A method for press bending of a grid-ribbed wall panel sandwich containing local bosses

Abstract

The grid rib wallboard core sandwich bending forming method with local boss of the present application mainly adopts core sandwich bending forming on the boss-containing to-be-formed area of the wallboard, that is, placing upper and lower pads on the upper and lower surfaces of the boss-containing to-be-formed area respectively and then performing three-point bending. When the present application is used for the bending forming of the grid rib wallboard with local boss, the boss periphery of the wallboard can be prevented from being pressed to form a crease or crack, and no filler is needed, so that the forming efficiency of such wallboard can be effectively improved, and the forming manufacturing cost thereof can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of metal plastic forming, in particular to a grid rib wallboard sandwich press bending forming method containing local bosses. BACKGROUND

[0002] The grid rib wallboard is a load-bearing component widely used on aerospace vehicles, and is also an important part of the aerodynamic shape of the vehicle. It is usually manufactured by first milling and cutting the internal grid rib structure, and then press bending the curved surface shape in sections. In addition to the skin and rib two basic structural elements, different parts of the grid rib wallboard often have local bosses of various forms and sizes for installing instruments, equipment or functional components. The presence of the boss significantly increases the local rigidity of the wallboard. When the wallboard is press bent, there is a large difference in deformation resistance between the local boss and the skin connected thereto, which easily causes serious uneven deformation. The transition position between the boss and the skin is extremely prone to creases and even cracking during deformation, making the forming very difficult. To solve this problem, the traditional method is to add filler to the grid inside the wallboard, so that the thickness of the skin and the filler after being stacked is basically the same as the boss, reducing the thickness and stiffness difference between the two, and then press bending, and then removing the filler. When using this filler press bending forming method, a large amount of cutting, filling and removal of fillers is involved, which not only consumes a lot of time, but also increases the cost of wallboard forming and manufacturing. SUMMARY

[0003] The purpose of the present application is to provide a grid rib wallboard sandwich press bending forming method containing local bosses, which solves the problem of creases or cracking at the transition position between the boss and the skin under pressure, and compared with the filler press bending forming method, the present method can effectively improve the forming efficiency of the grid rib wallboard containing local bosses and reduce the cost of wallboard forming.

[0004] In order to achieve the above purpose, the present application provides a grid rib wallboard sandwich press bending forming method containing local bosses, which uses sandwich press bending forming on the to-be-formed area containing the boss on the wallboard, that is, placing upper and lower pads on the upper and lower surfaces of the to-be-formed area containing the boss before three-point press bending.

[0005] The above-mentioned sandwich bending forming method for a mesh-reinforced wall panel with local bosses includes the following forming method: (a) dividing the planar mesh-reinforced wall panel to be formed into several forming areas, the forming areas being divided into two categories, one containing bosses and the other not containing bosses, and measuring the width of each forming area containing bosses; (b) designing upper and lower pads for each forming area containing bosses, wherein the maximum width of any forming area containing bosses is less than the width of the upper pad and less than the span width of the two lower support molds during three-point bending of the mesh-reinforced wall panel, the width of the lower pad is greater than the span width of the two lower support molds during three-point bending of the mesh-reinforced wall panel, and the lengths of both the upper and lower pads are greater than the lengths of the upper and lower pads during three-point bending of the mesh-reinforced wall panel. (c) Perform finite element simulation of bending forming on each area to be formed containing bosses on the planar mesh rib wall plate to determine the thickness of the upper and lower pads required to ensure that each area to be formed containing bosses is free of creases and cracks after bending, and the load magnitude when bending the outer surface of each area to be formed containing bosses to the target curvature after placing the pads; (d) Cut the upper and lower pads using large-format spring steel plates or titanium alloy plates as raw materials; (e) Perform area-by-area bending forming on the planar mesh rib wall plate to be formed. During the bending process, place the upper and lower pads on the upper and lower surfaces of each area to be formed containing bosses, and apply the corresponding bending load according to the simulation results.

[0006] In the above-mentioned method for forming a sandwich core of a mesh-ribbed wall panel with local bosses, in step (a), the length direction of the upper bending die is set as the X-axis, the bending step direction is set as the Y-axis, and when dividing the area to be formed, adjacent bosses in the Y-axis direction can be divided into the same area to be formed; the range of the area to be formed including the bosses is the smallest area that encloses each boss in the area to be formed.

[0007] In the above-mentioned sandwich bending forming method for mesh-reinforced wall panels with local bosses, the width of the lower pad is 60mm to 100mm wider than the span width of the two lower support dies; the lengths of the upper and lower pads are both 100mm to 200mm longer than the length of the upper bending die.

[0008] In the above-mentioned sandwich bending forming method for mesh-reinforced wall panels with local bosses, the spring steel plate material is 60Si2Mn or 65Mn.

[0009] In the above-mentioned sandwich bending forming method for mesh-reinforced wall panels with local bosses, in step (d), each forming area containing bosses shares a set of upper and lower pads. The width and length of the upper and lower pads are determined by step (b), and the thickness of the upper and lower pads is determined by step (c).

[0010] In the above-mentioned method for forming a sandwich panel with a mesh reinforcement wall panel containing local bosses, in step (d), the long edges of both the upper and lower pads are ground to remove sharp corners.

[0011] In the above-mentioned method for forming a sandwich panel with a mesh reinforcement wall panel containing local bosses, in step (e), for the area to be formed that does not contain bosses, no pad is required, and three-point bending is directly used for forming.

[0012] Compared with the prior art, the beneficial technical effects of the present invention are:

[0013] This invention proposes a sandwich bending forming method for mesh-reinforced wall panels with localized protrusions. When forming mesh-reinforced wall panels with localized protrusions using this method, only two spring steel or titanium alloy pads are needed. The protrusion-containing area of ​​the mesh-reinforced wall panel is sandwiched between the two spring steel or titanium alloy pads for bending. The addition of the spring steel or titanium alloy pads ensures more uniform stress distribution within the pressure area during bending and provides rigid support to the weakly rigid skin area, thus preventing creases or even cracks at the transition between the protrusions and the skin. Compared to the conventional method of large-scale filling before bending of the mesh area of ​​mesh-reinforced wall panels with localized protrusions, this method eliminates the need for any filler, effectively improving the forming efficiency of mesh-reinforced wall panels with localized protrusions and reducing the manufacturing cost of the wall panels. Attached Figure Description

[0014] The method for forming a sandwich panel with a mesh reinforcement containing local bosses according to the present invention is given by the following embodiments and figures.

[0015] Figure 1 This is a schematic diagram of the area to be formed in a preferred embodiment of the present invention, showing the division of the planar mesh reinforcement panel (including local bosses) to be formed.

[0016] Figure 2 This is a diagram showing the positions of the pad and mold before sandwich bending of the mesh-reinforced wall panel containing the boss area A in a preferred embodiment of the present invention.

[0017] Figure 3 This is a diagram showing the positions of the pad and mold in the preferred embodiment of the present invention before the core bending of the grid-reinforced wall panel containing the boss area B.

[0018] Figure 4 This is a diagram showing the positions of the pad and mold before sandwich bending of the grid-reinforced wall panel containing the boss area C in a preferred embodiment of the present invention.

[0019] Figure 5 This is a schematic diagram of the formed mesh-reinforced wall panel with local bosses in a preferred embodiment of the present invention. Detailed Implementation

[0020] The following will combine Figures 1-5 The present invention provides a further detailed description of the sandwich bending forming method for a mesh-reinforced wall panel with local bosses.

[0021] The method for forming a sandwich panel with a mesh reinforcement wall containing local bosses according to the present invention includes:

[0022] (a) Divide the planar grid rib wall panel to be formed into several regions to be formed. The regions to be formed are divided into two categories: one category contains bosses and the other does not contain bosses. Measure the width of each region to be formed that contains bosses.

[0023] (b) Design an upper pad and a lower pad for each area to be formed containing a boss, wherein the maximum width of the area to be formed containing the boss is less than the width of the upper pad and less than the span width of the two lower support dies when the mesh reinforcement wall plate is bent at three points, the width of the lower pad is greater than the span width of the two lower support dies when the mesh reinforcement wall plate is bent at three points, and the length of the upper pad and the lower pad are both greater than the length of the upper bending die when the mesh reinforcement wall plate is bent at three points.

[0024] Both the upper and lower pads are made of spring steel or titanium alloy.

[0025] The width of the lower pad is 60mm to 100mm wider than the span width of the two lower support molds;

[0026] The lengths of both the upper and lower pads are 100mm to 200mm longer than the length of the upper bending die;

[0027] (c) Perform finite element simulation of bending forming of each area containing bosses on the planar grid rib wall plate to determine the thickness of the upper and lower pads required to make each area containing bosses bend without creases or cracks, and the load magnitude when bending the outer surface of each area containing bosses to the target curvature after placing the pads.

[0028] When forming the area to be formed, which includes bosses, a sandwich forming method is used, that is, the area to be formed, which includes bosses, is sandwiched between the upper and lower pads on the mesh rib wall plate, the upper bending die is placed above the upper pad, and the lower pad is supported on two lower support dies.

[0029] (d) Using large-format spring steel plates as raw materials, cut upper and lower pads. The width and length of the upper and lower pads are determined by step (b), and the thickness of the upper and lower pads is determined by step (c).

[0030] The long edges of both the upper and lower pads should be lightly sanded to remove sharp corners, so as to avoid indentations, scratches or abrasions at the contact points between the mesh reinforcement wall panel and the long edges of the pad during bending.

[0031] (e) The planar grid rib wall panel to be formed is bent and formed area by area so that the grid rib wall panel finally meets the overall shape requirements. During the bending process, for each area to be formed containing bosses, upper pads and lower pads are placed on the upper and lower surfaces of the area respectively, and corresponding bending loads are applied according to the simulation results.

[0032] For areas to be formed that include bosses, upper and lower pads are placed on the upper and lower surfaces of the area to be formed, respectively, before three-point bending is performed; for areas to be formed that do not include bosses, no pads are needed, and three-point bending is used directly.

[0033] The present invention will now be described in detail with reference to specific embodiments, a sandwich bending forming method for a mesh-reinforced wall panel with local bosses.

[0034] (a) Based on the positional characteristics of the bosses on the planar mesh reinforcement panel 1 to be formed, the planar mesh reinforcement panel 1 to be formed is divided into five regions to be formed, such as... Figure 1 As shown, regions A, B, and C within the dashed boxes are the regions to be formed that contain bosses, while the regions between regions A and B, and between regions B and C, are the regions to be formed that do not contain bosses.

[0035] like Figure 1 Let the length direction of the upper bending die be the X-axis and the bending forming step direction be the Y-axis. When dividing the area to be formed, the bosses that are adjacent in the Y-axis can be divided into the same area to be formed. For example, bosses a1, a2, a3, a4 and a5 overlap in the Y-axis. Bosses a1, a2, a3, a4 and a5 are divided into the same area to be formed (area A). Boss a6 also overlaps with boss a1 in the Y-axis. Boss a6 is also divided into the area to be formed (area A). The range of area A is the smallest area that encloses bosses a1, a2, a3, a4, a5 and a6.

[0036] (b) Design the upper and lower pads, wherein the width of area A is 330mm, the width of area B is 380mm, the width of area C is 320mm, the span width of the two lower support molds when the mesh reinforcement wall panel is bent at three points is 500mm, the length of the upper bending mold when the mesh reinforcement wall panel is bent at three points is 4500mm, the width of the upper pad is designed to be 400mm, the width of the lower pad is designed to be 600mm, and the length of both the upper and lower pads is designed to be 4700mm.

[0037] Both the upper and lower pads are made of spring steel plates, and the spring steel plate material is 60Si2Mn;

[0038] (c) Perform finite element simulation of bending forming of each area containing bosses on the planar grid rib wall plate to determine the thickness of the upper and lower pads required to make each area containing bosses bend without creases or cracks, and the load magnitude when bending the outer surface of each area containing bosses to the target curvature after placing the pads.

[0039] Based on the actual finite element simulation results, it is determined that the thickness of the spring steel plate should be set to 2mm.

[0040] (d) Using large-format spring steel plates as raw materials, cut the upper and lower pads; grind the long edges of the upper and lower pads to remove sharp corners;

[0041] (e) The planar grid rib wall panel to be formed is bent and formed area by area so that the grid rib wall panel finally meets the overall shape requirements. During the bending process, the corresponding bending load is applied to each area to be formed containing the boss.

[0042] like Figure 2 When bending region A, region A of the mesh reinforcement wall panel 1 is first sandwiched between the upper pad 4 and the lower pad 5. The upper bending die 2 is placed above the upper pad 4, and the lower pad 5 is placed on the two lower support dies 3. Then, the corresponding bending load is applied, and region A is bent using a three-point bending method.

[0043] Move the area between area A and area B of panel 1 between the upper bending mold 2 and the two lower support molds 3. This area is the area to be formed without the boss. Directly use three-point bending and apply the corresponding bending load. That is, no pad is needed during the bending process.

[0044] Move area B of panel 1 between the upper bending die 2 and the two lower support dies 3, as follows: Figure 3 After placing the upper pad 4 and the lower pad 5 on the upper and lower surfaces of area B of the grid-reinforced wall panel 1 respectively, three-point bending is then performed.

[0045] Move the area between area B and area C of panel 1 between the upper bending mold 2 and the two lower support molds 3. This area is the area to be formed without the boss, and three-point bending is directly used.

[0046] Move area C of panel 1 between the upper bending die 2 and the two lower support dies 3, as follows: Figure 4 After placing the upper pad 4 and the lower pad 5 on the upper and lower surfaces of the area C of the grid-reinforced wall panel 1, a three-point bending is then performed.

[0047] After bending and shaping each of the above areas one by one, the entire mesh-ribbed wall panel is formed and manufactured. Figure 5 .

[0048] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method of coining a sandwich panel of grid stiffeners with local bosses, characterized in that, The forming method comprises: (a) dividing the plane grid rib wall plate to be formed into a plurality of forming regions, the forming regions are divided into two categories, one category contains bosses, and the other category does not contain bosses, and measuring the width of each forming region containing bosses; (b) designing the upper and lower pads, the maximum value of the width of the forming region containing bosses < the width of the upper pad < the span width of the two lower support dies during three-point bending of the grid rib wall plate, the width of the lower pad > the span width of the two lower support dies during three-point bending of the grid rib wall plate, and the lengths of the upper and lower pads are greater than the length of the upper bending die during three-point bending of the grid rib wall plate; (c) performing finite element simulation on the bending forming of each forming region containing bosses on the plane grid rib wall plate, selecting spring steel or titanium alloy plate as the pad in the simulation, determining the thickness of the upper and lower pads required to prevent defects such as creases and cracks after bending of each forming region containing bosses, and the load size when the outer shape of each forming region containing bosses is bent to the target curvature after the pads are placed; (d) cutting the upper and lower pads from a large-format spring steel or titanium alloy plate; (e) performing regional bending forming on the plane grid rib wall plate, and placing the upper and lower pads on the upper and lower surfaces of each forming region containing bosses during the bending process, and applying the corresponding bending load according to the simulation results. In step (a), the length direction of the upper bending die is the X-axis direction, the stepping direction of the bending forming is the Y-axis direction, and adjacent bosses in the Y-axis direction can be divided into the same forming region; the range of the forming region containing bosses is the minimum region that envelopes the bosses in the forming region.

2. The method of claim 1, wherein the method further comprises: The width of the lower pad is 60mm-100mm wider than the span width of the two lower support dies; the lengths of the upper and lower pads are 100mm-200mm longer than the length of the upper bending die.

3. The method of claim 1, wherein the method further comprises: The spring steel material is 60Si2Mn or 65Mn.

4. The method of claim 1, wherein the method further comprises: In step (d), each forming region containing bosses shares a set of upper and lower pads, the width and length of the upper and lower pads are determined in step (b), and the thickness of the upper and lower pads is determined in step (c).

5. The method of claim 1, wherein, In step (d), the long edges of the upper and lower pads are polished to remove sharp corners.

6. The method of claim 1, wherein the method further comprises: In step (e), for the forming region not containing bosses, no pad is needed, and three-point bending forming is directly adopted.

7. The method of claim 1, wherein the method further comprises: ​

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