fig. 10, the female die forming tool 10 includes a female die tool crown region 1, two female die tool stringer crown R-angle regions 2, two female die tool hat waist regions and two female die tool edge regions, and the two female die tool hat waist regions are connected with the female die tool crown region 1 through the two female die tool stringer crown R-angle regions 2 respectively and are enclosed to form a stringer accommodating cavity. The forming tool stringer outer rubber core mould sealing structure further comprises a forming tool stringer outer rubber core mould groove 7 and a forming tool sealing rubber strip area groove 8. Female die tooling cap top region 1 is aimed at stringer cap top 11, female die tooling cap waist region 3 is aimed at stringer cap waist 12, and female die tooling cap waist region 4 is aimed at stringer flange 13, and stringer assembly position accuracy can be guaranteed.
Further, as shown in fig. 7, the gradient of the stringer tape 13 may be 40 ° to 50 °, 40 ° to 45 °, or 45 ° to 50 °. The included angle beta between the cross section of the stringer end and the extending direction of the stringer crown 11 is a right angle. The design can ensure that the sticking problem can not occur in the demoulding process of the stringer.
In the processing technology of the hat-shaped stringer stiffened co-cured wallboard provided by the invention, the step 3) is to place the inner core mould and the flexible rubber core mould assembly into the inner cavity of the net-size stringer. The inner core mold and the flexible rubber core mold component can be prepared by the preparation method of the inner core mold and the flexible rubber core mold component. In the process of placing the stringer, the assembled inner core mold and flexible rubber core mold assembly can be positioned and placed in the inner cavity of the stringer by utilizing the forming tool stringer outer rubber core mold groove 7.
In the processing technology of the hat-shaped stringer stiffened co-cured wallboard provided by the invention, as shown in fig. 11, step 4) is to utilize laser projection positioning, fill the remaining gaps of the inner cavity of the stringer with the twister strips 15, seal a temporary vacuum bag, press the stringer and compact the stringer, and ensure that the inner cavities of the flexible rubber core mould 16 and the stringer are well matched. The cap bottom of the assembled rubber core mold, the twister strip 15, the stringer tape 13 and the skin overlaying area 5 of the female mold forming tool 10 are flush.
In the process for manufacturing the hat-shaped stringer stiffened co-cured panel provided by the present invention, as shown in fig. 5, step 5) is to provide a rigid stringer end cover plate 9 according to the first aspect of the present invention at an end of the net-size stringer. The stringer end rigid decking 9 may be, for example, metal decking, the material of which is selected taking into account a material having a coefficient of thermal expansion close to that of the hat stringer stiffened co-cured panel material. For example, the steel cover plate may be made of Invar steel, and more specifically, the Invar steel may be made of Invar steel. A cover plate groove 6 matched with a stringer end hard cover plate 9 is arranged on the female die forming tool 10; and arranging the stringer end hard cover plate 9 in the cover plate groove 6, wherein a second laminating part of the stringer end hard cover plate 9 is an inclined plane and is laminated with the rubber core mold.
In the processing technology of the hat-shaped stringer stiffened co-cured wallboard provided by the invention, step 6) is to perform skin 14 thread laying in a skin laying area 5, a stringer marginal strip 13 area and a hat bottom area of a flexible rubber core mould 16 of the female mould forming tool 10, form a skin 14 after the thread laying is finished, and take out an inner core mould. Wherein the skin 14 is laid on an automatic laying machine, for example. Spreading angle the spreading is carried out according to the angle specified in the drawing, which may be, for example, [ -45 °/45 °/45 °/90 °/45 °/0 °/45 °/90 °/45 °/45 °/45 ° ]. The wire laying gap meets the requirements of design drawings. The spreading gap can be, for example, ≦ 1mm.
In the processing technology of the hat-shaped stringer stiffened co-cured wallboard provided by the invention, step 7) is to fix a pneumatic external surface cover plate 17 on the outer surface of the skin 14. The fixing means may be, for example, positioning assembly using pins. And sealing the pneumatic outer surface vacuum bag 20 and the pneumatic outer surface cover plate 17 through a first sealing rubber strip 18, and specifically, sticking the first sealing rubber strip 18 in a tool bag sealing area. The pneumatic outer surface cover plate 17 is provided with a pneumatic outer surface vacuum bag 20, and the tubular vacuum bag 19 is communicated with the pneumatic outer surface vacuum bag 20. The curing pressure in the inner cavity of the rubber core mold is ensured to be the same as that outside the external vacuum bag in the curing process.
Further, the aerodynamic profile cover plate 17 may be prepared by the following method:
1. brushing a release agent on a cover plate forming tool, paving a layer of tool fabric prepreg with the resin content of 45% on the surface of the tool after the release agent is completely dried, wherein the paving angle is 0 degrees, the nominal thickness of the tool prepreg fabric is 0.23mm, sealing a temporary vacuum bag for pre-compaction after the layer of prepreg is paved, the compaction time is not less than 15min, and the compaction vacuum degree is lower than-80 KPa;
2. paving and pasting a second layer and a third layer which are tool fabric prepregs with the resin content of 38%, wherein the paving angle is 45 degrees, the nominal thickness of the tool prepreg fabric is 0.65mm, paying attention to gas guiding in the paving process, pre-compacting once after each layer is paved, the compacting time is not less than 15min, and the compacting vacuum degree is lower than-80 KPa;
3. paving and pasting a fourth layer of tooling fabric prepreg with the resin content of 45%, wherein the paving angle is 0 degrees, the nominal thickness of the tooling prepreg fabric is 0.23mm, sealing a temporary vacuum bag for pre-compaction after the fourth layer is paved and pasted, the compaction time is not less than 15min, and the compaction vacuum degree is lower than-80 KPa;
4. and sealing the final vacuum bag, paying attention to air guide in the bag sealing process, placing an air guide wire in the part allowance area, contacting edge air guide fibers, selecting a porous isolation film or a nonporous isolation film on the surface, determining the selection of the isolation film according to the size and the shape of an actual product, and generally proposing the use of the porous isolation film for large-size parts.
5. And curing, wherein the cover plate curing is a secondary curing process which comprises pre-curing and post-curing processes, the pre-curing pressure is 0.6Mpa, the whole curing process is vacuumized, the temperature is increased to 60 ℃ at the temperature rise rate of 0.5 ℃/min, and the temperature is kept for 16 hours.
6. Removing the bag after the precuring is finished, drilling a positioning hole by using a drilling jig, and demoulding after the drilling is finished;
7. and (3) placing the cover plate on the surface of a forming tool to carry out a post-curing process, wherein no pressure or vacuum exists in the post-curing process, the temperature is raised to 60 ℃ at the speed of 1.5 ℃/min, then raised to 200 ℃ at the speed of 0.5 ℃/min, kept for 15min, lowered to 190 ℃ at the speed of 1.5 ℃/min, kept for 8 hours, lowered to 60 ℃ at the speed of 1.5 ℃/min, and cured.
In the processing technology of the hat-shaped stringer stiffened co-cured wallboard provided by the invention, step 8) is demoulding after curing. Specifically, the step of demolding after curing comprises the following steps: respectively demoulding the hard cover plate 9 at the end of the stringer and the pneumatic contour cover plate 17, taking out the first auxiliary material in the inner cavity of the flexible rubber core mould 16, vacuum-sealing two ends of the flexible rubber core mould 16, vacuumizing to deform the flexible rubber core mould 16, then taking out the flexible rubber core mould 16 from the inner cavity of the stringer in a manual dragging mode, and taking out the second auxiliary material after the flexible rubber core mould 16 is taken out.
In step 8) of the present invention, in particular, the first auxiliary material includes a pneumatic outer vacuum bag 20, a first sealant strip 18, and the like.
In step 8), a second auxiliary material is further removed from the inner cavity of the flexible rubber core mold 16, wherein the second auxiliary material comprises a tubular vacuum bag 19 and the like, and specifically, the auxiliary material in the flexible rubber core mold 16 is separated from the inner cavity of the flexible rubber core mold 16 through a method of multiple rotations, and then the auxiliary material is removed through dragging.
In step 8), the vacuum sealing of the two ends of the flexible rubber core mold 16 comprises the steps of sealing one end of the flexible rubber core mold 16 by using a second sealing rubber strip and a vacuum bag, sealing the other end of the flexible rubber core mold 16 by using a third sealing rubber strip and a vacuum bag, ventilating and adhering the bag, vacuumizing by using a vacuum nozzle base arranged inside the flexible rubber core mold 16 to deform the flexible rubber core mold 16 to 40% -50% of the original size, then releasing the flexible rubber core mold 16 from an inner cavity of a long truss in a manual dragging mode, and taking out third auxiliary materials at the two ends after the flexible rubber core mold 16 is released. The third auxiliary material comprises a second sealing rubber strip, a third sealing rubber strip, a vacuum bag ventilation and sealing bag and the like.
The following examples are provided to further illustrate the advantageous effects of the present invention.
In order to make the purpose, technical solutions and advantageous technical effects of the present invention clearer, the present invention is described in further detail below with reference to examples. However, it should be understood that the embodiments of the present invention are only for explaining the present invention and are not for limiting the present invention, and the embodiments of the present invention are not limited to the embodiments given in the specification. The examples were made under conventional conditions, or conditions recommended by the material suppliers, without specifying specific experimental conditions or operating conditions.
Furthermore, it is to be understood that one or more method steps recited in the present disclosure are not exclusive of other method steps that may also be present before or after the recited combination of steps or that other method steps may also be inserted between the explicitly recited steps, unless otherwise indicated; it is also to be understood that a combined connection between one or more devices/apparatus as referred to in the present application does not exclude that further devices/apparatus may be present before or after the combined device/apparatus or that further devices/apparatus may be interposed between two devices/apparatus explicitly referred to, unless otherwise indicated. Moreover, unless otherwise indicated, the numbering of the various method steps is merely a convenient tool for identifying the various method steps, and is not intended to limit the order in which the method steps are arranged or the scope of the invention in which the invention may be practiced, and changes or modifications in the relative relationship may be made without substantially changing the technical content.
In the following examples, reagents, materials and instruments used are commercially available unless otherwise specified.
Example 1
The processing technology of the hat-shaped stringer ribbed co-cured wallboard comprises the following steps:
1. placing the inner core mould inside a tubular vacuum bag 19; placing the tubular vacuum bag 19 into the rubber inner cavity of the flexible rubber core mold 16 to obtain an inner core mold and a flexible rubber core mold assembly for standby;
2. finishing the manufacture of the cap-shaped stringer stiffened co-cured wallboard pneumatic profile composite cover plate; the pneumatic profile composite cover plate can be purchased and prepared by the preparation method of the pneumatic profile composite cover plate in the specific embodiment of the invention.
3. Finishing the preparation of the net-size stringer through manual paving and ultrasonic automatic cutting, turning the net-size stringer into a female die forming tool 10, aligning a stringer crown 11 with a female die tool crown area 1, aligning a stringer waist with a female die tool hat waist area 3, and aligning a stringer flange strip 13 with a female die tool flange strip area 4, so that the assembling position of the stringer can be ensured to be accurate;
4. assembling an inner core mould and a tubular vacuum bag 19 into an inner cavity of a flexible rubber core mould, and positioning and placing the flexible rubber core mould into the inner cavity of the stringer by utilizing the groove 7 of the outer rubber core mould of the forming tool stringer;
5. positioning by laser projection, assembling the twiddle strips 15 into the inner cavity of the stringer, sealing a temporary vacuum bag and compacting to ensure that the inner cavities of the rubber core mould and the stringer are well matched, and ensuring that the cap bottom part of the rubber core mould, the plane of the twiddle strips 15, the edge strip part of the stringer are twisted and flush with the skin paving area 5 of the forming female mould tool after the assembly is finished;
6. and (3) assembling a stringer end hard cover plate 9 in a groove of a stringer end female die forming tool 10, wherein the stringer end hard cover plate 9 and the rubber core die are in wedge-shaped fit, as shown in fig. 6.
7. And (3) carrying out skin 14 silk laying on a skin area, a stringer marginal strip area and a cap bottom area of the rubber core mold of the assembled female mold forming tool 10 by using an automatic silk laying machine, laying at a silk laying angle according to an angle specified by a drawing, wherein a silk laying gap meets the requirement of the design drawing, forming the skin 14 after silk laying is finished, and taking out the inner core mold after the skin silk laying is finished.
8. Positioning and assembling a pneumatic external-surface stringer end head hard cover plate 9 on the outer surface of a skin 14 by using pins, adhering a first sealing adhesive tape 18 in a tool bag sealing area, communicating a rubber core mold internal tubular vacuum bag 19 with a pneumatic external-surface vacuum bag 20, and ensuring that the curing pressure in a rubber core mold inner cavity is the same as that outside the external vacuum bag in the curing process.
9. Demoulding after curing, respectively demoulding the rigid cover plate 9 at the end of the stringer and the pneumatic profile cover plate 17, taking out the first auxiliary material in the inner cavity of the flexible rubber core mould 16, vacuum-sealing two ends of the flexible rubber core mould 16, vacuumizing to deform the flexible rubber core mould 16, then taking out the flexible rubber core mould 16 from the inner cavity of the stringer in a manual dragging mode, and taking out the second auxiliary material after the flexible rubber core mould 16 is taken out.
Comparative example 1
The other steps are the same as example 1 except that the stringer end rigid cover sheet 9 in step 6 is not present.
Comparative example 2
The female die forming tool 10 for the stringer end is not provided with the cover plate groove 6, the stringer end is provided with a thin gasket made of soft material with the thickness of 0.15-0.6 mm, and the soft material is carbon fiber fabric. The rest of the procedure was the same as in example 1.
And (3) detection results:
1. appearance detection
1.1 the scheme of the embodiment 1 and the scheme of the rigid cover plate at the end of the stringer are adopted to manufacture the hat-shaped stringer stiffened wall plate, the surface quality of the skin at the end of the stringer is good, the defects of folds, pits and the like are avoided, and the appearance inspection is qualified, as shown in figure 12.
1.2 adopt the scheme of comparative example 1, when there is no long purlin end hard cover plate, the long purlin end can produce the fold, and visual inspection is unqualified. As shown in fig. 13.
1.3 adopt the scheme of comparative example 2, have end soft material shim and polytetrafluoroethylene false twist strip, the female die frock stringer end does not set up the apron recess 6, as shown in fig. 14, the pit appears in stringer end after this scheme solidifies, local pit depth > 1mm, the visual inspection is unqualified.
2. Thickness measurement
2.1 stringer end thickness measurement
The specifications require that the nominal stringer end thickness be 2.057mm, with a thickness in the range 1.954mm to 2.160mm. From the thickness detection data distribution diagram of FIG. 15, it is seen that the thickness values of M1-M5 and N1-N5 are all in the range of 1.954 mm-2.160 mm, so the use of the stringer end cover plate mentioned in this patent can ensure that the stringer end thickness is qualified.
2.2 the thickness of the wall plate is measured by using a magnetic thickness gauge (one-point calibration). The panels were spaced 250mm apart along the course, and 13 thickness measurement points were arranged as shown in FIG. 16.
(1) Skin non-co-cured area
Nominal thickness of the skin non-co-cured area is 2.057mm; tolerance is +/-5%; single value received value: 1.954-2.159 mm. The thickness of the non-co-cured skin region meets the requirement.
TABLE 1 skin non-co-cured area thickness
(2) Co-cured areas
Nominal co-cured zone thickness 3.740mm; tolerance is +/-5%; single value received value: 3.553-3.927 mm. The thickness of the co-curing area meets the requirement.
TABLE 2 thickness of co-cured area
The hat-shaped stringer stiffened panel manufactured in example 1 was used, and the thicknesses of the skin region and the co-cured region were measured by a magnetic thickness gauge, and the measurement results were all acceptable.
(3) Stringer flat area
Nominal stringer planar area thickness 1.683mm; a tolerance of ± 8% mm; single value received value: 1.548-1.817 mm. The thickness of the plane of the stringer meets the requirement.
TABLE 3 stringer planar area thickness
(4) Stringer waists R
Nominal thickness of stringer waists R region 1.683mm; single value tolerance of +/-15%; mean tolerance ± 10%. Single value received value: 1.431-1.935 mm, mean acceptance value: 1.515-1.851 mm. The thickness of the R area of the long truss hat waist meets the requirement.
TABLE 4 stringer Bowls R zone thickness
And (3) detecting the thickness of the plane area of the stringer and the thickness of the R area by using a magnetic thickness gauge, wherein the thickness of the plane area of the stringer and the thickness of the R area are both qualified.
3. Ultrasonic testing
As can be seen from the C-scan detection image, the preset artificial defects are all normally detected, and the size deviation meets the standard requirement (Area +/-25%), which indicates that the setting of the detection sensitivity and the evaluation threshold is reasonable.
Macroscopic defects: in the detection area, no macroscopic defects were found.
Porosity: no areas of excessive porosity were found.
In conclusion, as can be seen from the ultrasonic detection image in fig. 17, the nondestructive detection is qualified.
4. Shape measurement
After the wall plate is cut, a film is pasted to detect the appearance of the pneumatic surface; along the course interval of 250mm, 5 detection sections (section 2-section 6) are arranged, and 8 film sticking detection points are arranged on each section. The layout of the pneumatic outline surface sticking model inspection points of the wall plate is shown in a figure 18, the layout of the pneumatic outline surface detection sandbag arrangement object of the wall plate is shown in a figure 19, and the pneumatic outline surface profile detection numerical value scatter diagram of the section 2-the section 6 is shown in a figure 20. The pneumatic outer profile of the part is inspected by a method for inspecting the wall plate by sticking a mold, the specification requires that the profile tolerance of the pneumatic outer profile is less than or equal to 0.75mm, the figure 20 is the detection value of the profile tolerance of the pneumatic outer profile of the section 2-the section 6, and the detection data result of the figure 20 shows that the profile tolerance of the section 2-the section 6 is less than 0.75mm, so that the pneumatic outer profile of the wall plate is qualified.
5. The parts prepared in example 1 are cut at positions where the stringer ends are prone to wrinkle, as shown in a transverse line area of fig. 21, the skin state of the stringer ends is observed by an olympus dsx1000 microscope, and the skin fiber thickness in the area is uniform as shown in fig. 22.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.
Claims (10)
1. The stringer end hard cover plate is characterized by comprising a rubber core die attaching part (91), wherein the rubber core die attaching part comprises a first attaching part (911) and a second attaching part (912) which are connected, two sides of the rubber core die attaching part are respectively provided with a retaining part (92), and each retaining part is respectively provided with a retaining hole (94); each retaining part is connected with the rubber core die attaching part through a cover plate R region (93); the thicknesses of the first bonding parts (911) are equal; the thickness of the second attaching portion (912) is gradually reduced.
2. The stringer end hard cover plate according to claim 1, wherein the thickness of the second joint section (912) decreases in the direction away from the first joint section (911), and the angle α of the tip of the second joint section (912) is 5 ° to 30 °;
the tail end of the sharp corner part is provided with a boss (9121).
3. The stringer end rigid decking of claim 1 wherein the thickness of the retainer (92) is greater than the thickness of the rubber core abutment (91);
and/or the thickness of the first bonding part (911) is 1mm to 5mm;
and/or the thickness of the retainer part (92) is 3 mm-8 mm.
4. The stringer end stiffened cover of claim 1 wherein said stringer end stiffened cover is made of a material selected from the group consisting of materials having a coefficient of thermal expansion similar to that of the stringer.
5. The stringer end stiffened cover sheet of claim 4, wherein said stringer coefficient of thermal expansion is 0.5 x10 -6 /℃～1.5×10 -6 /℃。
6. The stringer end hard cover of claim 4, wherein said stringer end hard cover is made of a metallic material; preferably, the material of the rigid cover plate at the end of the stringer is steel, and more preferably, the material is Invar steel;
and/or the coefficient of thermal expansion of the rigid cover plate at the end of the stringer is 0.5 multiplied by 10 -6 /℃～2×10 -6 /℃。
7. Use of a stringer-terminated rigid decking according to any one of claims 1 to 6 in the manufacture of hat stringer stiffened co-cured panels.
8. A processing technology of a hat-shaped stringer stiffened co-cured wallboard is characterized by comprising the following steps:
1) Assembling the inner core mold and the flexible rubber core mold to obtain an inner core mold and flexible rubber core mold assembly;
2) Turning the net-size stringer into a female die forming tool; the net stringer comprises a stringer crown, two symmetrically distributed stringer waists, and two symmetrically distributed stringer flanges;
3) Placing the inner core mould and the flexible rubber core mould assembly in the step 1) into an inner cavity of the net-size stringer;
4) Filling the twill strips into the residual gaps of the inner cavity of the stringer by utilizing laser projection positioning, sleeving a temporary vacuum bag on the outer surface of the stringer and compacting, wherein the assembled cap bottom of the rubber core die, the twill strips, the stringer flanges and the skin paving area of the female die forming tool are parallel and level;
5) The end of the net-size stringer is provided with a stringer-end hard cover plate as claimed in any one of claims 1 to 6; a cover plate groove matched with the hard cover plate at the end of the stringer is formed in the female die forming tool; arranging the rigid cover plate at the end of the stringer in the cover plate groove; the second laminating portion of stringer end stereoplasm apron is the inclined plane, laminates with the rubber mandrel.
6) Skin spreading and silk spreading are carried out on a skin spreading and pasting area of the female die forming tool, a fringe area of the stringer and a cap bottom area of the flexible rubber core die, skin is formed after silk spreading is finished, and the inner core die is taken out;
7) Fixing a pneumatic outer surface cover plate on the outer surface of the skin, arranging a pneumatic outer surface vacuum bag on the pneumatic outer surface cover plate, sealing the pneumatic outer surface vacuum bag and the pneumatic outer surface cover plate through a first sealing rubber strip, and communicating the tubular vacuum bag with the pneumatic outer surface vacuum bag;
8) And demolding after curing.
9. The process of making a hat stringer stiffened co-cured panel of claim 8, wherein said stringer tape has a slope of from 40 ° to 50 °.
10. The process of making a hat stringer stiffened co-cured panel of claim 8, wherein a cross section of said stringer ends is at a right angle to a direction of elongation of the stringer crown.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211215628.4A CN115675824A (en) | 2022-09-30 | 2022-09-30 | Processing technology of hard cover plate at stringer end and hat-shaped stringer stiffened co-cured wallboard |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211215628.4A CN115675824A (en) | 2022-09-30 | 2022-09-30 | Processing technology of hard cover plate at stringer end and hat-shaped stringer stiffened co-cured wallboard |
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| CN202211215628.4A Pending CN115675824A (en) | 2022-09-30 | 2022-09-30 | Processing technology of hard cover plate at stringer end and hat-shaped stringer stiffened co-cured wallboard |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117077325A (en) * | 2023-10-16 | 2023-11-17 | 成都飞机工业（集团）有限责任公司 | Vacuum-magnetic force cooperative skin profile precise milling tool design method |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117077325A (en) * | 2023-10-16 | 2023-11-17 | 成都飞机工业（集团）有限责任公司 | Vacuum-magnetic force cooperative skin profile precise milling tool design method |
| CN117077325B (en) * | 2023-10-16 | 2024-02-23 | 成都飞机工业（集团）有限责任公司 | Vacuum-magnetic force cooperative skin profile precise milling tool design method |
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