CN107103111A - Electronics function shape region feature point displacement field reconstructing method based on strain transducer - Google Patents

Abstract

The invention discloses a kind of electronics function shape region feature point displacement field reconstructing method based on strain transducer, including：Determine position and the quantity of structural parameters, material properties and the strain transducer distribution in electronics function shape face, gather the strain value of the lower function shape face strain transducer measurement of military service load effect, set up the structural finite element model in function shape face, the face model analysis of function shape, obtain Mode Shape, the strain mode vibration shape in function shape face, extract the corresponding strain mode vibration shape matrix of strain transducer nodes of locations, calculate generalized Modal coordinate, the corresponding Mode Shape matrix of abstraction function shape region feature point, reconstructs the displacement of function shape region feature point.The present invention is based on Modal Analysis Theory, in the case where structural loads information is unknown, the strain value measured using a small amount of strain transducer reconstructs the displacement field of electronics function shape region feature point, and then instructs the malformation compensation and electrical property compensation in electronics function shape face.

Description

Displacement Field Reconstruction Method of Feature Points on Functional Surface of Electronic Equipment Based on Strain Sensor

technical field

The invention belongs to the technical field of radar antennas, and in particular relates to a method for reconstructing a displacement field of a feature point on a functional surface of electronic equipment based on a strain sensor. The invention can be used to reconstruct the displacement field of the feature point of the functional surface of the electronic equipment, laying a foundation for the subsequent structural deformation compensation and electrical performance compensation of the functional surface of the electronic equipment, so as to ensure the service performance of the functional surface.

Background technique

The most notable feature of the functional surface of electronic equipment is the combination of electromechanical and electrical performance as the main performance of the functional surface of the entire electronic equipment. The mechanical structure performance serves the electrical performance and is the carrier and guarantee of the electrical performance. At present, the functional form of electronic equipment has been widely used in astronomical observation, airborne early warning, spaceborne imaging, ground air defense and other fields, and has become the mainstream of today's development.

With the continuous development and changes of military requirements, the functional form of electronic equipment is mainly developed in the direction of multi-function, lightweight and high performance. As the functional shape of electronic equipment develops in the direction of light weight, when it is subjected to external loads, the functional shape of electronic equipment is more prone to structural deformation, and the impact of structural deformation on the functional shape of electronic equipment is becoming more and more obvious, which leads to The electromagnetic performance of the functional form of electronic equipment is extremely deteriorated. Therefore, it is the key to ensure the system performance to reconstruct the displacement field of the functional surface under load, and to perform corresponding structural deformation compensation and electrical performance compensation.

At present, scholars at home and abroad mainly use two methods for displacement field reconstruction: (1) Response reconstruction method based on transmissibility, such as Li J, Law SS. Substructural response reconstruction in wavelet domain. Journal of Applied Mechanics, 2011, 78(4):41010 proposed a transmissibility response reconstruction method for multi-degree-of-freedom systems, which gave the generalized transmissibility matrix of the system, and used this matrix for structural response reconstruction. Although this method reconstructs the displacement field of the deformed surface, it needs to know the location of the excitation load, which limits the application of this method and is not very practical. (2) Ko displacement theory method, such as Yuan Shenfang, Yan Meijia, Zhang Jinjin, a deformation reconstruction method suitable for beam wings, used in Nanjing University of Aeronautics and Astronautics Journal, 2014, 46(6): 825-830 Ko displacement theory reconstructs the deformation of the beam wing structure, and verifies the feasibility and reliability of this method, but this method requires a large number of sensors under high reconstruction accuracy, and this method can only be used for simpler structure.

Therefore, under the premise of satisfying the reconstruction accuracy, it is necessary to reduce the number of sensors, and reconstruct the displacement field of the feature points of the functional surface of the electronic equipment without the need for structural load information, which will be used for the functional surface of the electronic equipment in the future. Structural deformation compensation and electrical performance compensation lay the foundation, thereby shortening the development cycle.

Contents of the invention

In order to solve the above-mentioned defects existing in the prior art, the object of the present invention is to provide a displacement field reconstruction method based on modal analysis, in the case of unknown structural load information, the strain value measured by a small number of strain sensors is used to reconstruct the electron The displacement field of the feature points of the functional surface of the equipment can guide the structural deformation compensation and electrical performance compensation of the functional surface of the electronic equipment.

The present invention is achieved through the following technical solutions.

The method for reconstructing the displacement field of the feature points of the functional surface of the electronic equipment based on the strain sensor comprises the following steps:

(1) Determine the structural parameters, material properties, and the location and number N of strain sensor distribution of the functional surface of the electronic equipment;

(2) Use the strain sensor to collect the strain value of the functional surface of the electronic equipment under the service load;

(3) According to the structural parameters and material properties of the functional surface of the electronic equipment, use ANSYS software to establish the structural finite element model of the functional surface of the electronic equipment;

(4) Use ANSYS software to conduct modal analysis on the structural finite element model of the functional surface of electronic equipment, and according to the results of the modal analysis, extract the first M-order modes of the functional surface, including the mode shape and strain mode shape ;

(5) From the strain mode shape of the functional surface, extract the strain mode matrix corresponding to the position node of the strain sensor;

(6) According to the strain value measured by the strain sensor in the step (2) and the strain mode shape matrix corresponding to the strain sensor position node in the step (5), calculate the generalized modal coordinates;

(7) From the mode shape of the functional surface, extract the mode matrix corresponding to the feature points of the functional surface;

(8) Combining the generalized modal coordinates calculated in step (6) and the mode shape matrix corresponding to the feature points of the functional surface extracted in step (7), reconstruct the displacement of the feature points of the functional surface.

Further, step (1) determines the structural parameters of the functional surface of the electronic equipment, including the number of rows, columns, unit spacing, unit form, T/R components, cold plate, functional surface frame and installation of the radiating unit in the functional surface. The parameters of the skeleton; determine the material properties of the radiation unit, including density, elastic modulus, and Poisson's ratio; determine the location and number N of strain sensor distribution.

Further, in step (2), the strain sensor is used to collect the strain value {ε}={ε _s1 ,ε _s2 ,...,ε _sN } measured by the functional surface strain sensor under the service load.

Further, in step (4), utilize ANSYS software to carry out modal analysis to the structural finite element model of functional shape, and according to the result of modal analysis, extract the front M order mode of functional shape, wherein, M=N-1; Mode shapes including functional surfaces Strain mode shapes ψ _i , where i=1,2,...M.

Further, step (5) is carried out as follows:

(5a) Determine the node numbers corresponding to the strain sensor position nodes according to the grid division results of the ANSYS software: for the 1st to N strain sensor position nodes, the corresponding node numbers are s1, s2, ..., sN;

(5b) According to the number s1, s2, ..., sN of the strain sensor position nodes, and the strain mode shape ψ _i of the first M mode of the functional shape, extract the strain sensor position nodes (s1, s2, ..., sN) corresponding to The strain mode shape matrix [ψ] _S of the :

in, Indicates the strain mode of the sj-th node corresponding to the i-th mode.

Further, step (6) is carried out as follows:

(6a) According to the mode superposition principle, the strain of the functional surface structure under load can be expressed as a linear combination of strain modes of each order:

In the formula, {q}={q ₁ ,q ₂ ,…,q _M } represents the generalized modal coordinates;

(6a) According to the strain value {ε} measured by the strain sensor in step (2) and the strain mode shape matrix [ψ] _S corresponding to the position node of the strain sensor in step (5), the generalized modal coordinates can be obtained:

{q}＝(([ψ] _S ) ^T ([ψ] _S )) ^-1 ([ψ] _S ) ^T {ε};

Among them, T is the matrix transpose symbol.

Further, step (7) is carried out as follows:

(7a) According to the results of ANSYS software grid division, determine the node numbers corresponding to the feature points of the functional surface: the first to P feature points, the corresponding node numbers are c1, c2, ..., cP;

(7b) Extract the mode shape matrix corresponding to the feature points (c1,c2,...,cP) of the functional surface from the mode shape of the first M-order state of the functional shape

in, Indicates the displacement mode of the cl-th node corresponding to the i-th order mode.

Further, in step (8), the generalized modal coordinates {q}={q ₁ ,q ₂ ,...,q _M } calculated in step (6) are combined with the feature points of the functional surface extracted in step (7) corresponding to Mode shape matrix Reconstruct the displacement {δ}={δ _c1 ,δ _c2 ,…,δ _cP } of the feature points of the functional surface:

Compared with the prior art, the present invention has the following characteristics:

1. Apply the modal analysis theory to the reconstruction of the displacement field of the feature points of the functional surface of the electronic equipment, and do not need structural load information, and use the strain values measured by a small number of strain sensors to reconstruct the displacement field of the feature points of the functional surface of the electronic equipment . This method effectively solves the problems that the traditional displacement field reconstruction method is not practical, has high cost and can only be applied to relatively simple structures.

2. When performing modal analysis on the functional surface of electronic equipment, according to the results of the modal analysis, extract the first M (M=N-1) order modes of the functional surface, including the mode shape and strain mode shape. By determining the selected modal order M, the dimension of the functional surface structure model of electronic equipment will be further reduced, the calculation time of the later model will be greatly reduced, and the calculation efficiency will be improved. Lay the foundation for electrical performance compensation and shorten the development cycle.

Description of drawings

Fig. 1 is a flow chart of the method for reconstructing the displacement field of the feature point displacement field of the electronic equipment function surface based on the strain sensor in the present invention;

Figure 2 is a schematic diagram of the arrangement of radiation units on the functional surface of electronic equipment;

Fig. 3 is a schematic structural diagram of the functional surface of the electronic equipment;

Fig. 4 is a position diagram of feature points on the functional surface of electronic equipment;

Fig. 5 is a sensor layout diagram;

Figure 6 is the grid model of the functional surface of electronic equipment in ANSYS software;

Fig. 7 is a schematic diagram of the constrained position of the functional surface of the electronic equipment.

detailed description

The invention will be further described in detail below in conjunction with the accompanying drawings and embodiments, but it is not used as a basis for any limitation on the invention.

Referring to Figure 1, the present invention is a strain sensor-based method for reconstructing the displacement field of feature points on the functional surface of electronic equipment, and the specific steps are as follows:

Step 1, determine the structural parameters of the functional surface of the electronic equipment, the location and quantity of strain sensor distribution.

1.1. Determine the structural parameters of the electronic equipment functional surface (in the present invention, the typical representative active phased array antenna of the electronic equipment functional surface is selected for example analysis), including (x, y direction) length L _x and Width L _y , the number of rows and columns of radiating elements in the functional plane, the spacing d _x , d _y of radiating elements in the x and y directions (as shown in Figure 2), the form of radiating elements, T/R components, cooling The parameters of the board, the functional surface frame and the installation skeleton, etc.

1.2. Determine the material properties of the radiation unit, including density, elastic modulus, and Poisson's ratio.

1.3. Determine the location and number N of strain sensor distribution.

Step 2, collect the strain value measured by the functional surface strain sensor under the service load.

Use the strain sensor to collect the strain value {ε}={ε _s1 ,ε _s2 ,…,ε _sN } measured by the functional surface strain sensor under the service load.

Step 3, establish the structural finite element model of the functional surface.

According to the determined T/R components in the functional surface, the material properties of the functional surface frame, installation skeleton and radiation unit, including density, elastic modulus and Poisson's ratio, use ANSYS software to establish the structural finite element model of the functional surface .

Step 4, the modal analysis of the functional surface, to obtain the modal mode shape and the strain mode shape of the functional surface.

Use ANSYS software to conduct modal analysis on the structural finite element model of the functional surface, and according to the results of the modal analysis, extract the first M (M=N-1) mode of the functional surface, including the mode shape of the functional surface Strain mode shapes ψ _i , where i=1,2,...M.

Step 5, extracting the strain mode shape matrix corresponding to the position node of the strain sensor.

5.1. Determine the node numbers corresponding to the strain sensor position nodes according to the grid division results of ANSYS software: the 1st to N strain sensor position nodes, the corresponding node numbers are s1, s2,..., sN respectively.

5.2. Extract the strain sensor position nodes ( _s1 , s2 ,…,sN) corresponding to the strain mode shape matrix [ψ] _S :

in, Indicates the strain mode of the sj-th node corresponding to the i-th mode.

In step 6, the generalized mode coordinates are calculated according to the strain value measured by the strain sensor and the strain mode shape matrix corresponding to the position node of the strain sensor.

6.1. According to the mode superposition principle, the strain of the functional surface structure under load can be expressed as a linear combination of strain modes of each order:

In the formula, {q}={q ₁ ,q ₂ ,…,q _M } represent the generalized mode coordinates.

6.2. According to the strain value {ε} measured by the strain sensor in step (2) and the strain mode shape matrix [ψ] _S corresponding to the position node of the strain sensor in step (5), the generalized modal coordinates can be obtained:

{q}＝(([ψ] _S ) ^T ([ψ] _S )) ^-1 ([ψ] _S ) ^T {ε} (3)

Among them, T is the matrix transpose symbol.

Step 7, extracting the mode shape matrix corresponding to the feature points of the functional surface.

7.1. According to the result of ANSYS software grid division, determine the node numbers corresponding to the feature points of the functional surface: for the 1st to P feature points, the corresponding node numbers are c1, c2, ..., cP.

7.2. Extract the mode shape matrix corresponding to the feature points (c1,c2,...,cP) of the functional surface from the mode shape of the first M (M=N-1) order state of the functional surface

in, Indicates the displacement mode of the cl-th node corresponding to the i-th order mode.

Step 8, combined with the generalized modal coordinates, reconstruct the displacement of the feature points of the functional surface.

Combining the generalized modal coordinates {q}={q ₁ ,q2,...,q _M } calculated in step (6) and the mode shape matrix corresponding to the feature points of the functional surface extracted in step (7) Reconstruct the displacement {δ}={δ _c1 ,δ _c2 ,…,δ _cP } of the feature points of the functional surface:

Advantages of the present invention can be further illustrated by following simulation experiments:

1. Determine the structural parameters of the functional surface of the electronic equipment, the location and quantity of the strain sensor distribution

1. Determine the structural parameters of the functional surface of electronic equipment

The present invention selects the active phased array antenna, a typical representative of the functional surface of the electronic equipment, for example analysis. The radiation units are arranged in a rectangular grid with equal intervals in the functional surface, and the central operating frequency is f=2.5GHz (wavelength λ=120mm). As shown in Figure 3 and Table 1, the number of rows of radiating elements in the x direction in the functional surface is 6, the number of columns of radiating elements in the y direction is 3, and the distance between the radiating elements in the x and y directions is d _x = d _y = 0.5 ·λ=60mm, the distribution position of feature points in the functional surface of electronic equipment is shown in Figure 4.

Table 1 Geometric Model Parameters of Functional Surfaces of Electronic Equipment

Table 2 Material properties of functional surfaces of electronic equipment

2. The location and quantity of strain sensor distribution

There are 10 strain sensors distributed on the functional surface of the electronic equipment, and the distribution positions of the strain sensors are shown in Figure 5.

2. Reconstruct the displacement field of the feature points of the functional surface of the electronic equipment

1. Establish the structural finite element model of the functional shape of electronic equipment

According to the geometric model size and material property parameters of the functional surface of the electronic equipment, the structural finite element model of the functional surface of the electronic equipment is established in the ANSYS software. Among them, according to the actual engineering, the material properties of the carrier layer such as the functional surface frame and the mounting bracket are set according to the material parameters of the aluminum alloy in Table 2, and the material properties of the radiation unit are set according to the material parameters of the printed circuit board. The unit type of the carrier layer is solid unit SOLID92, and the structural unit type of the radiation unit is surface unit SHELL63. The carrier layer and the radiation unit are connected to each other without relative displacement. For the geometric structure model of the functional surface of electronic equipment, the free mesh set by ANSYS software is used for mesh division, and the grid model of the functional surface of electronic equipment is obtained, as shown in Figure 6.

2. Modal analysis of the functional surface to obtain the mode shape and strain mode shape of the functional surface

2.1 According to the installation position of the bracket in the actual project, the force analysis of the cantilever beam structure is adopted, as shown in Figure 7, one end of the functional surface of the electronic equipment is fixed as a constraint condition;

2.2 Use ANSYS software to conduct modal analysis on the structural finite element model of the functional surface of electronic equipment, and according to the results of the modal analysis, extract the first 9 (M=N-1=10-1) order modes of the functional surface, including electronic equipment Mode shapes of equipment functional surfaces Strain mode shapes ψ _i , where i=1,2,...9.

3. Reconstruct the displacement field of the feature points of the functional surface of the electronic equipment

3.1 According to formulas (1), (2) and step (2), find out the generalized mode coordinate {q}:

{q}＝(([ψ] _S ) ^T ([ψ] _S )) ^-1 ([ψ] _S ) ^T {ε} (6)

In the formula, [ψ] _S is the strain mode shape matrix corresponding to the position node of the strain sensor, and {ε} is the strain value measured by the functional surface strain sensor under the service load.

3.2 According to the formulas (3), (4), (5) and step (7), the displacement {δ} of the feature points of the functional surface is reconstructed:

In the formula, [ψ] _S is the strain mode shape matrix corresponding to the position node of the strain sensor; is the mode shape matrix corresponding to the feature points of the functional surface; {ε} is the strain value measured by the functional surface strain sensor under the service load.

3. Results and analysis

According to the formula (1), the strain mode shape matrix corresponding to the position node of the strain sensor is obtained, combined with the steps (2), (6) and formula (6), the generalized mode coordinates can be obtained; and then through the step (7) Obtain the mode shape matrix corresponding to the feature points of the functional surface, and then use the formula (7) to reconstruct the displacement of the feature points of the functional surface, and obtain the displacement field of the feature points of the functional surface of the electronic equipment.

Table 3 shows the strain value {ε} measured by the functional surface strain sensor under the collected service load using the strain sensor, Table 4 shows the calculated generalized modal coordinate value {q}, and Table 5 shows the reconstructed function Displacement of feature points of shape and surface {δ}.

Table 3 Strain values measured by the sensor

Table 4 Generalized modal coordinate values

Table 5 Reconstructed functional surface feature point displacement

According to the reconstructed functional surface feature point displacement (Table 5), it can be seen that under the load, the deformation of the functional surface feature points in the Z direction is greater than its deformation in the X and Y directions, and the maximum deformation in the Z direction is It reaches 6.4493mm; among them, the overall deformation of the eighth feature point in the functional surface of electronic equipment is the largest, reaching 6.4495mm.

It can be seen from the above experiments that the application of the present invention can extract the strain mode shape matrix corresponding to the position node of the strain sensor and the mode shape matrix corresponding to the feature point of the functional shape surface, and calculate the generalized mode coordinates, which can be used to reconstruct the function of electronic equipment The displacement field of the feature points of the shape surface can guide the structural deformation compensation and electrical performance compensation of the functional shape surface of the electronic equipment.

Claims (8)

1. A method for reconstructing a displacement field of a functional surface characteristic point of electronic equipment based on a strain sensor is characterized by comprising the following steps:

(1) determining the structural parameters and material properties of the functional surface of the electronic equipment and the distribution positions and the quantity N of the strain sensors;

(2) acquiring a functional surface strain value of the electronic equipment under the action of service load through a strain sensor;

(3) establishing a structural finite element model of the functional surface of the electronic equipment by using ANSYS software according to the structural parameters and the material properties of the functional surface of the electronic equipment;

(4) performing modal analysis on a structural finite element model of the functional surface of the electronic equipment by using ANSYS software, and extracting M-order modes including a modal vibration mode and a strain modal vibration mode in front of the functional surface according to a result of the modal analysis;

(5) extracting a strain mode vibration mode matrix corresponding to a position node of the strain sensor from the strain mode vibration mode of the functional surface;

(6) calculating generalized modal coordinates according to the strain value measured by the strain sensor in the step (2) and a strain modal shape matrix corresponding to the position node of the strain sensor in the step (5);

(7) extracting a modal shape matrix corresponding to the characteristic point of the functional surface from the modal shape of the functional surface;

(8) and (4) reconstructing the displacement of the functional surface characteristic point by combining the generalized modal coordinate calculated in the step (6) and the modal shape matrix corresponding to the functional surface characteristic point extracted in the step (7).

2. The strain sensor-based electronic equipment functional surface feature point displacement field reconstruction method according to claim 1, wherein the step (1) determines the structural parameters of the electronic equipment functional surface, including the number of rows and columns of radiating elements in the functional surface, the unit spacing, the unit form, the parameters of the T/R assembly, the cold plate, the functional surface frame and the mounting framework; determining material properties of the radiating element, including density, elastic modulus, and poisson's ratio; the location and number N of strain sensor distributions are determined.

3. The method for reconstructing a displacement field of a functional surface feature point of an electronic device based on a strain sensor as claimed in claim 1, wherein in the step (2), the strain sensor is used to collect the strain value { } ═ f measured by the functional surface strain sensor under the action of the service load_s1,_s2,…,_sN}。

4. The strain sensor-based electronic equipment functional form of claim 1The method for reconstructing the surface feature point displacement field is characterized in that in the step (4), the ANSYS software is used for carrying out modal analysis on a structural finite element model of the functional surface, and M-order modes in front of the functional surface, including the modal mode of the functional surface, are extracted according to the result of the modal analysisStrain mode vibration type psi_iWherein i is 1, 2.. M, M is N-1.

5. The method for reconstructing the displacement field of the functional surface feature point of the electronic equipment based on the strain sensor as claimed in claim 1, wherein the step (5) is performed as follows:

(5a) determining the node number corresponding to the position node of the strain sensor according to the result of the ANSYS software grid division: the corresponding node numbers of the 1 st to N th strain sensor position nodes are s1, s2, … and sN respectively;

(5b) according to the serial numbers s1, s2, … and sN of the position nodes of the strain sensor and the strain mode type psi of the M-order mode in front of the functional shape_iAnd extracting a strain mode shape matrix [ psi ] corresponding to strain sensor position nodes (s1, s2, …, sN)]_S：

Wherein,the strain mode of the sj node corresponding to the ith order mode is shown.

6. The method for reconstructing the displacement field of the functional surface feature point of the electronic equipment based on the strain sensor as claimed in claim 1, wherein the step (6) is performed according to the following process:

(6a) according to the mode superposition principle, the strain of the functional surface structure under the action of the load can be expressed as the linear combination of strain modes of each order:

wherein { q } - } is₁,q₂,…,q_MDenotes the generalized modal coordinates;

(6a) according to the strain value { } measured by the strain sensor in the step (2) and the strain mode shape matrix [ psi ] corresponding to the position node of the strain sensor in the step (5)]_SThe generalized modal coordinates can be found:

{q}＝(([ψ]_S)^T([ψ]_S))^-1([ψ]_S)^T{}；

where T is the matrix transpose symbol.

7. The method for reconstructing the displacement field of the functional surface feature point of the electronic equipment based on the strain sensor as claimed in claim 6, wherein the step (7) is performed according to the following process:

(7a) determining the node number corresponding to the functional surface feature point according to the result of ANSYS software grid division: the 1 st to P th characteristic points respectively have the corresponding node numbers of c1, c2, … and cP;

(7b) extracting modal shape matrix corresponding to functional surface characteristic points (c1, c2, …, cP) from modal shape of M-order mode in front of functional surface

Wherein,and the displacement mode of the cl node corresponding to the ith order mode is shown.

8. The strain-based strain transfer of claim 7The method for reconstructing the displacement field of the functional surface feature point of the electronic equipment of the sensor is characterized in that in the step (8), the generalized modal coordinate { q } - { q } calculated in the step (6) is combined with₁,q₂,…,q_MThe modal shape matrix corresponding to the functional surface characteristic points extracted in the step (7)Reconstructing displacement { } ═ of functional shape surface feature points_c1,_c2,…,_cP}：