Strength analysis method for large opening structure of composite wing beam web plate

Abstract

This application provides a strength analysis method for a composite material wing sparb web structure with a large opening, characterized by the following steps: Step S1, determining the geometric dimensions, ply parameters, and large opening characteristics of the wing sparb web to be analyzed; Step S2, based on the geometric dimensions of the wing sparb web to be analyzed, extracting the wing sparb web from the sparse mesh model of the wing main box section, determining the mesh refinement region and boundary loading region of the extracted wing sparb web sparse mesh model, and meshing the mesh refinement region of the wing sparb web sparse mesh model based on the ply parameters. Refinement; Step S3: Based on the large opening feature, make an opening on the sparse mesh model of the wing spars web that has been extracted and refined, to obtain a refined mesh model of the wing spars web with a large opening; Step S4: Construct a solid mesh model of the cover and frame structure, nest the solid mesh model of the cover and frame structure with the refined mesh model of the wing spars web with a large opening, extract nodal displacements from the sparse mesh model of the main wing box section and apply them to the boundary loading area of ​​the nested refined mesh model of the wing spars web, and perform strength calculation.

Description

Technical Field

[0001] This application belongs to the field of aerospace structural strength technology, and specifically relates to a strength analysis method for a composite material wing spars with large openings in the web. Background Technology

[0002] In wing structural design, the spars web, as the main load-bearing component of the spars structure, participates in the overall stress distribution of the wing's main box section. It transmits tensile, compressive, shear, and bending loads generated by the bending of the main box section, accumulating gradually from the wingtip to the wing root, ultimately balancing the load through the support reaction at the wing root joint. However, due to structural inspection and maintenance requirements, multiple large openings are often required in the spars web. These large openings significantly weaken the overall load-bearing capacity of the spars structure, and the area near these openings experiences substantial loads and significant stress concentration. Accurately calculating the strength of the large openings in the spars web under complex load conditions is a challenging problem, involving factors such as the spars' geometry, ply parameters, opening characteristics, and load conditions.

[0003] Existing technologies lack research and analysis on the strength of large-opening structures in the web of spars, limiting the precise calculation and analysis of their strength. Therefore, a method is needed that can accurately calculate the strength of composite spar web structures with large openings. Summary of the Invention

[0004] The purpose of this application is to provide a strength analysis method for composite material wing beam web structures with large openings, in order to solve or mitigate at least one problem in the prior art.

[0005] The technical solution of this application is: a strength analysis method for a composite material wing beam web structure with a large opening, including:

[0006] Step S1: Determine the geometric dimensions, ply parameters, and large opening characteristics of the web of the wing beam that needs to be analyzed and calculated;

[0007] Step S2: Based on the required calculation and analysis of the geometric dimensions of the wing spar web, the wing spar web is cut out from the sparse mesh model of the main box section of the wing. The mesh refinement area and boundary loading area of ​​the cut-out wing spar web sparse mesh model are determined. The mesh refinement area of ​​the wing spar web sparse mesh model is refined based on the ply parameters.

[0008] Step S3: Based on the large opening feature, an opening is made on the sparse mesh model of the wing beam web that has been cut out and refined into a mesh, so as to obtain a refined mesh model of the wing beam web with a large opening.

[0009] Step S4: Construct a solid mesh model of the cover and frame structure, nest the solid mesh model of the cover and frame structure with the refined mesh model of the wing spars web with a large opening, extract nodal displacements from the sparse mesh model of the main wing box section and apply them to the boundary loading area of ​​the nested refined mesh model of the wing spars web, and perform strength calculation.

[0010] In at least one embodiment of this application, the geometric dimensions include the length, width and thickness of the web of the spar, the ply parameters include the ply material, the number of ply layers and the ply angle, and the large opening feature includes the opening size and the opening shape.

[0011] In at least one embodiment of this application, the mesh refinement region of the extracted sparse mesh model of the spar web is located in the central region, and the boundary loading region of the sparse mesh model of the spar web is located in the edge region.

[0012] In at least one embodiment of this application, when the solid mesh model of the cover and frame structure is nested with the refined mesh model of the wing beam web with a large opening, the connecting bolts in the nested connection model are simulated by beam elements, the connection between the solid mesh model of the cover and frame structure and the wing beam web body is connected by common nodes through split shell elements, and the nail hole edges connecting the solid mesh model of the cover and frame structure and the refined mesh model of the wing beam web are gripped and connected by rigid elements.

[0013] In at least one embodiment of this application, the method further includes: performing a safety margin analysis based on the strength calculation results to verify whether the large opening structure of the composite material wing beam web meets the requirements.

[0014] In at least one embodiment of this application, the safety margin analysis includes: hole edge strain safety margin analysis of the large opening structure of the composite material wing beam web, body stress level margin analysis of the cover and frame structure, and extrusion margin analysis of the wing beam web and metal nail hole.

[0015] In at least one embodiment of this application, the method for calculating the safety margin of the hole edge strain in the large opening structure of the composite material wing beam web is as follows:

[0016]

[0017] In the formula: Allowable principal strain for the large opening edge of the web of the composite wing beam; The absolute values ​​of the maximum and minimum working principal strains of the large opening edge element of the wing beam web are the maximum values. This refers to the safety margin of strain at the edge of the large opening hole in the web of the wing beam.

[0018] In at least one embodiment of this application, the body stress level margin of the cap and frame structure is calculated as follows:

[0019]

[0020] In the formula: S represents the allowable stress of the cover and frame structure; S represents the working stress of the cover and frame structure. This refers to the stress level margin of the cover and frame structure.

[0021] In at least one embodiment of this application, the compressive margin between the spar web and the metal nail hole is calculated as follows:

[0022]

[0023] In the formula: t is the allowable compressive stress of the web of the wing beam or the metal nail hole; F is the working load of the connecting bolt; t is the thickness of the web of the wing beam or the metal at the nail hole compression point; d is the diameter of the connecting bolt. This refers to the compression allowance between the web of the wing beam and the metal nail hole.

[0024] The method in this application fully considers factors such as the geometric dimensions, ply parameters, large opening characteristics, and load conditions of the wing spars. By nesting and connecting the cover and frame structure models with the wing spar web model, it can effectively analyze and calculate the strength problem of the large opening structure of the composite wing spar web. This provides support for the optimized design of the large opening structure of the composite wing spars of the wing and avoids problems such as the failure and damage of the large opening structure of the composite wing spars under load due to inaccurate or unrealistic calculations. Attached Figure Description

[0025] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.

[0026] Figure 1 This is a schematic diagram of a typical composite material spar with a large opening in the web.

[0027] Figure 2 This is a schematic diagram of the strength analysis method for the composite material wing beam web structure with a large opening in this application.

[0028] Figure 3 This is a schematic diagram of the sparse mesh model region division for the web of the wing beam in this application.

[0029] Figure 4 This is a detailed diagram of the mesh refinement of the large opening section of the web of the wing beam in this application.

[0030] Figure 5 This is a schematic diagram of the nested mesh model of the cover and frame structure and the wing beam web in this application.

[0031] Figure 6This is a schematic diagram of a refined mesh model of the web of a wing beam with applied nodal displacement in one embodiment of this application.

[0032] Figure 7 This is a horizontal strain contour map of the large opening structure of the composite material wing beam web in one embodiment of this application.

[0033] Figure 8 This is a stress level cloud diagram of the body structure of the lid and frame in one embodiment of this application.

[0034] Figure 9 This is a horizontal cloud diagram of the load on the connecting bolts in one embodiment of this application. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings.

[0036] like Figure 1 The diagram shows a typical composite spar web structure with an opening. Due to structural inspection and cover maintenance requirements, a large opening 2 is usually provided on the spar web 1, and a frame 3 is provided at the opening 2. The frame 3 is connected to the main structure of the spar web 1 by bolts 5, and a metal cover 4 and reinforcing ribs are provided on the frame 3 for reinforcement. In order to calculate the strength of the spar web with a large opening structure, this application proposes a strength analysis method with certain universality that can be used for composite spar webs with large openings.

[0037] like Figure 2 As shown, the strength analysis method for composite material wing beams with large openings in the web provided in this application includes:

[0038] Step S1: Determine the geometric dimensions, ply parameters, and large opening characteristics of the web of the wing beam that needs to be analyzed and calculated.

[0039] In this application, the geometric dimensions of the spar web mainly include its length, width, and thickness; the ply parameters mainly include information such as the ply material, number of ply layers, and ply angle; and the large opening features mainly include information such as the opening size and geometry of the spar web. Specifically, this application stores ply parameters by establishing a ply parameter library for composite spar webs, which contains standard readable composite material property cards for the spar web.

[0040] Step S2: Based on the required calculation and analysis of the geometric dimensions of the spar web, the spar web is extracted from the sparse mesh model of the main wing box section. The mesh refinement zone and boundary loading zone of the extracted sparse mesh model of the spar web are determined. The mesh refinement zone of the sparse mesh model of the spar web is then refined based on the ply parameters.

[0041] like Figure 3 The diagram shown in this embodiment of the application illustrates a sparse mesh model of the wing sparb web, extracted from the sparse mesh model of the wing main box section, based on the geometric dimensions of the wing sparb web to be analyzed and calculated. The edge regions of the sparse mesh model are boundary loading zones, while the central region is the mesh refinement zone. In this application, when refining the mesh refinement zone of the extracted sparse mesh model of the wing sparb web, the layup parameters of the refined mesh are inherited from the sparse mesh of the wing main box section.

[0042] Step S3: Based on the large opening feature, an opening is made on the sparse mesh model of the wing beam web that has been extracted and refined into a mesh, to obtain a refined mesh model of the wing beam web with a large opening.

[0043] like Figure 4 As shown, based on the large opening feature of the wing beam web determined in step S1, an opening is made on the sparse mesh model of the wing beam web after it has been cut and refined, thereby obtaining a refined mesh model of the wing beam web with a large opening.

[0044] Step S4: Construct a solid mesh model of the cover and frame structure, nest the solid mesh model of the cover and frame structure with the refined mesh model of the wing spars web with a large opening, extract nodal displacements from the sparse mesh model of the main wing box section and apply them to the boundary loading area of ​​the nested refined mesh model of the wing spars web, and perform strength calculation.

[0045] like Figure 5 The diagram shows a nested connection between the solid mesh model of the cap and frame structure established according to real parameters and the refined mesh model of the wing beam web with a large opening in this embodiment of the application. The connecting bolts in the nested connection model are simulated by beam elements (CBAR elements). The connection between the solid mesh model and the wing beam web body is achieved by shared node connection through split shell elements (CQUAD4). The nail hole edges connecting the solid mesh model of the cap and frame structure and the refined mesh model of the wing beam web are gripped and connected by rigid elements (RBE2).

[0046] like Figure 6As shown, the nodal displacements extracted from the sparse mesh model of the wing main box section are finally applied to the nodes corresponding to the boundary loading zone of the refined mesh model of the wing spars web to achieve the displacement boundary conditions under actual loading. The strength calculation can be performed by calling the linear static loading module in the finite element simulation software (such as NASTRAN software).

[0047] Table 1 shows the node displacements extracted from the sparse mesh model of the wing main box segment in this embodiment of the application.

[0048] Table 1 Nodal Displacements in Boundary Loading Zone

[0049] node xmm ymm zmm node xmm ymm zmm 9071101 26.00 15.90 151.58 9078701 26.41 -6.19 173.61 9071201 25.93 12.28 151.54 9078001 26.46 -10.03 173.66 9071301 25.83 8.63 151.53 9072101 26.11 16.07 154.58 9071401 25.72 4.96 151.53 9073101 26.21 16.26 157.64 9071501 25.60 1.29 151.55 9074101 26.31 16.45 160.74 9071601 25.49 -2.37 151.58 9075101 26.41 16.65 163.89 9071701 25.41 -6.00 151.62 9076101 26.50 16.86 167.07 9071001 25.39 -9.55 151.68 9077101 26.59 17.07 170.31 9078101 26.69 17.28 173.60 9072001 25.60 -9.57 154.72 9078201 26.68 13.41 173.55 9073001 25.77 -9.62 157.79 9078301 26.63 9.49 173.54 9074001 25.93 -9.67 160.90 9078401 26.57 5.56 173.53 9075001 26.08 -9.74 164.05 9078501 26.50 1.63 173.55 9076001 26.23 -9.82 167.21 9078601 26.44 -2.30 173.57 9077001 26.36 -9.90 170.44

[0050] Step S5: Based on the strength calculation results, perform a safety margin analysis to verify whether the large opening structure of the composite material wing beam web meets the requirements.

[0051] The safety margin of the hole edge strain in the large opening structure of the composite material wing beam web is calculated using the following formula:

[0052]

[0053] In the formula: Allowable principal strain for the large opening edge of the web of the composite wing beam; The absolute values ​​of the maximum and minimum working principal strains of the large opening edge element of the wing beam web are the maximum values. This refers to the safety margin of strain at the edge of the large opening hole in the web of the wing beam.

[0054] The stress margin of the cover and frame structure is calculated using the following formula:

[0055]

[0056] In the formula: S represents the allowable Mises stress of the cover and frame structure; S represents the working Mises stress of the cover and frame structure. This refers to the stress level margin of the cover and frame structure.

[0057] The compressive allowance between the web of the wing sparb and the metal nail hole can be calculated using the following formula:

[0058]

[0059] In the formula: t is the allowable compressive stress of the web of the wing beam or the metal nail hole; F is the working load of the connecting bolt; t is the thickness of the web of the wing beam or the metal at the nail hole compression point; d is the diameter of the connecting bolt. This refers to the compression allowance between the web of the wing beam and the metal nail hole.

[0060] like Figure 7 The figure shown is a horizontal strain contour plot at the edge of the large opening structure in the web of the wing beam in this embodiment of the present application. Under the composite material specifications selected in this embodiment of the present application, the allowable principal strain at the edge of the large opening structure is taken as 6000 με. The calculated result of the strain safety margin at the edge of the large opening structure in the web of the wing beam is as follows: .

[0061] like Figure 8 The figure shown is a stress level cloud diagram of the cap and frame structure in this embodiment of the application. Under the cap and frame structure selected in this embodiment, the allowable failure stress of the structure is 470 MPa. The calculated stress level margin of the cap and frame structure is as follows: .

[0062] like Figure 9 The figure shown is a horizontal cloud diagram of the load on the connecting bolts in this embodiment of the application. The connecting bolt grade used in this embodiment is YSA303-6, and the allowable compressive stress of the bolt holes in the wing beam web is 500 MPa. The calculated result of the compressive margin between the wing beam web and the metal bolt holes is as follows: .

[0063] The calculation results show that the uniform safety margin of the above structure or part is 19% at the maximum and 9% at the minimum, which meets the structural application requirements.

[0064] The method in this application fully considers factors such as the geometric dimensions, ply parameters, large opening characteristics, and load conditions of the wing spars. By nesting and connecting the cover and frame structure models with the wing spar web model, it can effectively analyze and calculate the strength problem of the large opening structure of the composite wing spar web. This provides support for the optimized design of the large opening structure of the composite wing spars of the wing and avoids problems such as the failure and damage of the large opening structure of the composite wing spars under load due to inaccurate or unrealistic calculations.

[0065] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method of strength analysis of a composite material wing spar web large opening structure, characterized by, include: Step S1: Determine the geometric dimensions, ply parameters, and large opening characteristics of the web of the wing beam that needs to be analyzed and calculated; Step S2: Based on the required calculation and analysis of the geometric dimensions of the wing spar web, the wing spar web is cut out from the sparse mesh model of the main box section of the wing. The mesh refinement area and boundary loading area of ​​the cut-out wing spar web sparse mesh model are determined. The mesh refinement area of ​​the wing spar web sparse mesh model is refined based on the ply parameters. Step S3: Based on the large opening feature, an opening is made on the sparse mesh model of the wing beam web that has been cut out and refined into a mesh, so as to obtain a refined mesh model of the wing beam web with a large opening. Step S4: Construct a solid mesh model of the cover and frame structure, nest the solid mesh model of the cover and frame structure with the refined mesh model of the wing spars web with a large opening, extract nodal displacements from the sparse mesh model of the main wing box section and apply them to the boundary loading area of ​​the nested refined mesh model of the wing spars web, and perform strength calculation.

2. The method of strength analysis of a composite spar web open-structure according to claim 1, wherein The geometric dimensions include the length, width, and thickness of the web of the spars; the ply parameters include the ply material, the number of ply layers, and the ply angle; and the large opening features include the opening size and the opening shape.

3. The method of strength analysis of a composite spar web open-structure of claim 1, wherein The mesh refinement zone of the extracted sparse mesh model of the wing beam web is located in the central region, while the boundary loading zone of the sparse mesh model of the wing beam web is located in the edge region.

4. The method of strength analysis of a composite spar web open-structure of claim 1, wherein When nesting the solid mesh model of the cap and frame structure with the refined mesh model of the wing beam web with a large opening, the connecting bolts in the nested connection model are simulated by beam elements. The connection between the solid mesh model of the cap and frame structure and the wing beam web body is achieved by using split shell elements for common node connection. The nail hole edges connecting the solid mesh model of the cap and frame structure and the refined mesh model of the wing beam web are captured and connected using rigid elements.

5. The strength analysis method of a composite spar web large opening structure according to any one of claims 1 to 4, characterized in that, Also includes: Safety margin analysis was performed based on the strength calculation results to verify whether the large opening structure of the composite material wing beam web meets the requirements.

6. The method of strength analysis of a composite spar web open-structure of claim 5, wherein The safety margin analysis includes: the hole edge strain safety margin analysis of the large opening structure of the composite material wing beam web, the body stress level margin analysis of the cover and frame structure, and the extrusion margin analysis of the wing beam web and metal nail hole.

7. The strength analysis method for a composite material wing beam with a large opening in the web as described in claim 6, characterized in that, The method for calculating the safety margin of the hole edge strain in the large opening structure of the composite material wing beam web is as follows: In the formula: Allowable principal strain for the large opening edge of the web of the composite wing beam; The absolute values ​​of the maximum and minimum working principal strains of the large opening edge element of the wing beam web are the maximum values. This refers to the safety margin of strain at the edge of the large opening hole in the web of the wing beam.

8. The strength analysis method for a composite material wing beam with a large opening in the web as described in claim 6, characterized in that, The stress margin of the cap and frame structure is calculated as follows: In the formula: S represents the allowable stress of the cover and frame structure; S represents the working stress of the cover and frame structure. This refers to the stress level margin of the cover and frame structure.

9. The strength analysis method for a composite material wing beam with a large opening in the web as described in claim 6, characterized in that, The compressive margin between the web of the wing beam and the metal nail hole is calculated as follows: In the formula: t is the allowable compressive stress of the web of the wing beam or the metal nail hole; F is the working load of the connecting bolt; t is the thickness of the web of the wing beam or the metal at the nail hole compression point; d is the diameter of the connecting bolt. This refers to the compression allowance between the web of the wing beam and the metal nail hole.

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