A variant wing skin deformation reconstruction method, computer storage medium and device

Abstract

The present invention belongs to the field of deformation measurement of variant wings, and relates to a method for reconstructing the deformation of a variant wing skin, a computer storage medium, and a device. The method comprises: dividing the skin into a fixed area skin and a deformation area skin according to the active and passive deformation of the variant wing. The fixed area skin is reconstructed using a general method, and the result is used as the boundary condition for the reconstruction of the deformation area skin; the internal support of the deformation area is simplified as a boundary condition and unit nodes are placed, and the degree of freedom of the unit nodes is used to characterize the deformation caused by the skeleton drive; double-layer strain sensors are arranged on the inner surface of some units according to the simulated strain cloud map; the sensor measurement values ​​are decoupled by bending, tension and compression, an error functional is constructed, and the node degrees of freedom of the unit are obtained by variation. The reconstruction results of the fixed area skin are superimposed, and the full-field deformation of the skin is obtained by interpolation. The present invention can solve the technical problems in the prior art that the skin reconstruction method is difficult to apply to the reconstruction of the variant wing skin and the reconstruction result has large errors.

Description

Technical Field

[0001] The present invention belongs to the field of deformation measurement of variant wings, and relates to a method, computer storage medium and equipment for reconstructing the deformation of the skin of a variant wing based on measurement of finite strain points on the inner surface. More specifically, it relates to a reconstruction method for reconstructing the deformation of the skin in a fixed area and the deformation area by partitioning the discrete strain data of the inner surface of the skin of a variant wing, and superimposing them to obtain the full-field deformation of the skin. Background Art

[0002] A morphing wing is an intelligent wing that actively changes its aerodynamic shape and characteristics to adapt to different flight conditions. This makes environmentally adaptable aircraft possible and is a key feature and development direction for future advanced aircraft. Unlike the hinged, discontinuously morphing structure of traditional wings, current morphing wings primarily deform on small and medium scales, such as varying the airfoil's camber, thickness, and twist. By continuously deforming the wing skin, they can significantly alter the overall aerodynamic performance and environmental adaptability of the aircraft with minimal actuation energy. Compared to traditional hinged, split-body deformation, the continuously changing skin surface can significantly alter the aircraft's lift-to-drag ratio and improve fuel efficiency. Therefore, unlike existing fixed-wing deformation reconstruction methods that simplify the overall structure, efficient and high-precision sensing of the skin's real-time, full-field deformation is key to the morphing wing's ability to effectively control deformation and precisely control the aircraft's aerodynamic characteristics.

[0003] The structure and deformation of the variant wing skin have the following characteristics: the overall skin structure can be divided into a fixed area and a deformation area, such as Figure 1 As shown in the figure, the deformation of the fixed area skin is consistent with that of the fixed wing skin, which is a passive deformation caused by external loads; the deformation of the deformation area skin is mainly an active deformation caused by the driven structure. During deformation, it is necessary to satisfy the elastic deformation in the tangential direction of the surface to achieve the required deformation amount, and it has greater rigidity in the normal direction of the surface to ensure that the surface streamline will not be affected by the external pressure changes during actual flight. Therefore, the skin material of the deformation area is generally a composite material, and the material needs to show different material properties in the tangential and normal directions. In order to achieve continuous deformation, the drive devices in the wing are dense, such as Figure 2 As shown, the inner surface of the skin contacts a large number of ribs, presenting complex boundary conditions. Existing deformation-sensing methods typically simplify the wing as a whole into structures such as cantilever panels. This simplification can significantly reduce computational effort when analyzing static load deformation. However, when considering aerodynamic characteristics and reconstructing a morphing wing, the shape of the skin in the deformation zone is crucial for adjusting the aircraft's launch performance to the environment, and this shape cannot be simply simplified.

[0004] The deformation characteristics of the skin in the deforming zone of a morphing wing require a reconstruction method that can adapt to the complex material properties and deformation conditions. Furthermore, the complex drive mechanism built into the morphing wing results in a narrow inner surface, making it impossible to accommodate the space required for sensors to be placed on the outer surface and over a large area. Consequently, a limited-point contact measurement method, typically adhesively bonded to the inner surface, can only be used. Therefore, it is urgent to develop a new finite-point contact deformation measurement method that can reconstruct and superimpose the fixed and deforming zones of the morphing wing to achieve full-field skin deformation reconstruction. Summary of the Invention

[0005] In response to the above-mentioned defects or improvement needs of the prior art, the present invention provides a variant wing skin deformation reconstruction method, computer storage medium and equipment, whose purpose is to solve the technical problems in the prior art that the skin reconstruction method is difficult to apply to variant wing skin reconstruction and the reconstruction result has large errors.

[0006] To achieve the above object, according to one aspect of the present invention, a method for deforming and reconstructing a wing skin is provided, comprising the following steps:

[0007] Step 1: Based on the active and passive deformations of the morphing wing, the entire wing skin is divided into a fixed area skin and a deforming area skin. The small deformation of the fixed area skin is reconstructed by simplifying it into a cantilever plate, and the reconstruction result of the fixed area skin is used as the fixed boundary condition for the large deformation reconstruction of the deforming area skin.

[0008] Step 2: Based on the characteristics of the driving skeleton structure inside the deformation zone skin, the internal skeleton structure is simplified into boundary conditions and unit nodes are placed so that the unit nodes coincide with the driving skeleton. The degrees of freedom of the unit nodes are used to characterize the deformation caused by the skeleton drive.

[0009] Step 3: Perform deformation simulation on the skin in the deformation zone to obtain the overall strain distribution cloud map of the structure during actual operation;

[0010] Step 4: Based on the distribution of the strain cloud diagram, double-layer strain sensors are arranged on the inner surface of the skin unit in the deformation area where the maximum strain exceeds the threshold value for measurement;

[0011] Step 5: When the morphing wing undergoes autonomous deformation, the deformation of the skin in the deformation zone includes the coupling of tensile and compressive deformation and bending deformation. Therefore, the strain data measured by the double-layer sensor is decoupled from the bending, tensile and compressive strains. The measured strain obtained by decoupling and the theoretical strain derived from the nodal degrees of freedom are used to construct an error functional. The variation is taken, and the obtained stationary point is the nodal degree of freedom in the unit local coordinate system. The deformation of the skin in the deformation zone is then obtained by interpolation. The deformation of the skin in the fixed zone is superimposed at the boundary position to obtain the full-field deformation of the entire structure of the morphing wing skin.

[0012] Among them, the nodal degrees of freedom u in the local coordinate system of the elemente The solution is as follows:

[0013]

[0014] In the above formula, K e It is a function that is only related to the location of the sensor points in the unit and the unit shape function, f e It is a function related to the sensor location in the unit, the unit shape function and the actual measurement value; B m 、B b and B s are the theoretical membrane strain matrix, theoretical curvature matrix, and theoretical transverse shear strain matrix, respectively; h is the distance between the neutral surface of the skin and the upper strain gauge in the double-layer strain sensor; ω is the virtual arrangement coefficient, λ is the transverse shear strain penalty coefficient; e ε , κ ε are the measured membrane strain and measured curvature at the neutral plane of the skin, respectively.

[0015] Further,

[0016] In step 2, the method of using the degrees of freedom of the unit nodes to characterize the deformation caused by the skeleton drive is as follows:

[0017] According to Mindlin's medium-thick plate theory, a four-node inverse shell element is constructed. Each node has three translational degrees of freedom uvw and rotational degrees of freedom θ along the xyz axis. x θ y θ z , then the displacement vector of each node is expressed as:

[0018]

[0019] The displacement vector of the entire unit is expressed as:

[0020]

[0021] In the above formula, the superscript e indicates analysis within the unit; in the table below, i indicates the node number, i = 1, 2, 3, 4.

[0022] Further,

[0023] The membrane deformation of any point (x, y) on the neutral surface of the element is expressed in the form of shape function node interpolation as follows:

[0024]

[0025] In the above formula, N k , L i , M i is the unit interpolation shape function, and its specific form is:

[0026]

[0027]

[0028] in,

[0029]

[0030] s, t are the isoparametric coordinates of a node in the local coordinate system. Assuming the length and width of the unit are 2a×2b, then:

[0031]

[0032] The theoretical displacement of any point (x, y, z) in the unit is expressed as:

[0033]

[0034] Further,

[0035] According to the first-order shear deformation theory, the strain is expressed by the theoretical displacement of formula (7), and the theoretical strain of the unit is obtained as follows:

[0036]

[0037]

[0038]

[0039] In the above formula, ε, κ, and γ represent the linear strain, curvature, and shear strain of the unit, respectively. The subscripts x0, y0, and x y represents the x direction, y direction and xy direction, Respectively represent the partial derivatives in the x direction and y direction, then e(u e ),κ(u e )、g(u e ) represent the theoretical membrane strain vector, theoretical curvature vector and theoretical transverse shear strain vector of the neutral surface of the element, respectively.

[0040] Further,

[0041]

[0042] Among them, k=i=1, 2, 3, 4.

[0043] Further,

[0044] In step 5, the measured strain value at the corresponding position of the inner surface is obtained based on the double-layer strain sensor in the inner surface unit of the wing deformation zone skin:

[0045]

[0046] In the above formula, the superscript +- represent the upper and lower strain gauges of the double-layer strain sensor, respectively, where ε 0° , ε 45° , ε 90° Indicates the actual measured values ​​of the strain gauge in three directions, They represent the measured linear strain in the x and y directions and the measured shear strain in the xy direction, respectively.

[0047] Furthermore,

[0048] When the distance d between the double-layer strain sensors and the distance h between the neutral surface of the skin and the upper strain gauge are known, the measured membrane strain e at the neutral surface of the skin is obtained. ε and the measured curvature κ ε :

[0049]

[0050]

[0051] Among them, the superscript ε Represents experimentally measured data.

[0052] Furthermore,

[0053] Construct the error functional form between the theoretical strain and the measured strain of the unit:

[0054] Φ(u e )=ω||e(u e )-e ε ||2+ω||κ(u e )-κ ε ||2+λ||g(u e )||2 (15)

[0055] In the above formula, Φ(u e ) represents the least square relationship between theoretical strain and measured strain; the second norm || e(u e )-e ε || 2 、||κ(u e )-κ ε || 2 、||g(u e )|| 2 They represent the least squares relationship between the theoretical and actual values ​​of membrane strain, curvature, and transverse shear strain, respectively; ω is the virtual arrangement coefficient. When a strain sensor is arranged in the unit, ω = 1. If no sensor is arranged, ω is set to an empirical value far less than 0; λ is the transverse shear strain penalty coefficient, which is equal to an empirical value far less than 0.

[0056] Derivative of formula (15) yields u corresponding to the stationary point e That is, the actual nodal degrees of freedom.

[0057] According to another aspect of the present invention, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the variant wing skin deformation and reconstruction method as described in any of the above items is implemented.

[0058] According to another aspect of the present invention, a variant wing skin deformation and reconstruction device is provided, characterized in that it includes the aforementioned computer-readable storage medium and a processor, and the processor is used to call and process the computer program stored in the computer-readable storage medium.

[0059] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0060] The present invention utilizes double-layer strain sensors to achieve the decoupling of the bending, tensile and compressive strains of the neutral layer of the skin by sticking the sensors on one side, ensuring the real-time full-field reconstruction of the variant wing skin with limited measuring points without affecting the aerodynamic characteristics of the aircraft. This avoids the experimental errors caused by inaccurate upper and lower symmetrical point distribution in traditional decoupling methods and reduces the difficulty of sensor layout. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 This is a simplified diagram of the variant wing model.

[0062] Figure 2 It is the overall discrete schematic diagram of the skin structure in the deformation zone;

[0063] Figure 3 It is a schematic diagram of a four-node inverse shell element;

[0064] Figure 4 It is the simulation strain cloud diagram;

[0065] Figure 5 It is a schematic diagram of the double-layer strain gauge arrangement;

[0066] Figure 6 This is a schematic diagram of a double-layer strain gauge rosette with one side attached;

[0067] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0068] 21-neutral layer of the skin structure, 22-neutral layer of the double-layer strain sensor, 31-fixed area, 32-deformation area. DETAILED DESCRIPTION

[0069] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0070] The problem addressed by this invention is the deformation reconstruction of a morphing wing skin. By using real-time strain data collected from the skin's inner surface, the full-field deformation of the morphing wing skin can be reconstructed without affecting the aircraft's aerodynamic characteristics, providing a theoretical basis for adaptive aircraft deformation.

[0071] Figure 1 The schematic diagram of the variant wing model can be divided into 31 fixed areas and 32 deformation areas. The deformation of the fixed area is mainly passive deformation caused by external loads, while the deformation area realizes autonomous deformation of the skin through the driving device inside the model and changes the aerodynamic performance of the aircraft through the changing skin surface. The small deformation in the fixed area can be reconstructed by the common general reconstruction methods of traditional fixed wing skin (such as modal superposition method, interpolation integral method, Ko displacement theory, etc.). The deformation of the fixed area at the position connected to the deformation area is used as the boundary condition for the reconstruction of the deformation area. The measured value of the sensor after deformation is substituted into formula (16) to perform real-time reconstruction of the deformation field of the variant wing skin.

[0072] Figure 2 This is a schematic diagram of the discretized skin structure in the deformation zone, showing the skeleton structure and unit division driven by the inner surface of the skin in the deformation zone. The skeleton structure is simplified to an external load, and the unit nodes are placed at the skeleton structure. When arranging sensors in practice, you can use the simulated strain cloud diagram as an example. Figure 4 As shown, the virtual point arrangement method is used to reduce the number of overall sensors at the position where the maximum strain value is less than the threshold τ, and the local arrangement of sensors in the unit can also be adjusted according to the position of the driving mechanism.

[0073] Figure 3 The general form of the four-node inverse shell element and the degrees of freedom in its local coordinate system, the nodes simplify the skeleton support, the discretized deformation zone skin structure, and calculate K e and f e matrix.

[0074] The preferred embodiments of the present invention are as follows:

[0075] Step 1: Based on the active and passive deformations of the morphing wing, the entire wing skin is divided into a fixed area skin and a deforming area skin. The small deformation reconstruction of the fixed area skin adopts a general method, which is simplified to the reconstruction method of a cantilever plate. The reconstruction result is used as the fixed boundary condition for the large deformation reconstruction of the deforming area skin.

[0076] Step 2: Based on the characteristics of the drive skeleton structure inside the variant wing and the distribution of the drive skeleton structure, the unit division of the structure is carried out. The skeleton structure is used as the boundary of the unit, and the unit nodes are made to coincide with the drive skeleton. The degree of freedom of the unit nodes is used to approximate the deformation caused by the skeleton drive, which can solve the problem of complex boundaries. Figure 3 The four-node inverse shell element is used to adaptively divide the skin in the deformation area.

[0077] According to Mindlin's medium-thick plate theory, a four-node inverse shell element is constructed, and each element is as follows: Figure 3 As shown, there are 4 nodes, each of which has three translational degrees of freedom uvw and rotational degrees of freedom θ along the xyz axis. x θ y θ z The degree of freedom of a node can be expressed in vector form as:

[0078]

[0079] The displacement vector of the entire unit is expressed as:

[0080]

[0081] In the above formula, the superscript e indicates the analysis within the unit; in the following table, i indicates the node number in the unit (i = 1, 2, 3, 4); u e Represents the displacement vector of the entire unit.

[0082] Then the membrane deformation at any point (x, y) on the neutral surface of the element can be expressed by the shape function node interpolation as follows:

[0083]

[0084] In the above formula, u i v i w i θ xi θ yi θ zi is the degree of freedom corresponding to the i-th node. N k , L i , M i is the unit interpolation shape function, and its specific form is:

[0085]

[0086]

[0087] in,

[0088] x ij =xi -x j

[0089] y ij =y i -y j

[0090] (i=1,2,3,4;j=1,2,3,4;i≠j), i and j are unit node numbers

[0091] In the above formula, x i y i is the coordinate position of the i-th node in the local coordinate system of the unit, x ij y ij is the coordinate distance between different nodes, st is the isoparametric coordinate of a point in the local coordinate system. Assuming that the length and width of the unit are 2a×2b and the origin of the coordinate system is located at the center of gravity of the unit, the relationship between its isoparametric coordinates and actual coordinates is:

[0092]

[0093] The theoretical displacement of any point (x, y, z) in the unit is expressed as:

[0094]

[0095] According to the first-order shear deformation theory, the strain can be expressed by the theoretical displacement of formula (7). Simplifying the formula into a matrix form can obtain the theoretical strain value of the unit:

[0096]

[0097]

[0098]

[0099] In the above formula, ε, κ, and γ represent the linear strain, curvature, and shear strain of the unit, respectively. The subscripts x0, y0, and x y represents the x direction, y direction and xy direction, Respectively represent the partial derivatives in the x direction and y direction, then e(u e ),κ(u e )、g(u e ) represent the theoretical membrane strain vector, curvature vector and transverse shear strain vector of the neutral plane of the unit, respectively; B m 、B b and B s They are membrane strain, curvature, and transverse shear strain-displacement matrices, respectively. The specific form is composed of the first-order differential of the shape function and the shape function itself. The specific form is:

[0100]

[0101] Among them, k=i=1, 2, 3, 4.

[0102] Step 3: Use finite element software such as Ansys and Abaqus to perform deformation simulation of the variant wing to obtain the overall strain distribution cloud diagram of the skin structure in the deformation area during actual operation. Figure 4 This is a cloud diagram of the strain distribution on the wing surface obtained when using Abaqus to simulate a certain load. Multiple analyses are used to determine the layout of the strain sensors.

[0103] Step 4: According to the distribution of the strain cloud map, double-layer strain sensors are arranged on the inner surface of the skin unit in the deformation area where the maximum strain exceeds the threshold. When the skin in the deformation area is subjected to different loads such as pure bending, bending and torsion, the final arrangement is as follows: Figure 5 shown. Figure 5 The positions of the double-layer strain gauges are arranged according to the strain cloud diagram obtained by simulation. They are mainly arranged near the fixed area where the overall strain is larger and on both sides of the end where the strain value is larger after torsion.

[0104] Step 5: When the variant wing undergoes autonomous deformation, the deformation of the skin in the deformation zone includes the coupling of tensile and compressive deformation and bending deformation. Therefore, the strain data measured by the double-layer sensor is decoupled from the bending, tensile and compressive strains, and the error functional is constructed using the measured strain obtained by decoupling and the theoretical strain derived from the nodal degrees of freedom. The variation is taken, and the stationary point obtained is the nodal degree of freedom in the local coordinate system of the unit. The deformation of the skin in the deformation zone is then obtained by interpolation. The deformation of the skin in the fixed zone is superimposed at the boundary position to obtain the full-field deformation of the overall structure of the variant wing skin.

[0105] Figure 6 In order to collect actual measured data, the strain sensor is pasted on the inner surface of the variant wing skin structure without affecting the contact between the outer surface of the skin and the external airflow, avoiding affecting the aerodynamic performance of the aircraft. In the figure, 21 is the neutral layer of the skin structure, and 22 is the neutral layer of the double-layer strain sensor.

[0106] Based on the double-layer strain sensor inside the inner surface unit of the wing deformation zone skin, such as Figure 6 , the measured strain value at the corresponding position on the inner surface can be obtained:

[0107]

[0108] In the above formula, the superscript +- represent the upper and lower strain gauges of the double-layer strain sensor, respectively, where ε 0° ε 45° ε 90° Indicates the actual measured values ​​of the strain gauges in three directions, The measured linear strain in the x-direction and y-direction and the measured shear strain in the xy-direction can be obtained through the strain gauge data at three different angles.

[0109] When the distance d between the two-layer strain sensors and the distance h between the neutral surface of the skin and the upper strain gauge are known, the measured membrane strain e at the neutral surface of the skin can be decoupled. ε and the measured curvature κ ε (superscript ε represents experimentally measured data):

[0110]

[0111]

[0112] Construct the error functional form between the theoretical strain and the measured strain of the unit:

[0113] Φ(u e )=ω||e(u e )-e ε ||2+ω||κ(u e )-κ ε ||2+λ||g(u e )||2 (15)

[0114] In the above formula, Φ(u e ) represents the least square relationship between theoretical strain and measured strain, and the second norm ||e(u e )-e ε || 2 、||κ(u e )-κ ε || 2 、||g(u e )|| 2 They represent the theoretical and actual least squares relationship between membrane strain, curvature and transverse shear strain respectively. ω is the virtual arrangement coefficient. When a strain sensor is arranged in the unit, ω = 1. If no sensor is arranged, in order to ensure that the matrix is ​​non-singular, the influence of the unit on the result must be minimized. In this case, a very small empirical coefficient is added, for example, ω = 10. -5 , λ is the transverse shear strain penalty coefficient. Since the actual transverse shear strain cannot be measured, a very small empirical value is taken based on the ratio of transverse shear strain to bending strain, for example, λ = 10 -5 .

[0115] Taking the variational form of the nodal degrees of freedom, that is, taking the derivative of Equation (15), the stationary point obtained is the required nodal degrees of freedom:

[0116]

[0117] The above formula is the solution for the nodal degree of freedom in the local coordinate system of the unit, K e It is only related to the location of the sensor points in the unit and the unit shape function, f e It is related to the location of sensor points in the unit, the unit shape function, and the actual measurement value. Then, by connecting the local solution of each unit through a common node and adding the inherent boundary conditions of the structure, the solution matrix can be made singular, and the deformation of the entire field can be reconstructed in real time.

[0118] The advantages of the present invention are as follows: the use of double-layer strain sensors can realize the decoupling of the bending, tensile and compressive strains of the neutral plane of the skin by sticking the sensors on one side, ensuring the completion of real-time full-field reconstruction of the variant wing skin with limited measuring points without affecting the aerodynamic characteristics of the aircraft, avoiding the experimental errors caused by the inaccurate upper and lower symmetrical point arrangement of the traditional decoupling method, reducing the difficulty of sensor arrangement, and improving the real-time reconstruction accuracy of the variant wing skin.

[0119] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for reconstructing a wing skin deformation, characterized in that: The steps include: Step 1: Based on the active and passive deformations of the morphing wing, the entire wing skin is divided into a fixed area skin and a deforming area skin. The small deformation of the fixed area skin is reconstructed by simplifying it into a cantilever plate, and the reconstruction result of the fixed area skin is used as the fixed boundary condition for the large deformation reconstruction of the deforming area skin. Step 2: Based on the structural characteristics of the driving skeleton inside the deformation zone skin, the internal support structure is simplified into boundary conditions and unit nodes are placed so that the unit nodes coincide with the driving skeleton. The degrees of freedom of the unit nodes are used to characterize the deformation caused by the skeleton drive. Step 3: Perform deformation simulation on the variant wing to obtain the overall strain distribution cloud diagram of the skin structure in the deformation area during actual operation; Step 4: Based on the distribution of the strain cloud diagram, double-layer strain sensors are arranged on the inner surface of the skin unit in the deformation area where the maximum strain exceeds the threshold value for measurement; Step 5: When the morphing wing undergoes autonomous deformation, the deformation of the skin in the deformation zone includes coupled tensile and compressive deformation and bending deformation. Therefore, the strain data measured by the double-layer sensor is decoupled into tensile and compressive strain and bending. The measured strain obtained by decoupling and the theoretical strain derived from the nodal degrees of freedom are used to construct an error functional. The variation is taken, and the obtained stationary point is the nodal degree of freedom in the unit local coordinate system. The deformation of the skin in the deformation zone is then obtained by interpolation. The deformation of the skin in the fixed zone is superimposed at the boundary position to obtain the full-field deformation of the entire structure of the morphing wing skin. Among them, the nodal degrees of freedom u in the local coordinate system of the element e The solution is as follows: In the above formula, K e It is a function that is only related to the location of the sensor points in the unit and the unit shape function, f e It is a function related to the sensor location in the unit, the unit shape function and the actual measurement value; B m 、B b and B s are the theoretical membrane strain matrix, theoretical curvature matrix, and theoretical transverse shear strain matrix, respectively; h is the distance between the neutral plane of the skin and the upper strain gauge in the double-layer strain sensor; ω is the virtual arrangement coefficient, λ is the transverse shear strain penalty coefficient; e ε , κ ε are the measured membrane strain and measured curvature at the neutral plane of the skin, respectively.

2. The method for deforming and reconstructing a wing skin according to claim 1, wherein: In step 2, the method of using the degrees of freedom of the unit nodes to characterize the deformation caused by the skeleton drive is as follows: According to Mindlin's medium-thick plate theory, a four-node inverse shell element is constructed. Each node has three translational degrees of freedom uvw and rotational degrees of freedom θ along the xyz axis. x θ y θ z , then the displacement vector of each node is expressed as: The displacement vector of the entire unit is expressed as: In the above formula, the superscript e indicates analysis within the unit; in the table below, i indicates the node number, i = 1, 2, 3, 4.

3. The method for deforming and reconstructing a wing skin according to claim 2, wherein: The membrane deformation of any point (x, y) on the neutral surface of the element is expressed in the form of shape function node interpolation as follows: In the above formula, N k , L i , M i is the unit interpolation shape function, and its specific form is: in, j=1,2,3,4 and j≠i; s, t are the isoparametric coordinates of a node in the local coordinate system. Assuming the length and width of the unit are 2a×2b, then: The theoretical displacement of any point (x, y, z) in the unit is expressed as:

4. The method for deforming and reconstructing a wing skin according to claim 3, wherein: According to the first-order shear deformation theory, the strain is expressed by the theoretical displacement of formula (7), and the theoretical strain of the unit is obtained as follows: In the above formula, ε, κ, and γ represent the linear strain, curvature, and shear strain of the unit, respectively. The subscripts x0, y0, and xy represent the x direction, y direction, and xy direction, respectively. Respectively represent the partial derivatives in the x direction and y direction, then e(u e ),κ(u e )、g(u e ) represent the theoretical membrane strain vector, theoretical curvature vector and theoretical transverse shear strain vector of the neutral surface of the element, respectively.

5. The method for deforming and reconstructing a wing skin according to claim 4, wherein: Among them, k=i=1,2,3,4.

6. The method for deforming and reconstructing a wing skin according to claim 1, wherein: In step 5, the measured strain value at the corresponding position of the inner surface is obtained based on the double-layer strain sensor in the inner surface unit of the deformation zone skin: In the above formula, the superscripts + and - represent the upper and lower strain gauges of the double-layer strain sensor, respectively, where ε 0° , ε 45° , ε 90° Indicates the actual measured values ​​of the strain gauge in three directions, They represent the measured linear strain in the x and y directions and the measured shear strain in the xy direction, respectively.

7. The method for deforming and reconstructing a wing skin according to claim 6, wherein: When the distance d between the double-layer strain sensors and the distance h between the neutral surface of the skin and the upper strain gauge are known, the measured membrane strain e at the neutral surface of the skin is obtained. ε and the measured curvature κ ε : The superscript ε represents experimentally measured data.

8. The method for deforming and reconstructing a wing skin according to claim 7, wherein: Construct the error functional form between the theoretical strain and the measured strain of the unit: Φ(u e )=ω||e(u e )-e ε ||2+ω||κ(u e )-k ε ||2+λ||g(u e )||2 (15) In the above formula, Φ(u e ) represents the least square relationship between theoretical strain and measured strain; the second norm || e(u e )-e ε || 2 、||κ(u e )-κ ε || 2 、||g(u e )|| 2 They represent the least squares relationship between the theoretical and actual values ​​of membrane strain, curvature, and transverse shear strain, respectively; ω is the virtual arrangement coefficient. When a strain sensor is arranged in the unit, ω = 1. If no sensor is arranged, ω is set to an empirical value much smaller than 0. λ is the transverse shear strain penalty coefficient, which is equal to an empirical value much smaller than 0; Derivative of formula (15) yields u corresponding to the stationary point e That is, the actual nodal degrees of freedom.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method for deforming and reconstructing a variant wing skin according to any one of claims 1 to 8 is implemented.

10. A variant wing skin deformation and reconstruction device, characterized in that: The method comprises the computer-readable storage medium according to claim 9 and a processor, wherein the processor is configured to call and process a computer program stored in the computer-readable storage medium.

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