Complex curved surface structure distribution aerodynamic force loading method

Abstract

The invention provides a complex curved surface structure distribution aerodynamic force loading method. The complex curved surface structure distribution aerodynamic force loading method comprises the steps that a geometric model of a complex curved surface structure is established; establishing a finite element model of the complex curved surface structure according to the geometric model; processing the original pneumatic discrete data by adopting a Fortran language to obtain pneumatic discrete data which can be identified by finite element software, and establishing a load domain; coupling the finite element model with the processed pneumatic discrete data to form a structural finite element model with pneumatic discrete load data, and performing simulation analysis based on the structural finite element model with the pneumatic discrete load data to obtain static strength and stability results of the complex curved surface. By applying the technical scheme provided by the invention, the technical problem that the real loading condition of the complex curved surface structure cannot be simulated in the prior art can be solved.

Description

Technical Field

[0001] The invention relates to the technical field of structural strength design simulation, and in particular to a method for distributing aerodynamic force loading on a complex curved surface structure. Background Art

[0002] At present, the structures of drone hoods, radomes, air inlets, etc. need to meet the requirements of the load equipment dimensions while enabling the aircraft to obtain better aerodynamic performance, and usually adopt complex curved surface structures. Under the action of aerodynamic loads in the air, the uneven distribution of aerodynamic force is extremely significant.

[0003] Due to the uneven distribution of aerodynamic forces under the action of aerodynamic loads in the air, when designing the static strength of a structure, if the structure is loaded in the conventional loading form (i.e., in the concentrated force form), it cannot accurately reflect the actual loading conditions of the structure. At the same time, the finite element software cannot recognize the aerodynamic distribution load data input by the aerodynamic professional, and cannot simulate the loading conditions. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0005] The present invention provides a method for distributing aerodynamic force loading on a complex curved surface structure, and the method comprises: establishing a geometric model of a complex curved surface structure; establishing a finite element model of the complex curved surface structure according to the geometric model; processing original aerodynamic discrete data by using Fortran language to obtain aerodynamic discrete data recognizable by finite element software, and establishing a load domain; coupling the finite element model with the processed aerodynamic discrete data to form a structural finite element model with aerodynamic discrete load data, and performing simulation analysis based on the structural finite element model with aerodynamic discrete load data to obtain static strength and stability results of the complex curved surface; wherein, processing the original aerodynamic discrete data by using Fortran language specifically comprises:

[0006] (1) Process the node coordinate data of the original aerodynamic discrete data to obtain the nodes file;

[0007] (2) Processing unit data to obtain elements file;

[0008] (3) Obtain the bdf file based on the nodes file and elements file;

[0009] (4) Process pressure data to obtain field files;

[0010] The coupling of the finite element model with the processed aerodynamic discrete data specifically includes:

[0011] (1) Import the bdf file and field file into patran;

[0012] (2) The data in the field file is converted into a pressure load and loaded onto the aerodynamic grid in the bdf file;

[0013] (3) Converting the node-based discrete load data on the aerodynamic grid into continuous load data based on a complex surface;

[0014] (4) Import the finite element model into Patran;

[0015] (5) Interpolate the continuous load data based on complex surfaces into the finite element model to achieve the coupling of aerodynamic data and structural finite element model.

[0016] Furthermore, the finite element model of the complex curved surface structure is simulated using shell elements.

[0017] Furthermore, the Fortran node processing program is run to automatically number the nodes and correspond them one by one with the X-coordinate, Y-coordinate and Z-coordinate, forming a nodes file that can be recognized by the finite element pre-processing software patran.

[0018] Furthermore, the Fortran unit processing program is run to automatically extract the data of the unit structure from the original pneumatic discrete data file to form an elements file that can be recognized by Patran.

[0019] Furthermore, the data in the nodes file and the elements file are integrated into a bdf file to form the finite element mesh data of the aerodynamic model that can be recognized by Patran.

[0020] Furthermore, the Fortran pressure data processing program is run to correspond the pressure data to the node data one by one to form a field file with the suffix csvl.

[0021] Furthermore, use the fields command in patran to import the field file.

[0022] Furthermore, the pressure command in patran is used to convert the data in the field file into a pressure load and load it onto the aerodynamic grid in the bdf file.

[0023] Furthermore, the field command in patran is used to transform the discrete load data based on nodes on the aerodynamic grid into continuous load data based on complex surfaces.

[0024] Furthermore, create a new group in patran and import the finite element model into the new group.

[0025] Furthermore, the pressure command in patran is used to interpolate the continuous load data based on the complex surface into the finite element model.

[0026] By applying the technical solution of the present invention, a method for distributing aerodynamic force loading on a complex curved surface structure is provided. The method for distributing aerodynamic force loading on a complex curved surface structure uses the Fortran language to process aerodynamic discrete data so that it can be successfully recognized by finite element software, and the discrete aerodynamic data is coupled with the structural finite element model to achieve distributed aerodynamic force loading on the complex curved surface. The distributed aerodynamic force loading method of the present invention can truly and accurately simulate the actual loading conditions of the complex curved surface, and provide reliable static strength and stability analysis results of the complex curved surface. Compared with the prior art, the technical solution of the present invention can solve the technical problem that the prior art cannot simulate the actual loading conditions of the complex curved surface structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The included drawings are used to provide a further understanding of the embodiments of the present invention, which constitute a part of the specification, are used to illustrate the embodiments of the present invention, and together with the text description, explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 A schematic flow chart of a method for distributing aerodynamic force loading on a complex curved surface structure according to a specific embodiment of the present invention is shown;

[0029] Figure 2 A schematic diagram of a geometric model of a complex curved surface structure provided according to a specific embodiment of the present invention is shown;

[0030] Figure 3 A schematic diagram of a finite element model of a complex curved surface structure provided according to a specific embodiment of the present invention is shown;

[0031] Figure 4 The original aerodynamic data cloud diagram is shown;

[0032] Figure 5 The figure shows a pneumatic data cloud diagram (taking into account the pressure difference) that can be identified by finite element software after being processed by Fortran language according to a specific embodiment of the present invention;

[0033] Figure 6 The finite element model provided according to a specific embodiment of the present invention and the processed pneumatic discrete data coupling model are shown. DETAILED DESCRIPTION

[0034] It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0036] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present invention. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0037] like Figures 1 to 6 As shown, according to a specific embodiment of the present invention, a method for loading aerodynamic forces distributed on a complex curved surface structure is provided, and the method for loading aerodynamic forces distributed on a complex curved surface structure comprises:

[0038] Establish geometric models of complex surface structures;

[0039] Establish finite element model of complex surface structure based on geometric model;

[0040] The original pneumatic discrete data are processed by Fortran language to obtain pneumatic discrete data recognizable by finite element software and establish the load domain;

[0041] The finite element model is coupled with the processed aerodynamic discrete data to form a structural finite element model with aerodynamic discrete load data;

[0042] Based on the structural finite element model with aerodynamic discrete load data, simulation analysis is carried out to obtain the static strength and stability results of complex curved surfaces.

[0043] By applying this configuration, a method for distributing aerodynamic force loading on a complex curved surface structure is provided. The method for distributing aerodynamic force loading on a complex curved surface structure uses Fortran language to process aerodynamic discrete data, so that the data can be successfully recognized by finite element software, and the discrete aerodynamic data is coupled with the structural finite element model to achieve distributed aerodynamic force loading on the complex curved surface. The distributed aerodynamic force loading method of the present invention can truly and accurately simulate the actual loading conditions of the complex curved surface, and provide reliable static strength and stability analysis results of the complex curved surface.

[0044] Furthermore, in the present invention, a geometric model of a complex curved surface structure is firstly established.

[0045] In the present invention, the curvature of the complex curved surface is generally relatively large, and its material can be glass fiber, carbon fiber or composite honeycomb sandwich structure according to the use requirements. The complex curved surface is connected to the surrounding structure by nails. Figure 2 shown.

[0046] Furthermore, after the geometric model of the complex curved surface structure is established, a finite element model of the complex curved surface structure is established according to the geometric model.

[0047] In the present invention, the finite element model of the complex curved surface structure is simulated by shell elements. Except for individual transition areas, all shell elements are established by tetrahedral elements. The elements are given corresponding attributes, and corresponding constraints are established at the connecting pin positions, such as Figure 3 As shown in the figure. The establishment of the finite element model of the complex curved surface structure of the full shell unit can accurately reflect the structural characteristics and details of the complex curved surface.

[0048] Furthermore, in the present invention, after establishing the finite element model of the complex curved surface structure, the original pneumatic discrete data is processed using the Fortran language to obtain the pneumatic discrete data recognizable by the finite element software. The present invention fully considers the characteristics of uneven force on the complex curved surface structure under the action of air load, and uses the Fortran language to process the original pneumatic discrete data, and the specific steps are as follows.

[0049] (1) Process the node coordinate data of the original aerodynamic discrete data to obtain the nodes file.

[0050] Since the original plt format pneumatic data is output in block form, the output file is divided into five blocks: node X coordinate, Y coordinate, Z coordinate, pressure data and unit, the data cannot be recognized by the finite element software.

[0051] In the present invention, the Fortran node processing program is run to automatically number the nodes and correspond them one by one with the X coordinate, the Y coordinate and the Z coordinate, so as to form a nodes file identifiable by the finite element pre-processing software patran.

[0052] (2) Process the unit data to obtain the elements file.

[0053] Specifically, the Fortran unit processing program is run to automatically extract the data of unit composition from the original pneumatic discrete data file to form the elements file that can be recognized by Patran.

[0054] (3) Obtain the bdf file based on the nodes file and elements file.

[0055] Specifically, the data in the nodes file and the elements file are integrated into a bdf file to form the finite element mesh data of the aerodynamic model that can be recognized by Patran.

[0056] (4) Process the pressure data to obtain the field file.

[0057] Specifically, the Fortran pressure data processing program is run to correspond the pressure data to the node data one by one to form a field file with the suffix csvl.

[0058] The bdf file and field file after the above processing can be recognized by the finite element software, thereby simulating the real load conditions of the complex surface structure. Figure 4 As shown, the aerodynamic cloud diagram that can be recognized by the finite element software after being processed by the above-mentioned Fortran language of the present invention is as follows Figure 5 shown.

[0059] Furthermore, in the present invention, after the original pneumatic discrete data is processed by Fortran language, the finite element model is coupled with the processed pneumatic discrete data to form a structural finite element model with pneumatic discrete load data, and the specific steps are as follows.

[0060] (1) Import the bdf file and field file into patran.

[0061] Specifically, you can use the fields command in patran to import the field file.

[0062] (2) The data in the field file is converted into a pressure load and loaded onto the aerodynamic grid in the bdf file.

[0063] Specifically, the pressure command in patran can be used to convert the data in the field file into a pressure load and load it onto the aerodynamic grid in the bdf file.

[0064] (3) The discrete load data based on nodes on the aerodynamic grid are transformed into continuous load data based on complex surfaces.

[0065] Specifically, the field command in patran can be used to transform the discrete load data based on nodes on the aerodynamic grid into continuous load data based on complex surfaces.

[0066] (4) Import the finite element model into Patran.

[0067] Specifically, create a new group in Patran and import the finite element model into the new group.

[0068] (5) Interpolate the continuous load data based on complex surfaces into the finite element model to achieve the coupling of aerodynamic data and structural finite element model.

[0069] Specifically, the pressure command in Patran can be used to interpolate continuous load data based on complex surfaces into the finite element model. The coupled finite element model is as follows: Figure 6 shown.

[0070] Furthermore, after obtaining the structural finite element model with aerodynamic discrete load data, a simulation analysis is performed based on the structural finite element model with aerodynamic discrete load data to obtain the static strength and stability results of the complex curved surface.

[0071] As a specific embodiment of the present invention, a structural strength finite element analysis can be performed based on a structural finite element model with aerodynamic discrete load data to obtain the load-transfer strength structure of composite materials, metal structures and nails, and the static strength and stability analysis of complex curved surfaces can be completed in combination with the allowable values ​​of materials and nails.

[0072] The present invention establishes a complex curved surface finite element model of a full shell unit, processes the original aerodynamic distribution load through the Fortran programming language, forms an aerodynamic load that can be recognized by the finite element software, fully considers the uneven aerodynamic distribution of the complex curved surface structure, accurately reflects the actual loading condition of the complex curved surface, couples the finite element model of the complex curved surface structure with the aerodynamic discrete data, and obtains the static strength and stability results of the complex curved surface through simulation analysis.

[0073] The present invention can accurately simulate the loading conditions of complex curved surfaces, can directly load original aerodynamic data on complex curved surface structures, improve the efficiency and accuracy of static strength simulation, reduce the accuracy problems caused by secondary load processing, and has good versatility, providing theoretical support and technical accumulation for subsequent structural design and aerodynamic analysis.

[0074] In order to further understand the present invention, the static strength analysis results after loading the real aerodynamic discrete load using the complex curved surface structure distributed aerodynamic loading method of the present invention are compared with the static strength analysis results after adding an equivalent concentrated load to the complex curved surface finite element model using the prior art. The comparative analysis results are shown in Table 1.

[0075] Table 1 Comparison of static strength analysis results under two loading forms

[0076]

[0077] From the comparison results in the above table, it can be seen that the difference in maximum compressive strain is the smallest at 10.1%, followed by the difference in maximum shear strain at 19.8%, the difference in displacement at 30.5%, and the difference in maximum tensile strain at 52.3%. The maximum compressive strain and shear strain under concentrated force loading are located in the nail hole connection area, the maximum compressive strain and shear strain under real aerodynamic discrete data loading are located in the complex surface transition area, the maximum tensile strain under concentrated force loading is located between the complex surface transition area and the head, and the maximum tensile strain under real aerodynamic discrete data loading is located in the nail hole connection area. According to the distribution of aerodynamic force, it can be seen that the aerodynamic force of the complex surface head is the largest, and then it decreases slightly along the axis, and then increases in the transition area and continues to decrease. From the force analysis, it can be seen that the maximum strain position under concentrated force loading is different from the real force situation, and the maximum strain position under aerodynamic discrete data loading is consistent with mechanical theory. This is because loading concentrated force does not consider the distribution of aerodynamic force, but only loads the equivalent aerodynamic force as the total load of the complex surface structure, and the strain and displacement are small. However, loading aerodynamic discrete data considers the actual loading conditions of the complex surface and accurately simulates the distribution of aerodynamic force, which is more in line with the real physical scene and the result is more accurate.

[0078] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for distributing aerodynamic force loading on a complex curved surface structure, characterized in that: The method for distributing aerodynamic force loading on a complex curved surface structure comprises: Establish geometric models of complex surface structures; Establishing a finite element model of a complex curved surface structure according to the geometric model; The original pneumatic discrete data are processed by Fortran language to obtain pneumatic discrete data recognizable by finite element software and establish the load domain; The finite element model is coupled with the processed aerodynamic discrete data to form a structural finite element model with aerodynamic discrete load data. Simulation analysis based on the structural finite element model with aerodynamic discrete load data is performed to obtain the static strength and stability results of complex curved surfaces; Among them, the processing of the original aerodynamic discrete data using Fortran language specifically includes: (1) Process the node coordinate data of the original aerodynamic discrete data to obtain the nodes file; (2) Processing unit data to obtain elements file; (3) Obtain the bdf file based on the nodes file and elements file; (4) Process pressure data to obtain field files; The coupling of the finite element model with the processed aerodynamic discrete data specifically includes: (1) Import the bdf file and field file into patran; (2) The data in the field file is converted into a pressure load and loaded onto the aerodynamic grid in the bdf file; (3) Converting the node-based discrete load data on the aerodynamic grid into continuous load data based on a complex surface; (4) Import the finite element model into Patran; (5) Interpolate the continuous load data based on complex surfaces into the finite element model to achieve the coupling of aerodynamic data and structural finite element model.

2. The method for distributed aerodynamic loading of complex curved surface structure according to claim 1, characterized in that: The finite element model of the complex curved surface structure is simulated using shell elements.

3. The method for distributed aerodynamic loading of complex curved surface structure according to claim 1 or 2, characterized in that: Run the Fortran node processing program to automatically number the nodes and correspond them one by one with the X-coordinate, Y-coordinate and Z-coordinate to form a nodes file that can be recognized by the finite element pre-processing software patran.

4. The method for distributed aerodynamic loading of complex curved surface structure according to claim 1, characterized in that: Run the Fortran unit processing program to automatically extract the unit structure data from the original pneumatic discrete data file to form the elements file that can be recognized by Patran.

5. The method for distributed aerodynamic loading of complex curved surface structure according to claim 1, characterized in that: Integrate the data in the nodes file and the elements file into a bdf file to form the finite element mesh data of the aerodynamic model that can be recognized by Patran.

6. The method for distributed aerodynamic loading of complex curved surface structure according to claim 1, characterized in that: Run the Fortran pressure data processing program to match the pressure data with the node data one by one to form a field file with the suffix csvl.

7. The method for distributed aerodynamic loading of complex curved surface structure according to claim 1, characterized in that: Use the fields command in patran to import the field file.

8. The method for distributed aerodynamic loading of complex curved surface structure according to claim 1, characterized in that: Use the pressure command in patran to convert the data in the field file into a pressure load and load it onto the aerodynamic grid in the bdf file.

9. The method for distributed aerodynamic loading of complex curved surface structure according to claim 1, characterized in that: The field command in patran is used to transform the discrete load data based on nodes on the aerodynamic grid into continuous load data based on complex surfaces.

10. The method for distributed aerodynamic loading of complex curved surface structure according to claim 1, characterized in that: Create a new group in Patran and import the finite element model into the new group.

11. The method for distributed aerodynamic loading of a complex curved surface structure according to any one of claims 1 to 10, characterized in that: The pressure command in Patran is used to interpolate continuous load data based on complex surfaces into the finite element model.

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