Method for cementing front edge structure of complex honeycomb sandwich

Abstract

The invention belongs to the technical field of composite material bonding, and particularly relates to a bonding method for a complex honeycomb sandwich front edge structure. The method comprises the steps that the rear beam is placed on a tool, a honeycomb core concave table and the molded surface of a rear beam side plate are connected in a matched and glued mode, and then an end rib and an end rib limiting device are fixed; the whole body is put into a drying oven to be verified, and polystyrene foam compensation is conducted at the glued joint according to the verification result; performing high-temperature curing on the glue joint of the skeleton structure in a drying oven; the second skin is placed on the framework, and then the framework structure is subjected to vacuum packaging and secondary glue joint verification in the autoclave; the third skin is placed on the framework structure, auxiliary materials are placed, the third skin is placed in the autoclave to be cured, and finally demolding is completed; compared with the prior art, the device has the advantages that the problem of positioning the relative position of each part when each part is glued is solved, the gluing error is greatly reduced, and the gluing accuracy is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of composite material bonding, and in particular relates to a method for bonding a complex honeycomb sandwich leading edge structure. Background Art

[0002] Fixed-wing aircraft usually have a complex honeycomb sandwich leading edge structure with a large aspect ratio, which is composed of beams, honeycomb structural parts with different functions, two side end ribs and skin. The preparation process of this type of structure mainly includes two parts, the preparation of the skeleton structure and the bonding of the skin to the skeleton structure. The preparation of the skeleton structure includes the bonding between different honeycomb cores, the bonding of the honeycomb core to the beam, and the bonding of the honeycomb core to the two side end ribs. The existing method of preparing complex honeycomb sandwich structural parts with a large aspect ratio mostly adopts the method of bonding the excess honeycomb core with other sub-components to prepare a skeleton and then CNC milling. This method has the disadvantages of long preparation cycle, high cost, complex tooling design and manufacturing, and the inability to share splicing tooling and bonding tooling.

[0003] If a net-size honeycomb core is used for bonding, through the integrated design of splicing and bonding tooling, each sub-component is accurately positioned to achieve efficient and low-cost manufacturing of a large aspect ratio honeycomb sandwich structure. However, the core of this preparation method lies in how to achieve accurate bonding between different sub-components and how to achieve accurate bonding between the skeleton structure and the skin. In the bonding process of this type of structure, there are several specific difficulties: it is difficult to accurately match the sub-components in the skeleton structure; when the skeleton is foamed and bonded, the honeycomb core is prone to shrinkage under pressurized conditions; and it is difficult to accurately bond the leading edge R zone when the skeleton structure and the skin are bonded for the second time.

[0004] For example, a Chinese patent with application number 201910050717.X and application date 2019.01.20, and the patent name is "A method for gluing and positioning a composite aircraft rudder with multiple joints", and its technical solution is: a method for gluing and positioning a composite aircraft rudder with multiple joints, characterized in that the steps are: S1 pre-installing parts on an assembly jig, and providing process ear positioning holes on the assembly jig; S2 positioning of the mold surface skin: positioning the mold surface skin through the process ear; S3 positioning of the rudder skeleton: fitting the honeycomb core and the ribs; S4 positioning of the non-mold surface skin: positioning the non-mold surface skin according to the process positioning holes; S5 packaging vacuum bag; S6 autoclave gluing: sending the parts into the autoclave for gluing; S7 demolding: removing the vacuum bag after taking out the can and taking out the rudder.

[0005] In the above patent, although the method can realize the gluing positioning of the aircraft rudder surface, the above patent technology has the following two disadvantages: first, the technical solution only uses the detachable limit block on the gluing fixture and the beam, rib and rear edge strip axis on the gluing fixture to solve the problem of positioning each part on the gluing fixture and positioning the relative position of each part when the rudder surface is pre-installed, but the detachable limit block and the beam, rib and rear edge strip axis cannot be accurately positioned only by the detachable limit block and the beam, rib and rear edge strip axis, and there is a certain error; secondly, the use of autoclave gluing in the technical solution will cause the honeycomb type to shrink at high temperature. Summary of the invention

[0006] In order to solve the above problems existing in the prior art, the present invention adopts a concave platform design of a net-size honeycomb core to achieve a method for gluing the leading edge structure of a complex honeycomb sandwich core, which can be precisely glued and reduces the risk of honeycomb core shrinkage by mechanical pressurization.

[0007] In order to solve the above technical problems, the technical solution of the present invention is as follows: A method for gluing a complex honeycomb sandwich leading edge structure, comprising the following steps: Step 1: Place the rear beam on the tooling, match and glue the honeycomb core concave platform with the rear beam side panel profile, then fix the end ribs with the end rib limiter, and then place the first isolation membrane, the second isolation membrane and the first skin on the skeleton structure in sequence; Step 2: Rotate the top holding device wheel until the first skin is in contact with the top of the frame structure, and then rotate the side shaping device wheel to make the first skin in contact with the side of the frame structure; Step 3: Put the whole into the oven for verification. After the verification is completed, make foam glue compensation at the glue joint according to the verification results; Step 4: Repeat step 2, and finally perform high-temperature curing on the glue joints of the skeleton structure in an oven; Step 5: Place adhesive film, first isolation film and second isolation film on the honeycomb core of the skeleton structure in sequence, lay foam glue and adhesive film on the end ribs and the end rib limiter at the joints with the honeycomb core and the back beam, and separate the joints with the second isolation film, finally place the second skin on the skeleton, vacuum-pack the skeleton structure and perform secondary bonding inspection in an autoclave; Step six: Make compensation based on the verification results of the secondary bonding verification, place the third skin on the skeleton structure, then place the auxiliary materials, and finally put it into the autoclave for curing. After curing, remove the auxiliary materials, top holding device, and end rib limit device to complete demoulding.

[0008] Furthermore, in the step one, the honeycomb core concave platform and the rear beam side panel profile are matched and glued by laying foam glue, and each glued surface is isolated by a non-porous isolation film; the honeycomb core concave platform and the rear beam side panel profile are matched and positioned by aligning the positioning holes on the tooling with the positioning holes on the rear beam ear pieces, and then inserting the positioning pins into the positioning holes.

[0009] Furthermore, in step one, the end ribs include a wing root side end rib and a wing tip side end rib, and the end rib limiting device includes a wing root side end rib limiting device and a wing tip side end rib limiting device; the wing root side end rib limiting device and the wing tip side end rib limiting device are both installed on the tooling, and the wing root side end rib limiting device is fixedly connected to the wing root side end rib, and the wing tip side end rib limiting device is fixedly connected to the wing tip side end rib.

[0010] Furthermore, the first isolation membrane, the second isolation membrane, the first skin, the second skin and the third skin are all positioned and installed through the positioning holes on the rear beam.

[0011] Furthermore, in step 1, the depth of the honeycomb core concave terrace formed by milling the honeycomb core is 2.5-3.5 mm.

[0012] Furthermore, the skeleton structure includes a rear beam, a honeycomb core and end ribs; both ends of the rear beam are connected to the end ribs.

[0013] Furthermore, the first isolation membrane is a porous isolation membrane; the second isolation membrane is a non-porous isolation membrane; the first skin is a process skin; the second skin is a glued skin; and the third skin is a cured skin.

[0014] Furthermore, after the process skin is fitted to the side of the skeleton structure, a feeler gauge is used to check the gap.

[0015] Furthermore, the lateral shaping device in step 2 includes a lateral shaping device pressure plate and a lateral shaping device base, and the lateral shaping device pressure plate is installed on the lateral shaping device base; the lateral shaping device base is positioned on the tooling by positioning inserts installed on both sides of the tooling; the lateral shaping device pressure plate is installed on both sides of the skeleton structure.

[0016] Furthermore, the verification parameters in step three are: heating to 60-65°C at a heating rate of no more than 1°C / min, and maintaining the temperature for 60-65 min; and cooling down after the temperature is maintained.

[0017] Furthermore, after the verification in step three is completed, it is necessary to remove the lateral shaping device, the top holding device and the first skin, and then check the verification results.

[0018] Furthermore, before repeating step 2 in step 4, the lateral contouring device and the top holding device need to be reinstalled.

[0019] Furthermore, after repeating the second step, the lateral dimensioning device is removed again.

[0020] Furthermore, in step 4, the high-temperature curing is carried out in an oven, wherein the curing parameters of the foam adhesive are as follows: the temperature is increased to 150-155°C at a heating rate of no more than 1°C / min, and the temperature is kept constant when the temperature reaches 150°C, and the constant temperature time is 4-4.5 h; the temperature is lowered after the constant temperature ends; during the cooling process from 150°C to 130°C, the cooling rate should be no higher than 1°C / min, and during the cooling process after 130°C, the cooling rate should be no higher than 0.3°C / min, and the pre-foaming process is terminated after the temperature is cooled to 60°C.

[0021] Furthermore, after placing the second skin on the frame in step five, a putty strip is laid on the side of the top holding device, and the top holding device and the frame structure are vacuum-sealed together and subjected to a secondary bonding inspection in an autoclave.

[0022] Furthermore, the auxiliary materials in step six include a non-porous isolation membrane, a porous isolation membrane, a breathable felt, a vacuum bag and a putty strip, and are placed in the order of the non-porous isolation membrane, the porous isolation membrane, the breathable felt, the vacuum bag and the putty strip, and finally the vacuum bag is evacuated for leak detection.

[0023] Furthermore, the curing parameters in the autoclave in step six are as follows: start vacuuming, the vacuum degree is -0.027MPa~-0.033MPa, and the negative pressure in the vacuum bag does not exceed -0.034MPa during the whole process; the external pressure is increased to 0.08~0.1MPa at a pressurization rate of 20~30 kPa / min, and the external pressure is maintained for 10~30 min; then the vacuum is vented to the atmosphere, and the vacuum venting rate does not exceed 1 kPa / min; after the venting is completed, the tank pressure is continued to be increased to 0.18~0.20 MPa, and this pressure is maintained until the curing process is completed; after the pressurization is completed, the temperature is started to rise, and the temperature is raised to 150~155℃ at a rate of 1~1.5℃ / min, and it is kept at this temperature for 4 hours; then the temperature is raised to 175~180℃ at a rate of 0.5℃ / min, and it is kept at this temperature for 2 hours; after the end, the temperature is lowered at a cooling rate of no more than 0.3℃ / min, and the temperature is lowered at 20~30 kPa / min Release the tank pressure at a rapid rate, and when the pressure is released and the temperature drops to 60 ℃, the curing is completed.

[0024] Furthermore, the tooling includes a tooling assembly, and the positioning inserts are installed on both sides of the tooling assembly.

[0025] According to the above technical solution, the beneficial effects of the present invention are as follows: 1. Compared with the prior art, the method adopted by the present invention solves the problem of locating the relative positions of various parts when they are glued, greatly reduces the glue error, and improves the accuracy of glue.

[0026] 2. The method of the present invention adopts a net-size honeycomb core. Compared with the use of excess honeycomb cores in the prior art, the use of excess honeycomb cores for the preparation of complex honeycomb sandwich leading edge structures with a large aspect ratio requires three CNC machining operations, while the use of net-size honeycomb cores for gluing only requires one CNC machining operation, which reduces the number of CNC machining operations during the preparation of structural parts and greatly improves production efficiency.

[0027] 3. The method of the present invention adopts positioning holes, honeycomb core concave platforms, wing root side end rib limiting devices and wing tip side end rib limiting devices, and the above positioning measures are used to achieve accurate positioning of the sub-components.

[0028] 4. The method of the present invention adopts mechanical pressurization of the top holding device, and vacuum-packages the top holding device and the honeycomb sandwich leading edge structure components together during assembly. By using weak vacuum, low vacuum atmosphere replacement rate, and slow heating rate during curing, accurate bonding of the leading edge R zone during secondary bonding of the skeleton structure and the skin is achieved.

[0029] 5. The wing root side end rib limiting device and the wing tip side end rib limiting device adopted in the method of the present invention realize accurate positioning of the wing root side end rib and the wing tip side end rib and the honeycomb core bonding surface, while preventing warping and deformation of both sides of the rear beam during the thermal process, thereby improving the accuracy of the skeleton bonding.

[0030] 6. In the method of the present invention, the skeleton structure is placed in an oven for curing, and foaming is performed by heating only without vacuuming. The glue is cured, avoiding the problem of lateral compression and shrinkage of the honeycomb core under high temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the design of the honeycomb core concave platform of the present invention.

[0032] Figure 2 It is a schematic diagram of positioning the lateral dimensional device and the top holding device of the present invention.

[0033] Figure 3 It is a schematic diagram of the skeleton forming and assembling of the present invention.

[0034] Figure 4 It is a schematic diagram of the adhesive assembly of the skin and the frame of the present invention.

[0035] Figure 5 It is a dimensional schematic diagram of the leading edge R zone of the present invention.

[0036] In the attached drawings: 1-honeycomb core concave platform; 2-positioning insert; 3-tooling assembly; 4-tooling surface; 5-lateral shaping device base hole; 6-top holding device hole; 7-wing root side end rib limiting device; 8-wing root side end rib; 9-rear beam; 10-honeycomb core; 11-technical skin; 12-non-porous isolation membrane; 13-porous isolation membrane; 14-wing tip side end rib; 15-wing tip side end rib limiting device; 16-lateral shaping device pressure plate; 17-lateral shaping device base; 18-tooling; 19-top holding device; 20-positioning hole; 21-foam; 22-film; 23-skin; 24-breathable felt; 25-rear beam side panel profile; 26-rear beam ear; 27-end rib limiting device hole; 28-leading edge R zone; 29-vacuum bag. DETAILED DESCRIPTION

[0037] The purpose, technical solutions and advantages of the embodiments of the present application are clearer. The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0038] Example 1 A method for gluing a complex honeycomb sandwich leading edge structure, comprising the following steps: Step 1: If Figure 1 and Figure 3 As shown, the rear beam 9 is placed on the tooling 18, and the honeycomb core concave platform 1 is matched and glued with the rear beam side plate profile 25, and then the end ribs are fixed with the end rib limiter, and then the first isolation membrane, the second isolation membrane and the first skin are placed on the skeleton structure in sequence; Step 2: If Figure 3 As shown, the top holding device 19 is rotated until the first skin is in contact with the top of the skeleton structure, and then the side shaping device is rotated to make the first skin in contact with the side of the skeleton structure; Step 3: Put the whole into the oven for verification. After the verification is completed, the foam glue 21 at the glue joint is compensated according to the verification result; Step 4: Repeat step 2, and finally perform high-temperature curing on the glue joints of the skeleton structure in an oven; Step 5: Place the adhesive film 22, the first isolation film and the second isolation film on the honeycomb core 10 of the skeleton structure in sequence, and lay the foam glue 21 and the adhesive film 22 on the end ribs and the end rib limiter at the bonding points between the honeycomb core 10 and the back beam 9, and separate the bonding points with the second isolation film, and finally place the second skin on the skeleton, and then vacuum-pack the skeleton structure and perform secondary bonding inspection in the autoclave; Step six: make compensation according to the verification results of the secondary bonding verification, place the third skin on the skeleton structure, then place the auxiliary materials, and finally put it into the autoclave for curing. After curing, remove the auxiliary materials, the top holding device 19, and the end rib limit device to complete demoulding.

[0039] The first isolation membrane is a porous isolation membrane 13; the second isolation membrane is a non-porous isolation membrane 12; the first skin is a process skin 11; the second skin is a glued skin; the third skin is a cured skin; the role of the porous isolation membrane 13 is to guide air, so that the small molecular components generated during the curing process can be discharged to prevent the small molecular gas from gathering; the role of the non-porous isolation membrane 12 is to isolate the skin and the adhesive film 22 during the verification process to prevent the inability to check the verification effect after bonding; the role of the process skin 11 is the same as that of the equalizing plate in the autoclave molding process, which maintains the shape of the skeleton structure during the skeleton splicing verification process, and secondly obtains the best foam glue 21 layup amount during the skeleton structure foaming verification process; the glued skin and the cured skin are both formal skins, which are used for verification when the skin and the skeleton are bonded and for curing the skin and the skeleton structure respectively.

[0040] Example 2 A method for gluing a complex honeycomb sandwich leading edge structure, comprising the following steps: Step 1: If Figure 1 and Figure 3 As shown, the rear beam 9 is placed on the tooling 18, and the honeycomb core concave platform 1 is matched and glued with the side plate profile 25 of the rear beam 9, and then the end ribs are fixed with the end rib limiter, and then the first isolation membrane, the second isolation membrane and the first skin are placed on the skeleton structure in sequence; Step 2: Rotate the top holding device 19 until the first skin is in contact with the top of the skeleton structure, and then rotate the side shaping device to make the first skin in contact with the side of the skeleton structure; Step 2 uses mechanical pressure to make the first skin completely in contact with the skeleton structure; Step 3: If Figure 3 As shown, the whole is placed in an oven for calibration. After the calibration is completed, the foam glue 21 at the bonding point is compensated according to the calibration results; Step 4: Repeat step 2, and finally perform high-temperature curing on the glue joints of the skeleton structure in an oven; Step 5: If Figure 4As shown, a glue film 22, a first isolation film and a second isolation film are sequentially placed on the honeycomb core 10 of the skeleton structure, and foam glue 21 and a glue film 22 are laid on the end ribs and the end rib limiter at the bonding points between the honeycomb core 10 and the rear beam 9, and the bonding points are separated by a second isolation film. Finally, the second skin is placed on the skeleton structure, and the skeleton structure is vacuum-packaged and subjected to a secondary bonding inspection in an autoclave; wherein the role of the glue film 22 is to use the glue film 22 to bond the second skin to the skeleton structure for the second time; Step 6: Compensate according to the verification result of the secondary bonding verification, place the third skin on the skeleton structure, then place the auxiliary materials, and finally put it into the autoclave for curing. After the curing is completed, remove the auxiliary materials, the top holding device 19, and the end rib limiting device to complete the demoulding; Figure 5 As shown, to remove the top holding device 19 , it is necessary to first rotate the rotating wheel of the top holding device 19 until the holding device leaves the component front edge R zone 28 , and then remove the top holding device 19 .

[0041] Before executing the above steps, the honeycomb core 10, the rear beam 9 and the end ribs can be trial-assembled. The specific trial-assembly steps are: placing the rear beam 9 on the tooling 18, connecting the positioning hole 20 on the rear beam ear piece 26 and the positioning hole 20 on the tooling 18 by positioning pins for positioning, matching the honeycomb core 10 with the honeycomb core concave platform 1 after CNC processing with the side plate profile 25 of the rear beam 9, and then placing the end ribs and the end rib limiting device on the tooling 18, and the end rib limiting device and the tooling 18 are positioned and connected by nuts; the purpose of trial assembly is to check whether the positioning is standard and whether it can be installed normally.

[0042] In step one, the honeycomb core concave platform 1 and the side panel profile 25 of the rear beam 9 are matched and glued by laying and gluing with foam glue 21, and the glued surfaces are isolated by a non-porous isolation membrane 12; the glued surfaces between the honeycomb core 10 and the rear beam 9 and between the honeycomb core 10 and the honeycomb core 10 are laid with foam glue 21, and the glued surfaces are isolated by a non-porous isolation membrane 12; the honeycomb core concave platform 1 and the side panel profile 25 of the rear beam are matched and positioned, and the positioning holes 20 on the tooling 18 overlap with the positioning holes 20 on the rear beam ear pieces 26, and then the positioning pins are inserted into the positioning holes 20.

[0043] In step one, the end ribs include a wing root side end rib 8 and a wing tip side end rib 14, and the end rib limiting device includes a wing root side end rib limiting device 7 and a wing tip side end rib 14 limiting device; the wing root side end rib limiting device 7 and the wing tip side end rib 14 limiting device are both installed on the tooling 18, and the wing root side end rib limiting device 7 is fixedly connected to the wing root side end rib 8, and the wing tip side end rib 14 limiting device is fixedly connected to the wing tip side end rib 14; the wing root side end rib limiting device 7 and the wing tip side end rib 14 limiting device are both positioned and installed on the tooling 18 through the end rib limiting device holes 27 on the tooling 18.

[0044] The first isolation membrane, the second isolation membrane, the first skin, the second skin and the third skin are all positioned and installed through the positioning holes 20 on the rear beam 9; Figure 4 As shown, the skin 23 can be the second skin or the third skin; the depth of the honeycomb core concave platform 1 milled out by the honeycomb core 10 in step one is 2.5~3.5 mm; the depth of the honeycomb core concave platform 1 milled out by the honeycomb core 10 can be 2.5mmm, 3.5 mm, and 3mm.

[0045] The skeleton structure includes a rear beam 9, a honeycomb core 10 and end ribs; both ends of the rear beam 9 are connected to the end ribs.

[0046] The first isolation membrane is a porous isolation membrane 13; the second isolation membrane is a non-porous isolation membrane 12; the first skin is a process skin 11; the second skin is a glued skin; the third skin is a cured skin; the role of the porous isolation membrane 13 is to guide air, so that the small molecular components generated during the curing process can be discharged to prevent the small molecular gas from gathering; the role of the non-porous isolation membrane 12 is to isolate the skin and the adhesive film 22 during the verification process to prevent the inability to check the verification effect after bonding; the role of the process skin 11 is the same as that of the pressure equalizing plate in the autoclave molding process, which maintains the shape of the skeleton structure during the skeleton splicing verification process, and secondly obtains the best foam glue 21 stacking amount during the skeleton structure foaming verification process; the glued skin and the cured skin are both formal skins, which are used for the verification of the bonding of the skin and the skeleton structure and the curing of the skin and the skeleton structure respectively; after the process skin 11 is fitted to the side of the skeleton structure, a feeler gauge is used to check the gap; like Figure 2As shown, in step two, the lateral supporting device includes a lateral supporting device pressure plate 16 and a lateral supporting device base 17, and the lateral supporting device pressure plate 16 is installed on the lateral supporting device base 17; the lateral supporting device base 17 is positioned on the tooling 18 by means of positioning inserts 2 installed on both sides of the tooling 18, and the lateral supporting device base 17 is fixed by installing positioning pins in the lateral supporting device base holes 5 of the positioning inserts 2; the lateral supporting device pressure plate 16 is installed on both sides of the skeleton structure; the tooling 18 includes a tooling assembly 3, and the positioning inserts 2 are installed on both sides of the tooling assembly 3, and the positioning inserts 2 are close to the tooling surface 4.

[0047] The verification parameters in step 3 are: heating to 60~65℃ at a heating rate of no more than 1℃ / min, and keeping the temperature constant for 60~65min; and cooling down after the constant temperature ends.

[0048] After the verification in step three is completed, it is necessary to remove the lateral dimensioning device, the top holding device 19 and the first skin, and then check the verification results; the inspection is carried out by visually inspecting the verification results, and then compensating the foam glue 21 at the joints based on the verification results.

[0049] Before repeating step 2 in step 4, the lateral dimensional device and the top holding device 19 need to be reinstalled again; after repeating step 2, the lateral dimensional device is removed again; Figure 2 As shown, the top holding device 19 is positioned and installed using the top holding device hole 6.

[0050] In step 4, the high-temperature curing is carried out in an oven, wherein the curing parameters of the foam glue 21 are as follows: the temperature is increased to 150-155°C at a heating rate of no more than 1°C / min, and the temperature is kept constant when the temperature reaches 150°C, and the constant temperature time is 4-4.5 hours; the temperature is lowered after the constant temperature ends; during the cooling process from 150°C to 130°C, the cooling rate should be no higher than 1°C / min, and during the cooling process after 130°C, the cooling rate should be no higher than 0.3°C / min, and the pre-foaming process is terminated after the temperature is cooled to 60°C.

[0051] After placing the second skin on the skeleton structure in step five, a putty strip is laid on the side of the top holding device 19, and the top holding device 19 and the skeleton structure are vacuum-sealed together and subjected to a secondary bonding inspection in an autoclave.

[0052] In step six, the auxiliary materials include a non-porous isolation membrane 12, a porous isolation membrane 13, a breathable felt 24, a vacuum bag 29 and a putty strip, and are placed in the order of the non-porous isolation membrane 12, the porous isolation membrane 13, the breathable felt 24, the vacuum bag 29 and the putty strip, and finally the vacuum bag 29 is evacuated for leak detection; the role of the vacuum bag 29 is to seal and protect the parts, and the role of the putty strip is to bond the vacuum bag 29 to the tooling 18.

[0053] The curing parameters in the autoclave in step 6 are as follows: start vacuuming, the vacuum degree is -0.027MPa~-0.033MPa, and the negative pressure in the vacuum bag 29 does not exceed -0.034MPa during the whole process; add external pressure to 0.08~0.1MPa at a pressurization rate of 20~30kPa / min, and maintain the external pressure for 10~30min; then vent to the atmosphere in vacuum, and the rate of venting to the atmosphere in vacuum does not exceed 1kPa / min; after the venting to the atmosphere is completed, continue to increase the tank pressure to 0.18~0.20MPa, and this pressure is used until the curing process is completed; after the pressurization is completed, start heating, and heat to 150~155℃ at a rate of 1~1.5℃ / min, and keep at this temperature for 4h; then heat to 175~180℃ at a rate of 0.5℃ / min, and keep at this temperature for 2h; after the end, cool down at a cooling rate of no more than 0.3℃ / min, and cool at 20~30kPa / min Release the tank pressure at a rapid rate, and when the pressure is released and the temperature drops to 60 ℃, the curing is completed.

[0054] The above description is a detailed description of the preferred feasible embodiment of the present application, but the embodiment is not intended to limit the patent application scope of the present application. All equivalent changes or modified changes made under the technical spirit suggested by the present application should fall within the patent scope covered by the present application.

Claims

1. A method for gluing a complex honeycomb sandwich leading edge structure, characterized in that: The steps include: Step 1: placing the rear beam (9) on the tooling (18), matching and gluing the honeycomb core concave platform (1) and the rear beam side panel profile (25), then fixing the end ribs and the end rib limiting device, and then placing the first isolation membrane, the second isolation membrane and the first skin on the skeleton structure in sequence; Step 2: Rotate the top holding device (19) until the first skin is in contact with the top of the frame structure, and then rotate the side shaping device to make the first skin in contact with the side of the frame structure; Step 3: Place the whole into an oven for calibration. After the calibration is completed, the foam glue (21) at the glue joint is compensated according to the calibration result. Step 4: Repeat step 2, and finally perform high-temperature curing on the glue joints of the skeleton structure in an oven; Step 5: placing a glue film (22), a first isolation film, and a second isolation film on the honeycomb core (10) of the skeleton structure in sequence, and laying a foam glue (21) and a glue film (22) on the end ribs and the end rib limiter at the joints between the honeycomb core (10) and the rear beam (9), and separating the joints with the second isolation film, and finally placing the second skin on the skeleton, and then vacuum-sealing the skeleton structure and performing a secondary bonding inspection in an autoclave; Step 6: Compensate according to the verification results of the secondary bonding verification, place the third skin on the skeleton structure, then place the auxiliary materials, and finally put it into the autoclave for curing. After curing, remove the auxiliary materials, the top holding device (19), and the end rib limit device to complete demoulding.

2. The method for bonding the leading edge structure of a complex honeycomb sandwich according to claim 1, characterized in that: In the step 1, the honeycomb core concave platform (1) and the rear beam side panel profile (25) are matched and glued by laying and gluing the foam glue (21), and each glued surface is isolated by a non-porous isolation film (12); the honeycomb core concave platform (1) and the rear beam side panel profile (25) are matched and positioned by aligning the positioning hole (20) on the tooling (18) with the positioning hole (20) on the rear beam ear piece (26), and then inserting the positioning pin into the positioning hole (20).

3. The method for bonding the leading edge structure of a complex honeycomb sandwich according to claim 1, characterized in that: In step one, the end rib comprises a wing root side end rib (8) and a wing tip side end rib (14), and the end rib limiting device comprises a wing root side end rib limiting device (7) and a wing tip side end rib limiting device (15); the wing root side end rib limiting device (7) and the wing tip side end rib limiting device (15) are both mounted on a tooling (18), and the wing root side end rib limiting device (7) is fixedly connected to the wing root side end rib (8), and the wing tip side end rib limiting device (15) is fixedly connected to the wing tip side end rib (14).

4. The method for bonding the leading edge structure of a complex honeycomb sandwich according to claim 1, characterized in that: The first isolation membrane, the second isolation membrane, the first skin, the second skin and the third skin are all positioned and installed through the positioning holes (20) on the rear beam (9).

5. The method for bonding the leading edge structure of a complex honeycomb sandwich core according to claim 1, characterized in that: The depth of the honeycomb core concave platform (1) milled out of the honeycomb core (10) in step 1 is 2.5-3.5 mm.

6. The method for bonding the leading edge structure of a complex honeycomb sandwich core according to claim 4, characterized in that: The first isolation membrane is a porous isolation membrane (13); the second isolation membrane is a non-porous isolation membrane (12); the first skin is a process skin (11); the second skin is a glued skin; and the third skin is a cured skin.

7. The method for bonding the leading edge structure of a complex honeycomb sandwich according to claim 6, characterized in that: After the technical skin (11) is attached to the side of the frame structure, a feeler gauge is used to check the gap.

8. The method for bonding the leading edge structure of a complex honeycomb sandwich according to claim 1, characterized in that: The skeleton structure comprises a rear beam (9), a honeycomb core (10) and end ribs; both ends of the rear beam (9) are connected to the end ribs.

9. The method for bonding the leading edge structure of a complex honeycomb sandwich according to claim 1, characterized in that: In step 2, the lateral shaping device comprises a lateral shaping device pressure plate (16) and a lateral shaping device base (17), and the lateral shaping device pressure plate (16) is mounted on the lateral shaping device base (17); the lateral shaping device base (17) is positioned and mounted on the tooling (18) via positioning inserts (2) mounted on both sides of the tooling (18); the lateral shaping device pressure plate (16) is mounted on both sides of the skeleton structure.

10. The method for bonding the leading edge structure of a complex honeycomb sandwich according to claim 1, characterized in that: The verification parameters in step 3 are: heating to 60~65℃ at a heating rate of no more than 1℃ / min, and keeping the temperature constant for 60~65min; and cooling down after the constant temperature ends.

11. The method for bonding the leading edge structure of a complex honeycomb sandwich according to claim 1, characterized in that: After the verification in step three is completed, it is necessary to remove the lateral shaping device, the top holding device (19) and the first skin, and then check the verification results.

12. The method for bonding the leading edge structure of a complex honeycomb sandwich according to claim 1, characterized in that: Before repeating step 2 in step 4, the lateral shaping device and the top holding device (19) need to be reinstalled.

13. The method for bonding the leading edge structure of a complex honeycomb sandwich core according to claim 12, characterized in that: After repeating the second step, the lateral dimensioning device is removed again.

14. The method for bonding the leading edge structure of a complex honeycomb sandwich according to claim 1, characterized in that: In step 4, the foam glue (21) is cured at high temperature in an oven, wherein the curing parameters are as follows: the temperature is raised to 150-155°C at a heating rate of no more than 1°C / min, and the temperature is kept constant when the temperature reaches 150°C, and the constant temperature time is 4-4.5 hours; after the constant temperature is completed, the temperature is lowered; during the cooling process from 150°C to 130°C, the cooling rate should be no higher than 1°C / min, and during the cooling process after 130°C, the cooling rate should be no higher than 0.3°C / min, and the pre-foaming process is terminated after the temperature is lowered to 60°C.

15. The method for bonding the leading edge structure of a complex honeycomb sandwich according to claim 1, characterized in that: After the second skin is placed on the frame in step five, a putty strip is laid on the side of the top holding device (19), and the top holding device (19) and the frame structure are vacuum-sealed together and subjected to a secondary bonding inspection in an autoclave.

16. The method for bonding the leading edge structure of a complex honeycomb sandwich according to claim 1, characterized in that: The auxiliary materials in step six include a non-porous isolation film (12), a porous isolation film (13), a breathable felt (24), a vacuum bag (29), and a putty strip, and are placed in the order of the non-porous isolation film (12), the porous isolation film (13), the breathable felt (24), the vacuum bag (29), and the putty strip. Finally, the vacuum bag (29) is evacuated for leak detection.

17. The method for bonding the leading edge structure of a complex honeycomb sandwich according to claim 1, characterized in that: The curing parameters in the autoclave in step 6 are as follows: start evacuating the vacuum to a vacuum degree of -0.027 MPa to -0.033 MPa, and the negative pressure in the vacuum bag (29) does not exceed -0.034 MPa during the whole process; increase the external pressure to 0.08 to 0.1 MPa at a pressurization rate of 20 to 30 kPa / min, and maintain the external pressure for 10 to 30 min; then vent the vacuum to the atmosphere, and the vacuum venting rate does not exceed 1 kPa / min; after the venting is completed, continue to increase the tank pressure to 0.18 to 0.20 MPa, and maintain this pressure until the curing process is completed; after the pressurization is completed, start heating, and heat to 150 to 155 °C at a rate of 1 to 1.5 °C / min, and maintain this temperature for 4 h; then heat to 175 to 180 °C at a rate of 0.5 °C / min, and maintain this temperature for 2 h; after the end, cool at a rate of no more than 0.3 °C / min, and cool at 20 to 30 kPa / min Release the tank pressure at a rapid rate, and when the pressure is released and the temperature drops to 60 ℃, the curing is completed.

18. The method for bonding the leading edge structure of a complex honeycomb sandwich core according to claim 9, characterized in that: The tooling (18) comprises a tooling component (3), and the positioning inserts (2) are mounted on both sides of the tooling component (3).

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