CN117232419A - Method and system for measuring thermal deformation of complex antenna structure - Google Patents

Abstract

The invention provides a method and system for measuring thermal deformation of a complex antenna structure. Combined with the photogrammetry test environment, measurement single points and coding points are arranged on the complex antenna structure; the temperature of the structure is changed, and photogrammetry technology is used to conduct multiple measurements on the structure at different temperatures. Measure and obtain the deformation of each point, process and analyze it to obtain the actual measurement results of the thermal performance of the structure; establish a finite element model based on the actual antenna structure, and simulate the actual temperature environment to conduct deformation analysis; make the actual measurement and finite element analysis results The coordinate system is basically consistent. Compare the consistency of the deformation in all directions between the actual measurement and simulation results, and adjust the finite element model to make the simulation results consistent with the actual measurement. The present invention uses photogrammetry to obtain the thermal deformation characteristics of complex antenna structures, and constructs its finite element model for analysis. It obtains a finite element model that is consistent with both the actual structure and the measured structure, and is suitable for large deformations of antenna structures with complex forms and materials. Measurement.

Description

A method and system for measuring thermal deformation of complex antenna structures

Technical field

The invention belongs to the field of thermal deformation measurement and evaluation of antenna structures, and particularly relates to a method and system for measuring thermal deformation of complex antenna structures based on photogrammetry and finite element analysis.

Background technique

The design of the support structure of a single-diameter antenna is often complex, and the materials used in the support structure of high-precision antennas usually have low density and excellent thermal properties to reduce gravity deformation and thermal deformation, such as carbon fiber reinforced composite materials (CFRP). Currently, it is one of the commonly used materials for antenna structures. It has the characteristics of anisotropy, low density, high strength, and low thermal expansion coefficient, and its thermal properties are relatively complex. For the testing of the thermal performance of such complex antenna structures, the deformation amount and deformation trend under temperature changes are mainly measured. Actual measurement and finite element analysis of the structural deformation are two measurement methods. Actual measurement needs to consider whether the measurement accuracy is sufficient. The current technical means for measuring thermal deformation of complex structures mainly include laser trackers, total stations, and photogrammetry. Their measurement principles are similar, and they all measure the space of multiple points distributed on the target. Changes in position, among which laser trackers and total stations require fixed measurement equipment, are not suitable for measurement of complex structures. Photogrammetry is more flexible. It is a measurement technology with high measurement accuracy and wide application scenarios. Its measurement accuracy can reach 3μm+3μm/m, capable of measuring deformations larger than tens of microns; finite element analysis can basically simulate the deformation characteristics of structures in various environments, thereby obtaining some deformation characteristics that cannot be measured in practice, but the accuracy of the model needs to be considered , because the model details, materials, loads, constraints, etc. will be different from the actual structure, which will lead to differences between the analysis results and the measurement results. Therefore, the finite element analysis is combined with the actual measurement results, and the finite element analysis results of the complex antenna structure are used to verify whether the measured thermal deformation trend of the structure is correct. The measured deformation amount is compared with the finite element analysis results to verify the finite element model. The accuracy was adjusted and the model parameters were adjusted to obtain test results of the thermal deformation characteristics of the antenna structure that were consistent with the results of photogrammetry and finite element analysis.

Contents of the invention

In view of the deficiencies in the prior art, the present invention provides a method and system for measuring thermal deformation of complex antenna structures.

In order to achieve the above objects, the present invention adopts the following technical solutions:

A method for measuring thermal deformation of complex antenna structures, which is characterized by including the following steps:

Step 1: Place the measurement structure in a temperature-controlled environmental chamber, and paste the measurement points as the measurement target and the coding points for picture splicing on the surface of the measurement structure;

Step 2: Use photogrammetry to photograph the measurement structure at different temperatures. After the photography is completed, the image is processed and calculated by a computer to obtain the three-dimensional coordinates of the measurement points at different temperatures;

Step 3: Process the three-dimensional coordinates obtained by shooting to obtain the deformation displacement of each measurement point. Draw a relationship between the deformation displacement and position of the measurement point based on the deformation displacement and observe the thermal deformation trend of the measurement structure, and judge the correctness of the measurement results accordingly;

Step 4: By fitting the deformation displacement and position relationship of the measurement point in each direction, calculate the thermal expansion rate of the measurement point in each direction;

Step 5: Establish a finite element model of the actual structure, constrain and apply loads to the finite element model according to the constraint state and actual load of the actual structure, extract the three-dimensional coordinates of the nodes corresponding to the measurement points at different temperatures, and calculate the The thermal expansion rate of the node corresponding to the measurement point in all directions;

Step 6: Compare the thermal expansion rates in all directions of the measurement point and the node corresponding to the measurement point, and adjust the material parameters of the finite element model;

Step 7: Use the adjusted finite element model to conduct performance simulation analysis of the antenna structure.

In order to optimize the above technical solutions, specific measures taken also include:

Further, in step 1, a temperature sensor is arranged on the surface of the measurement structure for detecting temperature changes of the measurement structure.

Further, the process of step 2 is as follows:

Control the temperature of the environmental chamber to be T ₁ and maintain it. After the temperature of the measured structure stabilizes, turn off the temperature control of the environmental chamber;

Take at least two consecutive sets of shots of the measurement structure at different positions and directions. In each set of shots, each measurement point and coding point is shot into more than two images, and ensure that all the images taken are completely overlapped to construct the entire measuring structure;

After the shooting is completed, the image is processed and calculated by a computer to obtain the three-dimensional coordinates of the measurement point at temperature T ₁ ;

Control and maintain the temperature of the environmental chamber at T _2. After the temperature of the measured structure stabilizes, turn off the temperature control of the environmental chamber and take at least two consecutive sets of shots of the structure to obtain the three-dimensional coordinates of the measurement points at temperature T ₂ .

Further, in step 2, ensure that the position of the reference ruler is fixed during the entire shooting process.

Further, in step 2, the temperature difference between temperatures T ₁ and T ₂ is not less than 50°C.

Further, the process of step 3 is as follows:

Convert the three-dimensional coordinates of all photographed measurement structures to the same coordinate system, compare the three-dimensional coordinates of the same measurement point at different temperatures in the same coordinate system, and obtain the deformation displacement of each measurement point, including the total displacement when the temperature changes and the total displacement when the temperature changes. Displacement in all directions;

According to the deformation displacement, draw the relationship between the deformation displacement and position of the measurement point, observe the thermal deformation trend of the measurement structure according to the principle of thermal expansion and contraction and the law of thermal deformation, and confirm the correctness of the measurement results. If the measurement results are incorrect, check the shooting data and the shooting process, reprocess the shooting data or shoot again.

Further, in step 4, the thermal expansion rate of the measurement point in each direction is calculated as follows:

A straight line is obtained by fitting the relationship between the displacement and coordinates of the measurement point in a certain direction. Divide the slope k of the straight line by the temperature difference ΔT to obtain the thermal expansion rate β of the measured structure in a certain direction.

Further, the process of step 5 is as follows:

Establish a finite element model of the actual structure, first constrain the finite element model according to the constraint state of the actual structure, then apply the actual gravity load and temperature load T ₁ , and extract the three-dimensional coordinates L ₁ of the node corresponding to the measurement point;

Change the temperature load, apply temperature load T ₂ to the finite element model, and analyze and obtain the three-dimensional coordinates L ₂ of the node corresponding to the measurement point in this state;

Compare L ₂ with L ₁ to obtain the simulated deformation amount and thermal expansion rate in all directions of the node corresponding to the measurement point in the finite element model under temperature change ΔT=T ₂ -T ₁ .

Further, in step 6, compare the thermal expansion coefficients of the measurement point and the node corresponding to the measurement point in each direction, and adjust the thermal expansion coefficient of the material used in the finite element model.

The invention also proposes a complex antenna structure thermal deformation measurement system, which is characterized by including:

The environmental chamber is temperature-controllable and is used to place the measurement structure. The surface of the measurement structure is pasted with measurement points as measurement targets and coding points for picture splicing;

Photographic device for photographing the measured structure at different temperatures;

The computer is used to perform the following operations: process and calculate the image after the shooting is completed to obtain the three-dimensional coordinates of the measurement points at different temperatures; the computer processes the three-dimensional coordinates obtained from the shooting to obtain the deformation displacement of each measurement point, and draw based on the deformation displacement Measure the relationship between the deformation, displacement and position of the measurement point and observe the thermal deformation trend of the measurement structure to judge the correctness of the measurement results; by fitting the relationship between the deformation, displacement and position of the measurement point in each direction, calculate the thermal expansion of the measurement point in each direction. Rate; establish a finite element model of the actual structure, constrain and apply loads to the finite element model according to the constraint state and actual load of the actual structure, extract the three-dimensional coordinates of the nodes corresponding to the measurement points at different temperatures, and calculate the The thermal expansion rate of the node corresponding to the measurement point in all directions; compare the thermal expansion rate of the measurement point and the node corresponding to the measurement point in all directions, and adjust the material parameters of the finite element model; use the adjusted finite element model to conduct the antenna structure Performance simulation analysis.

The beneficial effects of the present invention are: the present invention provides a method for measuring thermal deformation of a complex antenna structure based on photogrammetry and finite element analysis, which can obtain the deformation trend and amount of the complex structure, and make the measurement results consistent with the finite element analysis results. The invention effectively improves the accuracy of the finite element model, so that the finite element model can be used to predict other unmeasurable or difficult-to-measure performance of the antenna structure under current conditions.

This invention is not limited by structural materials and forms, and can measure the overall thermal deformation of complex antenna structures. Compared with existing methods such as strain gauge measurement, this method is more flexible and simple, and is not affected by factors such as connecting lines and distances. The difficulty of constructing the measurement environment is low, and the measurement accuracy is high; the present invention can use the adjusted finite element model to simulate and obtain other properties of complex structures; it has a wide range of application and can be applied to the measurement of large deformations of various complex structures.

Description of drawings

Figure 1 is a schematic diagram of the finite element model of a complex antenna structure.

Figures 2a to 2d are schematic diagrams of the fitting relationship between the deformation and position of the back frame in each direction measured under a temperature difference of 80°C. Figure 2a is dX and X; Figure 2b is dY and Y; Figure 2c is dZ and Z; Figure 2d It is dS and S (unit: mm).

Figures 3a to 3d are schematic diagrams of the fitting relationship between the deformation and position of the back frame in each direction simulated under a temperature difference of 80°C. Figure 3a is dX and X; Figure 3b is dY and Y; Figure 3c is dZ and Z; Figure 3d It is dS and S (unit: mm).

Figure 4a to Figure 4d are schematic diagrams of the thermal deformation trend of the back frame structure measured under a temperature difference of 80°C. Figure 4a is the displacement in the X direction; Figure 4b is the displacement in the Y direction; Figure 4c is the displacement in the Z direction; Figure 4d is the total deformation ( Unit: mm).

Figures 5a to 4d are schematic diagrams of the thermal deformation trend of the back frame structure simulated under a temperature difference of 80°C. Figure 5a is the displacement in the X direction; Figure 5b is the displacement in the Y direction; Figure 5c is the displacement in the Z direction; Figure 5d is the total deformation ( Unit: mm).

Detailed ways

The present invention will now be described in further detail with reference to the accompanying drawings.

In one embodiment, the present invention proposes a method for measuring thermal deformation of complex antenna structures, which specifically includes the following steps:

1. Place the measurement structure in a temperature-controlled environmental chamber, and paste single measurement points and coding points on the surface of the structure. The single point is the main target measurement point, and the coding points are used to splice different captured images; and arrange them on the surface of the structure. Temperature sensors to detect structural temperature changes.

2. Shooting and measurement process: Place the reference ruler to keep it stable. The position of the reference ruler is fixed during the entire shooting process; control the temperature of the environmental chamber to be T ₁ and maintain it. After the structural temperature stabilizes, turn off the temperature control of the environmental chamber to avoid Airflow, vibration, etc. have an impact on measurement accuracy; the object is photographed at different positions and directions, so that each single measurement point and coding point is photographed into more than two images, and all images taken are ensured to overlap completely to construct the The entire photographed structural object is taken out; after the shooting is completed, the image is processed and calculated by the computer to obtain the precise three-dimensional coordinates of the measuring point at the temperature T ₁ ; in order to obtain more control data, two groups of consecutive shots of the structure are taken at this temperature; the environment is controlled The cabin temperature is T ₂ and maintained until the structural temperature is stable. Turn off the environmental cabin temperature control and take two consecutive sets of shots of the structure to obtain the precise three-dimensional coordinates of the measurement points at the temperature T ₂ ; in order to obtain measurable deformation, the structural temperature difference must be sufficient Large (not less than 50℃), so that the deformation will not be covered by measurement errors.

3. Process the shooting data: Convert all the three-dimensional spatial coordinates obtained by shooting to the same coordinate system, and then compare the three-dimensional spatial coordinates of the same measurement point at different temperatures in the same coordinate system to obtain the temperature change ΔT of each measurement point on the structure. = the total displacement at T ₂ -T ₁ and the displacement in each coordinate direction, so as to obtain the deformation of the entire measured structure; according to the deformation displacement, draw the relationship between the deformation displacement and position of the measuring point, according to the principle of thermal expansion and contraction and thermal Deformation rules (the larger the structure, the greater the amount of thermal deformation). Observe the thermal deformation trend of the structure and confirm the correctness of the measurement results. If it does not comply with the thermal deformation rules, check the shooting data and shooting process, reprocess the data or re-shoot.

4. Since the thermal deformation amount Δl of the structure is proportional to the structural length l, the temperature difference ΔT and the thermal expansion coefficient α of the structure, that is, Δl = l·ΔT·a, therefore a straight line can be obtained by fitting the displacement and coordinate relationship of the measurement point in a certain direction , the linear slope k divided by the temperature difference ΔT can be used to obtain the thermal expansion rate β of the structure in a certain direction.

5. Establish a finite element model of the actual complex structure, and constrain the finite element model according to the constraint state of the actual structure (such as whether the structure is in an unconstrained state or has connection constraints with other structures) and actual loads (such as temperature load, gravity load) and load application; in order to be close to the actual measurement process, the established finite element model is first constrained, and gravity load (always existing) and temperature load T ₁ are applied to analyze it, and the three-dimensional shape of the node corresponding to the measurement point is extracted. Coordinate L ₁ ; since the constraints and gravity of the structure do not change during the actual measurement process, the temperature load is changed and a temperature load of T ₂ is applied to the structure. The three-dimensional coordinate L ₂ of the corresponding node in this state is obtained through analysis, and it is Comparing with L ₁ , the simulated deformation amount of the structural finite element model node under the temperature change ΔT=T ₂ -T ₁ and the thermal expansion rate in all directions are obtained.

6. Compare the thermal expansion rates of the simulated and measured structures in all directions, and adjust the material parameters in the finite element model; since the parameters of the materials used in the actual structure are often different from their theoretical values, theoretical values are generally used to construct the finite element model. The actual parameter values are unknown, so the thermal expansion coefficient of the materials used in the structure is mainly adjusted by comparing the actual thermal expansion rate, so that the finite element analysis results and the measured thermal expansion rates in all directions are basically consistent, thereby obtaining a more accurate finite element model.

7. Conduct simulation analysis on the adjusted structural finite element model for other properties that are difficult to obtain through actual measurements, such as the accuracy of the antenna reflection surface connected to a complex structure, whose thermal deformation is relatively smaller, and it is difficult to measure the temperature of a small-diameter antenna. influence on its surface shape accuracy.

Taking a 1.2-meter small sub-millimeter wave antenna back frame structure as an application example, combined with the finite element model of the complex structure shown in Figure 1, it can be seen that the overall complex structure consists of a reflector system and a back frame support system structure, so that the back frame structure Constraints are generated. The reflective surface system mainly includes the main reflector 1 and the secondary reflector. The back frame support system structure mainly includes the CFRP back frame 2, CFRP transition structure 3 and steel support plate 4. The measurement object is the CFRP structure, and the measured structure is in The environmental chamber is placed on a stable experimental platform.

Due to the symmetry of the measurement structure, four adjacent parts were selected for measurement. The structure was measured when the structural temperature was -40°C, normal temperature (25°C) and 40°C. The results were obtained when the temperature changes were 65°C and 80°C. The deformation of each point on the structure is measured, and the finite element model is adjusted based on the measurement results. After multiple measurements and processing, the slope of the fitting line of the relationship between the deformation and position of the back frame in different directions under two temperature differences was obtained, as shown in Table 1, where dX, dY, dZ and dS respectively represent the X direction, Y direction, Z direction and overall deformation.

Table 1 The slope of the fitting line between the deformation and position of the back frame

dX-X( ^10-5 ) dY-Y(10 ^-5 ) dZ-Z(10 ^-5 ) dS-S( ^10-5 ) 65℃-measurement 24.467 28.582 42.464 36.314 80℃-measurement 30.479 36.368 51.580 44.916

One group of the measured and simulated relationships between the deformation and position of the back frame in each direction under a temperature difference of 80°C is shown in Figures 2a-2d and Figure 3a-3d respectively. The deformation trends of the back frame are shown in Figures 4a-4d and Figure 5a- respectively. As shown in 5d. The finite element model was adjusted based on the measurement results to obtain the measured and simulated thermal expansion rates of the lower back frame in all directions, which are listed in Table 2. The actual measurement and simulation results are basically consistent. By analyzing the adjusted finite element model, the thermal deformation errors of the primary mirror under different temperature differences can be obtained, all of which are less than 3 μm.

Table 2 Thermal expansion rate of the back frame in each direction of the specified coordinate system - measurement and simulation results

X( ^10-6 ) Y( ^10-6 ) Z( ^10-6 ) S( ^10-6 ) Measurement mean 3.79 4.48 6.49 5.60 simulation 3.79 4.02 6.41 4.36

In another embodiment, the present invention proposes a complex antenna structure thermal deformation measurement system for implementing the complex antenna structure thermal deformation measurement method described in Embodiment 1. The measurement system includes:

The environmental chamber is temperature-controllable and is used to place the measurement structure. The surface of the measurement structure is pasted with measurement points as measurement targets and coding points for picture splicing;

Photographic device for photographing the measured structure at different temperatures;

The computer is used to perform the following operations: process and calculate the image after the shooting is completed to obtain the three-dimensional coordinates of the measurement points at different temperatures; the computer processes the three-dimensional coordinates obtained from the shooting to obtain the deformation displacement of each measurement point, and draw based on the deformation displacement Measure the relationship between the deformation, displacement and position of the measurement point and observe the thermal deformation trend of the measurement structure to judge the correctness of the measurement results; by fitting the relationship between the deformation, displacement and position of the measurement point in each direction, calculate the thermal expansion of the measurement point in each direction. Rate; establish a finite element model of the actual structure, constrain and apply loads to the finite element model according to the constraint state and actual load of the actual structure, extract the three-dimensional coordinates of the nodes corresponding to the measurement points at different temperatures, and calculate the The thermal expansion rate of the node corresponding to the measurement point in all directions; compare the thermal expansion rate of the measurement point and the node corresponding to the measurement point in all directions, and adjust the material parameters of the finite element model; use the adjusted finite element model to conduct the antenna structure Performance simulation analysis.

The working principles and processes of each component of the measurement system are consistent with the measurement method described in Embodiment 1, so they will not be repeated here.

The above are only preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above-mentioned embodiments. All technical solutions that fall under the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those of ordinary skill in the art, several improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims (10)

1. The method for measuring the thermal deformation of the complex antenna structure is characterized by comprising the following steps of:

step 1: placing the measuring structure in an environmental cabin with controllable temperature, and sticking a measuring point serving as a measuring target and a coding point for picture splicing on the surface of the measuring structure;

step 2: shooting the measurement structure at different temperatures by adopting a photogrammetry mode, and processing and calculating images through a computer after shooting is completed to obtain three-dimensional coordinates of measurement points at different temperatures;

step 3: processing the three-dimensional coordinates obtained by shooting to obtain deformation displacement of each measuring point, drawing a relation diagram of the deformation displacement and the position of the measuring point according to the deformation displacement, observing the thermal deformation trend of the measuring structure, and judging the correctness of the measuring result according to the relation diagram;

step 4: the thermal expansion rate of the measuring point in each direction is calculated by fitting the deformation displacement and the position relation of the measuring point in each direction;

step 5: establishing a finite element model of an actual structure, carrying out constraint and load application on the finite element model according to the constraint state and the actual load of the actual structure, extracting three-dimensional coordinates of nodes corresponding to the measuring points at different temperatures, and calculating the thermal expansion rates of the nodes corresponding to the measuring points at temperature changes in all directions;

step 6: comparing the thermal expansion rates of the measuring points and the nodes corresponding to the measuring points in all directions, and adjusting the material parameters of the finite element model;

step 7: and adopting the adjusted finite element model to perform performance simulation analysis on the antenna structure.

2. A method for measuring thermal deformation of a complex antenna structure as claimed in claim 1, wherein: in step 1, a temperature sensor is arranged on the surface of the measurement structure and is used for detecting the temperature change of the measurement structure.

3. A method for measuring thermal deformation of a complex antenna structure as claimed in claim 1, wherein: the process of step 2 is specifically as follows:

controlling the temperature of the environmental chamber to be T ₁ Keeping the temperature of the structure to be measured stable, and closing the temperature control of the environmental chamber;

at least two groups of shooting are carried out on the measuring structure in different positions and directions, each group of shooting enables each measuring point and each coding point to be shot into more than two images, and all the shot images are ensured to be completely overlapped to construct the whole measuring structure;

after shooting is completed, the computer processes and calculates the imageObtaining the temperature T ₁ Three-dimensional coordinates of the lower measurement point;

controlling the temperature of the environmental chamber to be T ₂ And keeping the temperature of the structure to be measured stable, closing the temperature control of the environmental chamber, and carrying out at least two groups of continuous shooting on the structure to obtain the temperature T ₂ The three-dimensional coordinates of the lower measurement point.

4. A method for measuring thermal deformation of a complex antenna structure according to claim 3, wherein: in step 2, the position of the reference ruler is ensured to be fixed in the whole shooting process.

5. A method for measuring thermal deformation of a complex antenna structure according to claim 3, wherein: in step 2, temperature T ₁ And T ₂ The temperature difference of (2) is not less than 50 ℃.

6. A method for measuring thermal deformation of a complex antenna structure as claimed in claim 1, wherein: the process of step 3 is specifically as follows:

converting the three-dimensional coordinates of all the shot measurement structures into the same coordinate system, and comparing the three-dimensional coordinates of the same measurement points at different temperatures under the same coordinate system to obtain deformation displacement of each measurement point, wherein the deformation displacement comprises total displacement during temperature change and displacement in all directions;

and drawing a relation diagram of deformation displacement and position of the measuring points according to the deformation displacement, observing the thermal deformation trend of the measuring structure according to the thermal expansion and contraction principle and the thermal deformation rule, confirming the correctness of the measuring result, and if the measuring result is incorrect, checking shooting data and shooting process, and reprocessing the shooting data or re-shooting.

7. A method for measuring thermal deformation of a complex antenna structure as claimed in claim 1, wherein: in step 4, the thermal expansion coefficients of the measurement points in all directions are calculated by the following modes:

fitting the displacement of the measuring point in a certain direction and the coordinate relation to obtain a straight line, and dividing the slope k of the straight line by the temperature difference delta T to obtain the thermal expansion rate beta of the measuring structure in a certain direction.

8. A method for measuring thermal deformation of a complex antenna structure as claimed in claim 1, wherein: the process of step 5 is specifically as follows:

establishing a finite element model of an actual structure, firstly constraining the finite element model according to the constraint state of the actual structure, and then applying actual gravity load and temperature load T ₁ Extracting three-dimensional coordinates L of a node corresponding to the measurement point ₁ ；

Varying the temperature load, applying a temperature load T to the finite element model ₂ Analyzing and obtaining the three-dimensional coordinate L of the node corresponding to the measuring point in the state ₂ ；

Will L ₂ And L is equal to ₁ Comparing to obtain the temperature change delta T=T of the node corresponding to the measuring point in the finite element model ₂ -T ₁ The amount of deformation and the thermal expansion coefficient in each direction were simulated.

9. A method for measuring thermal deformation of a complex antenna structure as claimed in claim 1, wherein: in step 6, the thermal expansion coefficients of the materials used by the finite element model are adjusted by comparing the thermal expansion rates of the measuring points and the nodes corresponding to the measuring points in all directions.

10. A complex antenna structure thermal deformation measurement system, comprising:

the environment cabin is controllable in temperature and is used for placing a measuring structure, and a measuring point serving as a measuring target and a coding point for picture splicing are stuck on the surface of the measuring structure;

the photographing device is used for photographing the measuring structure at different temperatures;

a computer for performing the operations of: processing and calculating the shot image to obtain three-dimensional coordinates of the measuring points at different temperatures; the computer processes the three-dimensional coordinates obtained by shooting to obtain deformation displacement of each measuring point, draws a relation diagram of the deformation displacement and the position of the measuring point according to the deformation displacement, observes the thermal deformation trend of the measuring structure, and judges the correctness of the measuring result; the thermal expansion rate of the measuring point in each direction is calculated by fitting the deformation displacement and the position relation of the measuring point in each direction; establishing a finite element model of an actual structure, carrying out constraint and load application on the finite element model according to the constraint state and the actual load of the actual structure, extracting three-dimensional coordinates of nodes corresponding to the measuring points at different temperatures, and calculating the thermal expansion rates of the nodes corresponding to the measuring points at temperature changes in all directions; comparing the thermal expansion rates of the measuring points and the nodes corresponding to the measuring points in all directions, and adjusting the material parameters of the finite element model; and adopting the adjusted finite element model to perform performance simulation analysis on the antenna structure.