A simulation analysis method for aluminum alloy honeycomb sandwich opening structure

Abstract

The present invention discloses a simulation analysis method for an aluminum alloy honeycomb sandwich opening structure, comprising: using a finite element simulation analysis method to determine the parameters of an aluminum alloy honeycomb sandwich structure without an opening; determining the opening size; selecting the shape of an opening frame, determining the opening frame size, and calculating the thickness d2 of the opening frame; determining the opening sizes of a first reinforcing plate, a second reinforcing plate, a second panel, and a third panel, wherein the opening size matches the opening of the opening frame; determining the major axis length a of the first reinforcing plate and the second reinforcing plate. JQ , short axis length b JQ and thickness d JQ ; Determine the size of the second honeycomb core with opening features and the size of the foam glue; For the initial honeycomb sandwich opening structure, use the finite element simulation analysis method to optimize the design, perform strength and stability calculations, ensure that the failure load difference meets the set threshold, and obtain a honeycomb sandwich opening structure that meets the requirements.

Description

Technical Field

[0001] The invention relates to a simulation analysis method for an aluminum alloy honeycomb sandwich opening structure, belonging to the technical field of aerospace structure design. Background Art

[0002] The honeycomb sandwich structure has a specific stiffness performance far higher than other structures. It is an ideal material for structures such as launch vehicle fairings, satellite brackets, and instrument mounting plates. It has been widely used in launch vehicles. Openings must be made on the honeycomb sandwich structure on the rocket to meet the needs of equipment operation, cable channels, local wave transmission, etc. At present, the honeycomb sandwich opening structure on the rocket structure is composed of a mouth frame, a reinforcement plate, and a glue filling area. The combined reinforcement structure is used to ensure the strength of the honeycomb sandwich structure at the opening. This structure can meet the load-bearing requirements, but the reinforcement structure is too strong. On the one hand, it makes the structure heavier. On the other hand, it causes stress concentration problems around the reinforcement area and reduces the overall load-bearing capacity of the honeycomb sandwich structure. In general, the opening reinforcement structure has low structural efficiency and low load-bearing capacity. Summary of the invention

[0003] The technical problem to be solved by the present invention is: to overcome the deficiencies of the prior art, the present invention proposes a simulation analysis method for an aluminum alloy honeycomb sandwich opening structure, which can achieve high-precision prediction of structural failure modes and bearing capacity, thereby achieving structural weight reduction and improving bearing capacity.

[0004] The technical solution adopted by the present invention is: a simulation analysis method for an aluminum alloy honeycomb sandwich opening structure, comprising:

[0005] According to the structural load-bearing and stiffness requirements, the finite element simulation analysis method is used to determine the parameters of the aluminum alloy honeycomb sandwich structure without openings, including the thickness d of the first honeycomb core. FW , the thickness of the first panel d MB ;

[0006] Determine the opening size;

[0007] Select the shape of the opening frame, determine the size of the opening frame, and calculate the thickness of the opening frame d2 = d FW -4×d MB ;

[0008] According to the shape and size of the opening frame, the opening sizes of the first reinforcing plate, the second reinforcing plate, the second panel and the third panel are determined, and the opening sizes are matched with the opening of the opening frame;

[0009] Determine the major axis length a of the first reinforcement plate and the second reinforcement plate JQ , short axis length b JQ and thickness d JQ ;

[0010] Determining the size of the second honeycomb core including the opening features, and the size of the foam glue;

[0011] The opening frame, the first reinforcing plate, the second reinforcing plate, the second panel and the third panel are connected by rivets to form an initial honeycomb sandwich opening structure, and the rivet holes are evenly distributed around the circumference of the opening;

[0012] For the initial honeycomb sandwich opening structure, the finite element simulation analysis method is used for optimization design, and strength and stability calculations are performed to ensure that the failure load difference meets the set threshold and obtain a honeycomb sandwich opening structure that meets the requirements.

[0013] Furthermore, the non-opening aluminum alloy honeycomb sandwich structure comprises a first panel and a first honeycomb core; in the finite element simulation analysis equivalent model of the non-opening aluminum alloy honeycomb sandwich structure, the first honeycomb core adopts a solid model, elastic parameters are assigned to the first honeycomb core, and the first panel and the first honeycomb core are bonded; when performing strength judgment in the finite element simulation analysis, the overall yielding of the skin is taken as the failure condition; when performing stability judgment in the finite element simulation analysis, the instability characteristic value is multiplied by a reduction factor of 0.7.

[0014] Furthermore, if the opening frame is a circular opening, the diameter R1 and depth d1 of the sunken ring of the inner circle of the circular opening frame are determined according to the requirements for the installation of the cover. The opening frame is a hollow structure, and the shell wall thickness d3 is the first panel thickness d MB 4 to 6 times of the opening frame outer diameter R3 = R1 + 2 × d FW .

[0015] Furthermore, if the opening frame is a rectangular opening, the width w1, height h1, fillet radius r1 and depth d1 of the inner circle sunken frame of the rectangular opening frame are determined according to the requirements for the installation of the cover. The opening frame is a hollow structure, and the shell wall thickness d4 is the first panel thickness d MB 4 to 6 times of the width of the opening frame, w3 = w1 + 2 × d FW 、Height h3=h1+2×d FW The outer fillet radius r2 is the thickness of the second honeycomb core d FW 0.5 to 1 times.

[0016] Furthermore, for the circular opening frame, the opening diameter of the second reinforcing plate located on one side of the sunken circular ring of the inner circle of the opening frame is equal to R1, and the opening diameter of the first reinforcing plate on the other side is equal to R.

[0017] Furthermore, for the rectangular opening frame, the opening width of the second reinforcing plate on one side of the inner circle sunken frame of the opening frame is equal to w1 and the height is equal to h1, and the opening width of the first reinforcing plate on the other side is equal to w and the height is equal to h.

[0018] Furthermore, the major axis length a JQ Take 2 to 3 times R * , short axis length b JQ Take 1.5 times R * ; Thickness d JQ Take the thickness of the first panel d MB 2 times; among them, R * is the diameter of the circumcircle of the opening.

[0019] Furthermore, the foam glue fills the honeycomb cells within a range of 20 mm around the opening of the second honeycomb core.

[0020] Furthermore, the distance between adjacent rivet holes ranges from 20 to 30 mm.

[0021] Furthermore, the finite element simulation analysis model of the honeycomb sandwich opening structure includes:

[0022] A simulation model of a second panel and a third panel with opening features, a first reinforcing plate and a second reinforcing plate with opening features, an opening frame, a second honeycomb core, and foam glue;

[0023] The second and third panels are shell models, the first and second reinforcement plates are shell models, the opening frame is a solid model, the second honeycomb core is a solid model, and the foam glue is a solid model. Elastic parameters, plastic parameters and strength parameters are given to each structure, rivet holes are not considered, and the components are bonded. The finite element simulation analysis method is used to calculate the strength and stability of the honeycomb sandwich opening structure. According to the failure mode, the structural parameters are adjusted. The structural parameters include the major axis length a JQ , short axis length b JQ and thickness d JQ , the outer diameter R3 and shell wall thickness d3 of the circular opening frame or the width w3 and height h3 and shell wall thickness d4 of the rectangular opening frame, update the structural parameters of the model and re-perform finite element simulation analysis to ensure that the failure load difference in each area is ≤5%, achieve equal strength design, and obtain the final honeycomb sandwich opening structure.

[0024] The advantages of the present invention compared with the prior art are:

[0025] (1) The present invention proposes a simulation analysis method for an aluminum alloy honeycomb sandwich opening structure. Based on the design principle of stiffness matching, the present invention proposes the optimal design scheme for the shape and size of the opening frame and the shape and size of the reinforcement plate for openings of different shapes and sizes, thereby achieving structural weight reduction, and basically realizing the coordinated load-bearing and equal strength design of the overall structure and the opening reinforcement structure, thereby improving the overall load-bearing capacity of the structure.

[0026] (2) The present invention proposes an optimized configuration and parameter determination method for the honeycomb sandwich opening structure, which can quickly obtain a design solution with high structural efficiency and greatly improve the design efficiency of the honeycomb sandwich opening structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a diagram of the honeycomb sandwich structure;

[0028] Figure 2 This is the exploded view of the honeycomb sandwich structure;

[0029] Figure 3 The following is the opening shape and size diagram;

[0030] Figure 4 This is the exploded view of the honeycomb sandwich opening structure;

[0031] Figure 5 Schematic diagram of the opening frame and glue filling area of ​​the honeycomb sandwich;

[0032] Figure 6 It is a diagram of the circular mouth frame structure;

[0033] Figure 7 Optimize the structural diagram for the circular mouth frame;

[0034] Figure 8 It is a rectangular frame structure diagram;

[0035] Fig. 9 Optimize the structure diagram for the rectangular mouth frame;

[0036] Fig.10 It is a schematic diagram of the circumscribed circle of the opening;

[0037] Fig.11 This is the equivalent model diagram of the finite element simulation analysis of the aluminum alloy honeycomb sandwich structure;

[0038] Fig.12 This is the equivalent model diagram of the finite element simulation analysis of the aluminum alloy honeycomb sandwich opening structure;

[0039] Fig.13 This is the cross-sectional view of the equivalent model for the finite element simulation analysis of the opening structure;

[0040] Fig.14 This is a partial enlarged view of the opening frame of the equivalent model of the finite element simulation analysis of the opening structure;

[0041] Fig.15 It is the finite element mesh model diagram;

[0042] Fig.16 It is the Mises stress diagram under axial pressure of 270kN;

[0043] Fig.17 It is the Mises stress diagram under axial pressure of 300kN;

[0044] Fig.18 This is the calculation result diagram of instability under axial pressure of 250kN;

[0045] Fig.19 It is the Mises stress diagram under axial pressure of 432kN;

[0046] Fig. 20 It is the Mises stress diagram under axial pressure of 456kN;

[0047] Fig.21 This is the instability calculation result diagram under axial pressure of 400kN. DETAILED DESCRIPTION

[0048] The present invention will be further described below in conjunction with the accompanying drawings.

[0049] like Figure 1 As shown, the aluminum alloy honeycomb sandwich structure includes a first honeycomb core 2 and a first panel 1. The materials of the first honeycomb core 2 and the first panel 1 are both aluminum alloys. The first panel 1 is glued to both sides of the first honeycomb core 2. The thickness of the first honeycomb core 2 is d FW , the thickness of the first panel 1 is d MB , the exploded diagram of the honeycomb sandwich structure is as follows Figure 2 shown.

[0050] like Figure 3 As shown, the opening shapes of the aluminum alloy honeycomb sandwich opening structure are divided into circular, elliptical and rectangular. The circular opening size is the diameter R, the elliptical opening size is the axis a and axis b, and the rectangular opening size is the width w and the height h.

[0051] like Figure 4 As shown, taking a flat plate with a circular opening as an example, the honeycomb sandwich opening structure includes a second honeycomb core 5 with an opening feature, a second panel 3 and a third panel 10 with an opening feature, a first reinforcing plate 4 and a second reinforcing plate 11 with an opening feature, and an opening frame 6. The materials of the honeycomb sandwich opening structure components are all aluminum alloy, and the components are all glued. The second honeycomb core 5 in the vicinity of the opening frame 6 is poured with foam glue 7, as shown in FIG. Figure 5 shown.

[0052] like Figure 4 As shown, the first reinforcing plate 4 and the second reinforcing plate 11 with opening features are elliptical, and the elliptical size of the outer contour is the axis a JQ , axis b JQ The opening size matches the opening frame 6, and the thickness is d JQ The thickness of the second honeycomb core 5 having an opening feature is the same as the thickness of the first honeycomb core 2, both of which are d FWThe opening size matches the opening frame 6; the opening size of the second panel 3 and the third panel 10 with an opening feature matches the opening frame 6, and the thickness is the same as the thickness of the first panel 1, both of which are d MB The opening frame 6, the first reinforcing plate 4 and the second reinforcing plate 11, the second panel 3 and the third panel 10 are connected by aluminum alloy rivets with a thickness of d FW +2×d MB .

[0053] The circular opening frame 13, such as Figure 6 As shown, the opening size refers to the design requirements. The outer diameter of the circular opening frame 13 is R2, and the thickness d2=d FW -2×d JQ , ensuring that the mouth frame is clamped by the second panel 3, the first reinforcing plate 4, the third panel 10, and the second reinforcing plate 11. The inner circle of the circular opening mouth frame 13 is designed with a sunken area as the cover connection interface, and the diameter of the sunken area is R1 and the depth is d1. The circular opening mouth frame 13 is connected to the first reinforcing plate 4, the second reinforcing plate 11, the second panel 3, and the third panel 10 by aluminum alloy rivets, and the connecting rivet holes are distributed as follows Figure 6 shown.

[0054] The circular opening optimizes the mouth frame 12, such as Figure 7 As shown, it is a hollow structure, and the shell wall thickness of the circular opening optimized opening frame 12 is d3. The outer diameter of the circular opening optimized opening frame 12 is R3, and other dimensions and connection nail hole distribution are the same as those of the circular opening opening frame 6.

[0055] Rectangular opening frame 8 such as Figure 8 As shown, the opening size refers to the design requirements. The rectangular opening frame 8 has a width of w2, a height of h2, a rounded radius of r2, and a thickness of d2=d FW -2×d JQ , ensuring that the mouth frame is clamped by the second panel 3, the first reinforcing plate 4, the third panel 10, and the second reinforcing plate 11. The inner frame of the rectangular opening mouth frame 8 is designed with a sunken step area as the cover connection interface. The width of the sunken area is w1, the height is h1, and the fillet radius is r1. The rectangular opening mouth frame 8 is connected to the first reinforcing plate 4, the second reinforcing plate 11, the second panel 3, and the third panel 10 with aluminum alloy rivets. The connecting rivet holes are distributed as follows: Figure 8 shown.

[0056] Rectangular opening optimized mouth frame 9 Fig. 9 As shown, it is a hollow structure, and the shell wall thickness of the rectangular opening optimized mouth frame 9 is d4. The width of the rectangular opening optimized mouth frame 9 is w3, the height is h3, and other dimensions and the distribution of connecting nail holes are the same as those of the rectangular opening mouth frame 8.

[0057] The parameter determination method of the aluminum alloy honeycomb sandwich opening structure is as follows:

[0058] In the first step, according to the structural load and stiffness requirements, the finite element simulation analysis method is used to determine the parameters of the open aluminum alloy honeycomb sandwich structure, including the thickness d of the first honeycomb core 2. FW , the thickness d of the first panel 1 MB The equivalent model of finite element simulation analysis of honeycomb sandwich structure is as follows: Fig.11 As shown, it includes a first panel 1 and a first honeycomb core 2. The first honeycomb core 2 adopts a solid model and is given elastic parameters. The components are bonded. When judging strength in finite element simulation analysis, the failure condition is not the collapse of the structure in the calculation, but the failure condition is the yielding of the skin as a whole; when judging stability in finite element simulation analysis, the instability characteristic value needs to be multiplied by a reduction factor of 0.7.

[0059] The second step is to determine the opening size according to the design requirements, such as the diameter R of the circular opening.

[0060] The third step is to select the form of the opening frame 6 and determine the size of the opening frame 6, with a thickness of d2 = d FW -4×d MB For a circular opening, the diameter R1 and depth d1 of the sunken area are determined according to the requirements for the installation of the cover, and the shell wall thickness d3 is the thickness d of the first panel 1. MB 4 to 6 times of the outer diameter, R3 = R1 + 2 × d FW For rectangular openings, the width w1, height h1, fillet radius r1 and depth d1 of the sunken area are determined according to the cover installation requirements, and the shell wall thickness d4 is the thickness of the first panel 1 d MB 4 to 6 times of the width of the opening frame 6, w3 = w1 + 2 × d FW 、Height h3=h1+2×d FW The fillet radius r2 is the thickness d of the second honeycomb core 5 FW 0.5 to 1 times.

[0061] The fourth step is to determine the opening sizes of the first reinforcing plate 4, the second reinforcing plate 11, the second panel 3, and the third panel 10 according to the opening shape and size, and the opening size is matched with the opening frame 6. For a circular opening, the opening diameter of the second reinforcing plate 11 located on one side of the frame sunken area is R1, and the opening diameter of the first reinforcing plate 4 on the other side is R; for a rectangular opening, the opening width of the second reinforcing plate 11 located on one side of the frame sunken area is w1 and the height is h1, and the opening width of the first reinforcing plate 4 on the other side is w and the height is h.

[0062] The fifth step is to determine the long axis length a of the first reinforcing plate 4 and the second reinforcing plate 11 according to the parameters of the honeycomb sandwich structure and the shape and size of the openings. JQ , short axis length b JQ , thickness d JQ .like Fig.10 As shown, the diameter R of the circumscribed circle of the opening is obtained * , for a circular opening R * = R, for elliptical opening R * = max(a,b), for rectangular openings, R * =(w 2 +h 2 ) 0.5 ; a JQ Take 2 to 3 times R * , b JQ Take 1.5 times R * ; Thickness d JQ Take the thickness d of panel 1 MB twice as much.

[0063] Step 6: According to the above dimensions, determine the dimensions of the second honeycomb core 5 with opening features and the dimensions of the foam glue 7. The second honeycomb core 5 fills the internal gaps, and the foam glue 7 fills the honeycomb cells within 20 mm around the opening of the second honeycomb core 5.

[0064] In the seventh step, the opening frame 6, the first reinforcing plate 4, the second reinforcing plate 11, the second panel 3 and the third panel 10 are connected by rivets. The rivet specification is generally φ4 and the spacing is generally 20-30 mm.

[0065] Step 8: For the preliminary structure, the simulation analysis method is used to optimize the design. The equivalent model of the finite element simulation analysis of the honeycomb sandwich opening structure is as follows: Fig.12 As shown, the cross-sectional diagram is Fig.13 As shown, the enlarged view of the part near the oral frame is as follows Fig.14 As shown, the simulation analysis model includes a second panel 3 and a third panel 10 with opening features, a first reinforcing plate 4 and a second reinforcing plate 11 with opening features, an opening frame 6, a second honeycomb core 5, and a foam glue 7. The second panel 3 and the third panel 10 adopt a shell model, the first reinforcing plate 4 and the second reinforcing plate 11 adopt a shell model, the opening frame 6 adopts a solid model, the second honeycomb core 5 adopts a solid model, and the honeycomb perfusion foam glue adopts a solid model, and each structure (each structure refers to the second panel 3, the third panel 10, the first reinforcing plate 4, the second reinforcing plate 11, the opening frame 6, the second honeycomb core 5, and the foam glue 7) is given elastic parameters, plastic parameters, and strength parameters, and rivet holes are not considered. Each component (each component refers to the second panel 3, the third panel 10, the first reinforcing plate 4, the second reinforcing plate 11, the opening frame 6, the second honeycomb core 5, and the foam glue 7) is bonded. The simulation analysis method is used to calculate the strength and stability of the honeycomb sandwich opening structure, and the structural parameters are adjusted according to the failure mode, including the major axis length a of the elliptical reinforcing plate. JQ and the minor axis length b JQ and thickness d JQ, the outer diameter R3 of the circular mouth frame and the shell wall thickness d3, the width w3 and height h3 of the rectangular mouth frame and the shell wall thickness d4, update the model parameters and re-simulate the analysis to ensure that the failure load difference in each area is ≤5%, achieve equal strength design, and obtain a lightweight and high-strength honeycomb sandwich opening structure.

[0066] Example 1

[0067] It is required to design an aluminum alloy honeycomb sandwich flat plate with a height of H = 1 meter, a width of W = 1 meter, a circular opening diameter of 250mm, and a load requirement of not less than 150kN.

[0068] The first step is to use the finite element simulation analysis method to determine the parameters of the open honeycomb sandwich structure:

[0069] (1) The panel material is aluminum alloy 2A12 with a thickness of d MB =0.5mm.

[0070] (2) Hexagonal honeycomb is used, the material is aluminum alloy 2A12, the specification of honeycomb core is 5×0.05, the thickness is d FW =20mm;

[0071] The finite element calculation model is as follows Fig.11 As shown, the finite element mesh model is Fig.15 The material properties are shown in Table 1 and Table 2.

[0072] Table 1 Panel material properties

[0073]

[0074] Table 2 Aluminum honeycomb material properties

[0075]

[0076]

[0077] The Mises stress of the open honeycomb sandwich structure is as follows: Fig.16 , Fig.17 As shown in the figure, the skin partially yields under the 270kN axial compressive load, and the skin yields on a large scale under the 300kN axial compressive load. It is believed that the structural bearing limit is between 270 and 300kN, and the residual strength coefficient is 1.1 to 1.2, which meets the design requirements.

[0078] The characteristic instability wave of the open honeycomb sandwich structure under 250kN axial compression load is as follows: Fig.17 As shown, considering the reduction factor of 0.7, the instability coefficient is 1.697*0.7=1.188.

[0079] In summary, the honeycomb sandwich structure meets the load-bearing requirements, and the load margin is between 1.11 and 1.2.

[0080] The second step is to make the opening circular with a diameter of R=250mm.

[0081] The third step is to use a circular opening to optimize the opening frame 12, with an opening diameter R = 250 mm and a thickness d2 = d FW -4×d MB =25-4×0.5=23mm. The cover can be installed, the connection width is 10mm, the diameter of the sunken area R1=250+10×2=270mm, the depth is d1=5mm, and the thickness of the shell wall of the mouth frame is d3=6×d MB =6×0.5=3mm, outer diameter R3=R1+2×d FW =270+2×25=320mm.

[0082] Step 4: The opening diameter of the second reinforcing plate 11 on one side of the mouth frame sunken area is R1=270 mm, and the opening diameter of the first reinforcing plate 4 on the other side is R=250.

[0083] The fifth step is to determine the axis a of the first reinforcing plate 4 and the second reinforcing plate 11 according to the parameters of the honeycomb sandwich structure and the shape and size of the openings. JQ , axis b JQ , thickness d JQ . Opening circumscribed circle diameter R * =R=250mm, axis a JQ =3R * =750mm, axis b JQ =1.5R * =375mm, thickness d JQ Take = 2d MB =1mm.

[0084] Step 6: The second honeycomb core 5 fills the internal gap, and the foam glue 7 fills the honeycomb cells within a range of 20 mm near the opening of the second honeycomb core 5 .

[0085] Step 7. The opening frame, reinforcement plate and panel are connected by rivets. The rivet specification is φ4 and the spacing is 25mm.

[0086] In the eighth step, the finite element simulation analysis method is used for simulation analysis, and the structural bearing capacity is 262kN.

[0087] Example 2

[0088] It is required to design an aluminum alloy honeycomb sandwich flat plate with a height of H = 1 meter and a width of W = 1 meter. The diameter of the circular opening is rectangular, with a width of 200mm, a height of 300mm, an allowable chamfer R2mm, and a load requirement of 400kN.

[0089] The first step is to use the finite element simulation analysis method to determine the parameters of the open honeycomb sandwich structure:

[0090] (1) The panel material is aluminum alloy 2A12 with a thickness of d MB =0.8mm.

[0091] (2) Hexagonal honeycomb is used, the material is aluminum alloy 2A12, the specification of honeycomb core is 5×0.05, the thickness is d FW =21mm;

[0092] The calculation model is the same as that in Example 1.

[0093] The Mises stress of the open honeycomb sandwich structure is as follows: Fig.19 , Fig. 20 As shown in the figure, the skin partially yields under the 432kN axial compressive load, and the skin yields on a large scale under the 456kN axial compressive load. It is believed that the structural bearing limit is between 432 and 456kN, and the residual strength coefficient is 1.08 to 1.14, which meets the design requirements.

[0094] The characteristic instability wave of the open honeycomb sandwich structure under 400kN axial compression load is as follows: Fig.21 As shown, considering the reduction factor of 0.7, the instability coefficient is 1.730*0.7=1.211.

[0095] In summary, the honeycomb sandwich structure meets the load-bearing requirements, and the load margin is between 1.08 and 1.14.

[0096] In the second step, the opening is rectangular with a width of w = 200 mm, a height of h = 300 mm, and a chamfer radius of R = 2 mm.

[0097] The third step is to optimize the opening frame 9 with a rectangular opening, the opening size of which is width w = 200 mm, height h = 300 mm, thickness d2 = d FW -4×d MB =35-4×0.8=31.8mm. The cover can be installed, the connection width is 10mm, the diameter width of the sunken area w1=220mm, the height h1=320mm, the depth d1=5mm, the fillet radius r1=3mm; the shell wall thickness of the mouth frame d3=6×d MB =6×0.8=4.8mm, the width of the opening frame w2=w1+2×d FW =290mm, height h2 = h1 + 2 × d FW =390mm, chamfer r2=d FW =35mm.

[0098] Step 4: The opening width of the second reinforcing plate 11 on one side of the mouth frame sunken area is w1=220mm and the height is h1=320mm, and the opening width of the first reinforcing plate 4 on the other side is w=200mm and the height is h=300mm.

[0099] The fifth step is to determine the axis a of the first reinforcing plate 4 and the second reinforcing plate 11 according to the parameters of the honeycomb sandwich structure and the shape and size of the openings. JQ , axis b JQ , thickness d JQ . Opening circumscribed circle diameter R * =(w 2 +h 2 ) 0.5 =360mm, axis a JQ =3R * =1080mm, axis b JQ =1.5R * =480mm, thickness d JQ Take = 2d MB =1.6mm. Due to the axis a JQ If the width of the flat plate is 1000mm, the elliptical reinforcing plate is cut off on both sides and has a width of 1000mm.

[0100] Step 6: The second honeycomb core 5 fills the internal gap, and the foam glue 7 fills the honeycomb cells within a range of 20 mm near the opening of the second honeycomb core 5 .

[0101] Step 7. The opening frame, reinforcement plate and panel are connected by rivets. The rivet specification is φ4 and the spacing is 25mm.

[0102] In the eighth step, the finite element simulation analysis method is used for simulation analysis, and the structural bearing capacity is 414kN.

[0103] Parts of the present invention that are not described in detail belong to the well-known technologies of those skilled in the art.

Claims

1. A simulation analysis method for an aluminum alloy honeycomb sandwich opening structure, characterized in that: include: According to the structural load-bearing requirements and stiffness requirements, a finite element simulation analysis method is used to determine the parameters of the aluminum alloy honeycomb sandwich structure without openings, including the thickness d of the first honeycomb core (2). FW , the thickness d of the first panel (1) MB ; Determine the opening size; Select the shape of the opening frame (6), determine the size of the opening frame (6), and calculate the thickness d2=d FW -4×d MB ; According to the shape and size of the opening frame (6), the opening sizes of the first reinforcing plate (4), the second reinforcing plate (11), the second panel (3) and the third panel (10) are determined, and the opening sizes are kept matching with the opening of the opening frame (6); Determine the major axis length a of the first reinforcing plate (4) and the second reinforcing plate (11) JQ , short axis length b JQ and thickness d JQ ; Determine the size of the second honeycomb core (5) containing the opening features, and the size of the foam glue (7); The opening frame (6), the first reinforcing plate (4), the second reinforcing plate (11), the second panel (3), and the third panel (10) are connected by rivets to form an initial honeycomb sandwich opening structure, and the rivet holes are evenly distributed around the circumference of the opening; For the initial honeycomb sandwich opening structure, the finite element simulation analysis method is used for optimization design, strength and stability calculations are performed to ensure that the failure load difference meets the set threshold and obtain a honeycomb sandwich opening structure that meets the requirements; The finite element simulation analysis model of the honeycomb sandwich opening structure includes: A simulation model of a second panel (3) and a third panel (10) having an opening feature, a first reinforcing plate (4) and a second reinforcing plate (11) having an opening feature, an opening frame (6), a second honeycomb core (5), and a foam adhesive (7); The second panel (3) and the third panel (10) adopt a shell model, the first reinforcing plate (4) and the second reinforcing plate (11) adopt a shell model, the opening frame (6) adopts a solid model, the second honeycomb core (5) adopts a solid model, and the foam glue (7) adopts a solid model. Elastic parameters, plastic parameters and strength parameters are given to each structure, rivet holes are not considered, and each component is bonded. The finite element simulation analysis method is used to calculate the strength and stability of the honeycomb sandwich opening structure, and the structural parameters are adjusted according to the failure mode. The structural parameters include the major axis length a JQ , short axis length b JQ and thickness d JQ , the outer diameter R3 and shell wall thickness d3 of the circular opening frame or the width w3 and height h3 and shell wall thickness d4 of the rectangular opening frame, update the structural parameters of the model and re-perform finite element simulation analysis to ensure that the failure load difference in each area is ≤5%, achieve equal strength design, and obtain the final honeycomb sandwich opening structure.

2. The simulation analysis method of an aluminum alloy honeycomb sandwich opening structure according to claim 1, characterized in that: The non-opening aluminum alloy honeycomb sandwich structure comprises a first panel (1) and a first honeycomb core (2); in a finite element simulation analysis equivalent model of the non-opening aluminum alloy honeycomb sandwich structure, the first honeycomb core (2) adopts a solid model, elastic parameters are assigned to the first honeycomb core (2), and the first panel (1) and the first honeycomb core (2) are bonded; When judging strength in finite element simulation analysis, the failure condition is that the skin as a whole enters yielding; When making stability judgment in finite element simulation analysis, the instability characteristic value is multiplied by the reduction factor 0.

7.

3. The simulation analysis method of an aluminum alloy honeycomb sandwich opening structure according to claim 2, characterized in that: If the opening frame (6) is a circular opening, the diameter R1 and depth d1 of the sunken ring of the inner circle of the circular opening frame are determined according to the requirements for the installation of the cover. The opening frame (6) is a hollow structure, and the shell wall thickness d3 is the thickness d of the first panel (1). MB 4 to 6 times of the opening frame outer diameter R3 = R1 + 2 × d FW .

4. The simulation analysis method of an aluminum alloy honeycomb sandwich opening structure according to claim 2, characterized in that: If the opening frame (6) is a rectangular opening, the width w1, height h1, fillet radius r1 and depth d1 of the inner circle sunken frame of the rectangular opening frame are determined according to the requirements for the installation of the cover. The opening frame (6) is a hollow structure, and the shell wall thickness d4 is the thickness d of the first panel (1). MB 4 to 6 times of the width of the opening frame (6), w3 = w1 + 2 × d FW 、Height h3=h1+2×d FW The radius of the outer fillet r2 is the thickness d of the second honeycomb core (5). FW 0.5 to 1 times.

5. The simulation analysis method of an aluminum alloy honeycomb sandwich opening structure according to claim 3, characterized in that: For the circular opening frame (6), the opening diameter of the second reinforcing plate (11) located on one side of the sunken circular ring of the inner circle of the opening frame is equal to R1, and the opening diameter of the first reinforcing plate (4) on the other side is equal to R.

6. The simulation analysis method of an aluminum alloy honeycomb sandwich opening structure according to claim 4, characterized in that: For the rectangular opening frame (6), the second reinforcing plate (11) located on one side of the inner circle sunken frame of the opening frame has an opening width equal to w1 and a height equal to h1, and the first reinforcing plate (4) on the other side has an opening width equal to w and a height equal to h.

7. The simulation analysis method of an aluminum alloy honeycomb sandwich opening structure according to claim 1, characterized in that: Long axis length a JQ Take 2 to 3 times R * , short axis length b JQ Take 1.5 times R * ; Thickness d JQ Take the thickness d of the first panel (1) MB 2 times; among them, R * is the diameter of the circumcircle of the opening.

8. The simulation analysis method of an aluminum alloy honeycomb sandwich opening structure according to claim 1, characterized in that: The foam glue (7) fills the honeycomb cells within a range of 20 mm around the opening of the second honeycomb core (5).

9. The simulation analysis method of an aluminum alloy honeycomb sandwich opening structure according to claim 1, characterized in that: The distance between adjacent rivet holes ranges from 20 to 30 mm.

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