A Design Method for Freeze-Thaw Sensitive Composite Materials for 3D Printing

Abstract

The present invention provides a design method for a freeze-thaw sensitive composite material for 3D printing, comprising the following steps: S1, selecting matrix materials with different thermal conductivity coefficients, thermal expansion coefficients, and specific heat capacities; S2, incorporating microcapsule phase change materials with different phase change temperatures and latent heat values into the matrix materials; S3, selecting to add reinforcing fibers to change the cementing effect between the matrix materials; S4, determining 3D printing process parameters, where the 3D printing process parameters include layer thickness, filling density, and temperature; S5, arranging and combining according to different matrix materials, microcapsule phase change materials, and reinforcing fibers and their ratios, manufacturing corresponding freeze-thaw sensitive composite materials through 3D printing with different process parameters, conducting corresponding physical and mechanical property tests, establishing a freeze-thaw sensitivity-process-property database based on the physical and mechanical property test results, and obtaining the mapping relationship between different parameters for subsequent further material development.

Description

Technical Field

[0001] The present invention relates to the technical field of geotechnical engineering, and particularly relates to a design method for a freeze-thaw sensitive composite material for 3D printing. Background Art

[0002] The infrastructure construction in alpine regions of our country is increasing day by day, and the projects often face the complex environment of frozen and thawed rock and soil masses. Under the action of freeze-thaw cycles, the mechanical properties of rock and soil masses often change significantly, showing problems such as strength reduction and increased permeability. These changes directly affect the stability of rock and soil masses and the safety of engineering structures. Therefore, in-depth study of the behavior of rock and soil masses in alpine regions under different environmental conditions is of great significance for engineering construction, especially to provide guarantee for key infrastructure construction projects in alpine regions.

[0003] Traditional testing methods include in-situ testing and laboratory tests. However, in-situ testing is often time-consuming and laborious, and there are also many difficulties in sampling for laboratory tests, and the repeatability of test results cannot be achieved. For this reason, using 3D printing technology to produce similar substitutes to simulate rock and soil masses in alpine regions for laboratory tests has become an effective alternative. However, the existing conventional 3D printing technology and its materials have not been able to fully reproduce the complex mechanical properties of rock and soil masses, and it is even more difficult to accurately reflect the influence of freeze-thaw cycles on their performance.

[0004] Therefore, the technical problem to be solved urgently at present is how to solve the limitations of current materials and technologies, and by designing a freeze-thaw sensitive composite material for 3D printing to simulate the thermal response of real rock and soil masses, so as to achieve more accurate simulation and performance testing of rock and soil masses under freeze-thaw cycles. Summary of the Invention

[0005] The present invention is made to solve the above problems, and the purpose is to provide a design method for a freeze-thaw sensitive composite material for 3D printing.

[0006] The present invention provides a design method for a freeze-thaw sensitive composite material for 3D printing, which has the following characteristics. Specifically, it includes the following steps: S1. Select matrix materials with different thermal conductivity coefficients, thermal expansion coefficients, and specific heat capacities to simulate the granular skeleton of rock and soil masses, match the thermal responses at different freeze-thaw cycle stages, increase the basic controllability of the freeze-thaw response, use the thermal conductivity coefficient to control heat transfer during the freeze-thaw process, induce controllable microcracks by the difference in thermal expansion coefficients to simulate frost heaving stress, and adjust the absorption of phase change energy by the difference in specific heat capacities, so as to achieve dynamic matching of different freeze-thaw cycle stages and enhance the response accuracy of the material to temperature field changes; S2. Incorporate microcapsule phase change materials with different phase change temperatures and latent heat values into the matrix material, and form a thermal response field with different spatial gradient distributions through the interfacial thermal resistance regulation of the microcapsule wall material to further simulate the water-ice phase change process; S3. Select and add reinforcing fibers to change the cementation effect between the matrix materials, and use them to regulate the strength and freeze-thaw durability of the freeze-thaw sensitive composite material, match the response of the physical and mechanical properties of the material to freeze-thaw, the reinforcing fibers are used to optimize the cementation effect and stress transfer path of the matrix material, suppress the expansion of freeze-thaw cracks through the bridging effect, achieve the coordinated control of strength and freeze-thaw durability, and match the progressive mechanical attenuation law of the material during the freeze-thaw cycle; S4. Determine the 3D printing process parameters, and the 3D printing process parameters include layer thickness, filling density, and temperature. By adjusting the layer thickness and filling density, an artificial pore network is constructed, and by adjusting the temperature, different phase change temperatures and thermal parameters are matched. Through systematic research on the relationship between the printing process parameters and the material properties, the parameter combination can be further optimized to balance the printing efficiency, material properties, and cost, and ensure that the final requirements of specific applications are met; S5. Arrange and combine different matrix materials, microcapsule phase change materials, and reinforcing fibers and their ratios, and fabricate the corresponding freeze-thaw sensitive composite materials through 3D printing with different process parameters, and conduct corresponding physical and mechanical property tests. The physical and mechanical property tests include uniaxial compressive strength, permeability coefficient, and freeze-thaw durability tests. Establish a freeze-thaw sensitivity - process - property database based on the physical and mechanical property test results, and obtain the mapping relationship between different parameters for subsequent further material development.

[0007] In the design method for a freeze-thaw sensitive composite material for 3D printing provided by the present invention, it may also have the following characteristics: Among them, the matrix material has a certain strength and processability, and has different thermal conductivity coefficients, thermal expansion coefficients, and specific heat capacities, and can form an effective composite material with other components. The matrix materials include polylactic acid, photocurable resin, and silicate cementitious materials.

[0008] In the design method of the freeze-thaw sensitive composite material for 3D printing provided by the present invention, it may further have the following characteristics: Among them, the steps of simulating the water-ice phase change process are specifically as follows: By precisely regulating the phase change temperature and latent heat value of the core material, the latent heat release and absorption process of the water-ice phase change are simulated in stages. At the same time, the directional design of the frost heave stress concentration area is realized through the spatial gradient distribution. The phase change temperature of the core material is -15°C to 5°C, and the latent heat value is 80 to 220 kJ / kg.

[0009] In the design method of the freeze-thaw sensitive composite material for 3D printing provided by the present invention, it may further have the following characteristics: Among them, the microcapsule phase change material is used to absorb and release heat, thereby regulating the temperature change of the material and imitating the thermodynamic behavior during the freeze-thaw process, including the water-ice phase change process. The microcapsule phase change material includes: encapsulated paraffin and anhydrous sodium sulfate. By mass, the content of the microcapsule phase change material in the freeze-thaw sensitive composite material is 5 to 15 wt%.

[0010] In the design method of the freeze-thaw sensitive composite material for 3D printing provided by the present invention, it may further have the following characteristics: Among them, the reinforcing fiber is used to regulate the strength and freeze-thaw durability of the matrix material, change the physical and mechanical properties of the material. The reinforcing fiber includes: sisal fiber, glass fiber, polyester fiber. The length of the reinforcing fiber is 0.5 to 2 cm. By mass, the content of the reinforcing fiber in the freeze-thaw sensitive composite material is 0.5 to 5 wt%.

[0011] In the design method of the freeze-thaw sensitive composite material for 3D printing provided by the present invention, it may further have the following characteristics: Among them, in the 3D printing process parameters, the printing layer thickness is 0.05 to 0.2 mm, the filling density is 50 to 100%, the filling method is honeycomb filling or grid filling, and the printing temperature is dynamically adjusted according to the phase change temperature of the matrix material and the microcapsule phase change material.

[0012] In the design method of the freeze-thaw sensitive composite material for 3D printing provided by the present invention, it may further have the following characteristics: Among them, the physical and mechanical property tests in step S5 include: obtaining the uniaxial compressive strength through the unconfined compressive strength test; obtaining the permeability coefficient through the permeability test; obtaining the freeze-thaw durability through the freeze-thaw cycle test. The physical and mechanical property tests are carried out according to the "Standard for Geotechnical Test Methods", GB / T50123-2019 and "Test Methods for Physical and Mechanical Properties of Artificial Frozen Soil", MT / T593.

[0013] Functions and Effects of the Invention

[0014] According to the design method of the freeze-thaw sensitive composite material for 3D printing involved in the present invention, the present invention has the following beneficial effects:

[0015] 1) By regulating the combination of the matrix material, microcapsule phase change material, and reinforcing fibers, and changing the corresponding printing process parameters, the present invention can achieve the precise simulation of real geotechnical bodies (such as moraine, clay, etc.), especially their strength changes, permeability changes, etc. during freeze-thaw cycles.

[0016] 2) By flexibly adjusting different material combinations and 3D printing process parameters, the present invention can meet the characteristic requirements of different geotechnical bodies and provide a customized solution for research.

[0017] 3) By conducting indoor freeze-thaw cycle-related tests on real geotechnical bodies using the freeze-thaw sensitivity composite material for 3D printing, the present invention can effectively reduce the demand for on-site testing and the complexity of indoor tests, and provide higher repeatability and controllability for the tests. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a flowchart for the selection of the freeze-thaw sensitivity composite material in the embodiments of the present invention.

[0019] Figure 2 is a schematic diagram for the design and testing of the freeze-thaw sensitivity composite material in the embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0021] It should be noted that the structures, ratios, sizes, etc. depicted in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in the art to understand and read, and are not used to limit the limited conditions under which the present invention can be implemented. Therefore, they do not have any technical essence. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle", etc. cited in this specification are only for the convenience of narration and are not used to limit the scope under which the present invention can be implemented. Any change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope within which the present invention can be implemented.

[0022] In order to make the technical means, creative features, achieved purposes, and effects of the present invention easy to understand, the following embodiments will specifically elaborate on the design method of the freeze-thaw sensitivity composite material for 3D printing of the present invention in conjunction with the drawings.

[0023] S1. Select matrix materials with differentiated thermal conductivity, thermal expansion coefficient, and specific heat capacity to simulate the particle skeleton of rock and soil, match the thermal response at different freeze-thaw cycle stages, and increase the basic controllability of freeze-thaw response.

[0024] The thermal conductivity controls the heat transfer during the freezing and thawing process, the difference in thermal expansion coefficients induces controllable microcracks to simulate frost heave stress, and the difference in specific heat capacity regulates the absorption of phase change energy, thereby achieving dynamic matching of different freeze-thaw cycle stages and enhancing the material's response accuracy to changes in temperature field.

[0025] The matrix material has certain strength and processability, and has differentiated thermal conductivity, thermal expansion coefficient, specific heat capacity, and can form an effective composite material with other components. The matrix material includes polylactic acid, photocurable resin and silicate gelling material.

[0026] Polylactic acid, or PLA, is an environmentally friendly material commonly used in 3D printing, with good biodegradability, low printing temperature and excellent surface quality. Due to its low melting point and good layer adhesion, PLA is suitable for rapid prototyping, but its tensile strength and heat resistance are relatively weak, making it unsuitable for use in high load or high temperature environments.

[0027] Photocurable resins are widely used in 3D printing for the manufacture of high-precision and complex models. They can print objects with smooth surfaces and rich details. At the same time, a variety of resin types can be selected to meet different physical property requirements. However, they are expensive, fragile, easy to break or crack, and are not suitable for parts that withstand impact or bending.

[0028] Silicate cementitious materials are widely used in the fields of construction and civil engineering. They have good printability and plasticity, and have high durability and compressive strength.

[0029] S2. Adding microcapsule phase change materials with different phase change temperatures and latent heat values ​​into the matrix material, the microcapsule phase change materials include: encapsulated paraffin wax and anhydrous sodium sulfate. The content of the microcapsule phase change materials in the freeze-thaw sensitive composite material is 5-15wt% by mass.

[0030] Microcapsule phase change materials are used to absorb and release heat, thereby regulating the temperature changes of the material and simulating the thermodynamic behavior during freezing and thawing, including the water-ice phase change process. By regulating the interfacial thermal resistance of the microcapsule wall material, a thermal response field with different spatial gradient distributions is formed to further simulate the water-ice phase change process.

[0031] The steps to simulate the water-ice phase change process are as follows: By precisely controlling the phase change temperature and latent heat value of the core material, the latent heat release and absorption processes of the water-ice phase change are simulated in stages. At the same time, through the spatial gradient distribution, the directional design of the frost heave stress concentration area is realized. Among them, the phase change temperature of the core material is -15°C to 5°C, and the latent heat value is 80 to 220 kJ / kg.

[0032] S3. Select to add reinforcing fibers to control the strength and freeze-thaw durability of the freeze-thaw sensitive composite material.

[0033] The reinforcing fibers include sisal fibers, glass fibers, and polyester fibers. The length of the reinforcing fibers is 0.5 to 2 cm. By mass, the content of the reinforcing fibers in the freeze-thaw sensitive composite material is 0.5 to 5 wt%.

[0034] The reinforcing fibers can change the bonding effect and stress transfer path between the matrix materials, change the physical and mechanical properties of the materials, inhibit the propagation of freeze-thaw cracks through the bridging effect, achieve the coordinated control of strength and freeze-thaw durability, and match the progressive mechanical attenuation law of the materials during freeze-thaw cycles.

[0035] S4. Determine the 3D printing process parameters. During the 3D printing process, the 3D printing process parameters such as layer thickness, filling density, and temperature have important effects on the structure and properties of the materials.

[0036] By adjusting the layer thickness and filling density, an artificial pore network is constructed. The printing layer thickness is 0.05 to 0.2 mm, the filling density is 50 to 100%, and the filling method is honeycomb filling or grid filling. The layer thickness determines the printing accuracy and surface quality. A thinner layer thickness can improve the accuracy but increase the printing time. The filling density directly affects the strength and material consumption. A high density can enhance the strength but increase the cost. Temperature control affects the fluidity and adhesion of the materials. Too high or too low temperature will cause quality problems. By adjusting the temperature, different phase change temperatures and thermal parameters are matched. The printing temperature is dynamically adjusted according to the phase change temperature of the matrix material and the microcapsule phase change material.

[0037] By systematically studying the relationship between the printing process parameters and the material properties, the parameter combination can be further optimized to balance the printing efficiency, material properties, and cost, and ensure that the final requirements of specific applications are met.

[0038] S5. According to different matrix materials, microcapsule phase change materials, and reinforcing fibers and their ratios, they are arranged and combined. Through 3D printing with different process parameters, the corresponding freeze-thaw sensitive composite materials are made, and the corresponding physical and mechanical property tests are carried out. The physical and mechanical property tests include uniaxial compressive strength, permeability coefficient, and freeze-thaw durability test. According to the physical and mechanical property test results, a freeze-thaw sensitivity-process-property database is established to obtain the mapping relationship between different parameters for subsequent further material development.

[0039] Table 1 Test Scheme

[0040]

[0041] As shown in Table 1, it is a freeze-thaw sensitivity - process - performance test scheme established according to parameter combinations. Specifically, the test can be designed as in Examples 1 - 3, which can provide data support for subsequent fabrication of alternative models of geotechnical materials with target properties using intelligent methods.

[0042] Example 1

[0043] Figure 1 It is a flow chart for the selection of freeze-thaw sensitive composite materials in the embodiments of the present invention.

[0044] As Figure 1 shown, the design method of the freeze-thaw sensitive composite material for 3D printing in this embodiment is as follows:

[0045] S1. Select polylactic acid, i.e., PLA, as the matrix material for printing.

[0046] S2. Select encapsulated paraffin wax as the microcapsule phase change material.

[0047] S3. Select sisal fiber as the reinforcing fiber.

[0048] S4. Determine the 3D printing process parameters: the layer thickness is 0.05 mm, the filling density is 50%, and the filling pattern is honeycomb filling.

[0049] S5. Based on PLA, encapsulated paraffin wax, and sisal fiber, fabricate the corresponding freeze-thaw sensitive composite material and conduct corresponding physical and mechanical property tests. The physical and mechanical property tests include uniaxial compressive strength, permeability coefficient, and freeze-thaw durability. Establish a freeze-thaw sensitivity - process - performance database according to the test results for subsequent further material development.

[0050] Mix PLA, encapsulated paraffin wax, and sisal fiber to obtain the freeze-thaw sensitive composite material for 3D printing.

[0051] The matrix material should have certain strength and processability, and be able to form an effective composite material with other components. As a matrix material, PLA is an environmentally friendly material commonly used in 3D printing, with good biodegradability, low printing temperature, and excellent surface quality. Due to its low melting point and good layer adhesion, PLA is suitable for rapid prototyping, but its tensile strength and heat resistance are relatively weak and it is not suitable for use in high-load or high-temperature environments.

[0052] To further simulate the phase change effect that occurs in the original geotechnical materials during the freeze-thaw process, microencapsulated phase change materials are introduced as part of the materials for simulation. The encapsulated paraffin in this embodiment is one type of microencapsulated phase change materials. Microencapsulated phase change materials can absorb and release heat, thereby regulating the temperature change of the materials and mimicking the thermodynamic behavior during the freeze-thaw process.

[0053] To control the strength, durability, etc. of the matrix material, reinforcing fibers are added. The sisal fibers in this embodiment are one type of reinforcing fibers, which improve the mechanical properties of the materials, especially in terms of compressive strength, tensile strength, etc. These fibers help enhance the structural stability and freeze-thaw durability of the composite materials.

[0054] In the 3D printing of the freeze-thaw sensitive composite material for 3D printing in this embodiment, the printing parameters are specifically as follows:

[0055] The layer thickness is 0.05 mm, the filling density is 50%, and the filling pattern is honeycomb filling.

[0056] During the 3D printing process, printing parameters such as layer thickness, filling density, temperature, etc. have important effects on the structure and properties of the materials. The layer thickness determines the printing accuracy and surface quality. A thinner layer thickness can improve the accuracy but increase the printing time; the filling density directly affects the strength and material consumption. A high density can enhance the strength but increase the cost; the temperature control affects the material fluidity and adhesion. Too high or too low temperature will cause quality problems. By systematically studying the relationship between the printing process parameters and the material properties, the parameter combination can be further optimized to balance the printing efficiency, material properties, and cost, and ensure that the final product meets the requirements of specific applications.

[0057] Figure 2 It is a schematic diagram of the design and test of the freeze-thaw sensitive composite material in the embodiment of the present invention.

[0058] As Figure 2 shown, physical and mechanical property tests are carried out on the freeze-thaw sensitive composite material for 3D printing in this embodiment, including compressive strength, tensile strength, permeability coefficient, and freeze-thaw cycle durability, etc. A freeze-thaw sensitivity - process - property database is established to provide data support for the subsequent production of alternative models of geotechnical materials with target properties using intelligent methods. Uniaxial compressive tests, triaxial tests, permeability tests, and freeze-thaw cycle tests are carried out according to the "Standard for Geotechnical Test Methods" and the "Physical and Mechanical Property Tests of Artificial Frozen Soil".

[0059] Example 2

[0060] As Figure 1 shown, the design method of the freeze-thaw sensitive composite material for 3D printing in this embodiment is specifically as follows:

[0061] S1. Select a photocurable resin as the base material for printing.

[0062] S2. Select encapsulated paraffin as the microcapsule phase change material.

[0063] S3, glass fiber is selected as the reinforcing fiber.

[0064] S4. Determine the 3D printing process parameters, the layer thickness is 0.1 mm, the filling density is 100%, and the filling method is grid filling.

[0065] S5. Based on photocurable resin, encapsulation paraffin and glass fiber, corresponding freeze-thaw sensitive composite materials are made, and corresponding physical and mechanical properties tests are carried out. The physical and mechanical properties tests include uniaxial compressive strength, permeability coefficient, freeze-thaw durability, and a freeze-thaw sensitivity-process-performance database is established based on the test results for further material development.

[0066] The photocurable resin, encapsulating paraffin wax and glass fiber are mixed to obtain a freeze-thaw sensitive composite material for 3D printing.

[0067] Photocurable resins are widely used in 3D printing for the manufacture of high-precision and complex models. They can print objects with smooth surfaces and rich details. At the same time, a variety of resin types can be selected to meet different physical property requirements. However, they are expensive, fragile, easy to break or crack, and are not suitable for parts that withstand impact or bending.

[0068] In the 3D printing of the freeze-thaw sensitive composite material for 3D printing in this embodiment, the printing parameters are as follows:

[0069] The layer thickness is 0.1 mm, the filling density is 100%, and the filling method is grid filling.

[0070] like Figure 2 As shown, the freeze-thaw sensitive composite material for 3D printing in this embodiment is tested for physical and mechanical properties, including compressive strength, tensile strength, permeability coefficient, and freeze-thaw cycle durability, etc., to establish a freeze-thaw sensitivity-process-performance database, and provide data support for the subsequent use of intelligent methods to make alternative models of rock and soil bodies with target properties. According to the "Standard for Geotechnical Test Methods" (GB / T50123-2019) and "Test for Physical and Mechanical Properties of Artificial Frozen Soil" (MT / T593), uniaxial compression tests, triaxial tests, permeability tests, and freeze-thaw cycle tests are carried out, wherein the uniaxial compression test is used to obtain the uniaxial compressive strength; the permeability test is carried out to obtain the permeability coefficient; and the freeze-thaw cycle test is carried out to obtain the freeze-thaw durability.

[0071] Example 3

[0072] like Figure 1As shown in the figure, the design method of the freeze-thaw sensitive composite material for 3D printing in this embodiment is specifically as follows:

[0073] S1. Select a silicate cementitious material as the matrix material for printing.

[0074] S2. Select anhydrous sodium sulfate as the microcapsule phase change material.

[0075] S3. Select polyester fiber as the reinforcing fiber.

[0076] S4. Determine the 3D printing process parameters, with a layer thickness of 0.2 mm, a filling density of 50%, and a filling pattern of honeycomb filling.

[0077] S5. Based on the silicate cementitious material, anhydrous sodium sulfate, and polyester fiber, prepare the corresponding freeze-thaw sensitive composite material and conduct corresponding physical and mechanical property tests. The physical and mechanical property tests include uniaxial compressive strength, permeability coefficient, and freeze-thaw durability. Establish a freeze-thaw sensitivity - process - property database for subsequent further material development.

[0078] Mix the silicate cementitious material, anhydrous sodium sulfate, and polyester fiber to obtain the freeze-thaw sensitive composite material for 3D printing.

[0079] Silicate cementitious materials are widely used in the fields of architecture and civil engineering, with good printability and plasticity, and high durability and compressive strength.

[0080] In the 3D printing of the freeze-thaw sensitive composite material for 3D printing in this embodiment, the printing parameters are specifically as follows:

[0081] The layer thickness is 0.2 mm, the filling density is 50%, and the filling pattern is honeycomb filling.

[0082] As Figure 2 shown, conduct physical and mechanical property tests on the freeze-thaw sensitive composite material for 3D printing in this embodiment, including compressive strength, tensile strength, permeability coefficient, and freeze-thaw cycle durability, etc. Establish a freeze-thaw sensitivity - process - property database to provide data support for subsequent making of alternative models of geotechnical bodies with target properties using intelligent methods. Conduct uniaxial compressive tests, triaxial tests, permeability tests, and freeze-thaw cycle tests according to the "Standard for Geotechnical Test Methods" and the "Test on Physical and Mechanical Properties of Artificial Frozen Soil".

[0083] Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for designing freeze-thaw sensitive composite materials for 3D printing, characterized in that: The specific steps include: S1. Select a matrix material with differentiated thermal conductivity, thermal expansion coefficient, and specific heat capacity to simulate the particle skeleton of rock and soil, match the thermal response at different freeze-thaw cycle stages, and increase the basic controllability of freeze-thaw response. The thermal conductivity is used to control the heat transfer during the freeze-thaw process. The difference in thermal expansion coefficient induces controllable microcracks to simulate frost heave stress. The difference in specific heat capacity regulates the absorption of phase change energy, thereby achieving dynamic matching of different freeze-thaw cycle stages and enhancing the response accuracy of the material to temperature field changes. S2. Adding microcapsule phase change materials with different phase change temperatures and latent heat values ​​into the matrix material, and regulating the interface thermal resistance of the microcapsule wall material to form a thermal response field with different spatial gradient distributions, further simulating the water ice phase change process; S3, selectively adding reinforcing fibers to change the bonding effect between the matrix materials, so as to adjust the strength and freeze-thaw durability of the freeze-thaw sensitive composite material, and match the response of the physical and mechanical properties of the material to freeze-thaw. The reinforcing fibers are used to optimize the bonding effect and stress transfer path of the matrix material, inhibit the expansion of freeze-thaw cracks through the bridging effect, achieve coordinated control of strength and freeze-thaw durability, and match the progressive mechanical attenuation law of the material in the freeze-thaw cycle; S4. Determine 3D printing process parameters, wherein the 3D printing process parameters include layer thickness, filling density and temperature. By adjusting the layer thickness and filling density, an artificial pore network is constructed. By adjusting the temperature, different phase change temperatures and thermal parameters are matched. By systematically studying the relationship between printing process parameters and material properties, the parameter combination can be further optimized, the printing efficiency, material properties and cost can be balanced, and the requirements of specific applications can be finally met. S5. Arrange and combine the matrix material, the microcapsule phase change material and the reinforcing fiber and their proportions, produce corresponding freeze-thaw sensitive composite materials through 3D printing with different process parameters, and conduct corresponding physical and mechanical property tests, wherein the physical and mechanical property tests include uniaxial compressive strength, permeability coefficient and freeze-thaw durability tests. According to the physical and mechanical property test results, a freeze-thaw sensitivity-process-performance database is established to obtain the mapping relationship between different parameters for further material development.

2. The method for designing a freeze-thaw sensitive composite material for 3D printing according to claim 1, characterized in that: in, The matrix material includes polylactic acid, light-curable resin or silicate gelling material.

3. The method for designing a freeze-thaw sensitive composite material for 3D printing according to claim 1, characterized in that: in, The steps of simulating the water ice phase change process are as follows: adjusting the phase change temperature of the microcapsule core material to -15°C to 5°C and the latent heat value distribution to 80 to 220 kJ / kg, and combining the spatial arrangement of the microcapsules to achieve simulation.

4. The method for designing a freeze-thaw sensitive composite material for 3D printing according to claim 1, characterized in that: in, The microcapsule phase change material comprises: encapsulated paraffin or anhydrous sodium sulfate. The content of the microcapsule phase change material in the freeze-thaw sensitive composite material is 5-15wt% by weight.

5. The method for designing a freeze-thaw sensitive composite material for 3D printing according to claim 1, characterized in that: in, The reinforcing fibers include sisal fibers, glass fibers or polyester fibers. The length of the reinforcing fibers is 0.5 to 2 cm. The content of the reinforcing fibers in the freeze-thaw sensitive composite material is 0.5 to 5 wt % by mass.

6. The method for designing a freeze-thaw sensitive composite material for 3D printing according to claim 1, characterized in that: in, Among the 3D printing process parameters, the printing layer thickness is 0.05-0.2 mm, the filling density is 50-100%, the filling method is honeycomb filling or grid filling, and the printing temperature is dynamically adjusted according to the phase change temperature of the matrix material and the microcapsule phase change material.

7. The method for designing a freeze-thaw sensitive composite material for 3D printing according to claim 1, characterized in that: in, The physical and mechanical properties test in step S5 includes: an unconfined compressive strength test to obtain uniaxial compressive strength, a permeability test to obtain permeability coefficient, and a freeze-thaw cycle test to obtain freeze-thaw durability. The physical and mechanical properties test is carried out in accordance with the "Standard for Geotechnical Test Methods", GB / T50123-2019 and the "Physical and Mechanical Properties Test of Artificial Frozen Soil", MT / T593.

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