Composite material wallboard curing deformation control method based on excessive patching of stringer

Abstract

The invention belongs to the field of composite material manufacturing and curing deformation control, and particularly relates to a composite material wallboard curing deformation control method based on stringer excessive modification, which comprises the following steps: preparing springback angles L at two sides of a T-shaped stringer according to a conventional process; determining an included angle corresponding to two sides L of the T-shaped stringer on the compensation molded surface of the T-shaped stringer forming die; manufacturing a T-shaped stringer forming die and a T-shaped stringer stiffened wall plate forming cementing die; laying and curing of the T-shaped stringer are completed on the T-shaped stringer mold; paving and compacting of the skin are completed on a forming glue joint mold; the T-shaped stringer is assembled on the skin prefabricated body, and an adhesive film is placed between the T-shaped stringer and the skin; a T-shaped stringer and skin combined body is subjected to bag making, curing and milling, manufacturing of the wallboard is completed, the deformation state of the dry stringer and the wet skin in the curing process is adjusted through a T-shaped stringer excessive modification method when the dry stringer and the wet skin are glued, and accurate control over curing deformation of the stringer stiffened wallboard is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of composite material manufacturing and curing deformation control, and in particular relates to a composite material wallboard curing deformation control method based on excessive shaping of long stringers. Background Art

[0002] Fiber-reinforced composites are increasingly being used in aircraft due to their high specific stiffness and strength, as well as their design flexibility. Primary load-bearing components, such as aviation composite wings, are key components in increasing the use of composite materials in aircraft, improving the operational performance of military aircraft and the fuel economy of civilian aircraft.

[0003] Composite wing panels usually adopt a T-shaped long stringer reinforced structure. Due to structural asymmetry, mismatch of thermal expansion properties and other reasons, wing panels manufactured using the autoclave molding process will inevitably experience curing deformation after curing, affecting the panel assembly and service performance.

[0004] Therefore, controlling the curing deformation of wing panels has become a key challenge in aircraft manufacturing. Due to their large size and complex thickness variations, methods for controlling curing deformation of wing panels are limited. Common methods such as optimizing curing process parameters and process solutions are ineffective in controlling curing deformation of wing panels. Summary of the Invention

[0005] In order to solve the problems of difficult assembly and reduced service performance caused by the curing deformation of T-type long stringer reinforced wall panels, the present invention provides a method for controlling the curing deformation of composite material wall panels based on excessive shaping of long stringers. The excessive shaping method of T-type long stringers is used to adjust the deformation state of the dry long stringers and the wet skin when being glued during the curing process, thereby achieving precise control of the curing deformation of the long stringer reinforced wall panels.

[0006] The technical solution of the present invention is: A method for controlling curing deformation of composite material wall panels based on excessive stringer shaping, the method comprising: Step 1: Obtain the design angles L on both sides of the T-shaped long stringer, and determine the rebound angles L on both sides of the T-shaped long stringer prepared according to a conventional process; Step 2: determining the angles L on both sides of the T-shaped long stringer on the compensation surface of the T-shaped long stringer forming mold according to the designed angles L on both sides of the T-shaped long stringer and the rebound angle; Step 3: According to the angle L on both sides of the T-shaped long stringer corresponding to the compensation surface of the T-shaped long stringer forming mold in step 2, a T-shaped long stringer forming mold and a forming and gluing mold for the T-shaped long stringer reinforced wall panel are manufactured; Step 4, completing the laying and curing of the T-shaped long stringer on the T-shaped long stringer mold; Step 5, completing the laying and compacting of the skin on the forming and gluing mold; Step 6: Assemble the T-shaped long stringer prepared in step 4 onto the skin preform in step 5, and place an adhesive film between the T-shaped long stringer and the skin; Step 7, bagging, curing, and milling the T-shaped long stringer and skin assembly of step 6 to complete the manufacture of the wall panel.

[0007] Furthermore, in step 1, the springback angles L on both sides of the T-shaped long stringer prepared according to conventional processes are determined, specifically: Prepare multiple test pieces with the same material, ply thickness, and manufacturing process as the T-shaped long stringer; measure the difference between the angle L on both sides of the test piece and the designed angle of the T-shaped long stringer, and average the multiple differences to obtain the rebound angle.

[0008] Furthermore, step 2 is specifically as follows: Determine the angles L on both sides of the T-shaped long stringer on the compensation surface of the T-shaped long stringer forming mold: 、 ; in, is the design angle of L on the left side of the T-shaped long girder, is the design angle of L on the right side of the T-shaped long girder, Compensate the angle on the left side of the T-shaped long stringer forming die. To compensate for the angle on the right side of the T-shaped long stringer forming die, is the rebound angle of the left side L of the T-type long stringer, is the rebound angle of the right side L of the T-type long beam, i =1, 2, …, n, where n is the number of T-beams in the panel, is the adjustment coefficient on the left side, is the adjustment factor on the right.

[0009] Furthermore, the adjustment coefficient R is determined according to the T-type girder spacing, T-type girder structure, and skin thickness, and its value range is (1, 2.5].

[0010] Furthermore, since the T-shaped long stringer has thickness or structural variations along its length, a discrete modeling method is used to determine the compensation profile of the T-shaped long stringer forming die.

[0011] Furthermore, step 4 is specifically as follows: The T-shaped long stringers are laid and cured in sequence on the T-shaped long stringer mold according to the molding process and the laying sequence, and are then milled to the net size.

[0012] Furthermore, step 5 is specifically as follows: The wall panel skin is laid out in the forming and bonding mold in the order of layering, and the skin preform is compacted. The compaction method is vacuum compaction, wire laying machine compaction, autoclave compaction, or a combination of different compaction methods.

[0013] Furthermore, in step 6, after the assembly of the T-shaped long stringer and the skin preform is completed, the T-shaped long stringer is positioned using an auxiliary positioning mold.

[0014] The beneficial effects of the present application are as follows: by fully combining the curing deformation characteristics of the long-beam reinforced wall panel, the T-shaped long beam is manufactured through excessive compensation of the forming mold surface, so that during the curing process of the pre-manufactured dry long beam and the wet skin, the end mechanical deformation is generated under the action of the curing pressure, thereby offsetting the thermal deformation of the opening caused by the temperature increase during the curing process of the dry long beam until it is completely bonded to the skin. After the curing is completed, the mechanical deformation of the opening caused by the release of the curing pressure on the dry long beam will offset the thermal deformation of the end caused by the temperature drop, thereby achieving precise control of the curing deformation of the T-shaped long beam reinforced wall panel by adjusting the coefficient R. The present invention has a good implementation effect on the control of the curing deformation of the wall panel with weaker rigidity along the direction perpendicular to the long beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the structure of the T-shaped long girder reinforced wall panel required to be manufactured in an embodiment of the present invention; Figure 2 Schematic diagram of a cross section of a long stringer in an embodiment of the present invention; Figure 3 It is a schematic diagram of the structure after the long stringer and the skin are assembled on the wall panel forming and gluing mold in an embodiment of the present invention.

[0016] Among them: 1 is the T-shaped long girder reinforced wall panel to be manufactured, 2 is the T-shaped long girder in the reinforced wall panel, 21 is the T-shaped long girder manufactured using a forming mold based on the theoretical outer surface of the long girder, 22 is the T-shaped long girder manufactured after excessive compensation of the mold surface, 3 is the skin in the reinforced wall panel (cured), 31 is the skin that has been completed and not yet cured, and 4 is the forming and gluing mold of the long girder reinforced wall panel. DETAILED DESCRIPTION

[0017] The present application is described in further detail below with reference to the accompanying drawings of the embodiments.

[0018] The embodiment of the present invention provides a method for controlling the curing deformation of composite wall panels based on excessive shaping of long stringers. The method is applicable to thermosetting resin-based composite T-shaped long stringer reinforced wall panels manufactured by autoclave molding process. Figure 1-3 , including the following steps: Step 1: The design angles of L on both sides are and The rebound angles of the T-type long stringer are and , based on the formula 、 Complete the compensation surface modeling of the T-shaped long stringer forming mold, α is the nominal angle L on both sides of the T-shaped long beam, β The angle between the two L corresponding to the mold compensation surface, i =1, 2, …, n (n is the number of stringers in the panel), l and r Representing the left and right sides respectively, R is the adjustment factor.

[0019] Step 2: Use the compensation profile to design and manufacture the forming molds of each T-shaped long stringer, and use the wall panel theory to design the profile to design and manufacture the forming and gluing molds of the long stringer reinforced wall panel.

[0020] Step 3: According to the molding process and laying sequence, each T-shaped long stringer is laid and cured in sequence on the long stringer forming mold in step 2, and then milled to the net size.

[0021] Step 4: Complete the laying of the wall panel skin layers on the forming and bonding mold in step 2 according to the order of the wall panel skin layers, and fully compact the skin preform.

[0022] Step 5: According to the wall panel design plan, assemble the long stringers prepared in step 3 to the theoretical positions on the skin preform in step 4 in sequence, and place an adhesive film compatible with the prepreg system between the long stringers and the skin.

[0023] Step 6: The long stringer-skin assembly obtained in step 5 is subjected to bagging, curing, milling and other processes to complete the wall panel manufacturing.

[0024] In step 1, the compensation surface modeling can be determined by experimental observation, finite element simulation, analytical solution analysis and other methods.

[0025] In step 1, the compensation profile modeling should adopt discrete modeling and other methods to fully consider the changes in thickness, structure, etc. of the long stringer along the length direction.

[0026] In step 1, the adjustment coefficient R should be determined based on the panel structural parameters such as the girder spacing, girder structure, and skin thickness, and its value range is (1, 2.5].

[0027] In step 4, the compaction method may be vacuum compaction, fiber placement machine compaction, autoclave compaction, etc., or a combination of different compaction methods.

[0028] In step 6, after the stringer-skin combination is completed, an auxiliary positioning mold should be used to position the stringer to prevent position deviation during the curing process.

[0029] Example An embodiment of the present invention provides a method for controlling the curing deformation of composite wall panels based on excessive stringer shaping. The method is applicable to thermosetting resin-based composite T-shaped stringer reinforced wall panels manufactured by an autoclave molding process, and includes the following steps: Step 1: For the T-shaped long girder reinforced wall panel 1 to be manufactured, it includes three T-shaped long girder 2 and skin 3, where the angle between the two L of the T-shaped long girder is Through finite element simulation, it is found that if the long stringer theoretical outline is used to design and manufacture the forming mold of the T-shaped long stringer, the T-shaped long stringer 21 manufactured based on the mold will rebound after the curing is completed, and the rebound angle is Since the thickness and structure of the T-shaped long stringer in this embodiment remain unchanged along the length direction, no discrete processing is required in the mold surface compensation modeling process. Taking R=2 for excessive springback angle compensation, the angle of the L-shaped surface on both sides of the T-shaped long stringer in the mold surface compensation model can be obtained. for .

[0030] Step 2: Based on the compensation profile, a T-shaped long stringer forming mold is designed and manufactured, and based on the design profile of the long stringer reinforced wall panel 1 , a wall panel forming and gluing mold 4 is designed and manufactured.

[0031] Step 3: Following the T-beam forming process, lay the layers in the designed layup sequence on the beam forming mold in Step 2, then solidify and mill to size. This method manufactures the three T-beams 22 required for the T-beam reinforced wall panel 1 to compensate for the excess trimming.

[0032] Step 4: Lay the skin 31 on the forming and bonding mold 4 according to the skin design layer, and put it into the autoclave for cold compaction.

[0033] Step 5: Assemble the long stringers 22 prepared in step 3 to the theoretical positions on the skin preform 31 prepared in step 4 in sequence, and place an adhesive film compatible with the prepreg system between the long stringers 22 and the skin preform 31 .

[0034] Step 6: The long stringer-skin assembly obtained in step 5 is subjected to bagging, curing, milling and other processes to complete the wall panel manufacturing.

[0035] The technical solution of the present invention fully combines the characteristics of the curing deformation of the long stringer reinforced wall panel, and manufactures the T-shaped long stringer through excessive compensation of the forming mold surface, so that the pre-manufactured dry long stringer and the wet skin will produce mechanical deformation of the end under the action of the curing pressure during the curing process, thereby offsetting the thermal deformation of the opening caused by the temperature increase during the curing process of the dry long stringer until it is completely bonded to the skin. After the curing is completed, the mechanical deformation of the opening caused by the release of the curing pressure on the dry long stringer will offset the thermal deformation of the end caused by the temperature drop, thereby achieving precise control of the curing deformation of the T-shaped long stringer reinforced wall panel by adjusting the change of the coefficient R. The present invention has a good implementation effect on the control of the curing deformation of the wall panel with weaker rigidity along the direction perpendicular to the long stringer.

[0036] Those skilled in the art will appreciate that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for controlling the curing deformation of composite wall panels based on excessive shaping of long girders, characterized in that: The method comprises: Step 1: Obtain the design angles L of the two sides of the T-shaped long stringer, and determine the rebound angles L of the two sides of the T-shaped long stringer obtained according to a conventional manufacturing process; Step 2: determining the angles L on both sides of the T-shaped long stringer on the compensation surface of the T-shaped long stringer forming mold according to the designed angles L on both sides of the T-shaped long stringer and the rebound angle; Step 3: According to the angle L on both sides of the T-shaped long stringer corresponding to the compensation surface of the T-shaped long stringer forming mold in step 2, a T-shaped long stringer forming mold and a forming and gluing mold for the T-shaped long stringer reinforced wall panel are manufactured; Step 4, completing the laying and curing of the T-shaped long stringer on the T-shaped long stringer mold; Step 5, completing the laying and compacting of the skin on the forming and gluing mold; Step 6: Assemble the T-shaped long stringer prepared in step 4 onto the skin preform in step 5, and place an adhesive film between the T-shaped long stringer and the skin; Step 7, bagging, curing, and milling the T-shaped long stringer and skin assembly of step 6 to complete the manufacture of the wall panel.

2. The method for controlling curing deformation of composite material wall panels based on excessive stringer shaping according to claim 1, characterized in that: In step 1, the springback angles L on both sides of the T-shaped long stringer prepared according to conventional processes are determined, specifically: Prepare multiple test pieces with the same material, ply thickness, and manufacturing process as the T-shaped long stringer; measure the difference between the angle L on both sides of the test piece and the designed angle of the T-shaped long stringer, and average the multiple differences to obtain the rebound angle.

3. The method for controlling curing deformation of composite wall panels based on excessive stringer shaping according to claim 1, characterized in that: Step 2 is as follows: Determine the angles L on both sides of the T-shaped long stringer on the compensation surface of the T-shaped long stringer forming mold: 、 ; in, is the design angle of L on the left side of the T-shaped long girder, is the design angle of L on the right side of the T-shaped long girder, Compensate the angle on the left side of the T-shaped long stringer forming die. To compensate for the angle on the right side of the T-shaped long stringer forming die, is the rebound angle of the left side L of the T-type long stringer, is the rebound angle of the right side L of the T-type long beam, i =1, 2, …, n, where n is the number of T-beams in the panel, is the adjustment coefficient on the left side, is the adjustment factor on the right.

4. The method for controlling curing deformation of composite material wall panels based on excessive stringer shaping according to claim 3, characterized in that: The adjustment coefficient R is determined according to the T-beam spacing, T-beam structure, and skin thickness, and its value range is (1, 2.5].

5. The method for controlling curing deformation of composite material wall panels based on excessive stringer shaping according to claim 3, characterized in that: Since the T-shaped long stringer has thickness or structure changes along the length direction, the discrete modeling method is used to determine the compensation surface of the T-shaped long stringer forming die.

6. The method for controlling curing deformation of composite material wall panels based on excessive stringer shaping according to claim 1, characterized in that: Step 4 is as follows: The T-shaped long stringers are laid and cured in sequence on the T-shaped long stringer mold according to the molding process and the laying sequence, and are then milled to the net size.

7. The method for controlling curing deformation of composite wall panels based on excessive stringer shaping according to claim 1, characterized in that: Step 5 is as follows: The wall panel skin is laid out in the forming and bonding mold in the order of layering, and the skin preform is compacted. The compaction method is vacuum compaction, wire laying machine compaction, autoclave compaction, or a combination of different compaction methods.

8. The method for controlling curing deformation of composite material wall panels based on excessive stringer shaping according to claim 1, characterized in that: In step 6, after the assembly of the T-shaped long stringer and the skin preform is completed, the T-shaped long stringer is positioned using an auxiliary positioning mold.

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