Manufacturing method of ribbed curvature component

Abstract

The invention provides a manufacturing method of a ribbed curvature component. The manufacturing method comprises the steps that a metal bar is machined and formed into a straight profile with a preset cross section through an extrusion technology; machining a connecting hole in the area, where the rib plate is to be arranged, of the straight profile, and machining a protruding part matched with the connecting hole in shape at the position, where the rib plate is to be connected with the straight profile, of the rib plate; the protruding parts on the rib plates are plastically deformed by utilizing a hot upsetting process so as to be connected and fixed in the corresponding connecting holes in the straight sectional material; and stretch bending treatment is conducted on the straight sectional material with the rib plate, so that the rib curvature component with the expected curvature profile is formed.

Description

Technical Field

[0001] This application relates to the field of manufacturing of aircraft structural components, and particularly to a manufacturing method for a ribbed curved member. Background Art

[0002] Aircraft lightweighting can bring lower fuel consumption, higher transport capacity, and a series of green economic benefits. For example, new generation large aircraft such as wide-body airliners use a large amount of carbon fiber composite materials in order to reduce weight and improve economy. Although the current usage of carbon fiber composite materials accounts for 50% of the total weight of structural materials, a large number of load-bearing skeletons connected to composite skins still use metal ribbed curved members considering strength and other aspects.

[0003] A metal ribbed curved member is a high-performance member with a slender shape, a curved feature, and local ribs. Due to the layout position and load-bearing function of the metal ribbed curved member in the aircraft, its forming quality will directly affect the assembly accuracy and service performance of the aircraft. Currently, the manufacturing methods for such metal ribbed curved members are mainly divided into the following four categories:

[0004] (1) Directly manufacture a curved blank including the ribbed member by forging, and then perform numerical control machining on the curved blank to obtain a ribbed curved member with a predetermined shape and size, and perform a hot straightening treatment on the ribbed curved member to calibrate the shape and size;

[0005] (2) Forge, roll, or extrude a straight blank including the ribbed member, then perform numerical control machining on the straight blank to process it into a predetermined size, and then use the hot press bending method to bend the straight blank to obtain a ribbed curved member, and finally perform a hot straightening treatment on the ribbed curved member to calibrate the shape and size;

[0006] (3) Forge, roll, or extrude a straight blank, use linear friction welding to weld the rib plate to the corresponding area of the straight blank to form a straight blank of the ribbed member, then use the hot press bending method to bend the straight blank to obtain a ribbed curved member, and finally perform a hot straightening treatment on the ribbed curved member to calibrate the shape and size;

[0007] (4) Forge, roll, or extrude a straight blank, use additive manufacturing to grow the reinforcing rib from the corresponding area of the straight blank, use the incremental hot press bending method to bend the straight blank including the ribbed member into a ribbed curved member, and finally perform a hot straightening treatment on the ribbed curved member to calibrate the shape and size.

[0008] However, the ribbed curved members manufactured by the above methods all have certain problems, and the material utilization rate is low, and the economic efficiency is poor.

[0009] Specifically, both of the above methods (1) and (2) directly process the ribbed component from the blank, with extremely low material utilization rate, only about 3.5% - 10%. Moreover, the workload of directly machining the special-shaped structural component including the ribbed component is extremely large, and strict requirements are imposed on the performance of the processing equipment. Also, during the press bending process of the above method (2), the ribbed component will undergo non-uniform deformation, which is extremely likely to cause cracking and wrinkling of the reinforcing ribs and unstable internal mechanical properties, thus making it difficult to control the accuracy and strength of the ribbed component.

[0010] Although the above methods (3) and (4) use the method of directly forming the reinforcing ribs to replace machining, improving the raw material utilization rate and effectively reducing the cost. However, whether welding the reinforcing ribs on the profile using linear friction welding or directly generating the reinforcing ribs on the profile using additive technology involves the process of melting and solidification of metal materials, and this process is extremely likely to cause large stress changes.

[0011] Even if it is possible to improve the mechanical property stability in the ribbed curved component generated by the above methods (3) and (4) through subsequent process means, this will undoubtedly increase the process complexity and prolong the part forming cycle, thus greatly increasing the manufacturing cost. Summary of the Invention

[0012] Therefore, in order to overcome the problems of low material utilization rate, high cost, and unstable internal mechanical properties of the existing manufacturing methods of ribbed curvature components, which are extremely prone to cracking or appearing cracks, the present application proposes a new manufacturing method for ribbed curvature components.

[0013] The present application solves the above technical problems through the following technical solutions:

[0014] Specifically, according to one aspect of the present application, there is provided a manufacturing method for a ribbed curvature component, which includes:

[0015] Processing a metal bar into a straight profile with a predetermined cross-section using an extrusion process;

[0016] Machining connection holes in the area of the straight profile where the rib plate is to be placed, and machining protrusions on the rib plate at the position where it is to be joined to the straight profile, with shapes matching the connection holes;

[0017] Using a hot upsetting process to plastically deform the protrusions on the rib plate and connect and fix them in the corresponding connection holes on the straight profile; and

[0018] Performing stretch bending on the straight profile with the rib plate to form a ribbed curvature component with a desired curvature profile.

[0019] In this application, after extruding a straight profile with a relatively regular shape through an extrusion process, the rib plate is connected and fixed to the straight profile. Compared with directly machining a profile member including a rib plate using numerical control technology, it reduces the waste and loss of metal raw materials, improves the material utilization rate, and also reduces the workload of numerical control machining, thereby effectively reducing the production cost.

[0020] Moreover, a ribbed profile is manufactured by firmly combining the rib plate with the straight profile using a hot upsetting process. This process has lower requirements for the surface finish and roughness of the metal straight profile, the processing equipment is simple and easy to operate, and the production cost is lower. Additionally, during the process of changing the shape of the metal by plastic deformation using the hot upsetting process, the metal remains in a solid state throughout, rather than being rapidly melted and then solidified into the desired shape. Since there is no change or mutation in the metal state, the mechanical properties of the manufactured structural member are more stable and controllable.

[0021] According to an embodiment of the present application, the manufacturing method further includes performing micro-shaping and stress relief treatment on the ribbed curvature member after stretch bending.

[0022] According to an embodiment of the present application, the micro-shaping operation includes detecting the outer shape of the ribbed curvature member and tapping the area that does not conform to the desired shape to correct the shape of the ribbed curvature member.

[0023] According to an embodiment of the present application, the stress relief treatment operation includes performing heat treatment on the ribbed curvature member to reduce the stress in the ribbed curvature member and make the stress distribution uniform.

[0024] According to an embodiment of the present application, the cross-section of the connection hole is in the shape of a dovetail. By manufacturing the cross-section of the connection hole in the shape of a dovetail, the aperture of the connection hole tapers upward. In the hot upsetting process, the protruding part of the plastic deformation is positioned in the connection hole and flows and extends around on the bottom surface of the connection hole, thus facilitating the shape matching with the connection hole. Due to the tapered aperture structure, the upper part of the connection hole will block the protruding part after plastic deformation from separating from the connection hole.

[0025] According to an embodiment of the present application, the angle range between the inclined surface and the bottom surface of the connection hole with a dovetail-shaped cross-section is 45° - 80°.

[0026] According to an embodiment of the present application, the protruding part is configured to have the same volume as the connection hole.

[0027] According to an embodiment of the present application, the protruding part is configured to have a height greater than the depth of the connection hole, and a length and width smaller than the corresponding length and width of the connection hole.

[0028] There is a protrusion with a length and width smaller than those of the connection hole, facilitating the placement of the initial protrusion into the connection hole. Moreover, by designing the volume of the protrusion to be the same as that of the connection hole but with a height higher than the depth of the connection hole, it is convenient to make the deformed protrusion completely located in the connection hole through plastic deformation. And through the mutual extrusion and large frictional force between the protrusion and the connection hole, a firm engagement between the protrusion and the connection hole is achieved, thereby connecting and fixing the protrusion in the connection hole of the straight profile.

[0029] According to an embodiment of the present application, the steps of plastically deforming the protrusion on the rib plate by using a hot upsetting process include sleeving an induction heating coil around the protrusion and energizing the induction heating coil to heat and soften the protrusion surrounded by the induction heating coil.

[0030] According to an embodiment of the present application, the steps of plastically deforming the protrusion on the rib plate by using a hot upsetting process further include first clamping and fixing the straight profile on one side or multiple sides away from the rib plate by using a hot upsetting part fixture, then placing the heated and softened protrusion into the connection hole, and pressing the rib plate against the straight profile.

[0031] According to an embodiment of the present application, the steps of plastically deforming the protrusion on the rib plate by using a hot upsetting process further include using pressure to cause the protrusion of the rib plate to plastically deform and flow in the connection hole to fill the connection hole of the straight profile, and pressing against all surfaces of the connection hole to connect and fix in the connection hole of the straight profile. Using the connection hole as a die for the softened and deformed protrusion, the softened protrusion is plastically deformed in the connection hole by pressure to fill the connection hole, thereby preventing the protrusion from disengaging from the connection hole by the shape fit between the connection hole and the deformed protrusion.

[0032] According to an embodiment of the present application, the operation of bending a straight profile with a rib plate includes laying the ribbed straight profile on the curved surface of a bending die, clamping the two ends of the ribbed straight profile by using two bending fixtures respectively, and pulling the two bending fixtures distally along the curved surface contour of the bending die to bend the ribbed straight profile into a ribbed curvature member with a desired curvature profile.

[0033] According to an embodiment of the present application, the cross-section of the straight profile is T-shaped.

[0034] On the basis of conforming to the common knowledge in the art, the above preferred conditions can be combined arbitrarily to obtain various preferred examples of the present application.

[0035] The beneficial technical effects and advantages that can be achieved by the clamping device for the planar biaxial test of composite materials according to the above embodiments of the present application are as follows:

[0036] Manufacturing a ribbed member by connecting and fixing a rib plate to a straight profile can significantly reduce the waste and loss of metal raw materials compared to directly machining the ribbed member, improve the material utilization rate, and also reduce the workload of numerical control machining, thereby effectively reducing the production cost.

[0037] Moreover, by using the hot upsetting process, the protruding part of the rib plate undergoes plastic deformation in the connection hole of the straight profile and is firmly combined with the straight profile. The requirements for the surface finish and roughness of the metal straight profile are low, the processing equipment is simple and easy to operate, and the production cost is low. At the same time, although the protruding part undergoes plastic deformation, it remains solid and does not involve a change in the metal form, so the mechanical properties are more stable.

[0038] In addition, through the appropriate shape design of the protruding part and the connection hole, the deformed protruding part will completely fill the bottom of the connection hole, thereby being firmly positioned and fixed in the connection hole, and the upper part of the connection hole will prevent the protruding part located at the bottom from disengaging from the connection hole. Brief Description of the Drawings

[0039] Figure 1 It is a flowchart of a manufacturing method of a ribbed curvature member according to a preferred embodiment of the present application.

[0040] Figure 2 It is an exemplary schematic diagram of an extruded straight profile according to a preferred embodiment of the present application.

[0041] Figure 3 It is an exemplary schematic diagram of a rib plate with a protruding part according to a preferred embodiment of the present application.

[0042] Figure 4 It is an exemplary schematic diagram of a straight profile with a connection hole according to a preferred embodiment of the present application.

[0043] Figure 5 It is an exemplary schematic diagram of a straight profile with a dovetail-shaped connection hole according to a preferred embodiment of the present application.

[0044] Figure 6 It is an exemplary schematic diagram of heating and softening the protruding part of the rib plate in the hot upsetting process according to a preferred embodiment of the present application.

[0045] Figure 7 It is an exemplary schematic diagram of placing the protruding part of the rib plate in the corresponding connection hole of the straight profile in the hot upsetting process according to a preferred embodiment of the present application.

[0046] Figure 8 It is an exemplary schematic diagram of applying pressure to the rib plate in the hot upsetting process according to a preferred embodiment of the present application.

[0047] Figure 9Exemplary schematic diagram showing the protruding part of the ribbed plate deforming to fill the connection hole on the straight profile in the hot upsetting process according to a preferred embodiment of the present application.

[0048] Figure 10 Exemplary schematic diagram of a straight profile with a ribbed plate according to a preferred embodiment of the present application.

[0049] Figure 11 Exemplary schematic diagram showing stretch-bending treatment of a straight profile with a ribbed plate according to a preferred embodiment of the present application.

[0050] Figure 12 Exemplary schematic diagram of a ribbed curvature member according to a preferred embodiment of the present application. Detailed implementation manners

[0051] To make the objectives, technical solutions and advantages of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings showing multiple embodiments according to the present application. It should be understood that all other embodiments obtained by those of ordinary skill in the art based on the embodiments described in the present application without creative efforts will fall within the scope of protection of the present application.

[0052] As Figure 1 shown, the present application provides a manufacturing method for manufacturing a ribbed curvature member, which includes:

[0053] Step 1, extruding and forming a straight profile, using an extrusion process to process a metal bar into a straight profile 1 with a predetermined cross-section as Figure 2 shown;

[0054] Step 2, machining a connection hole and a protruding part, machining a connection hole 11 as Figure 3 shown in the area of the straight profile 1 where the ribbed plate 2 is to be installed, and machining a protruding part 21 with a shape matching the connection hole 11 at the position where the ribbed plate 2 is to be joined to the straight profile 1; Figure 4

[0055] Step 3, as Figures 6 to 9 shown, connecting and fixing the protruding part 21 in the connection hole 11, using a hot upsetting process to plastically deform the protruding part 21 on the ribbed plate 2 and connect and fix it in the corresponding connection hole 11 on the straight profile 1; and

[0056] Figure 11 Step 4, as Figure 12 shown, stretch-bending and forming a ribbed curvature member, performing stretch-bending treatment on the straight profile 3 with a ribbed plate to form a ribbed curvature member 4 with a desired curvature profile as shown.

[0057] ​In Step 1, a relatively regular straight profile 1 is extruded through an extrusion process, such as Figure 2 the straight profile 1 with a T-shaped cross-section as shown. Compared with directly machining a profile member including rib plates using numerical control technology, it reduces the waste and loss of metal raw materials, improves the material utilization rate, and also reduces the workload of numerical control machining, thus effectively reducing the production cost.

[0058] In Step 2, as Figures 3 to 5 shown, the cross-section of the connecting hole 11 is made into a dovetail shape, and the protruding part 21 of the rib plate 2 is made into a rectangular shape. Moreover, the volume of the protruding part 21 is equal to that of the connecting hole 11, but the height is greater than the depth of the connecting hole 11, and the length and width are smaller than the length and width of the corresponding connecting hole 11.

[0059] In Step 2, the protruding part 21 with a length and width smaller than those of the connecting hole 11 facilitates placing the initial protruding part 21 into the connecting hole 11. By designing the volume of the protruding part 21 to be the same as that of the connecting hole 11 but with a height higher than the depth of the connecting hole 11, it is convenient to make the deformed protruding part 21 completely located in the connecting hole 11 through plastic deformation. And through the mutual extrusion and large frictional force between the protruding part 21 and the connecting hole 11, a firm joint between the protruding part 21 and the connecting hole 11 is achieved, thereby connecting and fixing the protruding part 21 in the connecting hole 11 of the straight profile 1.

[0060] The cross-section of the connecting hole 11 is made into a dovetail shape, and the aperture of the connecting hole 11 tapers upward. In the hot upsetting process, after the plastically deformed protruding part 21 is positioned in the connecting hole 11, under the action of pressure, as Figure 9 shown by the arrow in, it flows and extends around on the bottom surface of the connecting hole 11, thus facilitating the shape matching with the connecting hole 11. Due to the tapered aperture structure, after cooling and forming, the upper part (the opening part) of the connecting hole 11 will prevent the plastically deformed protruding part 21 from separating from the connecting hole 11.

[0061] Preferably, as Figure 5 shown, the angle α formed between the inclined surface and the bottom surface of the connecting hole 11 with a dovetail-shaped cross-section ranges from 45° to 80°.

[0062] Alternatively, the position and number of the connecting holes 11 can be determined according to the placement position of the rib plate 2 on the straight profile 1 and the designed dimensions, such that the rib plate 2 can be fixed on a predetermined area of the straight profile 1 through the connection and fixation of the protruding portion 21 in the connecting holes 11. Optionally, the cross-section of the connecting holes 11 can be other shapes, and the cross-section of the protruding portion 21 can also be other shapes, as long as in the initial state, the protruding portion 21 can be placed in the connecting holes 11, and during the plastic deformation of the hot upsetting process, the protruding portion 21 can be pressed into and filled with the connecting holes 11 and be connected and fixed to the straight profile 1.

[0063] In step three, as Figure 6 shown, the steps of causing plastic deformation of the protruding portion 21 on the rib plate 2 by using the hot upsetting process include sleeving the induction heating coil 22 around the protruding portion 21 and energizing the induction heating coil 22 to heat and soften the protruding portion 21 surrounded by the induction heating coil.

[0064] Moreover, as Figure 7 and 8 shown, the steps of causing plastic deformation of the protruding portion 21 on the rib plate 2 by using the hot upsetting process further include first clamping and fixing the straight profile 1 on one side or multiple sides away from the rib plate 2 by using the hot upsetting part fixture 23, then placing the heated and softened protruding portion 21 into the connecting holes 11, and pressing the rib plate 2 against the straight profile 1 from the side where the rib plate does not contact the straight profile 1 by using the pressures F1 and F2 respectively.

[0065] As Figure 8 and 9 shown, the pressures F1 and F2 cause the protruding portion 21 of the rib plate 2 to undergo plastic deformation and flow to fill the connecting holes 11, and press against all the surfaces in the connecting holes 11 and be connected and fixed in the connecting holes 11 of the straight profile 1. Taking the connecting holes 11 as the die for the softened deformation of the protruding portion 21, the softened protruding portion 21 undergoes plastic deformation in the connecting holes 11 under pressure to fill the connecting holes, thereby preventing the protruding portion 21 from detaching and separating from the connecting holes 11 by virtue of the shape fit between the connecting holes 11 and the deformed protruding portion 21, and finally forming the straight profile 3 with a rib plate as Figure 10 shown.

[0066] Manufacturing the straight profile 3 with a rib plate by firmly bonding the rib plate 2 and the straight profile 1 using the hot upsetting process has lower requirements for the surface finish and roughness of the metal straight profile, the processing equipment is simple and easy to operate, and the production cost is lower.

[0067] Moreover, during the process of changing the shape of the metal by using plastic deformation through the hot upsetting process, the metal remains in a solid state all the time, rather than being rapidly melted and then solidified into the desired shape of the metal. Therefore, there is no change in the metal form, and the mechanical properties are more stable.

[0068] In Step 4, as Figure 11 shown, the stretch bending process for the straight profile with stiffeners includes laying the straight profile 3 with stiffeners on the curved surface 42 of the stretch bending die 41, clamping both ends of the straight profile 3 with stiffeners using two stretch bending clamps 43 respectively, and applying tensile forces F3 and F4 to pull the two stretch bending clamps 43 along the contour of the curved surface 42 of the stretch bending die 41 towards the far side to bend the straight profile 3 with stiffeners into a Figure 12 stiffened curved member 4 with a desired curvature profile as shown.

[0069] Optionally, the manufacturing method may further include performing simple subsequent processes such as micro-shaping and stress relief on the stiffened curved member 4 after the stretch bending process. Through micro-shaping, the shape and dimensions of the finally obtained stiffened curved member 4 can be ensured, thus guaranteeing the proper installation and assembly of the stiffened curved member 4 on the aircraft fuselage. Moreover, the stress inside the stiffened curved member 4 is further reduced after the stress relief treatment, thereby effectively improving the mechanical properties of the stiffened curved member.

[0070] Specifically, the micro-shaping operation may include detecting the outer shape of the stiffened curved member 4 and knocking on the areas that do not conform to the desired shape to correct the shape of the stiffened curved member 4.

[0071] The stress relief treatment operation includes heat-treating the stiffened curved member 4 to reduce the stress in the stiffened curved member 4 and make the stress distribution uniform, finally obtaining a stiffened curved member with small and uniform internal stress and having the desired shape and dimensions.

[0072] Generally speaking, the manufacturing method provided in this application adopts a combined process of profile extrusion for blanking, machining to make dovetail holes and stiffeners, plastic connection of profile stiffeners, and stretch bending of profiled bars with stiffeners. By using plastic forming means, a stiffened curved member with the desired shape and dimensions, small internal stress gradient, and stable mechanical properties can be manufactured.

[0073] This manufacturing method manufactures the stiffened member by connecting and fixing the stiffeners to the straight profile. Compared with directly machining the stiffened member, it can greatly reduce the waste and loss of metal raw materials, improve the material utilization rate, and also reduce the workload of numerical control machining, thus effectively reducing the production cost.

[0074] Moreover, by using the hot upsetting process, the protruding part of the stiffener undergoes plastic deformation in the connection hole of the straight profile and firmly combines with the straight profile, with low requirements for the surface finish and roughness of the metal straight profile, simple and easy-to-operate processing equipment, and low production cost.

[0075] Meanwhile, during the process of connecting and fixing the protruding part of the rib plate to the connection hole, although the protruding part undergoes plastic deformation, it remains in a solid state throughout, without involving any change or mutation in the metal form. Therefore, the internal stress change is relatively small, which can effectively ensure the mechanical property stability of the ribbed component after forming. In addition, through the proper shape design of the protruding part and the connection hole, the deformed protruding part will completely fill the bottom of the connection hole, thus being firmly positioned and fixed in the connection hole. Moreover, the upper part of the connection hole will prevent the protruding part at the bottom from disengaging from the connection hole, thereby achieving a simple, firm, and reliable joint between the rib plate and the straight profile.

[0076] In addition, the manufacturing method of the ribbed curvature component provided by the present application improves the material utilization rate, reduces the manufacturing cost, and improves the forming accuracy, and conveniently, simply, and quickly realizes the low-cost precise manufacturing of the high-performance structure of the ribbed curvature component by using advanced processes.

[0077] Although the specific implementation manners of the present application have been described above, those skilled in the art should understand that these are only examples. The protection scope of the present application is defined by the appended claims. Without departing from the principle and essence of the present application, those skilled in the art can make various changes or modifications to these implementation manners, but these changes and modifications all fall within the protection scope of the present application.

Claims

1. A method for manufacturing a ribbed curvature member, wherein: The manufacturing method comprises: The metal bar is formed into a straight profile with a predetermined cross section by an extrusion process; A connecting hole is machined on the area of ​​the straight profile where the rib plate is to be placed, and a protrusion having a shape matching the connecting hole is machined on the part of the rib plate that is to be joined to the straight profile; Using a hot upsetting process, the protrusions on the rib plate are plastically deformed so as to be connected and fixed in corresponding connection holes on the straight profile; and The straight profile with the rib plate is subjected to a stretch-bending process to form a ribbed curvature component with a desired curvature profile.

2. The manufacturing method according to claim 1, wherein: The manufacturing method further comprises: After the stretching and bending treatment, the ribbed curvature component is subjected to slight shape correction and stress relief treatment.

3. The manufacturing method according to claim 2, wherein: The micro-calibration operation includes: The outer shape of the ribbed curvature component is detected, and the area that does not meet the expected shape is tapped to correct the shape of the ribbed curvature component.

4. The manufacturing method according to claim 2, wherein: The stress relief treatment operation comprises: The ribbed curvature component is heat treated to reduce stress in the ribbed curvature component and make the stress distribution uniform.

5. The manufacturing method according to claim 1, wherein: The cross section of the connecting hole is dovetail-shaped.

6. The manufacturing method according to claim 5, wherein: The angle formed between the inclined surface and the bottom surface of the connecting hole having the dovetail-shaped cross section is in the range of 45°-80°.

7. The manufacturing method according to claim 1, wherein: The protrusion is configured to have a volume equal to that of the connection hole.

8. The manufacturing method according to claim 7, wherein: The protrusion is configured to have a height greater than a depth of the connection hole, and a length and a width smaller than a length and a width of the corresponding connection hole.

9. The manufacturing method according to claim 1, wherein: The step of using the hot upsetting process to plastically deform the protruding portion on the rib plate comprises: An induction heating coil is sleeved around the protrusion, and power is supplied to the induction heating coil to heat and soften the protrusion surrounded by the induction heating coil.

10. The manufacturing method according to claim 9, wherein: The step of using the hot upsetting process to plastically deform the protruding portion on the rib plate also includes: Firstly, a hot upsetting part fixture is used to clamp and fix the straight profile on one or more sides of the straight profile away from the rib plate, and then the heated and softened protrusion is placed in the connecting hole, and the rib plate is pressed toward the straight profile.

11. The manufacturing method according to claim 10, wherein: The step of using the hot upsetting process to plastically deform the protruding portion on the rib plate also includes: The protruding portion of the rib plate undergoes plastic deformation under pressure, flows to fill the connection hole of the straight profile, and presses against all surfaces of the connection hole to be connected and fixed in the connection hole of the straight profile.

12. The manufacturing method according to claim 1, wherein: The operation of bending the straight profile with the rib plate includes: Lay the straight profile with ribs on the curved surface of the stretch-bending die, use two stretch-bending clamps to clamp the two ends of the straight profile with ribs respectively, and pull the two stretch-bending clamps toward the far side along the curved surface contour of the stretch-bending die respectively, so as to bend the straight profile with ribs into a ribbed curvature component with a desired curvature contour.

13. A method of manufacturing according to any one of the preceding claims, wherein: The cross section of the straight profile is T-shaped.

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