A full-field stress synchronous testing experimental system and method based on photoelasticity and infrared

Abstract

The present invention discloses a full-field stress synchronous testing experimental system and method based on photoelasticity and infrared, belonging to the field of mechanical testing technology. In this system: the intelligent photoelasticity testing system is used to use the photoelasticity testing method to obtain in real time the optical interference fringes caused by the force on the surface of the specimen on which the photoelastic material is affixed; the infrared testing system is used to use the infrared thermal imaging testing method to obtain in real time the temperature change caused by the force on the opposite side of the specimen on which the photoelastic material is affixed; the synchronous control system is used to control the frequency of change of the optical axis position and the fast axis position in the optical lens, the frequency of the optical interference fringes collected by the high-speed CMOS camera, the frequency of the applied load, and the frequency of the infrared thermal imaging collection. It is possible to realize the synchronous testing of the dynamic real-time photoelasticity method and the infrared high-speed thermal imaging related method, and the high-precision real-time full-field stress automatic analysis. By combining the advantages of the two methods, the full-field stress distribution and evolution of the rock-like solid material specimen can be intuitively detected through the experiment.

Description

Technical Field

[0001] The present invention relates to the field of mechanical testing technology, and in particular to a full-field stress synchronous testing experimental system and method based on photoelasticity-infrared. Background Art

[0002] At present, in the mechanical experimental determination of loaded objects, commonly used experimental techniques include strain gauges and acoustic emission, etc., but these experimental techniques are difficult to detect the full-field stress distribution and evolution characteristics. Photoelastic testing, as a classic mechanical testing method, is widely used in mechanical analysis because of its full-field and real-time characteristics. With the advancement of technology, the types of materials with temporary birefringence properties are increasing, and models can be made for different engineering backgrounds according to different material properties for experiments. However, photoelastic testing is limited to transparent materials, and mechanical experimental determination cannot be performed on non-transparent materials. In addition, photoelastic testing is also limited by the constant angle of the optical mirror in the light path. Therefore, it is difficult to use the photoelastic testing method to distinguish in real time the optical interference fringes generated by the force on the surface of the loaded object, resulting in unclear mechanical properties of the loaded object. Summary of the Invention

[0003] In order to solve the problems existing in the prior art, the present invention provides the following technical solutions.

[0004] The first aspect of the present invention provides a full-field stress synchronous testing experimental system based on photoelasticity and infrared, comprising: an intelligent photoelasticity testing system, an infrared testing system, a specimen loading system, and a synchronous control system;

[0005] The specimen loading system is used to apply a load to the specimen, which is a non-transparent rock-like solid material with a photoelastic patch material having similar mechanical properties attached to its surface;

[0006] The intelligent photoelastic testing system is used to obtain, in real time, the optical interference fringes generated by the stress on the surface of the test piece on which the photoelastic patch material is attached, using a photoelastic testing method, and then obtain the full-field stress distribution and the fringes evolution process as the stress changes.

[0007] The infrared testing system is used to obtain the temperature change of the opposite side of the test piece to which the photoelastic patch material is attached in real time due to the stress using the infrared thermal imaging testing method, and then obtain the full-field stress distribution and evolution process;

[0008] The synchronous control system is used to control the optical axis position of the polarizer and analyzer in the intelligent photoelastic testing system and the rotation frequency of the fast axis position of the first quarter-wave plate and the second quarter-wave plate, the frequency of the high-speed CMOS camera collecting optical interference fringes, the frequency of the specimen loading system applying load to the specimen, and the infrared thermal imaging collection frequency of the infrared testing system.

[0009] Preferably, the synchronous control system is controlled by the following method: whenever the specimen loading system applies a load to the specimen, the optical axis positions of the polarizer and the analyzer and the fast axis positions of the first quarter-wave plate and the second quarter-wave plate in the intelligent photoelastic testing system are rotated five times, the corresponding high-speed CMOS camera collects optical interference fringes five times, and the infrared thermal imaging of the infrared testing system is collected once.

[0010] Preferably, rotating the optical axis positions of the polarizer and analyzer and the fast axis positions of the first quarter wave plate and the second quarter wave plate in the intelligent photoelastic testing system five times comprises: rotating according to the angles in the following table;

[0011] α i 6 c π / 2 π / 2 0 0 5π / 8 5π / 8 π / 8 π / 8 3π / 4 3π / 4 π / 4 π / 4 7π / 8 7π / 8 3π / 8 3π / 8 π / 2 3π / 4 π / 4 0

[0012] Where α is the angle of rotation of the polarizer optical axis from the x-axis, θ is the angle of rotation of the fast axis of the first quarter-wave plate from the x-axis, β is the angle of rotation of the analyzer optical axis from the x-axis, and γ is the angle of rotation of the fast axis of the second quarter-wave plate from the x-axis.

[0013] Preferably, the specimen loading system includes a loading device and a loading control system, the loading device is provided with a clamp, and a specimen of non-transparent rock-like solid material with a photoelastic patch material attached to the surface is installed on the clamp, and the loading control system is used to control the loading device to apply a load to the specimen through the clamp; the synchronous control system controls the frequency at which the loading control system applies a load to the specimen.

[0014] Preferably, the intelligent photoelastic testing system includes a photoelastic testing optical path, a high-speed CMOS camera, a photoelastic image analysis system, a first controller, a second controller and a third controller; along the photoelastic testing optical path, a white light source, a filter, a polarizer, a first quarter-wave plate, a beam expander, a convex lens, a second quarter-wave plate, an analyzer and a collimator are arranged in sequence; the high-speed CMOS camera is used to receive the light signal of the collimator and output a photoelastic interference image according to the light signal and send it to the photoelastic image analysis system; the photoelastic image analysis system is used to use the photoelastic interference image to calculate and analyze the full-field stress distribution of the specimen and the fringe evolution process with stress change; the first controller is used to control the optical axis position of the polarizer and the analyzer; the second controller is used to control the fast axis position of the first quarter-wave plate and the second quarter-wave plate; the third controller is used to control the start and end of the filter; the specimen is located between the beam expander and the convex lens, so that the light beam output by the beam expander covers the specimen and is reflected to the convex lens.

[0015] A second aspect of the present invention provides a full-field stress synchronization test experimental method based on photoelasticity and infrared, using the full-field stress synchronization test experimental system based on photoelasticity and infrared as described in the first aspect, the method includes:

[0016] Step 1: the specimen loading system applies a load to the specimen;

[0017] Step 2: Turn on the white light source, and the white light is incident on the filter. The unfiltered white light is incident on the polarizer and converted into plane polarized light, and then enters the first quarter wave plate. The generated circularly polarized light is incident on the beam expander. The light beam output by the beam expander covers the test piece and is reflected from the test piece to the convex lens. After passing through the convex lens, it passes through the second quarter wave plate and the analyzer and enters the collimator. Finally, the high-speed CMOS camera receives the light signal from the collimator and outputs a photoelastic interference image according to the light signal and sends it to the photoelastic image analysis system; at the same time, the first controller is used to control the optical axis position of the polarizer and the analyzer, and the second controller is used to control the fast axis position of the first quarter wave plate and the second quarter wave plate; obtain full-field equal inclination angle data;

[0018] Step 3: Start the third controller to filter the white light incident on the filter into monochromatic light, so that the monochromatic light is incident on the polarizer. The subsequent method is the same as step 2; obtain full-field isotropic data;

[0019] Step 4: Calculate the full-field stress based on the full-field isopiped data and the full-field iso-difference line data;

[0020] Step 5: Repeat steps 1 to 4 to obtain the full-field stress under different loads and the evolution process with stress change;

[0021] Step 6: Using the infrared testing system and infrared thermal imaging testing method, the temperature change of the opposite side of the test piece to which the photoelastic patch material is attached due to the stress is obtained in real time, thereby obtaining the full-field stress distribution and evolution process;

[0022] There is no particular order for steps 5 and 6.

[0023] Preferably, the experiments are carried out in an experimental environment with constant temperature and humidity.

[0024] Preferably, before step 1, the temperature of the surface of the specimen is observed by an infrared thermal imager, and the experiment is started when the temperature of the surface of the specimen is uniform.

[0025] Preferably, the controlling of the optical axis positions of the polarizer and the analyzer by the first controller, and the controlling of the fast axis positions of the first quarter wave plate and the second quarter wave plate by the second controller comprises: each time the specimen loading system applies a load to the specimen, the optical axis positions of the polarizer and the analyzer, and the fast axis positions of the first quarter wave plate and the second quarter wave plate are rotated five times, the corresponding high-speed CMOS camera collects optical interference fringes five times, and the infrared thermal imaging of the infrared testing system is collected once.

[0026] Preferably, rotating the optical axis positions of the polarizer and analyzer and the fast axis positions of the first quarter wave plate and the second quarter wave plate five times comprises: rotating according to the angles in the following table;

[0027]

[0028]

[0029] Where α is the angle of rotation of the polarizer optical axis from the x-axis, θ is the angle of rotation of the fast axis of the first quarter-wave plate from the x-axis, β is the angle of rotation of the analyzer optical axis from the x-axis, and γ is the angle of rotation of the fast axis of the second quarter-wave plate from the x-axis.

[0030] The beneficial effects of the present invention are as follows: The system and method for synchronous full-field stress testing based on photoelasticity and infrared imaging can achieve dynamic, real-time simultaneous testing of intelligent photoelasticity and infrared high-speed thermal imaging, automatically and simultaneously collecting data from both experimental methods, thereby improving experimental reliability. It also enables high-precision, real-time, automatic full-field stress analysis, combining the advantages of both methods. Through experimental techniques, the full-field stress distribution and changes of rock specimens can be intuitively detected, and local stress and strain can be specifically analyzed. This overcomes the limitations of transparent materials in photoelastic testing and can also be applied to dynamic loading processes, improving the accuracy of stress calculations. Furthermore, it enables synchronous control, testing, and recording of the entire experimental process. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic structural diagram of a full-field stress synchronous testing experimental system based on photoelasticity and infrared according to the present invention;

[0032] The meanings of the symbols in the figure are as follows:

[0033] 1. White light source, 2. Filter, 3. Polarizer, 4. First quarter-wave plate, 5. Beam expander, 6. Convex lens, 7. Second quarter-wave plate, 8. Analyzer, 9. Collimator, 10. High-speed CMOS camera, 11. Loading device, 12. Fixture, 13. Test piece, 14. Photoelastic patch material, 15. First controller, 16. Second controller, 17. Photoelastic image analysis system, 18. Infrared high-speed camera, 19. Infrared image analysis system, 20. Loading control system, 21. Synchronous control system, 22. Third controller. DETAILED DESCRIPTION

[0034] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0035] Example 1

[0036] like Figure 1 As shown, an embodiment of the present invention provides a full-field stress synchronous testing experimental system based on photoelasticity and infrared, comprising: an intelligent photoelasticity testing system, an infrared testing system, a specimen loading system, and a synchronous control system; the specimen loading system is used to apply a load to a specimen, wherein the specimen is a non-transparent rock-like solid material and has a photoelastic patch material with similar mechanical properties attached to its surface; the intelligent photoelasticity testing system is used to use a photoelasticity testing method to obtain in real time the optical interference fringes generated by the stress on the surface of the specimen to which the photoelastic patch material is attached, thereby obtaining the full-field stress distribution and the evolution of the fringes as the stress changes; the infrared testing system is used to use an infrared thermal imaging testing method to obtain in real time the temperature change caused by the stress on the opposite surface of the specimen to which the photoelastic patch material is attached, thereby obtaining the full-field stress distribution and its evolution; the synchronous control system is used to control the optical axis positions of the polarizer and analyzer in the intelligent photoelasticity testing system, the frequency of the fast axis positions of the first and second quarter-wave plates, the frequency of the high-speed CMOS camera capturing the optical interference fringes, the frequency of the specimen loading system applying the load to the specimen, and the infrared thermal imaging acquisition frequency of the infrared testing system.

[0037] The specimen loading system may include a loading device 11 and a loading control system 20. The loading device 11 is provided with a fixture 12, on which a specimen 13 of a non-transparent rock-like solid material having a photoelastic patch material 14 attached to its surface is mounted. The loading control system 20 is used to control the loading device 11 to apply a load to the specimen 13 via the fixture 12. The synchronous control system 21 controls the frequency at which the loading control system 20 applies the load to the specimen 13. The loading rate can be set by the loading control system to control the stress and strain loading.

[0038] The intelligent photoelastic test system includes a photoelastic test optical path, a high-speed CMOS camera, a photoelastic image analysis system, a first controller, a second controller and a third controller; along the photoelastic test optical path are arranged in sequence: a white light source 1, a filter 2, a polarizer 3, a first quarter-wave plate 4, a beam expander 5, a convex lens 6, a second quarter-wave plate 7, an analyzer 8 and a collimator 9; the high-speed CMOS camera 10 is used to receive the light signal of the collimator and output a photoelastic interference image according to the light signal to the photoelastic image analysis system 17; the light The photoelastic image analysis system 17 is used to calculate and analyze the full-field stress distribution of the specimen and the fringe evolution process as the stress changes using the photoelastic interference image; the first controller 15 is used to control the optical axis position of the polarizer 3 and the analyzer 8; the second controller 16 is used to control the fast axis position of the first quarter wave plate 4 and the second quarter wave plate 7; the third controller 22 is used to control the start and end of the filter 2; the specimen 13 is located between the collimator 5 and the convex lens 6, so that the light beam output by the collimator 5 covers the specimen 13 and is reflected to the convex lens 6.

[0039] In an embodiment of the present invention, a high-power, high-intensity white light source is used as the white light source to facilitate subsequent interference on the surface of the specimen. The filter can allow certain wavelengths of light to pass through while blocking other wavelengths of light. In the present invention, it is used to filter out other light waves in white light to form monochromatic light. The polarizer can convert white light into plane-polarized light, one beam of which is completely absorbed and the other beam propagates forward along a fixed plane. The first quarter-wave plate is used to convert plane-polarized light into circularly polarized light. The beam expander can expand the input light beam diameter to a larger output beam diameter. By expanding the beam, the divergence angle of the light beam will be reduced accordingly, making the light beam more collimated. The convex lens is used to converge the divergent light rays. The second quarter-wave plate is used to convert circularly polarized light into plane polarized light. The analyzer can synthesize all light vectors into a single plane, forming a new light vector for analysis. The collimator can convert a light beam into parallel or quasi-parallel light. By ensuring that the light rays propagate parallel to each other, it can prevent the light from diffusing in unwanted directions, thereby improving the accuracy and efficiency of the optical system. A high-speed CMOS camera can record photoelastic images at a rate of 100,000 frames per second, matching the rate at which the specimen is loaded. It can also capture clear, high-resolution images even in low-light environments. The ultra-high-speed CMOS camera converts optical signals into electrical signals via a CMOS image sensor, which are then converted to digital signals via an analog-to-digital converter (ADC). The data is then transmitted to a computer or dedicated image processing system via a high-speed interface (such as CameraLink or USB 3.0) for processing and analysis. The loading device applies the load to the specimen via a fixture. Before the test begins, the specimen is secured between the upper and lower fixtures. The specimen is a non-transparent rock-like solid material with a photoelastic patch material applied to its surface. The rock specimen can be constructed using standard uniaxial compression specimen dimensions. The photoelastic patch material is applied to one side, and the other side is carefully sanded to ensure that the surface is free of visible holes and cracks. Photoelastic patch materials with birefringent properties similar to those of rock specimens (such as compressive strength, tensile strength, elastic modulus, Poisson's ratio, and other parameters) can be prepared, ensuring that the size of the photoelastic patch material can perfectly fit the surface of the rock specimen. A first controller can be used to control the optical axis positions of the polarizer and analyzer. During use, a preset module can be added to the first controller to change the angles α and β of the polarizer and analyzer's optical axes relative to the x-axis. A second controller is used to control the fast axis positions of the first and second quarter-wave plates. During use, a preset module can be added to the second controller to change the angles θ and γ of the fast axes of the first and second quarter-wave plates relative to the x-axis. Each time α, β, γ, and θ are changed, a high-speed CMOS camera records a photoelastic interference image at a rate of 100,000 frames per second. A photoelastic image analysis system receives all photoelastic interference images and, based on these images, uses a specific mechanical calculation method to determine the full-field stress distribution of the specimen and the fringe evolution process as stress changes.

[0040] Research conducted by the present inventors has revealed that the deformation of an object is often accompanied by changes in energy. Infrared thermal imagers can non-destructively detect the temperature distribution on an object's surface in real time, thereby reflecting the mechanical properties of the material's surface. Therefore, the present invention combines infrared and photoelastic testing techniques to reflect the full-field stress distribution and evolution of loaded rock from both thermal and mechanical perspectives. The infrared testing system is used to capture the energy changes caused by the force applied to the opposite side of the specimen to the photoelastic patch material. The infrared testing system includes an infrared high-speed camera 18 and an infrared image analysis system 19. Each infrared image captured by the infrared high-speed camera 18 is transmitted to the infrared image analysis system 19 for image processing and calculation of the full-field stress distribution. As the force increases and the number of acquisitions increases, more infrared images are captured, thereby reflecting the full-field stress evolution process through infrared mechanical images. The operating principle of an infrared high-speed camera is primarily based on the detection and conversion of infrared radiation. The object itself emits infrared radiation, which is captured by the infrared high-speed camera through specialized internal photosensitive elements and optical systems, converting them into electronic signals. These electronic signals are then processed and converted to form a visible image. The infrared high-speed camera has an acquisition frequency of up to 1,000 frames per second, matching the acquisition frequency of the pressure sensor. Its high sensitivity allows it to capture weak infrared signals, monitor the target in real time, and capture images, promptly detecting changes and anomalies. The infrared image analysis system operates primarily based on the detection and conversion of infrared radiation. Objects above absolute zero emit infrared radiation. The infrared image analysis system receives this radiation through the detector in the infrared high-speed camera and converts it into an electrical signal. After image processing such as amplification, filtering, and denoising, the electrical signal is converted into a temperature image. Finally, image analysis software analyzes and calculates the temperature image, converting it into full-field mechanical information.

[0041] In the present invention, a synchronous control system enables synchronized control of the loading system, intelligent photoelastic testing system, high-speed CMOS camera, and infrared testing system. For example, each time the specimen loading system applies a load to the specimen, the optical axes of the polarizer and analyzer, as well as the fast axes of the first and second quarter-wave plates in the intelligent photoelastic testing system, rotate five times. The corresponding high-speed CMOS camera captures optical interference fringes five times, and the infrared testing system captures infrared thermal imaging once.

[0042] In a preferred embodiment of the present invention, rotating the optical axis positions of the polarizer and analyzer and the fast axis positions of the first quarter wave plate and the second quarter wave plate in the intelligent photoelastic testing system five times includes: rotating according to the angles in the following table.

[0043]

[0044]

[0045] Where α is the angle of rotation of the polarizer optical axis from the x-axis, θ is the angle of rotation of the fast axis of the first quarter-wave plate from the x-axis, β is the angle of rotation of the analyzer optical axis from the x-axis, and γ is the angle of rotation of the fast axis of the second quarter-wave plate from the x-axis.

[0046] Each time a load is applied to the specimen, the first and second controllers simultaneously rotate α, θ, β, and γ five times. Each time, the corresponding optical interference fringes are captured by a high-speed CMOS camera. After five acquisitions, a stress value is calculated. Simultaneously, the infrared testing system uses a high-speed infrared camera to record infrared thermal imaging of the specimen surface, which is then used to calculate the stress value.

[0047] Therefore, the technical solution provided by the present invention enables simultaneous testing and recording of the entire experimental process through signal and synchronous control. It also enables dynamic, real-time simultaneous testing of intelligent photoelastic methods and infrared high-speed thermal imaging-related methods, enabling loading of rock specimens with different loading modes and rates. Data from both experimental methods can be automatically collected simultaneously and compared, thereby improving experimental reliability and enabling high-precision, real-time, full-field automatic stress analysis. Combining the advantages of both methods, the full-field stress distribution and changes of the rock specimen can be intuitively detected through experimental techniques, allowing for detailed analysis of local stress and strain. Compared to single measurement methods, the present invention combines photoelastic testing with infrared thermal imaging testing, providing more analytical context for full-field stress and strain measurement and overcoming the limitations of transparent materials in photoelastic testing. It can also be applied to dynamic loading processes, improving the accuracy of stress calculations. In specific applications, the loading method can be modified to suit experimental requirements, such as pendulum impact loading or Hopkinson bar loading, and the specimen can be replaced. Therefore, the present invention provides a new method for full-field stress and strain measurement.

[0048] Example 2

[0049] An embodiment of the present invention provides a full-field stress synchronization test experimental method based on photoelasticity and infrared, using the full-field stress synchronization test experimental system based on photoelasticity and infrared as described in Example 1. The method includes:

[0050] Step 1: the specimen loading system applies a load to the specimen;

[0051] Step 2: Turn on the white light source, and the white light is incident on the filter. The unfiltered white light is incident on the polarizer and converted into plane polarized light, and then enters the first quarter wave plate. The generated circularly polarized light is incident on the beam expander. The light beam output by the beam expander covers the test piece and is reflected from the test piece to the convex lens. After passing through the convex lens, it passes through the second quarter wave plate and the analyzer and enters the collimator. Finally, the high-speed CMOS camera receives the light signal from the collimator and outputs a photoelastic interference image according to the light signal and sends it to the photoelastic image analysis system. At the same time, the first controller is used to control the optical axis position of the polarizer and the analyzer, and the second controller is used to control the fast axis position of the first quarter wave plate and the second quarter wave plate; obtain full-field equal inclination angle data;

[0052] Step 3: Start the third controller to filter the white light incident on the filter into monochromatic light, so that the monochromatic light is incident on the polarizer. The subsequent method is the same as step 2; obtain full-field isotropic data;

[0053] Step 4: Calculate the full-field stress based on the full-field isopiped data and the full-field iso-difference line data;

[0054] Step 5: Repeat steps 1 to 4 to obtain the full-field stress under different loads and the evolution process with stress change;

[0055] Step 6: Using the infrared testing system and infrared thermal imaging testing method, the temperature change of the opposite side of the test piece to which the photoelastic patch material is attached due to the stress is obtained in real time, thereby obtaining the full-field stress distribution and evolution process;

[0056] There is no particular order for steps 5 and 6.

[0057] Among them, the experiments were carried out in a constant temperature and humidity environment.

[0058] In a preferred embodiment of the present invention, before step 1, the temperature of the surface of the specimen can be observed by an infrared thermal imager, and the experiment can be started when the temperature of the surface of the specimen is uniform.

[0059] Whenever a load is applied to the specimen in step 1, the optical axis positions of the polarizer and analyzer, as well as the fast axis positions of the first and second quarter-wave plates, are rotated five times in steps 2 and 3. The corresponding high-speed CMOS camera captures optical interference fringes five times, and the infrared thermal imaging of the infrared test system is captured once in step 6.

[0060] Specifically, the optical axis positions of the polarizer and analyzer and the fast axis positions of the first quarter wave plate and the second quarter wave plate are rotated five times, and can be rotated according to the angles in the following table:

[0061] α π 6 c π / 2 π / 2 0 0 5π / 8 5π / 8 π / 8 π / 8 3π / 4 3π / 4 π / 4 π / 4 7π / 8 7π / 8 3π / 8 3π / 8 π / 2 3π / 4 π / 4 0

[0062] Where α is the angle of rotation of the polarizer optical axis from the x-axis, θ is the angle of rotation of the fast axis of the first quarter-wave plate from the x-axis, β is the angle of rotation of the analyzer optical axis from the x-axis, and γ is the angle of rotation of the fast axis of the second quarter-wave plate from the x-axis.

[0063] By combining the five angles provided in the table, full-field iso-difference and isoclinometer data can be directly acquired through a simple plane polarization instrument optical system, enabling rapid and convenient quantitative full-field stress results.

[0064] Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the invention. Thus, the present invention is intended to include such changes and modifications as fall within the scope of the claims and their equivalents.

Claims

1. A full-field stress synchronous testing experimental system based on photoelasticity and infrared, characterized by: include: Intelligent photoelastic testing system, infrared testing system, specimen loading system and synchronous control system; The specimen loading system is used to apply a load to the specimen, which is a non-transparent rock-like solid material with a photoelastic patch material having similar mechanical properties attached to its surface; The intelligent photoelastic testing system is used to obtain, in real time, the optical interference fringes generated by the stress on the surface of the test piece on which the photoelastic patch material is attached, using a photoelastic testing method, and then obtain the full-field stress distribution and the fringes evolution process as the stress changes; The infrared testing system is used to obtain the temperature change of the opposite side of the test piece to which the photoelastic patch material is attached in real time due to the stress using the infrared thermal imaging testing method, and then obtain the full-field stress distribution and evolution process; The synchronous control system is used to control the optical axis positions of the polarizer and analyzer in the intelligent photoelastic testing system and the frequency of the fast axis positions of the first quarter-wave plate and the second quarter-wave plate, the frequency of the high-speed CMOS camera collecting optical interference fringes, the frequency of the specimen loading system applying load to the specimen, and the infrared thermal imaging acquisition frequency of the infrared testing system; The synchronous control system is controlled by the following method: whenever the specimen loading system applies a load to the specimen, the optical axis positions of the polarizer and analyzer, as well as the fast axis positions of the first and second quarter-wave plates in the intelligent photoelastic testing system, rotate five times; the corresponding high-speed CMOS camera captures optical interference fringes five times; and the infrared testing system captures infrared thermal imaging once; the high-speed CMOS camera records photoelastic images at a rate of 100,000 frames per second to match the rate at which the specimen is loaded; The intelligent photoelastic testing system includes a photoelastic testing optical path, a high-speed CMOS camera, a photoelastic image analysis system, a first controller, a second controller, and a third controller; a white light source, a filter, a polarizer, a first quarter-wave plate, a beam expander, a convex lens, a second quarter-wave plate, an analyzer, and a collimator are sequentially arranged along the photoelastic testing optical path; the high-speed CMOS camera is used to receive the optical signal from the collimator and output a photoelastic interference image according to the optical signal and send it to the photoelastic image analysis system; the photoelastic image analysis system is used to calculate and analyze the full-field stress distribution of the specimen and the fringe evolution process with stress changes using the photoelastic interference image; the first controller is used to control the optical axis positions of the polarizer and the analyzer; The second controller is used to control the fast axis position of the first quarter wave plate and the second quarter wave plate; the third controller is used to control the start and end of the filter; the specimen is located between the collimator and the convex lens so that the light beam output by the collimator covers the specimen and is reflected to the convex lens.

2. The photoelastic-infrared full-field stress synchronous testing experimental system according to claim 1, characterized in that: The optical axis positions of the polarizer and analyzer and the fast axis positions of the first quarter wave plate and the second quarter wave plate in the intelligent photoelastic testing system are rotated five times including: rotating according to the angles in the following table; Where α is the angle of rotation of the polarizer optical axis from the x-axis, θ is the angle of rotation of the fast axis of the first quarter-wave plate from the x-axis, β is the angle of rotation of the analyzer optical axis from the x-axis, and γ is the angle of rotation of the fast axis of the second quarter-wave plate from the x-axis.

3. The photoelastic-infrared based full-field stress synchronous testing experimental system according to claim 1, characterized in that: The specimen loading system includes a loading device and a loading control system. The loading device is provided with a clamp, and a specimen of non-transparent rock-like solid material with a photoelastic patch material attached to the surface is installed on the clamp. The loading control system is used to control the loading device to apply a load to the specimen through the clamp; the synchronous control system controls the frequency at which the loading control system applies the load to the specimen.

4. A full-field stress synchronous testing experimental method based on photoelasticity and infrared, characterized in that: Utilizing the photoelastic-infrared based full-field stress synchronous testing experimental system according to any one of claims 1 to 3, the method comprises: Step 1: the specimen loading system applies a load to the specimen; Step 2: Turn on the white light source, and the white light is incident on the filter. The unfiltered white light is incident on the polarizer and converted into plane polarized light, and then enters the first quarter wave plate. The generated circularly polarized light is incident on the beam expander. The light beam output by the beam expander covers the test piece and is reflected from the test piece to the convex lens. After passing through the convex lens, it passes through the second quarter wave plate and the analyzer and enters the collimator. Finally, the high-speed CMOS camera receives the light signal from the collimator and outputs a photoelastic interference image according to the light signal and sends it to the photoelastic image analysis system; at the same time, the first controller is used to control the optical axis position of the polarizer and the analyzer, and the second controller is used to control the fast axis position of the first quarter wave plate and the second quarter wave plate; obtain full-field equal inclination angle data; Step 3: Start the third controller to filter the white light incident on the filter into monochromatic light, so that the monochromatic light is incident on the polarizer. The subsequent method is the same as step 2; obtain full-field isotropic data; Step 4: Calculate the full-field stress based on the full-field isopiped data and the full-field iso-difference line data; Step 5: Repeat steps 1 to 4 to obtain the full-field stress under different loads and the evolution process with stress change; Step 6: Using the infrared testing system and infrared thermal imaging testing method, the temperature change of the opposite side of the test piece to which the photoelastic patch material is attached due to the stress is obtained in real time, thereby obtaining the full-field stress distribution and evolution process; There is no particular order for steps 5 and 6.

5. The photoelastic-infrared full-field stress synchronous testing experimental method according to claim 4, characterized in that: All experiments were carried out in a constant temperature and humidity environment.

6. The photoelastic-infrared full-field stress synchronous testing experimental method according to claim 4, characterized in that: Before step 1, the temperature of the specimen surface is observed by an infrared thermal imager. The experiment is started when the temperature of the specimen surface is uniform.

7. The photoelastic-infrared full-field stress synchronous testing experimental method according to claim 4, characterized in that: The method of controlling the optical axis positions of the polarizer and the analyzer using the first controller, and controlling the fast axis positions of the first quarter wave plate and the second quarter wave plate using the second controller includes: each time the specimen loading system applies a load to the specimen, the optical axis positions of the polarizer and the analyzer, and the fast axis positions of the first quarter wave plate and the second quarter wave plate are rotated five times, the corresponding high-speed CMOS camera collects optical interference fringes five times, and the infrared thermal imaging of the infrared testing system is collected once.

8. The photoelastic-infrared full-field stress synchronous testing experimental method according to claim 7, characterized in that: The optical axis positions of the polarizer and analyzer and the fast axis positions of the first quarter wave plate and the second quarter wave plate are rotated five times including: rotating according to the angles in the following table; Where α is the angle of rotation of the polarizer optical axis from the x-axis, θ is the angle of rotation of the fast axis of the first quarter-wave plate from the x-axis, β is the angle of rotation of the analyzer optical axis from the x-axis, and γ is the angle of rotation of the fast axis of the second quarter-wave plate from the x-axis.

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