A method for simultaneous micro- and macroscopic dynamic observation of the mechanical behavior of ice samples

Abstract

The present invention relates to a method for synchronous micro- and macroscopic dynamic observation of the mechanical behavior of ice samples. The measurement equipment used includes a load measurement system, a displacement measurement system, and a microscopic imaging system. The method comprises the following steps: (1) preparation of the ice sample; (2) placement and microscopic capture of the microscopic imaging system; (3) macroscopic data processing: for a Brazilian plate tensile test, the external load applied to the ice sample is recorded in real time by the load measurement system; a "force-time" variation curve is generated; for a uniaxial compression test, the load measurement system and the displacement measurement system work synchronously to generate a stress-strain curve; and (4) microscopic data analysis.

Description

Technical Field

[0001] The invention belongs to the technical field of experimental testing and relates to a method for fine-macro dynamic synchronous observation of the mechanical behavior of an ice sample. Background Art

[0002] Naturally formed sea ice is a complex polycrystalline material. Under natural growth conditions, sea ice exhibits a specific crystal shape and arrangement. Furthermore, due to the influx of air and saltwater during phase transitions, intercrystalline defects form within the ice, endowing it with unique physical and mechanical properties. Academic research on the microstructure of ice typically involves slicing ice samples into thin slices (typically less than 1 mm thick) and visualizing the ice crystals under cross-polarized light. This method only allows for the investigation of the influence of macroscopic crystal parameters, such as average grain size and number, on the macroscopic mechanical behavior of the ice sample. Further research has used digital image correlation (DIC) to conduct experiments on polycrystalline ice to characterize the development of intragranular strain inhomogeneities during transient creep deformation. This approach involves analyzing the microstructure of the ice sample slices before the experiment and spraying a specific coating onto the surface to create speckles. During the experiment, the strain field obtained using DIC is superimposed on the pre-experimental microstructure of the ice sample to investigate the influence of the microstructure on the strain inhomogeneity. DIC technology can provide displacement and strain distributions across the entire surface of an ice sample, revealing the complex deformation behavior of ice samples under load. However, because DIC relies on speckle patterns on the sample surface, the smooth surface of ice prevents most common materials used to create speckle patterns (such as paint and ink) from adhering to the ice. Therefore, specific surface treatment and the use of specialized materials to create speckle patterns are required, which can affect speckle formation and observation accuracy. Furthermore, DIC applied to ice relies on the assumption that the microstructure of the ice sample remains unchanged before and after the test. However, actual ice crystals undergo microscopic behaviors such as crystal deformation, inter-grain boundary slip, and dynamic recrystallization under mechanical loading, which are not observable with DIC. Furthermore, DIC primarily monitors surface deformation, and once a speckle pattern forms on the surface, it becomes difficult to capture the effects of internal defects on the mechanical behavior of the ice sample.

[0003] Currently, two main methods are used to study the effects of internal ice defects on its mechanical behavior: X-ray computed tomography (CT scanning) and acoustic imaging. CT scanning relies on a CT scanner scanning an ice sample from multiple angles, generating a series of cross-sectional images. These images are then reconstructed into a three-dimensional image using a computer to reveal the ice sample's internal structure, including the distribution and morphology of pores. However, the scanning and image reconstruction process can be time-consuming, and the ice sample's temperature must be kept constant during this time to prevent structural changes due to melting or recrystallization, which could affect the mechanical test results. Acoustic imaging involves a transmitter sending ultrasonic pulses into the ice sample. A receiver records the acoustic signals that are reflected or penetrate the ice sample. The acoustic wave propagation speed, attenuation, and reflection characteristics are used to assess information such as the location and size of internal pores. However, acoustic signals are susceptible to noise, and ice fractures inevitably produce sound, requiring highly specialized data processing and interpretation.

[0004] While the aforementioned methods can reveal the influence of microstructure on macromechanical properties to a certain extent, they do not fully reflect the deformation dynamics of the crystal structure and internal defects during the test. Therefore, the present invention proposes a new synchronous observation technique that combines polarized light imaging and laser transmission technology to dynamically and synchronously measure the microstructure and macromechanical behavior of ice samples during mechanical testing. This technique not only monitors the temporal evolution of the ice sample's microstructure in real time, but also deeply explores the relationship between micromechanisms and macroperformance, thereby providing a more comprehensive understanding of the mechanical properties of sea ice materials. Summary of the Invention

[0005] The purpose of this invention is to provide a method for dynamically and synchronously observing the microscopic behavior of ice crystal texture and pore defects, along with macroscopic indicators such as loading force (stress), loading displacement (strain), and loading velocity (strain rate) during mechanical testing of sea ice. To achieve this goal, the present invention proposes a method for dynamically and synchronously observing the microscopic and macroscopic mechanical behavior of ice samples. The technical solution is as follows:

[0006] A method for synchronous micro- and macroscopic dynamic observation of the mechanical behavior of an ice sample is disclosed. The measurement equipment used includes a load measurement system, a displacement measurement system, and a microscopic imaging system. The load measurement system includes a load sensor for measuring the external load applied to the ice sample during the test. The displacement measurement system includes a displacement sensor disposed on a pressure plate on a testing machine for measuring the displacement of the upper surface of the ice sample during the test. The microscopic imaging system includes a camera, a background light source with adjustable brightness, a polarizer, and a laser line light source for displaying microscopic structural information of the ice sample on the recording device. The method includes the following steps:

[0007] (1) Preparation of ice samples;

[0008] (2) Placement of microscopic imaging system and microscopic capture

[0009] Set up a steplessly dimming background light source at the rear of the testing machine, at a position highly parallel to the test area, with the distance between the background light source and the test area no greater than 30 cm. Place the prepared ice sample on the testing machine so that its plane is perpendicular to the light emitted by the background light source. Place polarizer a between the background light source and the ice sample, and polarizer b on the other side of the ice sample, with the planes of the two polarizers parallel to each other. Adjust the polarization direction of polarizer b so that it is perpendicular to the polarization direction of polarizer a. Place a camera in front of polarizer b.

[0010] Place a laser line light source on one side of the ice sample and adjust the angle of the laser line light source so that the "I"-shaped light beam it emits is parallel to the side edge of the ice sample; and the laser line light source is incident at a position half the thickness of the ice sample. During each test, either the background light source alone, the laser line light source alone, or both light sources are used simultaneously.

[0011] (3) Macro data processing: For the Brazilian plate tensile test, the load measurement system records the external load on the ice sample in real time and generates a "force-time" curve; for the uniaxial compression test, the load measurement system and the displacement measurement system work synchronously to generate a stress-strain curve;

[0012] (4) Micro-data analysis

[0013] Synchronized image sequence export: The images captured by the camera during the test are exported as an image sequence at the same frame rate as the test loading data collected by the load measurement system and displacement measurement system, ensuring that each frame of the image is synchronized with the test loading data;

[0014] Select analysis moments: Based on the changes in macroscopic mechanical data, including the "force-time" curve or the "stress-strain" curve, select key moments for analysis; key moments include load peaks and stress mutation points;

[0015] Comprehensive analysis of mesoscopic data.

[0016] Furthermore, the laser line light source is a green laser.

[0017] Furthermore, the method for preparing ice samples is as follows: prepare ice samples with a thickness of no more than 15 mm to obtain better development effects of crystal texture and pore defects; for uniaxial compression tests, cut into rectangular samples not exceeding 100 mm × 100 mm, and polish all cut surfaces to keep them smooth and flat, with two opposite surfaces strictly parallel and two adjacent surfaces strictly perpendicular; for Brazilian disk tests, cut disc-shaped samples from cylindrical ice core samples, polish until the circular planes are smooth and parallel, and the thickness is reduced to less than 10 mm.

[0018] Furthermore, the method of macro data processing is as follows:

[0019] In the Brazilian plate tensile test, the load measurement system records the external load on the ice sample in real time. During the test, the load sensor records the force on the ice sample at different time points during the loading process, generating a "force-time" curve.

[0020] During the uniaxial compression test, the load measurement system and the displacement measurement system work synchronously to record the external load on the ice sample and the compressive displacement of the upper pressure plate in real time; a stress-strain curve is generated for analyzing the mechanical characteristics of the stress peak and fracture point.

[0021] Furthermore, the method for comprehensive analysis of microscopic data is as follows: through polarized light imaging technology, the microscopic information of the crystal particle size and grain boundary characteristics of the ice sample can be obtained; and the addition of laser transmission technology allows the observation results to further observe the bubble distribution inside the ice sample and the characteristics of the brine discharge channel on the basis of crystal characteristics; through comparative analysis of the previous and next frame images, the nucleation position, expansion path and development speed of the crack are accurately observed; through observation of the crack propagation process, the role of grains, grain boundaries and bubble structures in crack generation and expansion is understood; combined with image data, the displacement changes and strain distribution of local areas of the ice sample are analyzed; the local deformation information of the focus area is used to explain the influence of different structural characteristics including grains and pores on local mechanical behavior.

[0022] As a method for synchronous micro- and macro-dynamic observation of the mechanical behavior of ice samples, the present invention has the following advantages:

[0023] 1. Synchronous Data Acquisition: This method ensures a precise correspondence between macroscopic mechanical behavior and microscopic structural changes by simultaneously recording load data and high-definition images. This synchronized observation provides more accurate data support for analyzing the mechanical properties and failure processes of ice.

[0024] 2. Detailed Texture Analysis: Utilizing polarized light transmission technology, this method enables detailed observation of ice crystal structural features, such as particle size and grain boundary characteristics. Utilizing laser transmission technology, this method can visually visualize the distribution of bubbles within the ice sample and the characteristics of brine drainage channels. This detailed structural analysis contributes to a deeper understanding of the influence of ice's internal structure on its macroscopic mechanical behavior.

[0025] 3. Visual Observation of Crack Behavior: Through polarized light and laser transmission techniques, coupled with continuous capture by a high-definition camera, this method allows for the intuitive observation of crack initiation and propagation, as well as their relationship with the microstructure, providing a crucial insight into the failure mechanisms of ice specimens. This is crucial for observing crack nucleation mechanisms and propagation patterns in ice.

[0026] 4. Improved experimental design: By manually selecting key moments for detailed analysis, this method allows researchers to adjust the observation focus according to the purpose and needs of the experiment, thereby exploring the mechanics and failure behavior of ice more flexibly. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is the arrangement of each device during the test.

[0028] Figure 2 This is a diagram showing the effects of the Brazilian disk sample under polarized light development, laser transmission, and the two placed together.

[0029] Figure 3 This is the macro loading force-time curve during the Brazilian disk tensile test.

[0030] Figure 4 This is a photo of the test scene captured during the Brazilian plate tensile test.

[0031] Figure 5 is the macroscopic stress-strain curve of the thin section uniaxial compression test.

[0032] Figure 6 This is a photo of the test scene during the thin slice uniaxial compression test.

[0033] Figure 7 This is a photo of the test scene during the uniaxial compression test of a thicker ice sample.

[0034] In the figure: 1. Stepless dimming backlight; 2. Polarizer a; 3. Upper pressure plate of loading device; 4. Lower pressure plate of loading device; 5. "I"-shaped laser emitter; 6. Ice sample; 7. Polarizer b; 8. High-definition camera. DETAILED DESCRIPTION

[0035] The present invention is described in detail below with reference to examples.

[0036] The measurement equipment used in this method includes a load measurement system and a displacement measurement system. The load measurement system includes a load sensor for measuring the external load on the ice specimen during the test. The displacement measurement system includes displacement sensors distributed on the test machine's upper platen for measuring the displacement of the ice specimen's upper surface during the test. The specific implementation steps are as follows:

[0037] 1. Preparation of Ice Samples

[0038] Prepare thin ice slice samples (no more than 15 mm thick) to obtain better visualization of crystal texture and pore defects. For uniaxial compression tests, first use a cutter to cut an ice sample about 15 mm thick from a larger ice block, and then cut it into rectangular samples no larger than 100 mm × 100 mm. All cut surfaces are polished with sandpaper or a planer to keep them smooth and flat, with the two opposite surfaces strictly parallel and the adjacent surfaces strictly perpendicular. For the Brazilian disk test, a disc-shaped sample about 15 mm thick is cut from a cylindrical ice core sample and polished with sandpaper or a planer until the circular plane is smooth and parallel, and the thickness is reduced to less than 10 mm.

[0039] 2. Placement of the imaging device and microscopic capture

[0040] At the back of the testing machine, a background light source with infinite dimming is set up at a position parallel to the height of the test area. The distance between the light source and the test area should not be greater than 30 cm. Place the prepared ice sample on the testing machine so that its plane is perpendicular to the light emitted by the light source. Then place a polarizer a between the light source and the ice sample, and place a polarizer b on the other side of the ice sample, and make the planes of the two polarized lights parallel to each other. Next, adjust the polarization direction of the polarizer b so that it is perpendicular to the polarization direction of the polarizer a, so as to ensure that the light passing through the polarized light a can hardly pass through the polarizer b after passing through the ice sample. Then place a high-definition camera in front of the polarizer b to capture the interaction between crystals during the loading process. At the same time, place a laser (green line light source) on one side of the ice sample, and adjust the angle of the laser so that the "I" shape emitted by the laser is parallel to the side edge of the ice sample, and the laser's incident position should be exactly half the thickness of the ice sample. The specific arrangement is as follows Figure 1 All of the above operations were performed in a low-temperature darkroom. After placing the above-mentioned developing device, the brightness of the electrodeless light source was adjusted until the ice sample had a good developing effect in the high-definition camera. The developing device was then placed. Note that during each experiment, the polarized light developing device and the laser transmission device can be used separately to investigate the interaction between crystals and the pore mechanical behavior, respectively.

[0041] 3. Macro data processing

[0042] 3.1 Brazilian plate tensile test

[0043] In the Brazilian disk tensile test, in order to simplify the stress state of the disk during loading to a quasi-two-dimensional problem, the diameter of the specimen is usually required to be much larger than its thickness. The tensile stress in the test can be calculated using the following formula:

[0044]

[0045] Among them, F t is the loading force during the Brazilian plate tensile test, D t is the diameter of the Brazilian dish, L t The thickness of the Brazilian dish.

[0046] 3.2 Uniaxial compression test

[0047] When conducting uniaxial compression tests, the testing machine adopts a constant speed (v constant) loading mode, and the macroscopic total strain is obtained through theoretical calculation:

[0048]

[0049] Among them, H c is the initial height of the sea ice sample, and H(t) is the corresponding sample height at time t.

[0050] The strain rate is calculated as follows:

[0051]

[0052] Where Δt is the time interval.

[0053] Calculation of the nominal compressive stress σ during the uniaxial compression test based on the loading force c =F c / A c , where F c is the loading force during uniaxial compression test, A c is the contact area.

[0054] 4. Micro-data analysis

[0055] After completing the test, a key step in the present invention is to process and analyze the microscopic test data to reveal the mechanical behavior and structural changes of the ice sample. This process includes the following technical steps:

[0056] Synchronous export of images and data: First, the test video captured by the HD camera is exported as an image sequence at the same frame rate as the data recorded by the force sensor, ensuring complete synchronization of the image data with the force data.

[0057] Selection and analysis of key moments: Based on the macroscopic force-time curve or stress-strain curve, several moments that require special attention are manually selected. These moments usually correspond to key mechanical events in the test, such as load peaks or mutation points.

[0058] Analysis of Intercrystal Interactions and Porosity: Images taken before and after selected moments are analyzed to observe and record how intercrystal interactions, bubble pores, and brine drainage channels affect the mechanical behavior of the ice specimen. This analysis relies on polarized light and laser transmission imaging, providing detailed information on crystal size, total crystal count, grain boundary characteristics, bubble distribution, and brine channel characteristics. The images of preceding and following frames can also be used to analyze displacement and local strain in key areas of interest.

[0059] Observation of crack behavior: Images obtained through polarized light and laser transmission technology can further observe and analyze the crack nucleation location and its propagation path.

[0060] The test process is further described below in conjunction with the examples.

[0061] Example 1: Brazilian plate tensile test scenario

[0062] 1. Use a microtome to cut a 15mm thick ice disc from the sea ice core. Sand the cut surface of the disc with sandpaper to create a smooth surface. Then, measure the geometric dimensions of the sample and place it on the loading device for preparation.

[0063] 2. According to Figure 1 The configuration shown in the figure adjusts the angle between the two polarized lights, the incident direction of the laser, and the intensity of the backlight source to achieve the best imaging effect, as shown in the figure. Figure 2 The advantage of this configuration is that it provides a certain degree of flexibility: if one only needs to focus on the deformation of the crystal structure, the polarized light imaging system can be used alone; if one only needs to focus on the effects of bubbles and brine pores on mechanical behavior, the laser transmission device can be used alone.

[0064] 3. Apply load to the Brazilian disk sample through the testing machine until the sample cracks. The relationship between macro loading force and time is Figure 3 Based on the maximum force value (655N) and the sample size (90mm diameter, 9mm thickness), the tensile strength of the ice sample can be calculated as 0.51MPa according to Formula 1.

[0065] 4. Analyze the micro-data. Figure 4 The development of the ice sample at several key moments corresponding to the loading curve is shown. Figure 4a shows that before the test, the green highlighted area on the right side of the specimen is more obvious than that on the left side, indicating that there are more bubbles and pores on the right side. Figure 4 b shows that during the loading process, the highlighted area on the right is more obvious, indicating that microcracks begin to form in this area, and obvious green microcracks appear at the contact point between the ice sample and the lower pressure plate, indicating that stress is concentrated here. Figure 4 c is the situation after the sample is broken, showing that although many micro cracks are formed in the right area, the existence of bubbles and pores hinders the expansion of macro cracks to a certain extent, and the final macro crack is along the Figure 4 The extension in the direction of the grain boundary marked in b indicates that during the Brazilian disk test, when the specimen is under tensile stress, the macro crack is more likely to extend in a position parallel to the grain boundary.

[0066] Example 2: Thin slice uniaxial compression test scenario

[0067] 1. First, use a microtome to cut a rectangular ice slice approximately 15 mm thick from the sea ice sample, with a cross-section of 50 mm x 100 mm. Next, use sandpaper to polish the cut surface of the ice slice until it is smooth and flat, and measure its geometric dimensions for subsequent experiments.

[0068] 2. Follow Figure 1 Set up the test device according to the instructions, adjust the polarizer angle of the cross-polarized light, the incident direction of the laser, and the intensity of the backlight to ensure the best imaging effect.

[0069] 3.Use the testing machine to carry out uniaxial compression test, and record the data of load cell and displacement sensor in real time to calculate the macro stress, strain and strain rate of ice sample. The macro stress-strain curve is shown in Figure 5 middle.

[0070] 4. After the test, select key time points for microscopic data analysis, such as stress mutation points and peak points during the rising period of the stress-strain curve. Figure 6 a shows the imaging effect of the ice sample under polarized light and laser transmission before the experiment. As the experiment progresses, Figure 6 b shows microcracks appearing at a recrystallization site; these cracks originate from the pore-dense locations and propagate along the brine drainage channels inside the crystal parallel to the loading direction, as shown in Figure 2. Figure 6 c. At this time, the generation of macro cracks causes a sudden drop in stress in the stress-strain curve. When loading continues, Figure 6 d shows that a new microcrack has been initiated at the triple grain boundary, but due to the obstruction of the crystal grain boundary below, the crack failed to develop downward. Figure 6 The highlighted area in e indicates that a large number of microcracks were generated on the right half of the specimen. Figure 6In figure f, these highlighted areas eventually formed macro cracks that crossed multiple grain boundaries, and the stress reached its peak at this time. Although the sample was not completely damaged in the subsequent process and still had a certain bearing capacity, this was mainly due to the loading strain rate of 5×10 -4 s -1 , the main deformation of ice sample is creep.

[0071] Example 3: Thick specimen uniaxial compression test scenario

[0072] For thicker sea ice samples, cross-polarized light cannot be used for visualization due to their physical properties. However, the effect of porosity can be analyzed using laser transmission technology. The procedures for steps 1 to 3 are similar to those in Example 2 and will not be described in detail here.

[0073] This example focuses on describing the simultaneous changes in macroscopic experimental phenomena and microscopic pore structure. The initiation and concentration of microcracks were first observed in the brine pores within the crystals and the bubble pores between the crystals. The formation of these microcracks is manifested in the specimen as enhanced green light development areas, such as Figure 7 a and Figure 7 As shown in Figure 2b, the developed area of ​​the latter is significantly increased compared to the former. The green and bright white developed areas represent the microcracks in the brine pores and bubble pores, respectively. As the stress increases, the microcracks continue to expand, cross and eventually form macrocracks, as shown in Figure 2b. Figure 7 c. The area marked by the red arrow in this figure shows a significant difference in laser transmittance, indicating the presence of macrocracks. The formation path of these cracks is hindered by microcracks in multiple directions, showing an uneven crack interface. Figure 7 The area marked by the white arrow in c shows the ductile damage area formed by the expansion of microcracks caused by brine pores. Before the formation of macrocracks, the stress reaches the maximum value, marking the maximum uniaxial compressive strength of the sea ice sample at this strain rate. Then the stress-strain curve enters the descending stage. After the formation of macrocracks, the local area of ​​the sample produces slip and dislocation along the crack interface, resulting in a significant expansion of the sample in the lateral direction, as shown in Figure 2. Figure 7 As shown in d.

[0074] The micro-macroscopic dynamic synchronous observation method of the mechanical behavior of ice samples of the present invention can realize the synchronous monitoring of the macroscopic mechanical properties of sea ice and the microscopic crystal interaction process and the deformation process of pore defects, and can be used for research on the mechanical properties of sea ice.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the operating procedures of the present invention. It should be pointed out that for ordinary technicians in this field, without departing from the essence of the principles and technical solutions of the present invention, they can still improve the technical solutions of the present invention or make equivalent replacements for some of the technical features therein. These improvements and replacements should also be regarded as the scope of protection of the present invention.

Claims

1. A method for synchronous micro- and macroscopic dynamic observation of the mechanical behavior of an ice sample, comprising measurement equipment including a load measurement system, a displacement measurement system, and a microscopic imaging system; the load measurement system including a load sensor for measuring the external load applied to the ice sample during the test; the displacement measurement system including a displacement sensor disposed on a platen on a testing machine for measuring the displacement of the upper surface of the ice sample during the test; and the microscopic imaging system including a camera, a background light source with adjustable brightness, a polarizer, and a laser line light source for displaying microscopic structural information of the ice sample on the recording device. The method comprises the following steps: (1) Preparation of ice samples; (2) Placement of microscopic imaging system and microscopic capture Set up a steplessly dimming background light source at the rear of the testing machine, at a position highly parallel to the test area, with the distance between the background light source and the test area no greater than 30 cm. Place the prepared ice sample on the testing machine so that its plane is perpendicular to the light emitted by the background light source. Place polarizer a between the background light source and the ice sample, and polarizer b on the other side of the ice sample, with the planes of the two polarizers parallel to each other. Adjust the polarization direction of polarizer b so that it is perpendicular to the polarization direction of polarizer a. Place a camera in front of polarizer b. Place a laser line light source on one side of the ice sample and adjust the angle of the laser line light source so that the "I"-shaped light beam it emits is parallel to the side edge of the ice sample; and the laser line light source is incident at a position half the thickness of the ice sample. During each test, either the background light source alone, the laser line light source alone, or both light sources are used simultaneously. (3) Macro data processing: For the Brazilian disk tensile test, the external load on the ice sample is recorded in real time through the load measurement system; Generate a "force-time" curve; for uniaxial compression tests, the load measurement system and displacement measurement system work synchronously to generate a stress-strain curve; (4) Micro-data analysis Synchronized image sequence export: The images captured by the camera during the test are exported as an image sequence at the same frame rate as the test loading data collected by the load measurement system and displacement measurement system, ensuring that each frame of the image is synchronized with the test loading data; Select analysis moments: Based on the changes in macroscopic mechanical data, including "force-time" curves or "stress-strain" curves, select key moments for analysis; Critical moments include load peaks and stress mutation points; Comprehensive analysis of mesoscopic data.

2. The method for synchronous micro- and macroscopic dynamic observation of the mechanical behavior of ice samples according to claim 1 is characterized in that: The laser line light source is a green laser.

3. The method for synchronous micro- and macroscopic dynamic observation of the mechanical behavior of ice samples according to claim 1 is characterized in that: The ice sample preparation method is as follows: prepare ice samples with a thickness of no more than 15 mm to obtain better visualization of crystal texture and pore defects; for uniaxial compression tests, cut into rectangular samples no larger than 100 mm × 100 mm, and polish all cut surfaces to maintain smoothness and flatness, with two opposing surfaces strictly parallel and two adjacent surfaces strictly perpendicular; for Brazilian disk tests, cut disc-shaped samples from cylindrical ice core samples, polish until the circular surfaces are smooth and parallel, and reduce the thickness to less than 10 mm.

4. The method for synchronous micro- and macroscopic dynamic observation of the mechanical behavior of ice samples according to claim 1 is characterized in that: The method of macro data processing is as follows: In the Brazilian plate tensile test, the load measurement system records the external load on the ice sample in real time. During the test, the load sensor records the force on the ice sample at different time points during the loading process, generating a "force-time" curve. In the uniaxial compression test, the load measurement system and the displacement measurement system work synchronously to record the external load of the ice sample and the compression displacement of the upper platen in real time; Generate stress-strain curves for analyzing the mechanical characteristics of stress peaks and fracture points.

5. The method for synchronous micro- and macroscopic dynamic observation of the mechanical behavior of ice samples according to claim 1 is characterized in that: The method for comprehensive analysis of microscopic data is as follows: through polarized light imaging technology, the microscopic information of the crystal particle size and grain boundary characteristics of the ice sample can be obtained; and the addition of laser transmission technology allows the observation results to further observe the bubble distribution inside the ice sample and the characteristics of the brine discharge channel on the basis of crystal characteristics; through comparative analysis of the previous and next frame images, the nucleation position, expansion path and development speed of the crack are accurately observed; through observation of the crack propagation process, the role of grains, grain boundaries and bubble structures in crack generation and expansion is understood; combined with image data, the displacement changes and strain distribution of local areas of the ice sample are analyzed; the local deformation information of the focus area is used to explain the influence of different structural characteristics, including grains and pores, on the local mechanical behavior.

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