A method and system for preparing a gradient freeze-thaw simulation material

Abstract

The application discloses a kind of preparation method and system of gradient freeze-thaw simulation material, the method is first according to simulation demand to determine target gradient parameter;Then design and prepare by base material, phase change material, heat conduction enhancer and moisture regulator constitute multilayer composite material, by adjusting each layer component to form phase change temperature, heat conduction performance and the controllable gradient of water content in material interior;Finally, the gradient material sample of assembled good cooperates with the preset gradient temperature control program, drives sample to occur non-uniform freeze-thaw.The application overcomes the defect that traditional homogeneous material cannot simulate freeze-thaw gradient effect in nature, realizes the high-precision, high-efficiency reproduction of temperature field, moisture field coupling, simulation error is small (≤±1.5 DEG C), and can be widely applied to frozen soil engineering, slope stability, environmental migration and agricultural freeze damage prevention and other fields of physical model test.

Description

Technical Field

[0001] This invention belongs to the technical field of remote sensing inversion method for soil organic matter layer thickness based on hybrid model, and relates to a method and system for preparing gradient freeze-thaw simulation material, particularly to a method for preparing gradient freeze-thaw simulation material for laboratory physical model experiments that can accurately simulate non-uniform freeze-thaw processes in nature, and a gradient freeze-thaw simulation system therewith. Background Technology

[0002] In fields such as geotechnical engineering, geological engineering, environmental engineering, and agricultural science, it is crucial to study the changes in the physical and mechanical properties of materials (such as soil, rock, and concrete) under freeze-thaw cycles. For example, freeze-thaw cycles are a major factor leading to roadbed settlement, slope instability, canal lining damage, and soil pollutant migration in cold regions.

[0003] Currently, homogeneous materials are commonly used in laboratory freeze-thaw cycle tests. The method typically involves alternating freezing and thawing of prepared homogeneous samples in a constant-temperature freezer and oven (or water bath). However, this method has significant drawbacks: It cannot simulate gradient effects: Natural freeze-thaw processes exhibit significant spatiotemporal inhomogeneity (gradient effects), such as temperature gradients, moisture migration gradients, and freeze-thaw rate gradients from the surface to deeper layers of soil. Traditional homogeneous materials and the "whole-body freeze-thaw" model cannot fully reproduce this complex gradient process, leading to significant deviations between experimental results and actual conditions. Material properties are uncontrollable: Existing simulated materials have fixed phase transition temperature ranges and uniform physical properties. Researchers find it difficult to flexibly adjust the distribution of freeze-thaw characteristics according to specific experimental objectives (such as simulating freeze-thaw differences at different depths and in different regions). Experimental efficiency is low and results in distortion: Traditional methods require manual transfer of samples between different devices, which is cumbersome, has low automation, and makes continuous gradient temperature control and data acquisition difficult. More importantly, it severs the coupling between the temperature field and the moisture field, making it impossible to simulate the key physical process of "moisture migration driven by temperature gradient." Therefore, there is an urgent need for a material preparation and testing method and system that can simulate complex gradient freeze-thaw processes with high precision and efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a method and system for preparing gradient freeze-thaw simulation materials. This method can achieve a controllable gradient distribution of freeze-thaw properties (such as phase change temperature, thermal conductivity, and water content) within the material, and can work in conjunction with an automated temperature control program to reproduce the non-uniform freeze-thaw process in the natural environment with high fidelity. The system can be adapted to this preparation method to achieve precise temperature control and data acquisition, ensuring the reliability and efficiency of the simulation experiment.

[0005] According to the purpose of this invention, a method for preparing a gradient freeze-thaw simulation material is provided, comprising the following steps: S1: Determine the gradient freeze-thaw parameters of the target simulation object. The parameters include at least the temperature gradient distribution, the number of freeze-thaw cycles, and the target phase change temperature and initial moisture content at different locations. S2: Based on the aforementioned gradient freeze-thaw parameters, design a formulation for a multilayer composite material to give different layers or regions of material differentiated physical properties in order to construct a physical property gradient; the physical properties include at least phase transition temperature, thermal conductivity, and initial moisture content; S3: Prepare materials for each layer or region according to the formula designed in S2, and assemble them according to the preset gradient direction to form an integral sample with a gradient structure. S4: Apply a gradient temperature control program that matches the gradient freeze-thaw parameters to the overall sample to drive a non-uniform freeze-thaw process inside the sample as expected.

[0006] Furthermore, in S2, the composite material includes a matrix material, a phase change material, a thermal conductivity enhancer, and a moisture regulator; the differentiated physical properties are achieved by adjusting the proportions of each component in the material.

[0007] Furthermore, the matrix material is selected from one or more of quartz sand, kaolin, bentonite, remolded soil, or natural soil.

[0008] Furthermore, the phase change material is selected from one or more of paraffin, fatty acids, salt water solution or ethylene glycol solution, and is used to precisely control the phase change temperature point of the material layer.

[0009] Furthermore, the thermal conductivity enhancer is selected from one or more of graphite powder, metal powder, or carbon fiber, and is used to adjust the thermal conductivity rate of the material layer.

[0010] Furthermore, the moisture regulator is a water-retaining agent or a water-repellent agent, used to control the moisture migration characteristics and retention capacity of the material layer.

[0011] Furthermore, in S3, when assembling different layers of materials, an insulating layer is laid between the layers to prevent material mixing but allow moisture to pass through.

[0012] Furthermore, the isolation layer is geotextile or a permeable filter.

[0013] Furthermore, the gradient direction can be a vertical gradient, a horizontal gradient, or a three-dimensional spatial gradient.

[0014] According to another objective of the present invention, the present invention provides a gradient freeze-thaw simulation system for implementing the above-described method, comprising: Composite material specimens with gradient structures; A multi-channel independent temperature control device is used to apply different temperature change programs to different positions of the sample; A data acquisition system is used to monitor in real time one or more of the following parameters: temperature, moisture content, and deformation parameters at different locations of the sample.

[0015] The beneficial effects of this invention are: The gradient freeze-thaw simulation material and supporting system prepared by this invention can accurately reproduce the gradient effect of freeze-thaw cycles in nature, with a temperature field simulation error of ≤±1.5℃. The material gradient distribution can be customized as needed, making it suitable for various fields such as frozen soil engineering, cold-region roadbed research, and agricultural frost damage prevention. The integrated material preparation and temperature control scheme significantly reduces manual operation, lowers experimental time by approximately 40%, and the amount of data collected in a single experiment is equivalent to 3-5 times that of traditional methods. Simultaneously, this invention achieves the coupling of the temperature field and the moisture field, simulating the key process of temperature gradient-driven water migration towards the freezing front, making the experimental results more closely resemble real natural conditions. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the gradient freeze-thaw simulation material (vertical gradient) of the present invention; Figure 2 This is a flowchart illustrating the preparation process of the gradient freeze-thaw simulation material of the present invention. Figure 3 This is a schematic diagram of the integrated gradient temperature control system applied to the present invention; Figure 4 This is a schematic diagram of the freeze-thaw cycle of a traditional homogeneous material. Figure 5 This is a schematic diagram of the freeze-thaw process of the gradient material of the present invention. Detailed Implementation

[0017] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0018] Example 1 like Figure 2 As shown, a method for preparing a gradient freeze-thaw simulation material includes the following steps: S1: Determine the gradient freeze-thaw parameters of the target simulation object. The parameters include at least the temperature gradient distribution, the number of freeze-thaw cycles, and the target phase change temperature and initial moisture content at different locations. S2: Based on the aforementioned gradient freeze-thaw parameters, design a formulation for a multilayer composite material to give different layers or regions of material differentiated physical properties in order to construct a physical property gradient; the physical properties include at least phase transition temperature, thermal conductivity, and initial moisture content; S3: According to the formula designed in S2, prepare materials for each layer or region separately, and assemble them according to the preset gradient direction to form an integral sample with a gradient structure; S4: Apply a gradient temperature control program that matches the gradient freeze-thaw parameters to the overall sample to drive a non-uniform freeze-thaw process inside the sample as expected.

[0019] Specifically, in S2, the composite material includes a matrix material, a phase change material, a thermal conductivity enhancer, and a moisture regulator; the differentiated physical properties are achieved by adjusting the proportions of each component in the material.

[0020] The matrix material is selected from one or more of the following: quartz sand, kaolin, bentonite, remolded soil, or natural soil.

[0021] The aforementioned phase change material is selected from one or more of paraffin wax, fatty acids, saline solution, or ethylene glycol solution.

[0022] The aforementioned thermal conductivity enhancer is selected from one or more of graphite powder, metal powder, or carbon fiber.

[0023] The aforementioned moisture regulator is either a water-retaining agent or a water-repellent agent. The water-retaining agent is sodium polyacrylate, and the water-repellent agent is silicone oil.

[0024] In S3, when assembling different layers of materials, an insulating layer is laid between the layers to prevent material mixing but allow moisture to pass through.

[0025] The aforementioned isolation layer is geotextile or permeable filter mesh; the gradient direction is a vertical gradient, a horizontal gradient, or a three-dimensional spatial gradient.

[0026] A gradient freeze-thaw simulation system includes: a composite material sample with a gradient structure, prepared by the above-described preparation method; a multi-channel independent temperature control device for applying different temperature change programs to different locations of the sample; and a data acquisition system for real-time monitoring of one or more of the following parameters: temperature, moisture content, and deformation parameters at different locations of the sample.

[0027] Specifically, the multi-channel independent temperature control device includes multiple independent temperature control elements and a central program controller. The independent temperature control elements are electrically connected to the central program controller, which is used to set and execute gradient temperature control programs.

[0028] The independent temperature control element is a cooling / heating plate or a temperature control probe, which is arranged on the outer side of different layers or different areas of the sample. The data acquisition system includes multiple sensors and a data recording module. The sensors are electrically connected to the data recording module for real-time acquisition and storage of monitoring data.

[0029] The sensors include a temperature sensor, a moisture content sensor, and a deformation sensor, which are deployed at different locations on the central region or surface of the sample. The multi-channel independent temperature control device interacts with the data acquisition system via a connection cable, and the central program controller integrates a display screen for real-time display of temperature control parameters and monitoring data.

[0030] Example 2 Preparation and testing of vertical gradient materials for simulating freeze-thaw frost heave in cold-region roadbeds Target gradient parameters were determined as follows: The simulation covered a 0-1m area below the roadbed surface layer, undergoing 5 freeze-thaw cycles, with a fast freezing rate at the surface and a slower rate at deeper layers. The temperature gradient distribution ranged from -15℃ at the surface layer to +8℃ at the bottom layer. The target phase change temperatures for each layer were: -2℃ at the surface layer, -1℃ at the second layer, -0.5℃ at the third layer, and no phase change at the bottom layer (simulating the unfrozen area). The initial moisture contents were 8% at the surface layer, 10% at the second layer, 12% at the third layer, and 15% at the bottom layer.

[0031] Gradient material formulation design: A four-layer vertical gradient structure is designed, and the matrix material is all selected from standard quartz sand; Layer 1 (0-20cm, surface layer): 5% by mass of low-melting-point paraffin (phase transition point -2℃) and 1% by mass of graphite powder (thermal conductivity enhancer) are added, with an initial moisture content of 8%; Layer 2 (20-50cm): Add 4% by mass of paraffin wax with a phase transition point of -1℃ and 0.5% by mass of graphite powder, with an initial moisture content of 10%; Layer 3 (50-80cm): Add 3% by mass of fatty acids with a phase transition point of -0.5℃, with an initial water content of 12%; Layer 4 (80-100cm, bottom layer): No phase change material added, initial moisture content 15%, with 0.3% sodium polyacrylate (water retention agent, moisture regulator) added by mass.

[0032] Gradient material layer preparation and assembly: Mix each layer of material according to the above formula, and control the compaction degree to be 95% consistent; fill layer 4 to layer 1 from bottom to top in a cylindrical mold (diameter 10cm, height 100cm), compact each layer after filling, and lay geotextile (isolation layer) between layers to ensure that the layers do not mix and allow moisture migration.

[0033] Deployment and trial operation of the gradient freeze-thaw simulation system: The assembled whole sample is placed in a multi-channel independent temperature-controlled environment chamber. Temperature / moisture sensors (data acquisition system components) are placed at the center of each layer of the sample, and independent temperature control elements (multi-channel independent temperature control device components) are placed on the outside of each layer. The sensors and temperature control elements are connected to the central program controller through connecting wires. A gradient temperature control program was set: the surface temperature cyclically changed between -15℃ and +10℃, with a single freezing time of 8 hours and a thawing time of 4 hours, and a temperature change rate of 5℃ / h; the second layer temperature cyclically changed between -10℃ and +12℃, with a freezing time of 10 hours and a thawing time of 4 hours, and a temperature change rate of 3℃ / h; the third layer temperature cyclically changed between -5℃ and +15℃, with a freezing time of 12 hours and a thawing time of 4 hours, and a temperature change rate of 2℃ / h; the bottom layer temperature fluctuated between +2℃ and +8℃, with no obvious freezing process; Five freeze-thaw cycles were run, and the temperature, moisture content and vertical deformation of each layer of the sample were monitored in real time through the data acquisition system. Data was recorded every 30 minutes.

[0034] Test results: The simulation error of temperature field in each layer is ≤ ±1.2℃, the amount of moisture migration conforms to the actual freeze-thaw law of roadbed in cold regions, the maximum deformation of the sample surface is 3.2mm, and the deviation from the field measured data is ≤8%, accurately reproducing the core process of freeze-thaw frost heave in roadbeds in cold regions.

[0035] Example 3 Preparation and testing of horizontal gradient materials to simulate freeze-thaw differences in different slope orientations Target gradient parameters were determined: the freeze-thaw difference between sunny and shady slopes in mountainous areas was simulated, with the gradient direction being horizontal; the freeze-thaw cycle number was 3 times, the target phase change temperature on the shady slope (left side) was -0.5℃ and the initial moisture content was 18%, and the target phase change temperature on the sunny slope (right side) was -3℃ and the initial moisture content was 12%; the temperature gradient distribution was from -8℃ on the left side to -15℃ on the right side, with the freezing duration on the left side being 50% longer than that on the right side.

[0036] Gradient material formulation design: Prepare long strip samples (80cm in length, 10cm in width, and 20cm in height). The matrix material is a mixture of kaolin and bentonite in a mass ratio of 4:1. Left side region (0-40cm, simulated shady slope): Add 6% by mass of fatty acid with a phase change point of -0.5℃ (phase change material), no thermal conductivity enhancer added, initial moisture content 18%, add 0.2% by mass of silicone oil (hydrophobic agent, moisture regulator). The right-side area (40-80cm, simulated sunny slope) is filled with 5% by mass of a salt solution (phase change material) with a phase change point of -3℃ and 1.5% by mass of metal powder (thermal conductivity enhancer). The initial moisture content is 12%, and no moisture regulator is added.

[0037] Gradient material layer preparation and assembly: Mix the materials on the left and right sides according to the formula and control the compaction degree to 93%; fill the rectangular mold in sections, and lay a permeable filter screen (isolation layer) at the junction of the left and right areas; after filling, compact the whole to ensure the integrity of the sample structure.

[0038] Deployment and trial operation of the gradient freeze-thaw simulation system: Independent cooling / heating plates (multi-channel independent temperature control device components) are arranged on the left and right sides of the sample. Temperature / moisture sensors and deformation monitoring points (data acquisition system components) are arranged every 10 cm along the horizontal direction inside the sample and connected to the central program controller. Set the gradient temperature control program: apply a cycle of "-8℃ freezing for 12 hours → +5℃ thawing for 6 hours" to the left cooling / heating plate, and apply a cycle of "-15℃ freezing for 8 hours → +5℃ thawing for 6 hours" to the right cooling / heating plate, and run 3 cycles continuously; The temperature, moisture content, and horizontal deformation of each monitoring point in the horizontal direction are monitored in real time by a data acquisition system to analyze the impact of the freeze-thaw difference between sunny and shady slopes on slope stability.

[0039] Experimental results: The phase change process on both sides is consistent with the target simulation scenario. The temperature field simulation error is ≤ ±1.5℃. The water migration distance on the shady slope side is 40% longer than that on the sunny slope side. The horizontal deformation difference reaches 2.1mm. It accurately reflects the freeze-thaw difference law of different slope orientations and provides reliable physical model data for slope stability analysis.

[0040] Example 4 like Figure 1 The diagram shown is a structural schematic of the gradient freeze-thaw simulation material (vertical gradient) of this invention. Figure 1 This visually demonstrates the cross-sectional structure of the core material—a multilayer composite sample with controllable physical property gradients—and illustrates how performance gradients can be achieved through layered design.

[0041] Figure 1 In the middle, 101: the outer wall contour of the sample mold or container.

[0042] 102-1, 102-2, 102-3, 102-4, ..., 102-n: These represent material layers with different physical properties. The composition ratio of each layer (102-x) is independently designed to achieve, for example, a higher phase transition temperature and lower thermal conductivity for layer 102-1 (top layer), and a lower phase transition temperature and higher thermal conductivity for layer 102-n (bottom layer). These differences are illustrated in the diagram using different fill patterns.

[0043] 103: Schematic line for interlayer isolation layer (such as geotextile, filter screen). Its function is to prevent mechanical mixing of interlayer materials with different proportions during the test, while allowing moisture to migrate under gradient drive.

[0044] 104: Vertical gradient indicator arrow. Indicates the material's physical properties (such as phase transition temperature, thermal conductivity, initial moisture content) and the resulting freeze-thaw rate, showing a continuous or stepwise change along the direction of this arrow (usually the depth direction).

[0045] like Figure 3 The diagram shown is a schematic of the integrated gradient temperature control system of the present invention, used to demonstrate the driving mechanism. Figure 1 The diagram illustrates the core control system for the freeze-thaw process of gradient materials. It demonstrates how this invention achieves precise response to the material gradient and reproduces the complex natural freeze-thaw process through "multi-channel independent temperature control" and "centralized program control."

[0046] Figure 3 In the middle: 301: Gradient material sample placed inside the box (i.e. Figure 1 (The structure shown).

[0047] 302-1, 302-2, 302-3, 302-4, 302-5...: Temperature / Moisture / Deformation Sensors. They are embedded or attached to different depths or positions of the sample (302) (corresponding to different material layers 102-x) to monitor the state parameters of each point in real time and feed the signals back to the controller (305).

[0048] 303-1, 303-2, 303-3, 303-4, 303-5, ...: Independent temperature control elements (such as semiconductor cooling chips, heating rods, circulating liquid plates). They are used to heat or cool different areas of the sample, and receive independent commands from the controller (305), thereby creating a non-uniform temperature field inside the sample.

[0049] 304: Central Program Controller. It is the brain of the system, with a built-in preset gradient temperature control program.

[0050] 305: Controller display screen. Used to display multiple independent temperature-time curves, either preset or measured. Each curve corresponds to a sensor (303-x) and a temperature control element (304-x), visually demonstrating "zoned independent control".

[0051] 306: System connection line. This indicates that the signal feedback line of the sensor (303) and the control signal line of the temperature control element (304) together form a closed-loop control system.

[0052] like Figure 4 and Figure 5 The diagram illustrates a comparison of the freeze-thaw process between the conventional method and the method of this invention. The side-by-side comparison reveals the fundamental advancements and technical effects of this invention compared to conventional techniques. It addresses the shortcoming of the prior art in "failing to simulate gradient effects."

[0053] Figure 4 In traditional methods: 401a: Homogeneous material sample, whose internal physical properties are the same throughout.

[0054] 402a: The front freezes at time t1, forming a horizontal straight line, indicating that the front moves down evenly and smoothly.

[0055] 403a: The melting front at time t2 also forms a horizontal straight line, indicating that the melting is equally uniform.

[0056] This indicates that traditional homogeneous materials can only produce simple, uniform freeze-thaw processes and cannot simulate the non-homogeneity of nature.

[0057] Figure 5 The method of this invention: 401b: Gradient material specimen (internal layering is shown by different filling patterns).

[0058] 402b: The freezing front at time t1 is a downward-curving curve. Its shape indicates that the freezing rate differs in layers with different material properties (e.g., it penetrates deeper in layers with high thermal conductivity).

[0059] 403b: The melting front at time t2 shows an upward-curving curve, and its shape differs from that of 402b. This indicates that the melting process is also non-uniform, and the influence of the material gradient differs from that of the freezing process.

[0060] The gradient material and collaborative control system of the present invention can actively generate non-uniform freeze-thaw fronts that match the material gradient, thereby faithfully reproducing the real processes in nature.

[0061] In summary, this invention achieves accurate reproduction of freeze-thaw rate, phase change temperature and moisture migration gradient through the coordinated design of material ratio and temperature control program. The overall temperature field simulation error can be controlled within ≤±1.5℃ (the error of traditional methods is usually ≥±5℃). This invention has high flexibility and scalability. The gradient distribution of materials (vertical, horizontal or complex three-dimensional) can be customized according to experimental needs, and it is widely applicable to research in many fields such as frozen soil slope stability, cold region roadbed deformation, agricultural soil freezing damage, and freeze-thaw damage of building components. This invention can significantly improve experimental efficiency. The integrated material preparation and temperature control scheme reduces the frequent manual sample transfer and parameter reset in traditional methods. A single experiment can complete the data acquisition of 3-5 cycles of traditional methods, and the overall experimental time is reduced by about 40%. The method of this invention can naturally couple the temperature field and the moisture field to simulate the core physical process of "temperature gradient driving moisture to migrate to the freezing front", making the experimental results closer to real natural conditions. The system of this invention has strong adaptability. The matching gradient freeze-thaw simulation system can accurately match the characteristics of gradient materials. Multi-channel independent temperature control ensures the stable application of the gradient temperature field. The data acquisition system realizes real-time monitoring of key parameters, providing comprehensive data support for experimental analysis.

[0062] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a gradient freeze-thaw simulation material, characterized in that, Includes the following steps: S1: Determine the gradient freeze-thaw parameters of the target simulation object. The parameters include at least the temperature gradient distribution, the number of freeze-thaw cycles, and the target phase change temperature and initial moisture content at different locations. S2: Based on the aforementioned gradient freeze-thaw parameters, design a formulation for a multilayer composite material to give different layers or regions of material differentiated physical properties in order to construct a physical property gradient; the physical properties include at least phase transition temperature, thermal conductivity, and initial moisture content; S3: Prepare materials for each layer or region according to the formula designed in S2, and assemble them according to the preset gradient direction to form an integral sample with a gradient structure. S4: Apply a gradient temperature control program that matches the gradient freeze-thaw parameters to the overall sample to drive a non-uniform freeze-thaw process inside the sample as expected.

2. The method for preparing gradient freeze-thaw simulation material according to claim 1, characterized in that, In S2, the composite material includes a matrix material, a phase change material, a thermal conductivity enhancer, and a moisture regulator; the differentiated physical properties are achieved by adjusting the proportions of each component in the material.

3. The method for preparing gradient freeze-thaw simulation material according to claim 2, characterized in that, The matrix material is selected from one or more of the following: quartz sand, kaolin, bentonite, remolded soil, or natural soil.

4. The method for preparing gradient freeze-thaw simulation material according to claim 2, characterized in that, The phase change material is selected from one or more of paraffin wax, fatty acids, salt water solution or ethylene glycol solution, and is used to precisely control the phase change temperature point of the material layer.

5. The method for preparing gradient freeze-thaw simulation material according to claim 2, characterized in that, The thermal conductivity enhancer is selected from one or more of graphite powder, metal powder, or carbon fiber, and is used to adjust the thermal conductivity rate of the material layer.

6. The method for preparing gradient freeze-thaw simulation material according to claim 2, characterized in that, The moisture regulator is a water-retaining agent or a water-repellent agent, used to control the moisture migration characteristics and retention capacity of the material layer.

7. The method for preparing gradient freeze-thaw simulation material according to claim 1, characterized in that, In S3, when assembling different layers of materials, an insulating layer is laid between the layers to prevent material mixing but allow moisture to pass through.

8. The method for preparing gradient freeze-thaw simulation material according to claim 7, characterized in that, The isolation layer is geotextile or permeable filter mesh.

9. The method for preparing gradient freeze-thaw simulation material according to claim 1, characterized in that, The gradient direction can be a vertical gradient, a horizontal gradient, or a three-dimensional spatial gradient.

10. A gradient freeze-thaw simulation system for implementing the method according to any one of claims 1-9, characterized in that, include: Composite material specimens with gradient structures; A multi-channel independent temperature control device is used to apply different temperature change programs to different positions of the sample; A data acquisition system is used to monitor in real time one or more of the following parameters: temperature, moisture content, and deformation parameters at different locations of the sample.

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