Flutter wind tunnel model of aircraft winglet and manufacturing method thereof

Abstract

The present invention relates to the technical field of manufacturing aircraft wind tunnel test models, and specifically discloses a flutter wind tunnel model of an aircraft winglet and a manufacturing method thereof. The flutter wind tunnel model of an aircraft winglet provided by the present invention is composed of a plurality of frame segments, each frame segment including a front wall panel, a rear wall panel, an upper skin and a lower skin. The plurality of frame segments are integrally formed, which can ensure the accuracy of the geometric shape and mass distribution of the winglet model, and can accurately simulate the dynamic characteristics. The manufacturing method can flexibly adjust the design parameters and perform rapid processing to realize the serialized design and manufacturing of the winglet model; the winglet model is manufactured by additive manufacturing, which can effectively improve the processing efficiency of the winglet model, reduce the processing cycle and processing cost, ensure the accuracy of the geometric shape and mass distribution of the winglet model, and can more accurately and effectively reflect the dynamic characteristics of the background aircraft winglet in the wind tunnel test, thereby improving the accuracy of the wind tunnel test.

Description

Technical Field

[0001] The invention relates to the technical field of manufacturing aircraft wind tunnel test models, in particular to a flutter wind tunnel model of an aircraft winglet and a manufacturing method thereof. Background Art

[0002] When an aircraft moves in an airflow, it is subject to aerodynamic, inertial, and elastic forces. The interaction of these three forces creates a self-excited vibration, also known as flutter. When the aircraft's flight speed exceeds the critical flutter speed, irreversible structural damage will occur. Therefore, in order to determine the aircraft's global or local critical flutter speed, study the impact of relevant structural parameters on flutter characteristics, and verify the flutter characteristics and theoretical calculation methods of the designed aircraft, it is necessary to manufacture flutter wind tunnel models of the aircraft's main components and conduct wind tunnel tests. The winglets in the flutter wind tunnel model must have similar dynamic characteristics to the simulated aircraft winglets, mainly including aerodynamic shape and mass distribution.

[0003] Despite the increasing application of additive manufacturing technology, it is currently rarely used in the design and manufacture of winglets for high-aspect-ratio aircraft flutter wind tunnel models. Furthermore, there is no established, proven, reliable, and applicable additive manufacturing design methodology that meets the requirements of wind tunnel testing. Currently, the design and manufacture of winglet flutter wind tunnel models used in aircraft primarily utilizes a metal beam coupled with a dimensional frame, where the dimensional frame is fabricated from wood or foam. Research on the design and manufacture of winglet models using additive manufacturing methods is limited.

[0004] The current design and fabrication method for flutter tunnel model winglets using a metal beam and dimensional foam structure begins by determining the scale of the flutter tunnel model based on the selected target wind tunnel parameters. The geometry, stiffness, and mass distribution data of the scaled-down flutter tunnel model winglet are then extracted from the stiffness and mass distribution data of an actual aircraft winglet. The winglet's metal beam and dimensional frame are then designed, and counterweights are then applied to ultimately meet the winglet's geometric and dynamic requirements. The metal beam, as the winglet's primary load-bearing component, provides the majority of its stiffness and strength, while the dimensional frame primarily handles aerodynamic shaping and aerodynamic force transmission, contributing less to the model's stiffness and resulting in lower structural efficiency.

[0005] The existing design and manufacturing methods for winglet models using metal beams and dimensional frame segments are already very mature, but the processing cost is high and the processing cycle is very long. The metal beam of this type of winglet model is a single beam, which serves as the main load-bearing component and provides most of the stiffness and strength. The metal beam is made by machining and milling, which consumes a lot of material. The dimensional frame segment is responsible for providing aerodynamic dimensions and aerodynamic force transmission, and usually uses a wooden frame or foam dimension. The wooden frame and foam rely on manual processing, which is time-consuming and labor-intensive. In addition, the connection between the metal beam and the dimensional frame segment of the model needs to be designed, positioned, and assembled. The assembly process requires complex positioning, low assembly efficiency, and large errors, which is not conducive to the accurate simulation of the aerodynamic shape and seriously affects the accuracy of subsequent wind tunnel tests. Summary of the Invention

[0006] The purpose of the present invention is to provide a flutter wind tunnel model of an aircraft winglet, which can accurately simulate the dynamic characteristics of the background aircraft winglet, improve the accuracy of wind tunnel tests, and has a simple structure and low cost.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] A flutter wind tunnel model of an aircraft winglet comprises a plurality of frame segments smoothly connected in sequence along the length direction of the winglet, wherein the plurality of frame segments are integrally formed, and each frame segment comprises:

[0009] A front wall panel and a rear wall panel are spaced apart along the width direction of the winglet;

[0010] An upper skin and a lower skin are laid along the width direction of the winglet, two ends of the upper skin are connected to two ends of the lower skin, and the front wall panel and the rear wall panel are placed between the upper skin and the lower skin and support the upper skin and the lower skin.

[0011] Preferably, the frame segment is made of nylon.

[0012] The present invention also aims to provide a method for manufacturing a flutter wind tunnel model of an aircraft winglet, which improves processing efficiency, reduces processing cycle and cost, and improves the processing accuracy of the winglet model.

[0013] To achieve this object, the present invention adopts the following technical solutions:

[0014] A method for manufacturing a flutter wind tunnel model of an aircraft winglet is applied to the manufacture of the above-mentioned flutter wind tunnel model of the aircraft winglet, the manufacturing method comprising:

[0015] The dynamic characteristic parameters of the winglet model are obtained according to the dynamic characteristic parameters of the winglet of the background aircraft and the scale ratio of the winglet model;

[0016] Dividing the winglet model into a plurality of frame segments according to the dynamic characteristic parameters of the winglet model, and obtaining the digital model of the upper skin and the lower skin of each frame segment;

[0017] Determining the size and position of the front wall panel and the rear wall panel according to the digital models of the upper skin and the lower skin, and obtaining the digital model of the winglet model;

[0018] The winglet model is manufactured by additive manufacturing according to the digital model of the winglet model.

[0019] Preferably, the dynamic characteristic parameters include aerodynamic shape numerical model, stiffness distribution data and mass distribution data.

[0020] Preferably, the energy method or the single closed chamber profile method is used to obtain the dynamic characteristic parameters of the background aircraft winglet.

[0021] Preferably, the scale ratio of the winglet model includes length ratio, speed ratio and density ratio.

[0022] Preferably, the stiffness ratio and mass ratio of the winglet model are obtained according to the length ratio, the speed ratio and the density ratio, and the dynamic characteristic parameters of the winglet model are obtained according to the dynamic characteristic parameters of the winglet of the background aircraft and the length ratio, the stiffness ratio and the mass ratio of the winglet model.

[0023] Preferably, the length ratio of the winglet model is obtained according to the size of the aerodynamic shape digital model of the background aircraft winglet, target wind tunnel parameters and blockage;

[0024] Obtaining the speed ratio of the winglet model according to the flutter characteristics of the background aircraft winglet and the steady wind speed section of the wind tunnel;

[0025] The density ratio of the winglet model is obtained according to the air densities corresponding to the flight altitude of the background aircraft winglet and the wind tunnel altitude.

[0026] Preferably, the winglet model is divided into a plurality of frame segments according to the dynamic characteristic parameters of the winglet model, and the digital mold bodies of the upper skin and the lower skin of each frame segment are obtained as follows:

[0027] Dividing the winglet model into a plurality of frame segments according to the aerodynamic shape numerical model and stiffness distribution data of the winglet model;

[0028] The aerodynamic shape numerical model of the cross section at the rigid center station is used as a constraint condition, the stiffness distribution data of each frame segment is used as a design target, and the thickness and mass of the upper skin and the lower skin are obtained in combination with the material of the winglet model.

[0029] Preferably, the size and position of the front wall panel and the rear wall panel are determined according to the digital models of the upper skin and the lower skin, and the digital mold body of the winglet model is obtained as follows:

[0030] Obtaining a target mass of each frame segment according to the frame segment of the winglet model and the mass distribution data of the winglet model, and obtaining a target mass of the front wall panel and the rear wall panel according to the target mass of each frame segment and the masses of the upper skin and the lower skin;

[0031] The target mass of the front wall panel and the rear wall panel is used as the design target, and the size and position of the upper skin and the lower skin are used as constraints to obtain the size and position of the front wall panel and the rear wall panel of each frame segment.

[0032] Beneficial effects of the present invention:

[0033] The aircraft winglet flutter wind tunnel model provided by the present invention is composed of multiple frame segments, each of which includes a front wall panel, a rear wall panel, an upper skin and a lower skin. It has a simple structure and low cost. The multiple frame segments are integrally formed, which can ensure the accuracy of the geometric shape and mass distribution of the winglet model, accurately simulate the dynamic characteristics of the background aircraft winglet, and improve the accuracy of wind tunnel testing.

[0034] The manufacturing method of the flutter wind tunnel model of the aircraft winglet provided by the present invention can flexibly adjust the design parameters and perform rapid processing, thereby realizing the serialized design and manufacturing of the winglet model; manufacturing the winglet model by additive manufacturing can effectively improve the processing efficiency of the winglet model, reduce the processing cycle and processing cost, ensure the geometric shape accuracy and mass distribution accuracy of the winglet model, and can more accurately and effectively reflect the dynamic characteristics of the background aircraft winglet in the wind tunnel test, thereby improving the accuracy of the wind tunnel test. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 1 is a schematic structural diagram of a flutter wind tunnel model of an aircraft winglet provided by an embodiment of the present invention;

[0036] Figure 2 The present invention is a flowchart of a method for manufacturing a flutter wind tunnel model of an aircraft winglet provided by an embodiment of the present invention.

[0037] In the picture:

[0038] 1. Upper skin; 2. Lower skin; 3. Front wall panel; 4. Rear wall panel. DETAILED DESCRIPTION

[0039] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved more clearly, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0040] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0041] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0042] like Figure 1 As shown, this embodiment provides a flutter wind tunnel model of an aircraft winglet, including a plurality of frame segments smoothly connected in sequence along the length direction of the winglet, the plurality of frame segments are integrally formed, each frame segment includes a front wall panel 3 and a rear wall panel 4 spaced apart along the width direction of the winglet and an upper skin 1 and a lower skin 2 laid along the width direction of the winglet, the two ends of the upper skin 1 are connected to the two ends of the lower skin 2, the front wall panel 3 and the rear wall panel 4 are placed between the upper skin 1 and the lower skin 2 and support the upper skin 1 and the lower skin 2.

[0043] The flutter wind tunnel model of an aircraft winglet provided in this embodiment is composed of multiple frame segments, each of which includes a front wall panel 3, a rear wall panel 4, an upper skin 1, and a lower skin 2. It has a simple structure and low cost. The multiple frame segments are integrally formed, which can ensure the accuracy of the geometric shape and mass distribution of the winglet model, accurately simulate the dynamic characteristics, and improve the accuracy of wind tunnel testing.

[0044] In this embodiment, the front wall panels 3 and rear wall panels 4 of multiple frame segments are smoothly connected in sequence to ensure the structural strength of the winglet model. The upper skin 1 and lower skin 2 of multiple frame segments are smoothly connected in sequence to ensure the geometric accuracy of the winglet model.

[0045] In this embodiment, multiple frame segments are formed by integrated laser sintering through additive manufacturing, which can effectively improve the processing efficiency of the winglet model, reduce the processing cycle and processing cost, ensure the geometric shape accuracy and mass distribution accuracy of the winglet model, and more accurately and effectively realize the dynamic characteristics of the winglet model in the wind tunnel test, thereby improving the accuracy of the wind tunnel test.

[0046] Furthermore, the material for processing the winglet model is nylon powder, and the nylon powder is melted and gradually accumulated by laser sintering and solidification to finally form the winglet model.

[0047] In this embodiment, the winglet model is divided into four sections according to actual parameters of the winglet model. The winglet model can also be divided into two, three, five or more sections, which is not limited here.

[0048] like Figure 2 As shown, this embodiment also provides a method for manufacturing a flutter wind tunnel model of an aircraft winglet, which is applied to the manufacture of the above-mentioned flutter wind tunnel model of the aircraft winglet. The manufacturing method can flexibly adjust the design parameters and perform rapid processing to realize the serialized design and manufacturing of the winglet model; the winglet model is manufactured by additive manufacturing, which can effectively improve the processing efficiency of the winglet model, reduce the processing cycle and processing cost, ensure the geometric shape accuracy and mass distribution accuracy of the winglet model, and can more accurately and effectively realize the dynamic characteristics of the winglet model in the wind tunnel test, thereby improving the accuracy of the wind tunnel test.

[0049] The manufacturing method comprises the following steps:

[0050] Step 1: Obtain the dynamic characteristic parameters of the winglet model according to the dynamic characteristic parameters of the background aircraft winglet and the scale ratio of the winglet model.

[0051] Specifically, the dynamic characteristic parameters of the winglet of the background aircraft and the dynamic characteristic parameters of the winglet model both include aerodynamic shape numerical model, stiffness distribution data, and mass distribution data.

[0052] Based on the finite element method, the energy method or the single closed chamber cross-section method is used to obtain the dynamic characteristic parameters of the background aircraft winglet. This can accurately obtain the dynamic characteristic parameters of the background aircraft winglet, and simply and quickly obtain the coordinate position of the rigid center of the background aircraft winglet and the stiffness distribution data with high reliability and accuracy. Specifically, the energy method or the single closed chamber cross-section method is used to extract the coordinate position of the rigid center of the background aircraft winglet and the stiffness distribution data in the finite element model. Based on the mass distribution data of the background aircraft or similar models, the distribution position and mass of each mass point in the winglet area are obtained.

[0053] In this embodiment, the scale ratios of the background aircraft winglet include length ratio, velocity ratio, and density ratio. Dynamic characteristic parameters of the winglet model, including stiffness distribution data and mass distribution data, are derived based on the length ratio, velocity ratio, density ratio, and the dynamic characteristic parameters of the background aircraft winglet. Using the calculated dynamic characteristic parameters of the winglet model as design input data provides a dynamic similarity basis for the design and manufacture of the winglet model, thereby creating a high-precision winglet flutter wind tunnel model.

[0054] Furthermore, the length ratio of the winglet model is obtained based on the size of the aerodynamic shape digital model of the background aircraft winglet, the target wind tunnel parameters and the blockage degree. The speed ratio of the winglet model is obtained based on the flutter characteristics of the background aircraft winglet and the steady wind speed section of the wind tunnel. The density ratio of the winglet model is obtained based on the air density corresponding to the flight altitude of the background aircraft winglet and the wind tunnel altitude. By accurately calculating the length ratio, speed ratio and density ratio of the winglet model, the stiffness ratio, mass ratio, moment of inertia ratio and frequency ratio of the winglet model can be further derived, ensuring the dynamic similarity of the winglet model with the real winglet of the background aircraft during the design and manufacturing process, and providing a basis for verifying the dynamic similarity accuracy of the design and manufacturing method through wind tunnel testing.

[0055] Step 2: Divide the winglet model into multiple frame segments according to the dynamic characteristic parameters of the winglet model, and obtain the digital model of the upper skin 1 and the lower skin 2 of each frame segment.

[0056] Specifically, the winglet model is rationally divided into multiple frame segments based on the aerodynamic shape digital model, stiffness distribution data and mass distribution data of the winglet model, ensuring the consistency of the stiffness and mass distribution of the winglet model with the background aircraft winglet stiffness and mass distribution, and ensuring the continuity and accuracy of the frame segment division position.

[0057] The aerodynamic shape digital model of the cross section including the rigid center station is used as a constraint condition, the stiffness distribution data of each frame segment is used as a design target, and the material of the winglet model is combined to obtain the thickness and mass of the upper skin 1 and the lower skin 2. In this embodiment, the cross-sectional stiffness of the winglet model at different rigid center stations is used as a target, the digital model of the aerodynamic shape of each cross section is given as a constraint condition, and then according to the parameters of the additive manufacturing nylon powder material to be used in the manufacture of the winglet model, the dimensions of the upper skin 1 and the lower skin 2 of the winglet model at each rigid center station can be obtained, and the structural design is carried out to obtain the digital model of the upper skin 1 and the lower skin 2 of each frame segment. After the structural design of the upper skin 1 and the lower skin 2 is completed, the mass of the upper skin 1 and the lower skin 2 of each frame segment is sorted out to provide input data and constraint conditions for the front and rear wall panels of the subsequent design model, ensuring that the design of the front and rear wall panels can achieve the final mass distribution data of the winglet model to meet the design target requirements.

[0058] Step 3: Determine the size and position of the front wall panel 3 and the rear wall panel 4 according to the digital models of the upper skin 1 and the lower skin 2, and obtain the digital model of the winglet model.

[0059] Specifically, based on the frame segments of the winglet model and the mass distribution data of the winglet model, the target mass of each frame segment is obtained, and the target mass of the front wall panel 3 and the rear wall panel 4 is obtained based on the target mass of each frame segment and the mass of the upper skin 1 and the lower skin 2. The target mass of the front wall panel 3 and the rear wall panel 4 is used as the design target, and the size and position of the upper skin 1 and the lower skin 2 are used as constraints to obtain the size and position of the front wall panel 3 and the rear wall panel 4 of each frame segment. Then, the structural design is performed based on the size and position of the front wall panel 3 to obtain the digital model of the winglet model, thus completing the structural design of the winglet model, ensuring the consistency between the structural mass and the target mass of each frame segment, ensuring that the mass distribution of the winglet model is consistent with the design target requirements, and achieving the consistency between the dynamic characteristics of the winglet model and the dynamic characteristics of the background aircraft winglet.

[0060] Step 4: According to the digital model of the winglet model, the winglet model is manufactured by additive manufacturing.

[0061] Specifically, a three-dimensional design drawing of the winglet model is input into the additive manufacturing equipment, and the winglet model is cut into multiple cross-sections along the predetermined coordinate axes by the molding equipment. The nylon powder material is melted and stacked layer by layer using a laser sintering molding and solidification method to finally form a complete winglet model. Manufacturing the winglet model through additive manufacturing improves the processing efficiency of the winglet model, reduces the processing cycle and processing cost, and can achieve the processing of different types of winglet models by modifying parameters, which provides good flexibility. The processed winglet model can accurately simulate the dynamic characteristics of the background aircraft winglet, improving the accuracy of the wind tunnel test.

[0062] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A method for manufacturing a flutter wind tunnel model of an aircraft winglet, applied to a flutter wind tunnel model of an aircraft winglet, characterized in that: The flutter wind tunnel model of the aircraft winglet comprises a plurality of frame segments that are smoothly connected in sequence along the length direction of the winglet, wherein the plurality of frame segments are integrally formed, and each of the frame segments comprises: A front wall plate (3) and a rear wall plate (4) are arranged at intervals along the width direction of the winglet; An upper skin (1) and a lower skin (2) are laid along the width direction of the winglet, two ends of the upper skin (1) are connected to two ends of the lower skin (2), and the front wall panel (3) and the rear wall panel (4) are placed between the upper skin (1) and the lower skin (2) and support the upper skin (1) and the lower skin (2); The method for manufacturing the flutter wind tunnel model of the aircraft winglet comprises: The dynamic characteristic parameters of the winglet model are obtained according to the dynamic characteristic parameters of the winglet of the background aircraft and the scale ratio of the winglet model; Dividing the winglet model into a plurality of frame segments according to the dynamic characteristic parameters of the winglet model, and obtaining the digital model of the upper skin (1) and the lower skin (2) of each frame segment; Determining the size and position of the front wall panel (3) and the rear wall panel (4) according to the digital models of the upper skin (1) and the lower skin (2), and obtaining the digital model of the winglet model; manufacturing the winglet model by additive manufacturing according to the digital model of the winglet model; The dynamic characteristic parameters include aerodynamic shape numerical model, stiffness distribution data and mass distribution data; The winglet model is divided into a plurality of frame segments according to the dynamic characteristic parameters of the winglet model, and the digital mold bodies of the upper skin (1) and the lower skin (2) of each frame segment are obtained as follows: Dividing the winglet model into a plurality of frame segments according to the aerodynamic shape numerical model and stiffness distribution data of the winglet model; The aerodynamic shape numerical model of the cross section at the rigid center station is used as a constraint condition, the stiffness distribution data of each frame segment is used as a design target, and the thickness and mass of the upper skin (1) and the lower skin (2) are obtained in combination with the material of the winglet model; The size and position of the front wall panel (3) and the rear wall panel (4) are determined according to the digital models of the upper skin (1) and the lower skin (2), and the digital mold body of the winglet model is obtained as follows: According to the frame segments of the winglet model and the mass distribution data of the winglet model, the target mass of each frame segment is obtained, and according to the target mass of each frame segment and the mass of the upper skin (1) and the lower skin (2), the target mass of the front wall panel (3) and the rear wall panel (4) are obtained; The target mass of the front wall panel (3) and the rear wall panel (4) is used as a design target, and the size and position of the upper skin (1) and the lower skin (2) are used as constraints to obtain the size and position of the front wall panel (3) and the rear wall panel (4) of each frame segment.

2. The method for manufacturing a flutter wind tunnel model of an aircraft winglet according to claim 1, characterized in that: The material of the frame section is nylon.

3. The method for manufacturing a flutter wind tunnel model of an aircraft winglet according to claim 1, characterized in that: The energy method or the single closed chamber section method is used to obtain the dynamic characteristic parameters of the winglet of the background aircraft.

4. The method for manufacturing a flutter wind tunnel model of an aircraft winglet according to claim 1, characterized in that: The scale ratio of the winglet model includes length ratio, speed ratio and density ratio.

5. The method for manufacturing a flutter wind tunnel model of an aircraft winglet according to claim 4, characterized in that: The stiffness ratio and mass ratio of the winglet model are obtained according to the length ratio, the speed ratio and the density ratio, and the dynamic characteristic parameters of the winglet model are obtained according to the dynamic characteristic parameters of the winglet of the background aircraft and the length ratio, the stiffness ratio and the mass ratio of the winglet model.

6. The method for manufacturing a flutter wind tunnel model of an aircraft winglet according to claim 4, characterized in that: Obtaining the length ratio of the winglet model according to the size of the aerodynamic shape digital model of the background aircraft winglet, target wind tunnel parameters, and blockage; Obtaining the speed ratio of the winglet model according to the flutter characteristics of the background aircraft winglet and the steady wind speed section of the wind tunnel; The density ratio of the winglet model is obtained according to the air densities corresponding to the flight altitude of the background aircraft winglet and the wind tunnel altitude.

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