A method for designing equivalent structure of aircraft wing

Abstract

The present invention relates to an equivalent structural design method for an aircraft wing, which belongs to the technical field of equivalent models, and solves the problem in the prior art that the equivalent model of an aircraft wing cannot truly reflect the damage state of the wing under an impact state. The design method of the present invention comprises: step S1: structural characteristic analysis of the target aircraft wing; step S2: designing an equivalent wing model according to the structural characteristics of the target wing based on the principle of structural consistency; step S3: performing material strength equivalent design: determining the equivalent material and the corresponding equivalent thickness according to the material characteristics of each part of the wing; step S4: performing consistency check on the equivalent wing model based on finite element simulation analysis. The present invention realizes the equivalent structural design of the aircraft wing, and can truly simulate the damaged state of the aircraft wing.

Description

Technical Field

[0001] The invention relates to the technical field of equivalent models, and in particular to a design method for an equivalent structure of an aircraft wing. Background Art

[0002] The damage of aircraft wing components has a great impact on the flight capability of the entire aircraft, and is also a key consideration in the structural strength assessment of the aircraft. Therefore, by accurately evaluating the damage resistance of the wing equivalent structure, it is possible to reflect the structural performance of the wing under strong impact.

[0003] Although the existing modular aircraft equivalent structure can meet the strength requirements and has the characteristics of high construction efficiency and low cost, it is too simplified and has a large difference from the real aircraft structure, and cannot reflect the real physical and mechanical properties. In addition, the simple equivalent structure cannot demonstrate or simulate its internal damage state and cannot reflect its comprehensive structural effect, making the adaptability of this simple target worse, so it is impossible to accurately evaluate the damage state of this type of product after being impacted.

[0004] Therefore, it is necessary to provide an aircraft wing equivalent structure to achieve accurate simulation of the aircraft wing structure. Summary of the invention

[0005] In view of the above analysis, the present invention aims to provide an aircraft wing equivalent structure design method to solve the problem that the existing equivalent wing model has a simple structure and cannot accurately reflect the physical properties and internal impact resistance of the wing.

[0006] The purpose of the present invention is mainly achieved through the following technical solutions:

[0007] A method for designing an equivalent structure of an aircraft wing comprises the following steps:

[0008] Step S1: Before designing the equivalent structure, the structural characteristics of the target aircraft wing are analyzed;

[0009] Step S2: Based on the principle of structural consistency, an equivalent wing model is designed according to the structural characteristics of the target wing;

[0010] Step S3: Perform material strength equivalent design: determine equivalent materials and corresponding equivalent thicknesses according to the material properties of each part of the wing;

[0011] Step S4: performing consistency check on the equivalent wing model based on finite element simulation analysis.

[0012] Furthermore, in step S2, the principle of equivalent design of the target wing is: retain the load-bearing structure and the fuel tank, omit functional components and tiny connectors, retain the wing's external structure and simplify the design of the skin structure.

[0013] In the step S2, the equivalent wing model after equivalent design of the target wing includes: an equivalent wing spar, an equivalent wing rib, an equivalent skin, an equivalent leading edge flap, an equivalent aileron and an equivalent fuel tank; the equivalent leading edge flap and the equivalent aileron are designed to be in the same shape as the target wing, and are fixedly connected to the main part of the equivalent wing model; the equivalent skin cover is arranged on the outside of the equivalent wing spar and the equivalent wing rib, and the equivalent skin is a multi-section flat plate; a plurality of equivalent wing spars and a plurality of equivalent wing ribs are arranged in an interlaced manner to form a plurality of closed cabins; a row of closed cabins from the wing root to the wing tip in the direction close to the center position of the chord among the plurality of closed cabins is selected as the oil storage cabin; the equivalent fuel tank is arranged in the oil storage cabin.

[0014] The equivalent skin is determined as follows:

[0015] Step S21: Cutting the skin surface of the target wing at the rib located in the middle thereof to obtain its airfoil cross section; the airfoil cross section is a closed shuttle-shaped structure, including two upper and lower airfoil camber lines;

[0016] Step S22: dividing the aerofoil section into two sections at the maximum thickness of the aerofoil section;

[0017] Step S23: connecting the upper end point and the lower end point at the maximum thickness of the airfoil section to the leading edge end point and the trailing edge end point of the airfoil section respectively, so as to convert the upper and lower airfoil surface cambers of the airfoil section into four straight line segments, each straight line segment corresponds to a plane plate, and further convert the skin surface of the target wing into four plane plates;

[0018] Step S24: re-segmenting the airfoil section at the midpoint after segmentation, and further dividing the airfoil section into four sections; sequentially connecting the leading edge endpoint, each endpoint after segmentation, and the trailing edge endpoint to obtain a multi-segment plane plate of the skin surface; after re-segmentation, the equivalent multi-segment plane plate of the skin surface of the wing is closer to the real surface, so as to obtain a wing aerodynamic performance equivalent to the target wing;

[0019] In the step S4, the equivalent wing model composed of the equivalent skin composed of the four-segment plane panels obtained in the step S23 is subjected to a consistency check. If the consistency check of the equivalent wing model fails, the step S24 is executed, and the equivalent skin is equivalent to multiple sections of plane panels and then the equivalent wing model is subjected to a consistency check. If the lift consistency of the equivalent wing model is still not passed with the lift consistency of the target wing, the skin surface equivalent method in the step S24 is repeated until the consistency check of the equivalent wing model passes.

[0020] Furthermore, in step S2, the equivalent wing beam is an I-shaped steel beam.

[0021] Furthermore, in step S2, the number of equivalent spars is equal to the number of spars of the target wing; and the length and arrangement of the multiple equivalent spars correspond to the length and arrangement of the spars of the target wing.

[0022] Furthermore, in step S2, the equivalent wing rib is a plurality of flat plates located in the same plane, and the plurality of flat plates of the equivalent wing rib are respectively connected between two adjacent equivalent wing spars.

[0023] Furthermore, in step S3, according to the material strength equivalence principle, thickness equivalence design is performed on each part of the equivalent wing model, and the thickness equivalence formula of the equivalent wing model plate is: ,

[0024] in,

[0025] is the ultimate strength of the wing's actual structural material;

[0026] is the ultimate strength of the equivalent material;

[0027] is the material density of the actual structure of the wing;

[0028] is the standard equivalent material density;

[0029] is the material thickness of the actual structure of the wing;

[0030] is the thickness of the equivalent material.

[0031] Furthermore, the equivalent wing spar, equivalent wing rib, equivalent leading edge flap and equivalent aileron are made of 45# steel; the equivalent skin is made of carbon fiber composite plate or LY-12 duralumin.

[0032] Furthermore, the step S4: performing aerodynamic analysis on the equivalent wing model and verifying its structural performance:

[0033] Step S41: using simulation analysis software to establish an external flow field of the equivalent wing model;

[0034] Step S42: Determine the flight condition of the equivalent wing model according to the use condition of the real wing;

[0035] Step S43: obtaining a wing surface pressure distribution diagram of the equivalent wing model through simulation analysis;

[0036] Step S44: The surface pressure obtained by the aerodynamic analysis calculation of the wing is imported into the finite element analysis software to perform strength verification calculation of the equivalent wing model to verify its consistency with the lift force on the real wing.

[0037] Furthermore, in step S44, the strength check calculation of the equivalent wing model includes:

[0038] Step S441: Open the static structural analysis in the Ansys Workbench software, import the built wing model including the internal structure, and assign material parameters of the equivalent wing model according to the material strength equivalent design result in step S3;

[0039] Step S442: meshing the equivalent wing model as a whole using solid units to establish a finite element model of the equivalent wing;

[0040] Step S443: applying a fixed constraint at the wing root of the equivalent wing model, and turning on the standard earth gravity to consider the deadweight of the structure; importing the wing surface pressure calculated in step S43 into the static structural analysis of Ansys Workbench to complete the loading of the load;

[0041] Step S444: Calculate the stress distribution diagram of the equivalent wing model through Ansys Workbench software; analyze whether the equivalent wing model meets the strength requirements according to the stress distribution diagram; and calculate whether the lift force on the equivalent wing model is consistent with the lift force of the target wing.

[0042] Furthermore, in step S41, the equivalent wing model is imported into FLUENT, and the flow field outside the equivalent wing model is established using FLUENT software; when the equivalent wing model and the air are subjected to finite element mesh division, the mesh of the air around the equivalent wing model and the equivalent wing model itself is encrypted, and the mesh size of the air far away from the equivalent wing model is increased.

[0043] Furthermore, in step S44, if the strength check of the equivalent wing model fails, the thickness of each component of the equivalent wing model is gradually increased by 5% until the strength check passes.

[0044] The technical solution of the present invention can achieve at least one of the following effects:

[0045] 1. The present invention discloses a method for designing an aircraft wing equivalent structure. The method adopts a full-size structure similar to a real wing, which can not only reflect the structure of a real wing, but also meets the strength conditions basically consistent with those of a real wing through the equivalent design principle of material strength and structure. The performance test is performed using the aircraft wing equivalent structure of the present invention, which can truly reflect the damage characteristics of the wing after being impacted (physical impact, explosion, etc.).

[0046] 2. The present invention discloses a method for designing an equivalent structure of an aircraft wing, in which an equivalent fuel tank corresponding to the size and position of the actual fuel tank is set, thereby overcoming the problem that the existing equivalent structure can only evaluate a single perforation damage effect. Instead, the ignition effect after the wing is impacted can be directly evaluated, thereby greatly improving the consistency of the wing damage performance evaluation.

[0047] 3. The present invention discloses a method for designing an equivalent structure of an aircraft wing. By designing an equivalent structure of a wing, the internal structure is greatly reduced, the processing process is simplified, and the manufacturing cost is reduced while ensuring that the physical and mechanical properties are basically consistent, thus providing a strong guarantee for carrying out damage tests on the wing.

[0048] 4. The present invention discloses a method for designing an equivalent structure of an aircraft wing, which adopts a multi-segment plane (at least two segments) for an equivalent wing skin, simplifies the structural design and processing costs, and performs consistency verification through subsequent simulation analysis, so that the equivalent wing model can simulate the dynamic performance and load-bearing capacity of a real wing.

[0049] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The accompanying drawings are only used for the purpose of illustrating specific embodiments and are not to be considered as limiting the present invention. In the entire drawings, the same reference symbols represent the same components;

[0051] Figure 1 It is a structural schematic diagram of an equivalent wing model obtained by adopting the design method of the present invention;

[0052] Figure 2 Schematic diagram of the internal structure of the equivalent wing model - without skin;

[0053] Figure 3 It is a structural schematic diagram of the spar assembly of the equivalent wing model;

[0054] Figure 4 It is a schematic diagram of the structure of a single spar of the equivalent wing model;

[0055] Figure 5 It is a structural diagram of the rib of the equivalent wing model;

[0056] Figure 6 The leading edge flap structure diagram of the equivalent wing model;

[0057] Figure 7It is the aileron structure diagram of the equivalent wing model;

[0058] Figure 8 It is a schematic diagram of the fuel tank structure of the equivalent wing model;

[0059] Fig. 9 It is a schematic diagram of the structure of the fixed support device of the equivalent wing model;

[0060] Fig.10 It is a schematic diagram of the combined state of the equivalent wing model and the fixed support device;

[0061] Fig.11 This is one of the schematic diagrams of the equivalent structure of the skin;

[0062] Fig.12 The second schematic diagram of the skin equivalent structure

[0063] Fig.13 This is the third schematic diagram of the skin equivalent structure;

[0064] Fig.14 It is a schematic diagram of finite element mesh division of the equivalent wing model in the air flow field;

[0065] Fig.15 is the force distribution diagram of the wing surface of the equivalent wing model;

[0066] Fig.16 It is the local mesh diagram of the equivalent wing model;

[0067] Fig.17 Schematic diagram of load loading state of equivalent wing model;

[0068] Fig.18 It is the stress cloud diagram of the overall structure of the equivalent wing model;

[0069] Fig.19 It is the stress cloud diagram of the internal structure of the equivalent wing model;

[0070] Fig. 20 It is the stress cloud diagram of the skin structure of the equivalent wing model;

[0071] Fig.21 It is the displacement cloud diagram of the overall structure of the equivalent wing model;

[0072] Fig. 22 is the direction diagram of the resultant force on the wing surface.

[0073] Reference numerals:

[0074] 1-equivalent wing beam; 2-equivalent wing rib; 3-equivalent skin; 31-first plane plate; 32-second plane plate; 4-equivalent leading edge flap; 5-equivalent aileron; 6-equivalent fuel tank; 7-fixed support device; 71-longitudinal beam; 72-cross beam; 73-triangular bracket; 74-diagonal rib. DETAILED DESCRIPTION

[0075] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0076] Example 1

[0077] A specific embodiment of the present invention discloses a method for designing an equivalent structure of an aircraft wing, comprising the following steps:

[0078] Step S1: Before designing the equivalent structure, the structural characteristics of the target aircraft wing are analyzed.

[0079] Specifically, the wings of the target aircraft are truncated delta wings with a three-beam structure, consisting of a bismaleimide (BMI)-based carbon fiber reinforced composite skin, a titanium alloy main wing spar and a composite auxiliary wing spar.

[0080] Specifically, the wing of the target aircraft includes: wing spars, wing ribs, skins, leading edge flaps, ailerons, fuel tanks, electronic equipment, hydraulic systems and electronic control systems.

[0081] The wing spar is the longitudinal support member of the wing, which is used to bear the bending moment and shear force on the wing; the wing spar is usually made of high-strength materials, such as titanium alloy or composite materials; the wing spar is responsible for bearing and transmitting the bending moment and shear force during flight. The wing rib is a transverse structure inside the wing, connecting the wing spar and the skin, providing lateral support, maintaining the shape of the wing, and helping to disperse the load. The skin is the outer covering of the wing, usually made of composite materials, such as carbon fiber reinforced plastic. The skin not only provides an aerodynamic shape, but also participates in bearing aerodynamic loads. The leading edge flap is a movable wing surface used to control the lift and pitch of the aircraft.

[0082] The leading edge flaps can be moved down or up to change the lift characteristics of the wing. The ailerons are located at the trailing edge of the wing and are used to control the roll of the aircraft. The ailerons work in conjunction with the leading edge flaps to improve flight performance. The fuel tanks are properly housed and protected inside the wing structure.

[0083] Step S2: Based on the principle of structural consistency, an equivalent wing model is designed according to the structural characteristics of the target wing;

[0084] In the step S2, when the wing structure of the target aircraft is equivalently designed, the leading edge flaps and ailerons on the wing of the target aircraft that are hingedly connected to the wing body are equivalent to equivalent leading edge flaps 4 and equivalent ailerons 5 that are fixedly connected to the main part of the equivalent wing model; that is, the leading edge flaps and ailerons of the real wing are hingedly connected to the wing body, and in this embodiment, the hinge connection is equivalent to a fixed connection.

[0085] In the present invention, the connection mode of the leading edge flap and the aileron to the wing body is changed from a hinged connection to a fixed connection; on the one hand, the structural composition is simplified, and processing and manufacturing are convenient; on the other hand, the fixed connection mode will not reduce the structural strength of the entire structure, and will not affect the accuracy of the test when the wing damage performance test is performed.

[0086] In step S2, the principle of equivalent design of the target wing is: retain the load-bearing structure and the fuel tank, omit the functional components and small connectors, retain the wing shape structure and simplify the design of the skin structure, and the overall shape structure and projected area of ​​the wing are the same as those of the target wing, and the equivalent wing model is obtained as follows: Figure 1 , Figure 2 shown.

[0087] Specifically, the functional components include: electronic equipment, hydraulic system and electric control system inside the wing; since the functional components have almost no effect on the structural physical properties of the wing, the above functional components are omitted when the wing is designed with an equivalent structure.

[0088] Further, in step S2, if Figure 1 , Figure 2 As shown, the equivalent wing model after equivalent design of the target wing includes: an equivalent wing spar 1, an equivalent wing rib 2, an equivalent skin 3, an equivalent leading edge flap 4, an equivalent aileron 5 and an equivalent fuel tank 6.

[0089] Among them, Figure 3 , Figure 4 As shown, the equivalent wing spar 1 is an I-shaped steel beam, and the number of equivalent wing spars 1 is equal to the number of wing spars of the target wing; the length and arrangement of the multiple equivalent wing spars 1 correspond to the length and arrangement of the wing spars of the target wing. Most of the spars in the wings of the target aircraft are web-type metal spars, which are riveted by two upper and lower parallel edge strips and a web vertically connected between the two edge strips, and the web is its load-bearing component.

[0090] like Figure 4 As shown, an I-shaped steel beam with the same strength and stiffness is used as an equivalent structure of a metal spar structure consisting of two upper and lower flanges and a web, namely, an equivalent spar 1.

[0091] like Figure 2 , Figure 5As shown, the equivalent wing rib 2 is a multi-section flat plate structure, and the multi-section flat plates are located in the same plane, and the multi-section flat plates of the equivalent wing rib 2 are respectively connected between two adjacent equivalent wing beams 1.

[0092] Furthermore, considering the convenience of processing and production and the simplification of the processing technology, the equivalent skin 3 is configured as a plurality of flat plates with different sizes and shapes.

[0093] like Figure 6 , Figure 7 As shown, the equivalent leading edge flap 4 and the equivalent aileron 5 are designed to have the same shape as the target wing.

[0094] like Figure 2 As shown, the equivalent fuel tank 6 is used as a fuel storage structure and is arranged in a closed cabin formed between the equivalent wing beam 1 and the equivalent wing rib 2. Since the fuel tank capacity of the aircraft wing is about 1586 liters and the area covers the entire main wing part, the equivalent fuel tank 6 is arranged in the middle of the equivalent wing model in consideration of factors such as processing, model weight, transportation, experimental operation difficulty, and fuel price.

[0095] In step S2, Figure 2 As shown, a plurality of equivalent wing spars 1 and a plurality of equivalent wing ribs 2 are arranged in an interlaced manner to form a plurality of closed cabins; a row of closed cabins from the wing root to the wing tip close to the center of the chord among the plurality of closed cabins is selected as an oil storage cabin.

[0096] Furthermore, during the processing, the joints between the equivalent wing beam 1 and the equivalent wing rib 2 are sealed with oil-proof sealing glue to prevent oil leakage, or a sealed aluminum alloy or stainless steel oil tank with the same size as the oil storage compartment is placed in the oil storage compartment to store oil. In this embodiment, the chord direction is parallel to the rib direction. Specifically, Figure 8 As shown, the equivalent fuel tank 8 is composed of a plurality of tank structures; the total volume of the equivalent fuel tank 8 is about 0.06 cubic meters, which can be filled with 60 liters of fuel.

[0097] In the present invention, an equivalent oil tank 8 is arranged inside the equivalent wing model, and oil is stored inside the equivalent oil tank. When the equivalent wing model is subjected to impact (physical impact / detonation impact), the equivalent oil tank 8 can simulate the state of the oil tank, which is closer to the damage state of the real wing; at the same time, it can truly simulate the temperature increase effect on the wing structure caused by fuel fire, and simulate the damage resistance of the wing under the temperature change state.

[0098] Specifically, the dimensions of each structural component of the equivalent wing model are consistent with those of the real wing, the number and structure of the wing main beams are the same as those of the real wing, and at the same time, the equivalent leading edge flaps and equivalent ailerons are designed as one with the main structure of the equivalent wing, and the skin is equivalent to multiple sections (at least two sections) of flat panels.

[0099] In this embodiment, the equivalent skin 3 adopts a multi-segment plane, and the equivalent skin 3 is determined as follows:

[0100] Step S21: Cut the skin surface of the target wing at the rib located in the middle to obtain its airfoil cross section; Fig.11 As shown, the airfoil section is a closed shuttle-shaped structure, including two upper and lower airfoil camber lines;

[0101] Step S22: dividing the aerofoil section into two sections at the maximum thickness of the aerofoil section (i.e., the maximum distance between the upper and lower aerofoil arcs);

[0102] Step S23: Connect the upper end point and the lower end point of the maximum thickness of the airfoil section to the leading edge end point and the trailing edge end point of the airfoil section respectively, so that the upper and lower wing surface arcs of the airfoil section are equivalent to four straight line segments, each straight line segment corresponds to a plane plate, and then the skin surface of the target wing is equivalent to multiple plane plates. Specifically, in step S23, the upper half of the skin surface of the target wing is equivalent to the first plane plate 31 and the second plane plate 32, and similarly, the lower half of the skin surface of the target wing is equivalent to the third plane plate and the fourth plane plate.

[0103] Step S24: re-segmenting the airfoil section at the midpoint after segmentation, and further dividing the airfoil section into four sections; sequentially connecting the leading edge endpoint, each endpoint after segmentation, and the trailing edge endpoint to obtain a multi-segment flat plate of the skin surface; after re-segmentation, the equivalent multi-segment flat plate of the skin surface of the wing is closer to the real surface, so as to obtain a wing aerodynamic performance (wing lift) equivalent to the target wing.

[0104] Furthermore, first, the equivalent wing model composed of the equivalent skin 3 composed of four sections of flat panels obtained in step S23 is checked for consistency. If the wing lift of the equivalent wing model cannot reach the consistency with the lift of the target wing after simulation analysis, the equivalent design in step S24 is repeated for the skin surface.

[0105] That is to say, the airfoil section is further segmented at the midpoint of the distance between the maximum thickness of the airfoil section and the leading edge endpoint and the trailing edge endpoint (i.e., the middle of the two airfoil sections); after the further segmentation, four midpoint endpoints are formed, of which two are the leading edge midpoint endpoints and two are the trailing edge midpoint endpoints; the leading edge endpoint (one endpoint), the leading edge midpoint endpoint (two endpoints), the maximum thickness endpoint (two endpoints), the trailing edge midpoint endpoint (two endpoints) and the trailing edge endpoint (one endpoint) are sequentially connected, so that the wing surface arc is equivalent to eight vertically symmetrical straight line segments, each straight line segment corresponds to a plane plate, and then the skin curved surface is equivalent to eight vertically symmetrical plane plates; such as Fig.12 As shown, it can be seen that the equivalent plane structure is closer to the actual skin surface of the target wing.

[0106] Furthermore, if Fig.13 As shown, repeat step S24, segment the airfoil section multiple times, and then connect each endpoint in turn, so as to convert the skin surface into multiple vertically symmetrical planes, so that the equivalent planes are closer to the real skin surface, until the dynamic performance of the equivalent skin 3 passes the consistency check with the target wing.

[0107] Step S3: Perform material strength equivalent design: determine the equivalent material and the corresponding equivalent thickness according to the material properties of each part of the wing.

[0108] Specifically, according to the material strength equivalence principle, the thickness of each part in the equivalent wing model is designed equivalently, and the thickness equivalent formula of the equivalent wing model plate is:

[0109] ,

[0110] in,

[0111] is the ultimate strength of the wing's actual structural material;

[0112] is the ultimate strength of the equivalent material;

[0113] is the material density of the actual structure of the wing;

[0114] is the standard equivalent material density;

[0115] is the material thickness of the actual structure of the wing;

[0116] is the thickness of the equivalent material.

[0117] For example, the wing adopts a triple beam structure, which is made of composite wall panels and titanium alloy main wing beams and composite auxiliary wing beams. The materials used are 42% titanium alloy, 35% composite materials (Fiberite977-3 toughened epoxy composite materials, bismaleimide resin-based composite materials), and 23% aluminum alloy. Specifically, the front beam (main beam) of the target wing is a machined titanium alloy forging, the middle beam and the rear beam are made of a mixture of resin transfer molding composite materials and titanium alloys, and the wing skin is made of bismaleimide (BMI) resin-based composite materials.

[0118] In this embodiment, aluminum alloy and steel are used as the main equivalent materials, and the density of steel is about 7.85. ,On the premise of ensuring that the equivalent structure is consistent with the original structure, the material thickness is determined by the above thickness equivalent formula. The equivalent material strength of the skin is about 420MPa, and the equivalent material strength of the wing spar and rib is about 539MPa.

[0119] Exemplarily, the equivalent wing model materials are shown in Table 1 below:

[0120] Table 1 Equivalent parameters of equivalent wing model

[0121]

[0122] As shown in Table 1, the equivalent wing beam 1, the equivalent wing rib 2, the equivalent leading edge flap 4 and the equivalent aileron 5 are made of 45# steel; the equivalent skin 3 is made of carbon fiber composite plate or LY-12 hard aluminum.

[0123] In this embodiment, the selection of equivalent materials mainly considers the selection of economical and readily available materials under the premise of close density, and the material thickness is calculated according to the thickness equivalent formula to achieve structural consistency between the equivalent wing model and the target wing. The selection of equivalent materials and thickness setting of the present invention effectively reduce the cost of the equivalent wing model.

[0124] Step S4: Perform consistency check on the equivalent wing model based on finite element simulation analysis: Use numerical simulation methods to calculate the aerodynamic characteristics and static force distribution of the entire equivalent wing model, obtain the maximum local stress, and check whether it meets the strength requirements; at the same time, calculate the consistency of the lift of the equivalent wing model with the target wing.

[0125] The step S4: performing aerodynamic analysis on the equivalent wing model and verifying its structural performance.

[0126] Step S41: using simulation analysis software to establish an external flow field of the equivalent wing model;

[0127] Step S42: Determine the flight condition of the equivalent wing model according to the use condition of the real wing;

[0128] Step S43: obtaining a wing surface pressure distribution diagram of the equivalent wing model through simulation analysis;

[0129] Step S44: The surface pressure obtained by the aerodynamic analysis calculation of the wing is imported into the finite element analysis software to perform strength verification calculation of the equivalent wing model to verify its consistency with the lift force on the real wing.

[0130] In step S41, since the cost of wind tunnel experiments and flight experiments is too high, in the present invention, CFD numerical calculation is used to solve the aerodynamic law, and the equivalent wing model with a completely closed equivalent skin is imported into FLUENT, and the flow field outside the equivalent wing model is established using FLUENT software, and the k-omega (SST) turbulence model is used.

[0131] Since the gas properties of air itself are not taken into consideration, such as Fig.14 As shown, in the present invention, when the equivalent wing model and the air are meshed by finite element, in order to improve the calculation accuracy, the mesh of the air around the wing and the equivalent wing model itself is encrypted, and the mesh size of the air far away from the wing is increased; specifically, the distance corresponding to 1.5 times the wing thickness is used as the boundary of the distance between the air and the equivalent wing model, that is, when the distance between the air and the wing is less than or equal to 1.5 times the wing thickness, its mesh density is consistent with the mesh density of the equivalent wing model, and when the distance between the air and the wing is greater than 1.5 times the wing thickness, its mesh density is gradually increased from near to far; finally, the hexahedral meshing of the equivalent wing model and the air model and the local mesh encryption are completed; the overall meshing of the equivalent wing model and the air model is as follows Fig.14 shown.

[0132] In step S42, the flight conditions of the equivalent wing model are set considering the working state of the aircraft: the angle of attack of the aircraft is set to 5°, the cruising altitude is set to 11000 meters, and the air density is set to ρ = 0.4kg / m 3 ; The temperature is set to T = 216.65K; The aircraft's supersonic cruising speed is set to 1.82 Mach.

[0133] In step S43, the method of using FLUENT software to solve the wing surface pressure is as follows: the energy equation is enabled, the pressure basis is selected as the solver type; aluminum alloy is selected as the solid material, and the control parameters of calculation stability and convergence are adjusted to make the calculation result convergent and numerically stable. The wing surface pressure distribution diagram can be obtained by iterative solution, such as Fig.15 shown.

[0134] In this embodiment, only the force and deformation of the equivalent wing model and the real wing under the action of aerodynamic loads are required to be consistent, that is, only the static characteristics of the equivalent wing model are considered.

[0135] In step S44, the strength check calculation of the equivalent wing model is performed: a one-way fluid-solid coupling analysis is performed based on Ansys Workbench software and the ANSYS-FLUENT one-way fluid-solid coupling interface is used to connect the solution part of the fluid flow analysis schematic diagram to the setting part of the static structure analysis schematic diagram, such as Fig.16 shown.

[0136] In step S44, the strength check calculation of the equivalent wing model includes:

[0137] Step S441: Open the static structural analysis in Ansys Workbench software, import the built wing model including the internal structure (excluding the fixture), and assign the material parameters (engineering data) of the equivalent wing model according to the material strength equivalent design result in step S3. For example, all internal structures are made of 45# steel with a density of 7.85 , elastic modulus 207Gpa, Poisson's ratio 0.3, LY-12 hard aluminum alloy material is used for the skin, density is 2.7 , elastic modulus 70Gpa, Poisson's ratio 0.3.

[0138] Step S442: The equivalent wing model is meshed using solid units: the internal structure (excluding the skin) is meshed into a 3 mm hexahedral mesh, and the equivalent skin 3 is meshed into a 6 mm hexahedral mesh; a finite element model of the equivalent wing is established; wherein the local mesh of the equivalent wing model is, for example Fig.16 shown.

[0139] Step S443: Set up the analysis interface, use binding contact connection between the skin and the internal structure, add a fixed support device 7 in the static structure module, apply a fixed constraint at the wing root of the equivalent wing model, and turn on the standard earth gravity to consider the dead weight of the structure; import the wing surface pressure calculated in step S43 into the static structure analysis of Ansys Workbench to complete the load loading, such as Fig.17 shown.

[0140] Step S444: Calculate the stress distribution diagram of the equivalent wing model using Ansys Workbench software; the stress distribution diagram of the equivalent wing model is as follows: Fig.18 , Fig.19 , Fig. 20 As shown; analyze whether the equivalent wing model meets the strength requirements based on the stress distribution diagram; at the same time, calculate whether the lift exerted on the equivalent wing model is consistent with the lift of the target wing.

[0141] Furthermore, if the lift of the equivalent wing model differs too much from the lift of the target wing, the skin surface equivalent method in step S24 is repeated until the consistency check of the equivalent wing model passes.

[0142] Specifically, Fig.21As shown in the figure, the stress distribution of the equivalent wing model gradually increases from the wing tip to the wing root. At this time, the maximum equivalent stress of the internal structure is 456.75MPa, which is less than the strength limit of 45# steel material 540MPa, that is, the strength of each part is within the allowable strength range of the material, and the design meets the strength requirements.

[0143] Specifically, the average equivalent stress on the equivalent skin 3 is 121.1 MPa, and analysis shows that the equivalent stresses on other parts of the skin are all within the strength limit of the LY12-hard aluminum alloy material, so the design meets the strength requirements.

[0144] Furthermore, in step S44, if the strength check of the equivalent wing model fails, the thickness of each component of the equivalent wing model is increased by 5% until the strength check passes.

[0145] Specifically, the maximum deformation of the equivalent wing model is located at the leading edge of the wing at the wingtip, with a maximum deformation of 240.51 mm, which is less than 2% of the wing span (13.56 m), i.e., 271.2 mm, so the design meets the deformation requirements.

[0146] Furthermore, in step S444, a probe is used to add monitoring points in the workbench to check the resultant force on the wing surface, such as Fig. 22 As shown; the horizontal upward component of the resultant force on the surface of the equivalent wing model acts as the aerodynamic lift.

[0147] Because the main external loads on the wing are aerodynamic force (lift) and the mass force (gravity) of the wing itself, the aerodynamic force is basically equal to the weight of the wing itself, maintaining the flight state of the aircraft; among them, the aerodynamic force is approximately equal to the lift force on the wing. In this embodiment, the wing load of the actual aircraft is 375kg / mm 2 , wing area is 78mm 2 When the aircraft is in supersonic cruise, it can be considered that the lift on the two wings of the aircraft is approximately equal to the total mass of the entire aircraft, where the total mass of the aircraft is approximately equal to the wing load multiplied by the wing area, and the total mass of the aircraft is approximately 29250kg. The gravity on the aircraft is approximately 286650N, so the actual lift on a single wing is approximately 143325N. In this equivalent wing model, the resultant force on the wing surface in the vertical direction (y-axis) is 149030N, which is basically consistent with the actual lift on the wing, indicating that the equivalent wing target design is reasonable.

[0148] In this embodiment, in step S44, when the error between the wing lift of the equivalent wing model and the lift of the real wing is set to be no more than 10%, it is considered that the lift of the equivalent wing model is consistent with that of the real wing.

[0149] Further, step S5: after the verification is completed, the equivalent wing model is constructed, including:

[0150] Step 51: Processing the equivalent wing spar 1. The equivalent wing spar 1 is integrally processed to ensure the integrity of the structure of the equivalent wing spar 1 and to ensure that its strength is not affected. Then, the edge is bent and punched to facilitate connection with other components.

[0151] Step 52: Processing the equivalent wing rib 2. The equivalent wing rib 2 is processed in sections, and the equivalent wing ribs 2 between adjacent equivalent wing spars 1 are processed separately, and then fixed to the equivalent wing spars 1 and / or the equivalent skin 3 by rivets or bolts;

[0152] Step 53: Processing the equivalent skin 3. Cut the aluminum plate into the required shape of the equivalent skin 3, and punch rivet holes at the contact points between the edge of the equivalent skin 3 and the equivalent wing spar 1 and the equivalent wing rib 2, and then fix the equivalent skin 3 with the equivalent wing spar 1 and the equivalent wing rib 2 by rivets.

[0153] Step 54: Processing the equivalent front flap 4 and the equivalent aileron 5. A whole piece of solid steel plate with variable thickness is cut according to the shape and size of the equivalent front flap 4 and the equivalent aileron 5, so that the frames of the equivalent front flap 4 and the equivalent aileron 5 and the internal connecting beams thereof form a whole; in this embodiment, the frames of the equivalent front flap 4 and the equivalent aileron 5 and the internal connecting beams are formed by integral cutting, and no welding is required, which can simplify the processing process of the component and improve the structural stability compared with the welded structure.

[0154] Step 55: Processing the equivalent fuel tank 6. The equivalent fuel tank 6 is made of thin aluminum alloy or stainless steel material, and the material is cut into the required size and shape. The aluminum plates are connected by welding to form a closed space for storing oil, and holes of appropriate size are reserved for pouring fuel. After the fuel is poured, it is sealed and assembled into a closed compartment composed of the equivalent wing rib 2 and the equivalent wing spar 1 of the equivalent wing model.

[0155] Step 56: The equivalent wing model is fixedly mounted on the fixed support device 7. The fixed support device 7 and the flat plate at the wing root are welded, and the fixed support device 7 is placed flat on the ground and finally compacted and stabilized with sandbags.

[0156] Furthermore, in this embodiment, the fixing support device 7 is used to fix the equivalent wing model when the equivalent wing model is subjected to an impact damage (physical impact, blasting impact, etc.) test.

[0157] In a specific embodiment of the present invention, Fig. 9As shown, the fixed support device 7 includes: a longitudinal beam 71, a transverse beam 72, a triangular bracket 73 and an oblique rib 74. The longitudinal beam 71 is provided with two, which are respectively vertically fixed above the transverse beam 72; a triangular bracket 73 is fixedly installed at the bottom of the longitudinal beam 71, and the triangular bracket 73 is arranged perpendicular to the transverse beam 72, and the triangular bracket 73 is used to support the fixed support device 7 as a whole; the oblique rib 74 is obliquely arranged on the side of the longitudinal beam 71, and is fixedly connected to the longitudinal beam 71 and the transverse beam 72, so as to support and position the longitudinal beam 71.

[0158] The aircraft's fixture is capable of firmly connecting the wing to the fuselage while allowing the necessary flexibility and torsion to accommodate load changes during flight. Fig.10 As shown, a fixed support device 7 is used as a fixing device for the equivalent wing model, and the equivalent wing model is fixed on the fixed support device 7, and the equivalent wing model is kept in a vertical state, so as to simulate the influence of the fuselage on the wing when the wing is impacted.

[0159] The equivalent wing structure design method of the present invention sets strength verification and verification of wing aerodynamic performance to achieve structural consistency between the equivalent wing model and the target wing, and sets a feedback adjustment mechanism according to the verification result, so as to achieve consistency adjustment of the equivalent wing model by changing the material thickness or adjusting the number of equivalent planes of the skin surface, so that the equivalent wing model after the design is completed can achieve strength performance and lift consistent with the target wing, so as to achieve the authenticity of impact damage simulation of the target wing and the effectiveness of the simulation results.

[0160] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for designing an equivalent structure of an aircraft wing, characterized in that: The following steps are involved: Step S1: Analyze the structural characteristics of the wing of the target aircraft; Step S2: Based on the principle of structural consistency, an equivalent wing model is designed according to the structural characteristics of the target wing; Step S3: Perform material strength equivalent design: determine equivalent materials and corresponding equivalent thicknesses according to the material properties of each part of the wing; Step S4: performing consistency check on the equivalent wing model based on finite element simulation analysis; In step S2, the principle of equivalent design of the structural features of the target wing is: retain the load-bearing structure and the fuel tank, omit the functional components and tiny connectors, retain the wing shape structure and simplify the design of the skin structure; In the step S2, the equivalent wing model after equivalent design of the target wing comprises: an equivalent wing spar (1), an equivalent wing rib (2), an equivalent skin (3), an equivalent leading edge flap (4), an equivalent aileron (5) and an equivalent fuel tank (6); the equivalent leading edge flap (4) and the equivalent aileron (5) are designed to have the same shape as the target wing and are fixedly connected to the main body of the equivalent wing model; the equivalent skin (3) is arranged outside the equivalent wing spar (1) and the equivalent wing rib (2), and the equivalent skin (3) is a multi-section plane plate; the multiple equivalent wing spars (1) and the multiple equivalent wing ribs (2) are arranged in an interlaced manner to form a plurality of closed cabins; a row of closed cabins from the wing root to the wing tip in the direction close to the center of the chord among the multiple closed cabins is selected as the fuel storage cabin; the equivalent fuel tank (6) is arranged in the fuel storage cabin; The equivalent skin (3) is determined as follows: Step S21: Cutting the skin surface of the target wing at the rib located in the middle thereof to obtain its airfoil cross section; the airfoil cross section is a closed shuttle-shaped structure, including two upper and lower airfoil camber lines; Step S22: dividing the aerofoil section into two sections at the maximum thickness of the aerofoil section; Step S23: connecting the upper end point and the lower end point at the maximum thickness of the airfoil section to the leading edge end point and the trailing edge end point of the airfoil section respectively, so as to convert the upper and lower airfoil surface cambers of the airfoil section into four straight line segments, each straight line segment corresponds to a plane plate, and further convert the skin surface of the target wing into four plane plates; Step S24: re-segmenting the airfoil section at the midpoint after segmentation, and further dividing the airfoil section into four sections; sequentially connecting the leading edge endpoint, each endpoint after segmentation, and the trailing edge endpoint to obtain a multi-segment plane plate of the skin surface; after re-segmentation, the equivalent multi-segment plane plate of the skin surface of the wing is closer to the real surface, so as to obtain a wing aerodynamic performance equivalent to that of the target wing; In the step S4, the equivalent wing model composed of the equivalent skin (3) composed of the four-segment plane panels obtained in the step S23 is subjected to consistency check. If the consistency check of the equivalent wing model fails, the step S24 is executed to convert the equivalent skin (3) into a plurality of plane panels and then perform consistency check on the equivalent wing model. If the lift of the equivalent wing model still fails to pass the consistency with the lift of the target wing, the skin surface equivalent method in the step S24 is repeated until the consistency check of the equivalent wing model passes. In step S3, according to the material strength equivalence principle, thickness equivalence design is performed on each part of the equivalent wing model, and the thickness equivalence formula of the equivalent wing model plate is: ， in, is the ultimate strength of the wing's actual structural material; is the ultimate strength of the equivalent material; is the material density of the actual structure of the wing; is the standard equivalent material density; is the material thickness of the actual structure of the wing; is the thickness of the equivalent material; Step S4: Perform aerodynamic analysis on the equivalent wing model and verify its structural performance: Step S41: using simulation analysis software to establish an external flow field of the equivalent wing model; Step S42: determining the flight condition of the equivalent wing model according to the use condition of the real wing; Step S43: obtaining a wing surface pressure distribution diagram of the equivalent wing model through simulation analysis; Step S44: importing the surface pressure obtained by the aerodynamic analysis calculation of the wing into the finite element analysis software to perform strength verification calculation of the equivalent wing model to verify its consistency with the lift force on the real wing; In step S44, the strength check calculation of the equivalent wing model includes: Step S441: Open the static structural analysis in the Ansys Workbench software, import the built wing model including the internal structure, and assign material parameters of the equivalent wing model according to the material strength equivalent design result in step S3; Step S442: meshing the equivalent wing model as a whole using solid units to establish a finite element model of the equivalent wing; Step S443: applying a fixed constraint at the wing root of the equivalent wing model, and turning on the standard earth gravity to consider the deadweight of the structure; importing the wing surface pressure calculated in step S43 into the static structural analysis of Ansys Workbench to complete the loading of the load; Step S444: Calculate the stress distribution diagram of the equivalent wing model through Ansys Workbench software; analyze whether the equivalent wing model meets the strength requirements according to the stress distribution diagram; and calculate whether the lift force on the equivalent wing model is consistent with the lift force of the target wing.

2. The aircraft wing equivalent structure design method according to claim 1, characterized in that: In step S2, the equivalent wing beam (1) is an I-shaped steel beam.

3. The aircraft wing equivalent structure design method according to claim 1, characterized in that: In step S2, the number of the equivalent wing spars (1) is equal to the number of wing spars of the target wing; and the length and arrangement of the multiple equivalent wing spars (1) correspond to the length and arrangement of the wing spars of the target wing.

4. The aircraft wing equivalent structure design method according to claim 1, characterized in that: In step S2, the equivalent wing rib (2) is a plurality of flat plates located in the same plane, and the plurality of flat plates of the equivalent wing rib (2) are respectively connected between two adjacent equivalent wing beams (1).

5. The aircraft wing equivalent structure design method according to claim 4, characterized in that: The equivalent wing beam (1), the equivalent wing rib (2), the equivalent leading edge flap (4) and the equivalent aileron (5) are made of 45# steel; the equivalent skin (3) is made of carbon fiber composite plate or LY-12 hard aluminum.

6. The aircraft wing equivalent structure design method according to claim 1, characterized in that: In the step S41, the equivalent wing model is imported into FLUENT, and the flow field outside the equivalent wing model is established using the FLUENT software; when the equivalent wing model and the air are divided into finite element grids, the grids of the air around the equivalent wing model and the equivalent wing model itself are encrypted, and the grid size of the air far away from the equivalent wing model is increased.

7. The aircraft wing equivalent structure design method according to claim 1, characterized in that: In the step S44, if the strength check of the equivalent wing model fails, the thickness of each component of the equivalent wing model is gradually increased by 5% until the strength check passes.

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