A design method and system for bolt-connected split receiver flange structure

Abstract

The present invention belongs to the field of aero-engines, relates to composite material numerical simulation and structural design technology, and provides a design method and system for a bolted split casing flange structure, the method comprising: establishing a finite element simulation of the bolted flange structure of the split casing, the simulation comprising two metal pressure plates and two L-shaped parts; obtaining the aerodynamic load of the bolted flange structure of the split casing under service conditions, and calculating the equivalent load applied to the finite element simulation according to the aerodynamic load using a stress equivalent formula and structural geometry differences; performing a strength analysis on the finite element simulation according to the equivalent load, and iteratively optimizing the bolt flange structure parameters according to the strength analysis results until a bolt flange structure that meets the strength reserve design requirements is obtained. The method of the present invention improves the iterative optimization efficiency, provides support for the forward design and engineering application of the flange structure, and improves the iteration speed and R&D efficiency of the bolted composite split casing structure.

Description

Technical Field

[0001] The present invention belongs to the field of aero-engines, relates to composite material numerical simulation and structural design technology, and in particular to a design method and system for a bolt-connected split casing flange structure. Background Art

[0002] Fiber-reinforced composites are widely used in aeroengines due to their high specific strength, high specific stiffness, fatigue resistance, and strong designability. Composite casings can significantly reduce the mass of the casing itself, which is of great significance for improving engine efficiency. The use of composite casings can greatly improve the efficiency and performance of aircraft and aeroengines, but their connection structure is often the weak link in actual load-bearing conditions.

[0003] At present, bolt connection structure is a commonly used form of flange connection for composite material casings, which can transmit higher loads. Therefore, targeted design and research are carried out on the bolt connection structure of composite material casings so that the connection position meets the strength design requirements without excessive redundant design. For example: Liu Yulin et al. conducted a strength analysis on the bolted flange structure of the resin-based composite casing based on the experimental results, and established a progressive damage simulation model of the flange structure (from Liu Yulin, Strength Analysis and Experimental Research on the Connection of the Flanged Structure of Resin-based Composite Casings, Nanjing University of Aeronautics and Astronautics); for example: Lei Xianhua et al. used the finite element method to compare the strength of the casing with a bolted flange structure. The results showed that for a split casing, not considering the front and rear connecting parts of the casing in the strength calculation will cause errors in the calculation results, so the influence of the front and rear connecting parts (generally the connecting casing) should be considered (from Lei Xianhua, Du Wenjun, Gong Mengxian. Stress Analysis of Casing. Gas Turbine Test and Research); for another example: Dong Benhan et al. cited a variety of experimental mechanics methods when studying the bolted flange structure of the casing, from which they obtained the connection characteristics of the flange structure, as well as the deformation, stress and internal force and stress of the bolt at the casing flange structure during loading (from Dong Benhan, Gao Pengfei, Wang Zhenhua. Hybrid Method for Stress Analysis of Casing Flanged Structure. Aeroengine).

[0004] Based on the above content, it can be seen that most current studies are based on the existing typical parts of the casing bolt connection flange structure, establish corresponding strength simulation models, and verify the accuracy of the strength model by comparing with the test results. They explored the influence of the casing flange structure size parameters on the strength, but did not design the flange typical parts according to the actual load conditions and structural form of the casing flange full-size parts. They did not establish the connection between the casing flange structure and its typical parts, and could not directly apply the results of the typical parts to the casing flange structure. In addition, due to the complex contact between the bolts and nuts and the application of tightening force, the calculation efficiency will be greatly affected during the calculation, and even non-convergence will occur, which hinders the forward design of the casing flange structure.

[0005] Therefore, it is necessary to provide a simple, effective and highly applicable method to solve the current problems of lack of design methods for typical parts of bolted composite split receiver flange structures and low calculation efficiency. Summary of the Invention

[0006] In order to solve the problems of the lack of typical design methods for bolt-connected composite split receiver flange structures and low calculation efficiency, the present invention discloses a design method for bolt-connected split receiver flange structures, which includes the following steps:

[0007] S1. Establish a finite element simulation of a bolt flanging structure of a split receiver, wherein the finite element simulation comprises two metal pressure plates and two L-shaped parts, wherein the two L-shaped parts are simplified parts of the upper and lower receiver halves, respectively;

[0008] S2. Obtaining an aerodynamic load of the bolt flanging structure of the split casing under a service condition, and calculating an equivalent load applied to the finite element simulation component based on the aerodynamic load;

[0009] S3. Perform a strength analysis on the finite element simulation component according to the equivalent load, and iteratively optimize the parameters of the bolt flanging structure of the split receiver according to the strength analysis result until a bolt flanging structure that meets the strength reserve design requirements is obtained.

[0010] Furthermore, in step S1, a finite element simulation of the bolt flanging structure of the split receiver is established, including:

[0011] S11. Select a bolt flange structure on a split receiver as a typical component, wherein the typical component includes a bolt, a metal pressure plate, and a section of an upper receiver half and a section of a lower receiver half connected by the bolts;

[0012] S12. Simplify the upper and lower casing halves into L-shaped parts, respectively, and map the outermost contour lines of the bolts to the metal pressure plate and the longitudinal mounting edges of the L-shaped parts, respectively, to obtain a simplified model including the metal pressure plate and the two L-shaped parts;

[0013] S13, meshing the simplified model to obtain a finite element simulation part.

[0014] Furthermore, in step S2, the aerodynamic load of the bolt flanging structure of the split casing under service conditions is obtained, and the equivalent load applied to the finite element simulation component is calculated according to the aerodynamic load, including:

[0015] S21, matching the position of the end of the L-shaped member on the split casing, and obtaining the aerodynamic load borne by the matched position under service conditions;

[0016] S22. Based on the constructed stress equivalent formula, convert the aerodynamic load into a tensile load, where the tensile load includes a lateral load at the matching position and a vertical load at the matching position;

[0017] S23. Perform a geometric structure difference analysis based on the dimensional parameters of the L-shaped member and the dimensional parameters of the split casing to convert the tensile load into an equivalent load, wherein the equivalent load includes a lateral load at the matching position and a vertical load at the matching position.

[0018] Furthermore, in step S22, the stress equivalent formula includes the formula and , according to the formula and The aerodynamic load is converted into a tensile load, wherein To match the position lateral load, To match the vertical load at the position, Q is the pressure load, R is the radius of the split receiver, S is the length of the L-shaped part, and L is the width of the L-shaped part.

[0019] Furthermore, in step S23, a geometric structure difference analysis is performed based on the dimensional parameters of the L-shaped member and the dimensional parameters of the split casing to convert the tensile load into an equivalent load, including:

[0020] S231. Define the equivalent load applied to the finite element simulation component to include a simulation component lateral load and a simulation component vertical load;

[0021] S232, using the matching position lateral load as the simulation component lateral load;

[0022] S233, obtain the distance between the center of the bolt hole on the L-shaped member and the outer edge of the mounting edge, using the formula Calculate the vertical load of the simulation component, wherein: is the vertical load of the simulated component, a is the distance between the center of the bolt hole on the L-shaped component and the outer edge of the installation edge, is a variable, taking values∈(0, ), d Express Integration; X is a variable, taking value∈(a, ), dx represents the integral with respect to X.

[0023] Furthermore, in step S3, strength analysis is performed on the finite element simulation component according to the equivalent load, including:

[0024] S31. For the finite element simulation component, the mesh of the metal pressure plate and the mesh of the longitudinal installation edge of the L-shaped component are divided into a group based on the outermost contour line of the bolt and bounded;

[0025] S32, establishing friction constraints on the unbound meshes in the finite element simulation component, and applying a forced displacement equal to the bolt setback length to the bound meshes on the outer sides of the two metal pressure plates;

[0026] S33. Fix one end of the finite element simulation component, apply the equivalent load to the other end to obtain stress distribution, obtain the current strength reserve based on the stress distribution and failure criterion, and perform strength analysis based on the current strength reserve and strength reserve design requirements.

[0027] Furthermore, in step S33, the failure criteria include a Hashin failure criterion and a maximum stress failure criterion, the Hashin failure criterion being that the current strength reserve is ≥ 1.5 times the strength reserve design requirement, and the maximum stress failure criterion being that the current strength reserve is ≥ 1.05 times the strength reserve design requirement.

[0028] An embodiment of the present invention further provides a design system for a bolt-connected split casing flange structure, comprising a simulation component construction module, an equivalent load calculation module, and a structural parameter iterative optimization module.

[0029] The simulation component construction module is used to establish a finite element simulation component of the bolt flange structure of the split receiver, and the finite element simulation component includes two metal pressure plates and two L-shaped components, wherein the two L-shaped components are simplified components of the upper half of the receiver and the lower half of the receiver respectively;

[0030] The equivalent load calculation module is used to obtain the aerodynamic load of the bolt flange structure of the split casing under service conditions, and calculate the equivalent load applied to the finite element simulation component based on the aerodynamic load;

[0031] The structural parameter iterative optimization module is used to perform strength analysis on the finite element simulation component according to the equivalent load, and iteratively optimize the parameters of the bolt flange structure of the split receiver according to the strength analysis results until a bolt flange structure that meets the strength reserve design requirements is obtained.

[0032] Compared with the prior art, the at least one technical solution adopted in the embodiments of this specification can achieve the following beneficial effects:

[0033] 1. The method of the present invention can quickly design the flange structure according to the structural characteristics of the composite casing itself and the actual working conditions.

[0034] 2. By converting the aerodynamic load on the composite casing flange structure into a tensile load, and then converting the tensile load on the flange structure into an equivalent load of a typical part based on the structural differences between the casing flange structure and the finite element simulation part, consistency of load effects is achieved, so that the calculation results of the finite element simulation part can support the strength design of the full-size part. At the same time, the stress distribution calculation model is optimized by mesh grouping and binding and applying friction constraints, thereby improving the efficiency of iterative calculation.

[0035] 3. Compared with the existing technology, the present invention takes into account the load changes caused by the differences between the casing flange structure and the finite element simulation parts, and optimizes the stress distribution calculation model. It can perform forward design on the casing flange structure of resin-based composite materials with different material systems and preparation processes, thereby improving the iteration speed and R&D efficiency of the composite casing structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0037] Figure 1 A flow chart of a design method for a bolt-connected split receiver flange structure disclosed in an embodiment of the present invention;

[0038] Figure 2 This is an execution diagram of a design method for a bolt-connected split receiver flange structure disclosed in an embodiment of the present invention;

[0039] Figure 3 A schematic diagram of a finite element simulation component disclosed in an embodiment of the present invention;

[0040] Figure 4 This is an architectural diagram of a design system for a bolt-connected split-casing flange structure disclosed in an embodiment of the present invention;

[0041] Among them, 401 is a simulation component construction module; 402 is an equivalent load calculation module; and 403 is a structural parameter iterative optimization module. DETAILED DESCRIPTION

[0042] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0043] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the features of the following embodiments and embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of this application.

[0044] An embodiment of the present invention discloses a method for designing a bolt-connected split receiver flange structure. Taking a resin-based composite split receiver with a radius of 400 mm and a height of 500 mm, which is subjected to a maximum pressure of 0.4 MPa during use, as an example, the present invention designs the parameters of its connection structure (including bolts, nuts, and a metal pressure plate, the material of which is GH4169).

[0045] See also Figure 1 and Figure 2 As shown, the method includes the following steps:

[0046] S1. Establish a finite element simulation of a bolt flanging structure of a split receiver, wherein the finite element simulation comprises two metal pressure plates and two L-shaped parts, wherein the two L-shaped parts are simplified parts of the upper and lower receiver halves, respectively;

[0047] S2. Obtaining an aerodynamic load of the bolt flanging structure of the split casing under a service condition, and calculating an equivalent load applied to the finite element simulation component based on the aerodynamic load;

[0048] S3. Perform a strength analysis on the finite element simulation component according to the equivalent load, and iteratively optimize the parameters of the bolt flanging structure of the split receiver according to the strength analysis result until a bolt flanging structure that meets the strength reserve design requirements is obtained.

[0049] Furthermore, in step S1, a finite element simulation of the bolt flanging structure of the split receiver is established, including:

[0050] S11. Select a bolt flanging structure on a split receiver as a typical part, wherein the typical part includes a bolt, a metal pressure plate, and a section of an upper receiver and a section of a lower receiver connected by bolts.

[0051] S12. Simplify the upper and lower casing halves into L-shaped parts, respectively, and map the outermost contour lines of the bolts to the metal pressure plate and the longitudinal mounting edges of the L-shaped parts, respectively, to obtain a simplified model including the metal pressure plate and the two L-shaped parts.

[0052] During specific implementation, the length of the L-shaped part needs to meet the clamping requirements of the strength test and is generally not less than 100 mm. During the implementation of the present invention, the length of the L-shaped part is set to 100 mm and the width is 50 mm (two holes for bolts to pass through are provided in its width direction). The flange height and thickness of the L-shaped part, as well as the dimensions of the metal pressure plate and bolts are consistent with the flange structure of the composite split receiver. For example, the flange height and thickness can be set to 37 mm and 4 mm respectively, the width of the metal pressure plate is set to 50 mm and the thickness is 3 mm. The bolts are M8 bolts, and the center of the bolt hole is 11 mm away from the inner edge of the mounting edge.

[0053] When building a simplified model, you can import the L-shaped part, metal pressure plate and bolt model into the Ansa software, map the outermost contour line of the nut to the metal pressure plate and the longitudinal mounting edge flange, and then delete the bolt and nut structure.

[0054] S13, mesh the simplified model to obtain Figure 3 The finite element simulation shown.

[0055] Furthermore, in step S2, the aerodynamic load of the bolt flanging structure of the split casing under service conditions is obtained, and the equivalent load applied to the finite element simulation component is calculated according to the aerodynamic load, including:

[0056] S21, matching the position of the end of the L-shaped member on the split casing, and obtaining the aerodynamic load borne by the matched position under service conditions;

[0057] S22. Based on the constructed stress equivalent formula, convert the aerodynamic load into a tensile load, where the tensile load includes a lateral load at the matching position and a vertical load at the matching position;

[0058] S23. Perform a geometric structure difference analysis based on the dimensional parameters of the L-shaped member and the dimensional parameters of the split casing to convert the tensile load into an equivalent load, wherein the equivalent load includes a lateral load at the matching position and a vertical load at the matching position.

[0059] Furthermore, in step S22, the stress equivalent formula includes the formula and , according to the formula and The aerodynamic load is converted into a tensile load, wherein To match the lateral load of the position, For the matching position vertical load, Q is the pressure load, R is the radius of the split receiver, S is the length of the L-shaped part, and L is the width of the L-shaped part. Based on the parameters provided in step S12 above, it can be calculated that F1 is 7762N and F2 is 1935N.

[0060] Furthermore, in step S23, a geometric structure difference analysis is performed based on the dimensional parameters of the L-shaped member and the dimensional parameters of the split casing to convert the tensile load into an equivalent load, including:

[0061] S231. Define the equivalent load applied to the finite element simulation component to include a simulation component lateral load and a simulation component vertical load;

[0062] S232, using the matching position lateral load F1 as the simulation component lateral load T1;

[0063] S233, obtain the distance between the center of the bolt hole on the L-shaped member and the outer edge of the mounting edge, using the formula Calculate the vertical load of the simulation component, where: is the vertical load of the simulated component, a is the distance between the center of the bolt hole on the L-shaped component and the outer edge of the installation edge, is a variable, taking values∈(0, ), d Express Integration; X is a variable, taking value∈(a, ), dx represents the integral of X. Through calculation, the lateral load of the simulated part is 7762N, and the vertical load of the simulated part is 2515N.

[0064] Furthermore, in step S3, strength analysis is performed on the finite element simulation component according to the equivalent load, including:

[0065] S31. For the finite element simulation part, the mesh of the metal pressure plate and the mesh of the longitudinal installation edge of the L-shaped part are divided into a group based on the outermost contour line of the bolt and bounded.

[0066] S32. Establish friction constraints on the unbound meshes in the finite element simulation component, and apply a forced displacement equal to the bolt setback length to the bound meshes on the outer sides of the two metal pressure plates. In practice, when M8 bolts are used, the converted forced displacement is 0.45 mm.

[0067] S33. Fix one end of the finite element simulation component, apply the equivalent load to the other end to obtain stress distribution, obtain the current strength reserve based on the stress distribution and failure criterion, and perform strength analysis based on the current strength reserve and strength reserve design requirements.

[0068] Furthermore, in step S33, the failure criteria include the Hashin failure criterion and the maximum stress failure criterion. The Hashin failure criterion is that the current strength reserve is ≥ 1.5 times the design strength reserve requirement, and the maximum stress failure criterion is that the current strength reserve is ≥ 1.05 times the design strength reserve requirement. If the strength reserve requirement is not met, parameters such as the metal plate thickness, flange size, flange thickness, bolt hole spacing, and bolt hole margin can be modified to form a new bolt flange structure, which is then subjected to strength analysis.

[0069] The method of the present invention has the following advantages:

[0070] 1. The method of the present invention can quickly design the flange structure according to the structural characteristics of the composite casing itself and the actual working conditions.

[0071] 2. By converting the aerodynamic load on the composite casing flange structure into a tensile load, and then converting the tensile load on the flange structure into an equivalent load of a typical part based on the structural differences between the casing flange structure and the finite element simulation part, consistency of load effects is achieved, so that the calculation results of the finite element simulation part can support the strength design of the full-size part. At the same time, the stress distribution calculation model is optimized by mesh grouping and binding and applying friction constraints, thereby improving the efficiency of iterative calculation.

[0072] 3. Compared with the existing technology, the present invention takes into account the load changes caused by the differences between the casing flange structure and the finite element simulation parts, and optimizes the stress distribution calculation model. It can perform forward design on the casing flange structure of resin-based composite materials with different material systems and preparation processes, thereby improving the iteration speed and R&D efficiency of the composite casing structure.

[0073] Based on the same inventive concept, an embodiment of the present invention also provides a design system for a bolted split receiver flanging structure, as described in the following embodiments. Since the principle of solving the problem by the design system for a bolted split receiver flanging structure is similar to the design method for a bolted split receiver flanging structure disclosed in the above embodiments, the implementation of the design system for a bolted split receiver flanging structure can refer to the implementation of the design method for a bolted split receiver flanging structure, and the repeated parts will not be repeated. As used below, the term "unit" or "module" can be a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, implementation in hardware, or a combination of software and hardware, is also possible and conceivable.

[0074] Figure 4 This is a structural block diagram of a design system for a bolt-connected split casing flange structure disclosed in an embodiment of the present invention, such as Figure 4As shown, the system includes a simulation component construction module 401, an equivalent load calculation module 402 and a structural parameter iterative optimization module 403, and the structure is described below.

[0075] The simulation component construction module 401 is used to establish a finite element simulation component of the bolt flange structure of the split receiver, and the finite element simulation component includes two metal pressure plates and two L-shaped components, wherein the two L-shaped components are simplified components of the upper half of the receiver and the lower half of the receiver respectively;

[0076] The equivalent load calculation module 402 is used to obtain the aerodynamic load of the bolt flange structure of the split casing under service conditions, and calculate the equivalent load applied to the finite element simulation component based on the aerodynamic load;

[0077] The structural parameter iterative optimization module 403 is used to perform strength analysis on the finite element simulation component according to the equivalent load, and iteratively optimize the parameters of the split receiver bolt flange structure according to the strength analysis results until a bolt flange structure that meets the strength reserve design requirements is obtained.

[0078] In this embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the design method of any of the above-mentioned bolt-connected split receiver flange structures is implemented to solve the current problems of lack of design methods for typical parts of bolt-connected composite material split receiver flange structures and low computational efficiency.

[0079] Specifically, the computer device may be a computer terminal, a server or a similar computing device.

[0080] In this embodiment, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program for executing any of the above-mentioned methods for designing a bolt-connected split receiver flange structure.

[0081] Specifically, computer-readable storage media include permanent and non-permanent, removable and non-removable media that can be used to store information by any method or technology. The information can be computer-readable instructions, data structures, program modules or other data. Examples of computer-readable storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, tape disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable storage media does not include transitory media such as modulated data signals and carrier waves.

[0082] Obviously, those skilled in the art should understand that the various modules or steps of the above-mentioned embodiments of the present invention can be implemented using a general-purpose computing device, they can be concentrated on a single computing device, or distributed across a network composed of multiple computing devices. Alternatively, they can be implemented using program code executable by the computing device, so that they can be stored in a storage device and executed by the computing device. In some cases, the steps shown or described can be performed in a different order than herein, or they can be made into separate integrated circuit modules, or multiple modules or steps can be made into a single integrated circuit module for implementation. Thus, the embodiments of the present invention are not limited to any specific combination of hardware and software.

[0083] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A design method for a bolt-connected split receiver flange structure, characterized in that: include: Establishing a finite element simulation of a bolt flange structure of a split receiver, the finite element simulation comprising two metal pressure plates and two L-shaped parts, wherein the two L-shaped parts are simplified parts of the upper and lower receiver halves, respectively, including: selecting a bolt flange structure on the split receiver as a typical part, the typical part comprising a bolt, a metal pressure plate, and a section of the upper and lower receiver halves connected by bolts; simplifying the upper and lower receiver halves into L-shaped parts, respectively, mapping the outermost contour lines of the bolts to the metal pressure plate and the longitudinal mounting edges of the L-shaped parts, respectively, to obtain a simplified model comprising the metal pressure plate and the two L-shaped parts; and meshing the simplified model to obtain a finite element simulation; Obtaining the aerodynamic load of the bolt flanging structure of the split receiver under service conditions, and calculating the equivalent load applied to the finite element simulation component based on the aerodynamic load, including: matching the position of the end of the L-shaped component on the split receiver to obtain the aerodynamic load borne by the matched position under service conditions; converting the aerodynamic load into a tensile load based on a constructed stress equivalent formula, wherein the tensile load includes a lateral load at the matching position and a vertical load at the matching position; and performing a geometric structure difference analysis based on dimensional parameters of the L-shaped component and dimensional parameters of the split receiver to convert the tensile load into an equivalent load, wherein the equivalent load includes a lateral load at the matching position and a vertical load at the matching position; A strength analysis is performed on the finite element simulation component according to the equivalent load, and parameters of the split receiver bolt flange structure are iteratively optimized according to the strength analysis results until a bolt flange structure that meets the strength reserve design requirements is obtained.

2. The design method of the bolt-connected split-casing flange structure according to claim 1 is characterized in that: The stress equivalent formula includes the formula and , according to the formula and The aerodynamic load is converted into a tensile load, wherein To match the lateral load of the position, To match the vertical load at the position, Q is the pressure load, R is the radius of the split receiver, S is the length of the L-shaped part, and L is the width of the L-shaped part.

3. The design method of the bolt-connected split-casing flange structure according to claim 2 is characterized in that: According to the dimensional parameters of the L-shaped member and the dimensional parameters of the split casing, a geometric structure difference analysis is performed to convert the tensile load into an equivalent load, including: Defining that the equivalent load applied to the finite element simulation component includes a simulation component lateral load and a simulation component vertical load; Using the matching position lateral load as the simulation part lateral load; Get the distance between the center of the bolt hole on the L-shaped part and the outer edge of the mounting edge, using the formula Calculate the vertical load of the simulation component, where: is the vertical load of the simulated component, a is the distance between the center of the bolt hole on the L-shaped component and the outer edge of the installation edge, is a variable, taking values∈(0, ), d Express Integration; X is a variable, taking value∈(a, ), dx represents the integral with respect to X.

4. The design method of the bolt-connected split-casing flange structure according to claim 1 is characterized in that: Performing strength analysis on the finite element simulation component according to the equivalent load includes: For the finite element simulation part, the mesh of the metal pressure plate and the mesh of the longitudinal installation edge of the L-shaped part are divided into a group based on the outermost contour line of the bolt and bounded; Establishing friction constraints on unbound meshes in the finite element simulation component, and applying a forced displacement equal to the bolt setback length to the bound meshes on the outer sides of the two metal pressure plates; Fix one end of the finite element simulation component, apply the equivalent load to the other end to obtain stress distribution, obtain the current strength reserve based on the stress distribution and failure criterion, and perform strength analysis based on the current strength reserve and strength reserve design requirements.

5. The design method of the bolt-connected split-casing flange structure according to claim 4 is characterized in that: The failure criteria include the Hashin failure criterion and the maximum stress failure criterion. The Hashin failure criterion is that the current strength reserve is ≥ 1.5 times the strength reserve design requirement, and the maximum stress failure criterion is that the current strength reserve is ≥ 1.05 times the strength reserve design requirement.

6. A design system for bolt-connected split-casing flange structures, characterized in that: include: A simulation component construction module, wherein the simulation component construction module is used to establish a finite element simulation component of a bolt flange structure of a split receiver, the finite element simulation component comprising two metal pressure plates and two L-shaped components, wherein the two L-shaped components are simplified components of the upper and lower receiver halves, respectively, including: selecting a bolt flange structure on the split receiver as a typical component, wherein the typical component comprises a bolt, a metal pressure plate, and a section of the upper and lower receiver halves connected by bolts; simplifying the upper and lower receiver halves into L-shaped components, respectively, mapping the outermost contour lines of the bolts to the metal pressure plate and the longitudinal mounting edges of the L-shaped components, respectively, to obtain a simplified model comprising the metal pressure plate and the two L-shaped components; and meshing the simplified model to obtain a finite element simulation component; An equivalent load calculation module is used to obtain the aerodynamic load of the bolt flange structure of the split casing under service conditions, and calculate the equivalent load applied to the finite element simulation part based on the aerodynamic load, including: matching the position of the end of the L-shaped part on the split casing to obtain the aerodynamic load borne by the matched position under service conditions; based on the constructed stress equivalent formula, converting the aerodynamic load into a tensile load, wherein the tensile load includes a lateral load at the matching position and a vertical load at the matching position; and performing a geometric structure difference analysis based on the dimensional parameters of the L-shaped part and the dimensional parameters of the split casing to convert the tensile load into an equivalent load, wherein the equivalent load includes a lateral load at the matching position and a vertical load at the matching position. A structural parameter iterative optimization module is used to perform a strength analysis on the finite element simulation component according to the equivalent load, and iteratively optimize the parameters of the bolt flange structure of the split receiver according to the strength analysis results until a bolt flange structure that meets the strength reserve design requirements is obtained.

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