A flap equivalence design and verification method

Abstract

The application belongs to the technical field of aircraft strength, and particularly relates to a flap equivalence design and verification method. The method comprises the following steps: obtaining a preliminary material system, constructing a finite element model of a flap structure according to the preliminary material system; applying an aerodynamic load to the finite element model of the flap structure, and obtaining a first stress-strain field of the flap structure through finite element solving analysis; changing the material system in the finite element model of the flap structure, and obtaining a second stress-strain field of the flap structure after the material system is changed through finite element solving analysis; comparing and analyzing the first stress-strain field and the second stress-strain field to obtain a stress-strain field error; if the stress-strain field error is not greater than an error threshold, the next step is entered; if the stress-strain field error is greater than the error threshold, the material system in the finite element model of the flap structure is further changed, and the next step is returned to; and a flap structure test is carried out for examination and verification.

Description

Technical Field

[0001] The present application belongs to the field of aircraft strength technology, and in particular relates to a flap equivalence design and verification method. Background Art

[0002] Flaps are located at the trailing edge of the wing and are subject to high aerodynamic loads while also meeting stringent weight requirements. Composite materials, as a new type of functional material with high modulus, low density, and strong designability, are increasingly being used in flap structural material selection. The composite material system selected in the early design of the flap may be changed during subsequent mass production due to various reasons such as cost and upgrades. Different composite material systems have different strength properties, and the equivalent design and verification of the strength properties of different composite material systems is a key issue that urgently needs to be addressed.

[0003] Therefore, it is desired to have a technical solution to overcome or at least alleviate at least one of the above-mentioned deficiencies of the prior art. Summary of the Invention

[0004] The purpose of this application is to provide a flap equivalence design and verification method to solve at least one problem existing in the prior art.

[0005] The technical solution of this application is:

[0006] A first aspect of the present application provides a flap equivalence design and verification method, comprising:

[0007] Step 1: Obtain a preliminary material system and construct a finite element model of the flap structure based on the preliminary material system;

[0008] Step 2: applying an aerodynamic load to the finite element model of the flap structure, and obtaining a first stress-strain field of the flap structure through finite element solution analysis;

[0009] Step 3: changing the material system in the finite element model of the flap structure, and obtaining a second stress-strain field of the flap structure after the material system is changed through finite element analysis;

[0010] Step 4: Compare and analyze the first stress-strain field and the second stress-strain field to obtain a stress-strain field error;

[0011] If the stress-strain field error is not greater than the error threshold, proceed to step five;

[0012] If the stress-strain field error is greater than the error threshold, returning to step three to further modify the material system in the finite element model of the flap structure;

[0013] Step 5: Conduct flap structure tests for assessment and verification;

[0014] If the assessment verification fails, return to step 3 to further modify the material system in the finite element model of the flap structure;

[0015] If the assessment verification is passed, the material system corresponding to the flap structure that meets the strength equivalence design requirements is output.

[0016] In at least one embodiment of the present application, the material system includes a plurality of material performance parameters, namely, spanwise modulus, chordwise modulus, shear modulus, Poisson's ratio, and ply parameters.

[0017] In at least one embodiment of the present application, the flap structure is a flap box segment.

[0018] In at least one embodiment of the present application, the error threshold is 5%.

[0019] In at least one embodiment of the present application, the ply parameters of the material system in the finite element model of the flap structure are changed.

[0020] A second aspect of the present application provides a flap equivalence design and verification system, comprising:

[0021] A finite element model building module is used to obtain a preliminary material system and build a finite element model of the flap structure based on the preliminary material system;

[0022] a first stress-strain field solving module, configured to apply an aerodynamic load to the finite element model of the flap structure and obtain a first stress-strain field of the flap structure through finite element solution analysis;

[0023] A second stress-strain field solving module is used to change the material system in the finite element model of the flap structure, and obtain a second stress-strain field of the flap structure after the material system is changed through finite element solution analysis;

[0024] an error determination module, configured to compare and analyze the first stress-strain field and the second stress-strain field to obtain a stress-strain field error;

[0025] If the stress-strain field error is not greater than the error threshold, then enter the assessment and verification module;

[0026] If the stress-strain field error is greater than the error threshold, returning to the second stress-strain field solving module to further modify the material system in the finite element model of the flap structure;

[0027] Assessment and verification module, used to carry out flap structure tests and conduct assessment and verification;

[0028] If the assessment verification fails, returning to the second stress-strain field solving module, further changing the material system in the finite element model of the flap structure;

[0029] If the assessment is passed, the material system that meets the strength equivalence design requirements will be output.

[0030] In at least one embodiment of the present application, the material system includes a plurality of material performance parameters, namely, spanwise modulus, chordwise modulus, shear modulus, Poisson's ratio, and ply parameters.

[0031] In at least one embodiment of the present application, the flap structure is a flap box segment.

[0032] In at least one embodiment of the present application, the error threshold is 5%.

[0033] In at least one embodiment of the present application, the ply parameters of the material system in the finite element model of the flap structure are changed.

[0034] The invention has at least the following beneficial technical effects:

[0035] The flap equivalence design and verification method of this application conducts a theoretical analysis of the flap structure strength, and solves the strength assessment problem of the equivalent design of flaps using different systems of composite materials through the method of equivalent evaluation of working stress and strain and experimental verification. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a schematic diagram of a finite element model of a flap structure according to one embodiment of the present application;

[0037] Figure 2 This is a schematic diagram of the stress-strain field before changing the material system according to one embodiment of the present application;

[0038] Figure 3 This is a schematic diagram of the stress-strain field after changing the material system according to one embodiment of the present application;

[0039] Figure 4 This is a schematic diagram of the assessment and verification of an implementation method of the present application. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the implementation of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below in conjunction with the drawings in the embodiments of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of this application, not all of the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain this application, and should not be understood as limitations on this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The embodiments of this application are described in detail below in conjunction with the drawings.

[0041] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be understood as limiting the scope of protection of this application.

[0042] The following is combined with Figures 1 to 4 This application is described in further detail.

[0043] A first aspect of the present application provides a flap equivalence design and verification method, comprising:

[0044] Step 1: Obtain a preliminary material system and construct a finite element model of the flap structure based on the preliminary material system;

[0045] Step 2: Apply aerodynamic loads to the finite element model of the flap structure, and obtain the first stress and strain field of the flap structure through finite element solution analysis;

[0046] Step 3: Modify the material system in the finite element model of the flap structure, and obtain the second stress-strain field of the flap structure after the material system is modified through finite element analysis;

[0047] Step 4: Compare and analyze the first stress-strain field and the second stress-strain field to obtain the stress-strain field error;

[0048] If the stress-strain field error is not greater than the error threshold, proceed to step five;

[0049] If the stress-strain field error is greater than the error threshold, return to step 3 and further change the material system in the finite element model of the flap structure;

[0050] Step 5: Conduct flap structure tests for assessment and verification;

[0051] If the verification fails, return to step 3 and further modify the material system in the finite element model of the flap structure;

[0052] If the assessment is successful, the material system corresponding to the flap structure that meets the strength equivalence design requirements will be output.

[0053] The flap equivalence design and verification method of the present application, first, in step one, a material system is selected at the initial stage of design to obtain a preliminary material system, and a finite element model of the flap structure is constructed based on the preliminary material system. The material system includes a variety of material performance parameters, namely spanwise modulus, chordwise modulus, shear modulus, Poisson's ratio, and ply parameters. In step two, aerodynamic loads are applied to the finite element model of the flap structure, and the stress-strain field before the material system is changed is obtained through finite element solution analysis; in step three, the material system in the finite element model is changed, and the stress-strain field after the material system is changed is obtained through finite element solution analysis. In step four, by comparing and analyzing the stress-strain field before and after the material system is changed, if the stress-strain field error is within 5%, proceed to step five for experimental verification; if the stress-strain field error exceeds 5%, return to step three and re-change the ply parameters in the material system.

[0054] In one embodiment of the present application, taking the equivalent design of composite material of a flap box section structure of an aircraft as an example:

[0055] 1) Construct a finite element model of the flap box structure. The material system is the material system selected in the early design stage, such as Figure 1 As shown;

[0056] 2) Apply aerodynamic loads and obtain the stress and strain field of the flap box structure through finite element analysis, such as Figure 2 As shown;

[0057] 3) The material system in the model of step 2) is replaced with the material system to be replaced later by modifying the basic material performance data, including span modulus, chord modulus, shear modulus, Poisson's ratio, and ply parameters. The stress and strain field of the flap box section structure after the material system is changed is obtained through finite element analysis, such as Figure 3 As shown;

[0058] 4) Comparing the stress and strain fields of the flap box section with the initial material system obtained in step 2) and the later material system-changing flap box section, the error was found to be within 1%;

[0059] 5) Carry out flap box section test, apply load, and conduct assessment and verification; by comparing the experimental strain value with the theoretical strain value, the error between the two is within 5%, such as Figure 4 As shown in the figure, it shows that the flap box section meets the strength equivalence design requirements after the material system is changed.

[0060] Based on the above-mentioned flap equivalence design and verification method, the second aspect of the present application provides a flap equivalence design and verification system, comprising:

[0061] A finite element model building module is used to obtain a preliminary material system and build a finite element model of the flap structure based on the preliminary material system;

[0062] The first stress and strain field solving module is used to apply aerodynamic loads to the finite element model of the flap structure and obtain the first stress and strain field of the flap structure through finite element solution analysis;

[0063] The second stress-strain field solving module is used to change the material system in the finite element model of the flap structure and obtain the second stress-strain field of the flap structure after the material system is changed through finite element solution analysis;

[0064] an error determination module, configured to compare and analyze the first stress-strain field and the second stress-strain field to obtain a stress-strain field error;

[0065] If the stress-strain field error is not greater than the error threshold, the assessment and verification module is entered;

[0066] If the stress-strain field error is greater than the error threshold, the method returns to the second stress-strain field solving module to further modify the material system in the finite element model of the flap structure.

[0067] Assessment and verification module, used to carry out flap structure tests and conduct assessment and verification;

[0068] If the assessment fails, the system returns to the second stress-strain field solution module to further modify the material system in the finite element model of the flap structure.

[0069] If the assessment is passed, the material system that meets the strength equivalence design requirements will be output.

[0070] In a preferred embodiment of the present application, the material system includes multiple material performance parameters, namely, spanwise modulus, chordwise modulus, shear modulus, Poisson's ratio, and ply parameters. The flap structure for which the equivalent design and verification are performed is the flap box section. The error threshold for determining the magnitude of the stress-strain field error is 5%. When the stress-strain field error is greater than the error threshold, the system returns to the second stress-strain field solution module to modify the ply parameters of the material system in the finite element model of the flap structure.

[0071] The flap equivalence design and verification method and system of this application solves the equivalence design and verification of flaps using different composite material systems through rapid strength evaluation and experimental assessment and verification, providing support for the equivalence application of composite materials of different systems.

[0072] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A flap equivalence design and verification method, characterized in that: include: Step 1: Obtain a preliminary material system and construct a finite element model of the flap structure based on the preliminary material system; Step 2: applying an aerodynamic load to the finite element model of the flap structure, and obtaining a first stress-strain field of the flap structure through finite element solution analysis; Step 3: changing the material system in the finite element model of the flap structure, and obtaining a second stress-strain field of the flap structure after the material system is changed through finite element analysis; Step 4: Compare and analyze the first stress-strain field and the second stress-strain field to obtain a stress-strain field error; If the stress-strain field error is not greater than the error threshold, proceed to step five; If the stress-strain field error is greater than the error threshold, returning to step three to further modify the material system in the finite element model of the flap structure; Step 5: Conduct flap structure tests for assessment and verification; If the assessment verification fails, return to step 3 to further modify the material system in the finite element model of the flap structure; If the assessment verification is passed, the material system corresponding to the flap structure that meets the strength equivalence design requirements is output.

2. The flap equivalence design and verification method according to claim 1, characterized in that: The material system includes a variety of material performance parameters, namely, spanwise modulus, chordwise modulus, shear modulus, Poisson's ratio, and ply parameters.

3. The flap equivalence design and verification method according to claim 2, characterized in that: The flap structure is a flap box segment.

4. The flap equivalence design and verification method according to claim 3, characterized in that: The error threshold is 5%.

5. The flap equivalence design and verification method according to claim 4, characterized in that: The ply parameters of the material system in the finite element model of the flap structure are changed.

6. A flap equivalence design and verification system, characterized in that: include: A finite element model building module is used to obtain a preliminary material system and build a finite element model of the flap structure based on the preliminary material system; a first stress-strain field solving module, configured to apply an aerodynamic load to the finite element model of the flap structure and obtain a first stress-strain field of the flap structure through finite element solution analysis; A second stress-strain field solving module is used to change the material system in the finite element model of the flap structure, and obtain a second stress-strain field of the flap structure after the material system is changed through finite element solution analysis; an error determination module, configured to compare and analyze the first stress-strain field and the second stress-strain field to obtain a stress-strain field error; If the stress-strain field error is not greater than the error threshold, then enter the assessment and verification module; If the stress-strain field error is greater than the error threshold, returning to the second stress-strain field solving module to further modify the material system in the finite element model of the flap structure; Assessment and verification module, used to carry out flap structure tests and conduct assessment and verification; If the assessment verification fails, returning to the second stress-strain field solving module, further changing the material system in the finite element model of the flap structure; If the assessment verification is passed, the material system corresponding to the flap structure that meets the strength equivalence design requirements is output.

7. The flap equivalence design and verification system according to claim 6, characterized in that: The material system includes a variety of material performance parameters, namely, spanwise modulus, chordwise modulus, shear modulus, Poisson's ratio, and ply parameters.

8. The flap equivalence design and verification system according to claim 7, characterized in that: The flap structure is a flap box segment.

9. The flap equivalence design and verification system according to claim 8, characterized in that: The error threshold is 5%.

10. The flap equivalence design and verification system according to claim 9, characterized in that: The ply parameters of the material system in the finite element model of the flap structure are changed.

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