Calculation method for the stability of skin and stiffened panels of typical multi-web structures under various loads

Abstract

The embodiment of the present application discloses a calculation method for the stability of the skin and stiffened panels of a typical multi-web structure under various loads, which belongs to the field of structural design technology. The method includes: determining the type of ribs of the stiffened panel model and defining the model parameters; adding different connection methods and boundary conditions to the stiffened panel model to obtain multiple stiffened panels; modeling and modal analysis of multiple stiffened panels to obtain the buckling eigenvalues ​​of multiple stiffened panels; based on the buckling eigenvalues ​​of multiple stiffened panels, fitting the calculation formula of the critical stress coefficient of multiple stiffened panels for different types of stiffened panels and boundary conditions. The present application can be applied to the stability design of aircraft wall panel structures, guide the addition of stiffened panel boundaries, improve the stability of stiffened structures, and achieve further upgrades of aerospace equipment.

Description

Technical Field

[0001] The present application relates to a calculation method for the stability of a typical multi-web structure skin and a stiffened plate under various loads, and belongs to the technical field of structural design. Background Art

[0002] Stability is a prominent problem in aircraft panel structures, and the stability of the pressure surface of the panel structure under aerodynamic forces is particularly concerned. In recent years, many scholars at home and abroad have made a lot of useful contributions to the problem of structural stability by using approximate analytical methods, numerical methods or experimental methods.

[0003] Structural stability analysis is a method in engineering that is used to evaluate the stability and buckling resistance of a structure under external forces. Buckling refers to the sudden loss of the original stable equilibrium state of a structure when subjected to compression or other forms of load, resulting in structural deformation or failure. Buckling analysis is very important in the fields of architecture, machinery, aerospace, etc.

[0004] Buckling analysis is mainly used to study the stability of structures under specific loads and determine the critical load of structural instability. Buckling analysis includes linear buckling analysis and nonlinear buckling analysis. In buckling analysis, by calculating the response of the structure under different load conditions, its buckling load can be determined, and the deformation mode and instability mechanism of the structure when the load is reached can be analyzed. Buckling load = buckling factor × actual load, which is actually an amplification factor that characterizes the stability of the structure. The larger the buckling factor, the larger the load at the time of structural buckling relative to the actual initial load, and the structure is unlikely to become unstable. The smaller the buckling factor, the closer the load at the time of structural buckling to the actual initial load. The buckling factor is 1, which means that the structure has buckled and become unstable as soon as the actual load is added.

[0005] However, due to the complexity of the stability problem and the particularity of the wall panel structure itself, there are still many problems that have not been well solved in the field of aircraft structural stability research, such as the calculation of the critical stress coefficient of stiffened panels and the boundary criterion problem of stiffened panels with different rib types. Summary of the invention

[0006] In order to solve the above technical problems, an embodiment of the present application provides a calculation method for the stability of the skin and stiffened plates of a typical multi-web structure under various loads. Based on information such as the type, material and load of the structure's ribs, a mathematical expression of the critical stress coefficient K is derived. Through large-scale calculations, critical stress coefficient curves for different aspect ratios are obtained, and a stability analysis boundary addition criterion is further established to give the critical stress coefficient and boundary conditions of the stiffened plate.

[0007] Other features and advantages of the present application will become apparent from the following detailed description, or may be learned in part by the practice of the present application.

[0008] The present application provides a calculation method for the stability of the skin and stiffened panels of a typical multi-web structure under various loads, the method comprising:

[0009] Determine the rib type of the stiffened plate model and define the model parameters; wherein the rib types of the stiffened plate model include T-type, Z-type, I-type, and C-type; the model parameters include material elastic modulus, Poisson's ratio, density, and plate thickness;

[0010] Adding different connection modes and boundary conditions to the stiffened plate model to obtain a plurality of stiffened plates; wherein the connection modes include adhesive connection and MPC connection, the boundary conditions include axial compression, shear load, pure bending load, bidirectional compression load, compression-shear coupling load and bending-shear coupling load, and the plurality of stiffened plates include axial compression load stiffened plates, shear load stiffened plates, bending load stiffened plates, bidirectional compression load stiffened plates, compression-shear coupling load stiffened plates and bending-shear coupling load stiffened plates;

[0011] Modeling and modal analysis of multiple stiffened panels are performed to obtain the buckling eigenvalues ​​of multiple stiffened panels;

[0012] Based on the buckling eigenvalues ​​of multiple stiffened panels, the calculation formulas of the critical stress coefficients of multiple stiffened panels are fitted for different types of stiffened panels and boundary conditions.

[0013] Furthermore, for the axially compressive stiffened plate, the calculation formula of the critical stress coefficient is expressed as:

[0014] ;

[0015] In the formula, K c represents the compression critical stress coefficient, b Indicates the width of the loading edge, Indicates the thickness of the plate, represents the elastic Poisson's ratio of the material, E represents the elastic modulus of the material, F Indicates the magnitude of the load applied to the loading side, represents the buckling eigenvalue, e represents the natural constant, and A and B represent the fitting parameters.

[0016] Furthermore, for the shear load stiffened plate, the calculation formula of the critical stress coefficient is expressed as:

[0017] ;

[0018] In the formula, K s represents the shear critical stress coefficient.

[0019] Furthermore, for the bending load stiffened plate, the calculation formula of the critical stress coefficient is expressed as:

[0020] ;

[0021] In the formula, K b represents the critical stress coefficient for bending.

[0022] Furthermore, for the stiffened plate under biaxial compression load:

[0023] If the biaxially compressively loaded stiffened plate is a square plate, and , is the axially uniformly distributed compressive stress, is the transversely uniformly distributed compressive stress, and the critical stress is calculated as follows:

[0024] ;

[0025] In the formula, represents the critical stress in the x-direction, represents the critical stress coefficient;

[0026] If the biaxially compressive stiffened plate is a rectangular flat plate, and , calculate the critical stress using the formula:

[0027] ;

[0028] In the formula, represents the critical stress.

[0029] Furthermore, for the stiffened plate with compression-shear coupled load:

[0030] Under uniform axial compression and uniform shear load, the critical stress is calculated according to the following related equation:

[0031] ;

[0032] In the formula, R c represents the pressure coefficient, R s represents the shear coefficient, F c Indicates the magnitude of the applied pressure load, F s represents the magnitude of the applied shear load, represents the compression-shear coupled buckling eigenvalue, represents the pure compressive buckling eigenvalue, represents the pure shear buckling eigenvalue.

[0033] Furthermore, for the stiffened plate under bending-shear coupled load, the critical stress is calculated according to the following related equation:

[0034] ,

[0035] In the formula, R b represents the bending coefficient, F b Indicates the magnitude of the applied bending load.

[0036] Furthermore, the method also includes: establishing a stability analysis boundary addition criterion based on the critical stress coefficient calculated by the calculation formula of the critical stress coefficient of the multiple stiffened plates.

[0037] Furthermore, the established stability analysis boundary addition criteria are:

[0038] For unidirectional compression load, the compression critical stress coefficient of MPC connection method is lower than that of adhesive connection method, and the compression critical stress coefficients under the same connection method are: I-type > T-type > C-type > Z-type;

[0039] For shear load, the shear critical stress coefficient of the MPC connection method is lower than the compression critical stress coefficient of the adhesive method, and the shear critical stress coefficients under the same connection method are: I-type > T-type > C-type > Z-type;

[0040] For bending load, the bending critical stress coefficient of MPC connection method is lower than that of adhesive connection method, and the bending critical stress coefficient under the same connection method is: I-type > T-type > C-type > Z-type;

[0041] For bidirectional compression loads, under different sizes and connection forms, for critical stress: I-type > T-type > C-type > Z.

[0042] The technical solution provided in the embodiments of the present application has at least the following advantages:

[0043] Based on the structure's rib type, material, load and other information, this application derives the mathematical expression of the critical stress coefficient K. Through large-scale calculations, critical stress coefficient curves with different aspect ratios are obtained, and the stability analysis boundary addition criteria are further established. This method can be applied to the stability design of aircraft wall panel structures, guide the addition of stiffened panel boundaries, improve the stability of stiffened structures, and achieve further upgrades in aerospace equipment.

[0044] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0046] Figure 1 It is an overall flow chart of a calculation method for the stability of the skin and stiffened panels of a typical multi-web structure under various loads, shown in an exemplary embodiment of the present application;

[0047] Figure 2 is a schematic diagram of different rib cross-sections shown in an exemplary embodiment of the present application;

[0048] Figure 3 Schematic diagram of different connection modes of a stiffened plate model shown in an exemplary embodiment of the present application, wherein (a) represents adhesive connection, and (b) represents MPC connection;

[0049] Figure 4 is a schematic diagram of six boundary conditions shown in an exemplary embodiment of the present application; wherein (a)-(f) represent axial compression, shear load, pure bending load, bidirectional compression load, compression-shear coupled load and bending-shear coupled load, respectively;

[0050] Figure 5 is a fitting curve of the compression critical stress coefficient shown in an exemplary embodiment of the present application Figure 1 ;

[0051] Figure 6 is a fitting curve of the compression critical stress coefficient shown in an exemplary embodiment of the present application Figure 2 ;

[0052] Figure 7 is a fitting curve of the compression critical stress coefficient shown in an exemplary embodiment of the present application Figure 3 ;

[0053] Figure 8 is a fitting curve of the compression critical stress coefficient shown in an exemplary embodiment of the present application Figure 4 ;

[0054] Fig. 9 is a fitting curve of the compression critical stress coefficient shown in an exemplary embodiment of the present application Figure 5 ;

[0055] Fig.10 is a fitting curve of the compression critical stress coefficient shown in an exemplary embodiment of the present application Figure 6 ;

[0056] Fig.11is a fitting curve of the compression critical stress coefficient shown in an exemplary embodiment of the present application Figure 7 ;

[0057] Fig.12 is a fitting curve of the compression critical stress coefficient shown in an exemplary embodiment of the present application Figure 8 ;

[0058] Fig.13 is a schematic diagram of the compression critical stress coefficient of a stiffened plate shown in an exemplary embodiment of the present application;

[0059] Fig.14 is a fitting curve of the shear critical stress coefficient shown in an exemplary embodiment of the present application Figure 1 ;

[0060] Fig.15 is a fitting curve of the shear critical stress coefficient shown in an exemplary embodiment of the present application Figure 2 ;

[0061] Fig.16 is a fitting curve of the shear critical stress coefficient shown in an exemplary embodiment of the present application Figure 3 ;

[0062] Fig.17 is a fitting curve of the shear critical stress coefficient shown in an exemplary embodiment of the present application Figure 4 ;

[0063] Fig.18 is a schematic diagram of the shear critical stress coefficient of a stiffened plate shown in an exemplary embodiment of the present application;

[0064] Fig.19 is a fitting curve of the bending critical stress coefficient shown in an exemplary embodiment of the present application Figure 1 ;

[0065] Fig. 20 is a fitting curve of the bending critical stress coefficient shown in an exemplary embodiment of the present application Figure 2 ;

[0066] Fig.21 is a fitting curve of the bending critical stress coefficient shown in an exemplary embodiment of the present application Figure 3 ;

[0067] Fig. 22 is a fitting curve of the bending critical stress coefficient shown in an exemplary embodiment of the present application Figure 4 ;

[0068] Fig.23 is a fitting curve of the bending critical stress coefficient shown in an exemplary embodiment of the present application Figure 5 ;

[0069] Fig.24 is a fitting curve of the bending critical stress coefficient shown in an exemplary embodiment of the present application Figure 6 ;

[0070] Fig.25 is a fitting curve of the bending critical stress coefficient shown in an exemplary embodiment of the present application Figure 7 ;

[0071] Fig.26 is a fitting curve of the bending critical stress coefficient shown in an exemplary embodiment of the present application Figure 8 ;

[0072] Fig. 27 is a schematic diagram of the bending critical stress coefficient of a stiffened plate shown in an exemplary embodiment of the present application;

[0073] Fig.28 Schematic diagram of the critical stress of each plate under longitudinal compression and transverse compression shown in an exemplary embodiment of the present application; wherein (a) represents the critical stress of the stiffened plate under bidirectional compression when i≤1, (b) represents the critical stress of the stiffened plate under bidirectional compression when i≥1, i= a / b ; a and b represent the length and width of the loaded side respectively. DETAILED DESCRIPTION

[0074] Here, exemplary embodiments will be described in detail, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims.

[0075] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0076] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0077] The term "multiple" as used in this application refers to two or more than two. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the related objects are in an "or" relationship.

[0078] See also Figure 1 , Figure 1 This is an overall flow chart of a calculation method for the stability of a typical multi-web structure skin and stiffened panels under various loads, shown in an exemplary embodiment of the present application. The present application embodiment provides a calculation method for the stability of a typical multi-web structure skin and stiffened panels under various loads, the method comprising steps S100 to S400, which are described in detail as follows.

[0079] S100: Determine the rib type of the stiffened plate model and define model parameters; wherein the rib types of the stiffened plate model include T-type, Z-type, I-type, and C-type; and the model parameters include material elastic modulus, Poisson's ratio, density, and plate thickness.

[0080] In this embodiment, please refer to Figure 2 , is a schematic diagram of different rib cross sections, Figure 2 In the figure, examples of rib types T-type, Z-type, I-type, and C-type are given from left to right.

[0081] S200: adding different connection methods and boundary conditions to the stiffened plate model to obtain a plurality of stiffened plates; wherein the connection methods include adhesive connection and MPC connection, the boundary conditions include axial compression, shear load, pure bending load, bidirectional compression load, compression-shear coupling load and bending-shear coupling load, and the plurality of stiffened plates include axial compression load stiffened plates, shear load stiffened plates, bending load stiffened plates, bidirectional compression load stiffened plates, compression-shear coupling load stiffened plates and bending-shear coupling load stiffened plates.

[0082] In this embodiment, please refer to Figure 3 , which is a schematic diagram of different connection methods of the stiffened plate model. Figure 3 (a) indicates adhesive connection. Figure 3 (b) in the figure indicates MPC connection. Adhesive connection refers to connection using glue material. MPC connection usually refers to multi-point coupling connection. MPC connection is mainly used to simulate complex contact problems in the engineering field, such as processing the interaction between different materials in finite element analysis. As one of the MPC connection methods, nail connection will be used as an example in the subsequent embodiments.

[0083] See also Figure 4 , which is a schematic diagram of six boundary conditions. Figure 4In the figure, (a)-(f) represent the six boundary conditions: axial compression, shear load, pure bending load, biaxial compression load, compression-shear coupled load and bending-shear coupled load, respectively. a and b Respectively represent the length and width of the loading side, xOy represents the rectangular coordinate system, represents the bending stress, is the uniformly distributed compressive stress in the axial direction (end a); is the uniformly distributed compressive stress in the transverse direction (end b) (pressure is positive); represents shear stress.

[0084] S300: Modeling and modal analysis are performed on multiple stiffened panels to obtain the buckling eigenvalues ​​of the multiple stiffened panels.

[0085] In this embodiment, the large-scale rapid modeling and modal analysis of the stiffened plates are realized based on the secondary development of Abaqus software, and the buckling eigenvalues ​​of the corresponding stiffened plates are obtained.

[0086] S400: Based on the buckling eigenvalues ​​of multiple stiffened panels, the calculation formula of the critical stress coefficient of multiple stiffened panels is fitted for different types of stiffened panels and boundary conditions.

[0087] In this embodiment, the calculation formula of the critical stress coefficient of the plurality of stiffened plates can be obtained by curve fitting.

[0088] Specifically, for the axially compressive stiffened plate, under different types of stiffened plates and boundary conditions, the fitting curves of the compression critical stress coefficient are as follows: Figures 5 to 12 As shown, in Figures 5 to 12 In the figure, the unit of the horizontal axis loading edge width b is mm, and the critical stress coefficient of the stiffened plate is as follows: Fig.13 shown. Fig.13 In the figure, the horizontal axis is the aspect ratio of the loaded side, and the vertical axis is the compression critical stress coefficient. Therefore, the calculation formula for the compression critical stress coefficient can be obtained as:

[0089] ;

[0090] In the formula, K c represents the compression critical stress coefficient, b Indicates the width of the loading edge, Indicates the thickness of the plate, represents the elastic Poisson's ratio of the material, E represents the elastic modulus of the material, F Indicates the magnitude of the load applied to the loading side, represents the buckling eigenvalue, e represents the natural constant, and A and B represent the fitting parameters.

[0091] For the shear load stiffened plate, the fitting curves of the shear critical stress coefficient under different types of stiffened plates and boundary conditions are as follows: Figures 14 to 17 As shown, Figures 14 to 17 In the figure, the unit of the horizontal axis loading edge width b is mm, and the shear critical stress coefficient of the stiffened plate is as follows: Fig.18 As shown, Fig.18 In the equation, the horizontal axis is the width-to-length ratio of the loaded side, and the vertical axis is the shear critical stress coefficient. Therefore, the calculation formula for the shear critical stress coefficient can be obtained as:

[0092] ;

[0093] In the formula, K s represents the shear critical stress coefficient.

[0094] It should be noted that please combine Figure 2 , Reinforced plate is a reinforcing rib structure added to the bottom or edge of the flat plate, usually used to increase the load-bearing capacity of the flat plate, reduce deformation and improve overall stability. This structure is widely used in various engineering fields, especially in situations where high strength and stability are required. Fig.18 The shear critical stress coefficient of the flat plate shown in FIG. 1 serves as a reference in this embodiment, so the calculation formula of the shear critical stress coefficient of the flat plate is not given in detail here.

[0095] For the bending load stiffened plate, the fitting curves of the bending critical stress coefficient under different types of stiffened plates and boundary conditions are as follows: Figures 19 to 26 As shown, Figures 19 to 26 The unit of the horizontal axis loading edge width b is mm. The bending critical stress coefficient of the stiffened plate is as follows: Fig. 27 Therefore, the calculation formula of the bending critical stress coefficient can be obtained as follows:

[0096] ;

[0097] In the formula, K b represents the critical stress coefficient for bending.

[0098] For stiffened panels loaded in biaxial compression:

[0099] The critical stress of each plate under longitudinal compression and transverse compression is as follows: Fig.28 shown.

[0100] For a square plate, and , is the axially uniformly distributed compressive stress, is the transversely uniformly distributed compressive stress, and the critical stress is calculated as follows:

[0101] ;

[0102] In the formula, represents the critical stress in the x-direction, represents the critical stress coefficient.

[0103] For rectangular plates and , the critical stress can be calculated using the following formula:

[0104] ;

[0105] In the formula, represents the critical stress.

[0106] For stiffened panels with compression-shear coupled loads:

[0107] For a rectangular plate under uniform axial compression and uniform shear load, the critical stress can be calculated according to the following related equations:

[0108] ;

[0109] .

[0110] ;

[0111] ;

[0112] In the formula, R c represents the pressure coefficient, R s represents the shear coefficient, F c Indicates the magnitude of the applied pressure load, F s represents the magnitude of the applied shear load, represents the compression-shear coupled buckling eigenvalue, represents the pure compressive buckling eigenvalue, represents the pure shear buckling eigenvalue.

[0113] Stiffened plates for coupled bending and shear loads:

[0114] ;

[0115] ; represents the critical bending stress.

[0116] ;

[0117] In the formula, R b represents the bending coefficient, F bIndicates the magnitude of the applied bending load.

[0118] In some embodiments, after step S400, the method further includes step S500: establishing a stability analysis boundary addition criterion based on the critical stress coefficient calculated by the calculation formula of the critical stress coefficient of the plurality of stiffened panels.

[0119] Specifically, in step S500, for the critical stress coefficient obtained in step S400:

[0120] For uniaxial compression load, the critical stress coefficient of nail connection compression K C are lower than the adhesive method, and under the same connection method K C : I-type > T-type > C-type > Z-type, which indicates that the connection method and the shape of the ribs have a significant influence on the critical compressive stress of the stiffened plate.

[0121] For shear load, the critical stress coefficient of nail connection shear K S are lower than the adhesive method, and under the same connection method K C : I-type > T-type > C-type > Z-type, indicating that the gluing method can improve the overall stability of the structure due to its more uniform stress distribution, thus showing a higher shear critical stress coefficient under shear load. In contrast, the nailing method has a lower shear critical stress coefficient due to the stress concentration effect at the connection part.

[0122] For bending load, the critical stress coefficient of the nail connection bending K b are lower than the adhesive method, and under the same connection method K b : I-type > T-type > C-type > Z-type, indicating that I-type ribs can provide higher stiffness and better bending performance due to their larger cross-sectional moment of inertia, and therefore exhibit the highest bending critical stress coefficient;

[0123] For bidirectional compression load, it can be seen from the figure that the critical stress is :I-type > T-type > C-type > Z-type, indicating that the shape and connection method of the ribs have a significant impact on the bidirectional compression bearing capacity of the stiffened plate. Specifically, the I-type ribs can provide higher stiffness and stability under bidirectional compression loads due to their larger section moment of inertia and symmetry, and therefore exhibit the highest critical stress.

[0124] The above content is only a preferred exemplary embodiment of the present application and is not intended to limit the implementation scheme of the present application. A person skilled in the art can easily make corresponding changes or modifications based on the main concept and spirit of the present application. Therefore, the scope of protection of the present application shall be based on the scope of protection required by the claims.

Claims

1. A calculation method for the stability of the skin and stiffened panels of a typical multi-web structure under various loads, characterized in that: The method comprises: Determine the rib type of the stiffened plate model and define the model parameters; wherein the rib types of the stiffened plate model include T-type, Z-type, I-type, and C-type; the model parameters include material elastic modulus, Poisson's ratio, density, and plate thickness; Adding different connection modes and boundary conditions to the stiffened plate model to obtain a plurality of stiffened plates; wherein the connection modes include adhesive connection and MPC connection, the boundary conditions include axial compression, shear load, pure bending load, bidirectional compression load, compression-shear coupling load and bending-shear coupling load, and the plurality of stiffened plates include axial compression load stiffened plates, shear load stiffened plates, bending load stiffened plates, bidirectional compression load stiffened plates, compression-shear coupling load stiffened plates and bending-shear coupling load stiffened plates; Modeling and modal analysis of multiple stiffened panels are performed to obtain the buckling eigenvalues ​​of multiple stiffened panels; Based on the buckling eigenvalues ​​of multiple stiffened panels, the calculation formulas of the critical stress coefficients of multiple stiffened panels are fitted for different types of stiffened panels and boundary conditions.

2. The calculation method of the stability of the skin and stiffened panels of a typical multi-web structure under various loads according to claim 1 is characterized in that: For the axially compressive stiffened plate, the critical stress coefficient can be calculated as: ； In the formula, K c represents the compression critical stress coefficient, b Indicates the width of the loading edge, Indicates the thickness of the plate, represents the elastic Poisson's ratio of the material, E represents the elastic modulus of the material, F Indicates the magnitude of the load applied to the loading side, represents the buckling eigenvalue, e represents the natural constant, and A and B represent the fitting parameters.

3. The calculation method of the stability of the skin and stiffened panels of a typical multi-web structure under various loads according to claim 2 is characterized in that: For shear load stiffened panels, the critical stress coefficient can be calculated as: ； In the formula, K s represents the shear critical stress coefficient.

4. The calculation method of the stability of the skin and stiffened panels of a typical multi-web structure under various loads according to claim 3 is characterized in that: For the stiffened plate under bending load, the critical stress coefficient can be calculated as: ； In the formula, K b represents the critical stress coefficient for bending.

5. The calculation method of the stability of the skin and stiffened panels of a typical multi-web structure under various loads according to claim 4 is characterized in that: For stiffened panels loaded in biaxial compression: If the biaxially compressively loaded stiffened plate is a square plate, and , is the axially uniformly distributed compressive stress, is the transversely uniformly distributed compressive stress, and the critical stress is calculated as follows: ； In the formula, represents the critical stress in the x-direction, represents the critical stress coefficient; If the biaxially compressive stiffened plate is a rectangular flat plate, and , calculate the critical stress using the formula: ； In the formula, represents the critical stress.

6. The calculation method of the stability of the skin and stiffened panels of a typical multi-web structure under various loads according to claim 4 is characterized in that: For stiffened panels with compression-shear coupled loads: Under uniform axial compression and uniform shear load, the critical stress is calculated according to the following related equation: ； In the formula, R c represents the pressure coefficient, R s represents the shear coefficient, F c Indicates the magnitude of the applied pressure load, F s represents the magnitude of the applied shear load, represents the compression-shear coupled buckling eigenvalue, represents the pure compressive buckling eigenvalue, represents the pure shear buckling eigenvalue.

7. The calculation method of the stability of the skin and stiffened panels of a typical multi-web structure under various loads according to claim 6 is characterized in that: For the stiffened plate with bending-shear coupling load, the critical stress is calculated according to the following related equation: ； In the formula, R b represents the bending coefficient, F b Indicates the magnitude of the applied bending load.

8. The calculation method for the stability of the skin and stiffened panels of a typical multi-web structure under various loads according to any one of claims 1 to 7, characterized in that: The method further includes: establishing a stability analysis boundary addition criterion based on a critical stress coefficient calculated using a calculation formula for critical stress coefficients of the plurality of stiffened panels.

9. The calculation method of the stability of the skin and stiffened panels of a typical multi-web structure under various loads according to claim 6 is characterized in that: The established stability analysis boundary addition criteria are: For unidirectional compression load, the compression critical stress coefficient of MPC connection method is lower than that of adhesive connection method, and the compression critical stress coefficients under the same connection method are: I-type > T-type > C-type > Z-type; For shear load, the shear critical stress coefficient of the MPC connection method is lower than the compression critical stress coefficient of the adhesive method, and the shear critical stress coefficients under the same connection method are: I-type > T-type > C-type > Z-type; For bending load, the bending critical stress coefficient of MPC connection method is lower than that of adhesive connection method, and the bending critical stress coefficient under the same connection method is: I-type > T-type > C-type > Z-type; For bidirectional compression loads, under different sizes and connection forms, for critical stress: I-type > T-type > C-type > Z.

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