Constructive model construction method and system for simulating mechanical properties of fresh water ice

Abstract

The invention discloses a constitutive model construction method and system for simulating mechanical properties of fresh water ice. The constitutive model construction method comprises the steps of obtaining experimental data, constructing a geometric model and a contact area expansion model, setting a temperature-related yield criterion, carrying out numerical simulation and optimizing model parameters. The system comprises a memory, a computer and a display, and can automatically finish simulation analysis and output a result. By introducing the temperature-dependent yield criterion and the contact area expansion model, the mechanical behaviors of ice in different stages are comprehensively described, the simulation precision is improved, the authenticity of working conditions is enhanced by adopting a random generation method, and efficient and accurate mechanical property simulation of fresh water ice is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ice material mechanics simulation, in particular to a constitutive model construction method and system for simulating the mechanical properties of freshwater ice. BACKGROUND

[0002] Currently, the simulation of freshwater ice mechanical properties is an important topic in the field of materials science and engineering, mainly involving material mechanics, fracture mechanics, and numerical simulation, etc. It usually includes the following steps S:

[0003] Model establishment: based on experimental data, a stress-strain relationship model of freshwater ice is constructed, covering the elastic segment, plastic segment, softening segment, and failure and destruction segment.

[0004] Parameter setting: according to the experimental results, the key parameters in the model are set, such as elastic modulus, tensile strength, fracture energy, etc., and adjusted in combination with temperature influence.

[0005] Numerical simulation: using finite element analysis software (such as ABAQUS, ANSYS, etc.) to simulate the mechanical behavior of freshwater ice, which may involve nonlinear problems, and need to handle stress distribution and fracture behavior under complex loading conditions.

[0006] Data analysis: after the simulation is completed, the results are analyzed in detail, including stress-strain curve, fracture energy release behavior, and the influence of temperature on deviatoric stress, etc., so as to evaluate the precision and applicability of the model.

[0007] Currently, traditional models such as Duncan-Chang model mainly focus on linear elasticity and strain hardening stage when describing the mechanical properties of freshwater ice, and the behaviors of initial compaction stage, strain softening stage and residual strength stage are not covered. In addition, the stress-strain relationship of the tension segment is related to the element size, which may lead to an increase in the cost of numerical modeling and bring challenges to the definition of fracture energy release behavior. Although researchers have proposed various improved models, such as constitutive models based on triaxial tests and yield criteria considering temperature influence, these models still have limitations in parameter selection and applicable range. Especially under different temperature conditions, the variation law of ice expansion angle and its influence on the yield surface have not been fully solved. The definition of yield surface shape in existing plastic damage models mainly depends on classical theories such as Drucker-Prager model and Rankine criterion, which may deviate when describing the complex failure behavior of ice. The influence of temperature on deviatoric stress can be fitted based on the results of triaxial test of ice, but existing models fail to fully combine such experimental data to improve accuracy. Therefore, it is of great significance to develop an improved constitutive model that comprehensively considers the stress-strain relationship, fracture energy release behavior and temperature influence of ice. SUMMARY

[0008] To this end, the present application provides a constitutive model construction method and system for simulating the mechanical properties of freshwater ice, to obtain the complex mechanical behavior of ice materials under different loading conditions and environmental factors, and solve the limitation problem that the traditional model cannot comprehensively describe the stress-strain relationship of ice materials under complex loading environment.

[0009] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0010] A constitutive model construction method for simulating the mechanical properties of freshwater ice, comprising the following steps:

[0011] Through triaxial compression and uniaxial tension experiments, the stress-strain curves of freshwater ice samples at different temperatures are obtained, the basic physical and mechanical parameters are recorded, and the deviatoric stress and expansion angle data are collected, and the experimental results are outputted;

[0012] Based on the actual geometric shape of the freshwater ice sample, a geometric model is constructed, and a contact area expansion model is defined;

[0013] The basic physical and mechanical parameters recorded in the experiment are used as the basic physical and mechanical parameters of the model, and a temperature-dependent yield criterion is defined;

[0014] Numerical simulation and analysis of mechanical response under complex loading conditions are carried out, and finite element analysis software is used to simulate random impact load and stress distribution under temperature gradient;

[0015] The simulation results are compared and analyzed with the experimental results, and the basic physical and mechanical parameters of the model are optimized, the stress-strain curves of the key monitoring points, the fracture energy release behavior and the influence law of temperature on the deviatoric stress are extracted, and the deviatoric stress coefficient and yield strength in the yield criterion are adjusted through iterative optimization method to minimize the error.

[0016] On the basis of the above technical solutions, the present application is further described as follows:

[0017] As a further scheme of the present application,

[0018] The triaxial compression and uniaxial tension experiments are used to obtain the stress-strain curves of freshwater ice at different temperatures, record the basic physical and mechanical parameters, collect the deviatoric stress and expansion angle data, and output the experimental results, which specifically include:

[0019] The stress-strain curves of freshwater ice at different temperatures are obtained through triaxial compression test and uniaxial tension test, the basic physical and mechanical parameters include density, elastic modulus, compressive strength, tensile strength and fracture energy, and the relationship data of deviatoric stress and expansion angle are collected, and the experimental results are outputted;

[0020] The constructing the geometric model and defining the contact area expansion model specifically comprises:

[0021] The geometric model of the freshwater ice is established according to the actual geometric shape of the freshwater ice sample by using computer-aided design software, the geometric model comprises a contact area expansion model, the outer contour size of the contact area expansion model is AxBxC, and the calculation method of the outer contour size of the contact area expansion model based on the outer contour size axbxc of the contact area is A=a*alpha, B=b*alpha, and C=c*beta, wherein alpha is a transverse influence coefficient with a value range of 2-3, and beta is a longitudinal influence coefficient with a value range of 1.5-2.

[0022] As a further scheme of the present application,

[0023] The basic physical and mechanical parameters recorded in the experiment are taken as the model basic physical and mechanical parameters, and a temperature-related yield criterion is defined, and the method specifically comprises:

[0024] The basic physical and mechanical parameters recorded in the experiment are taken as the model basic physical and mechanical parameters, and a temperature-related yield criterion is defined based on the relationship between deviatoric stress and hydrostatic pressure.

[0025] The function form of the yield criterion is f(sigma)=sigma_m+alpha(T)*sigma_d-k(T).

[0026] Wherein, sigma_m is the hydrostatic pressure, sigma_d is the deviatoric stress, alpha(T) is the temperature-related deviatoric stress coefficient, and k(T) is the temperature-related yield strength.

[0027] As a further scheme of the present application,

[0028] The specific method of the random impact load simulation is:

[0029] A simulation impact surface is generated above the freshwater ice, the simulation impact surface is meshed, the center point of each mesh is taken as a simulation impact point, the simulation impact points are labeled in a sequential numbering manner, 5% of the total impact points are selected as actual impact points by using a random number generation algorithm, the size of the simulation impact load is randomly generated in the range of 0.5kN to 2.0kN, and the direction is randomly distributed in the range of ±15° in the vertical direction.

[0030] As a further scheme of the present application,

[0031] The specific method of the stress distribution simulation under the action of the temperature gradient is:

[0032] A temperature field distribution is set in the geometric model of the freshwater ice, the temperature field changes linearly in a certain direction, and the influence of the temperature gradient on the deviatoric stress and the expansion angle is calculated through thermal-mechanical coupling analysis.

[0033] As a further scheme of the present application,

[0034] The temperature range is -20℃ to 0℃, and the values of the temperature-dependent deviatoric stress coefficient α(T) and the yield strength k(T) are set based on experimental data and adjusted by an iterative optimization method.

[0035] As a further scheme of the present application,

[0036] The key monitoring points include surface nodes and internal nodes of the fresh water ice, and the monitoring data include stress-strain relationship, fracture energy release behavior and the influence law of temperature on deviatoric stress.

[0037] As a further scheme of the present application,

[0038] The iterative optimization method minimizes the error between the simulation results and the experimental data by adjusting the deviatoric stress coefficient and the yield strength in the yield criterion.

[0039] A constitutive model construction system for simulating the mechanical properties of fresh water ice comprises a memory and a computer, the memory stores an analysis program designed by the constitutive model construction method for simulating the mechanical properties of fresh water ice, the computer is preinstalled with computer-aided design software and finite element analysis software, the computer is in communication connection with the memory, runs the analysis program and is associated with the computer-aided design software and the finite element analysis software to realize automatic analysis on the mechanical properties of fresh water ice, and outputs the simulation results to be stored in the memory.

[0040] The memory stores data including experimental data, simulation results and optimized model parameters.

[0041] As a further scheme of the present application,

[0042] The system further comprises a display in communication connection with the computer, and the computer controls the display to display the simulation analysis process and the simulation analysis results.

[0043] The present application has the following beneficial effects:

[0044] The method and the system can more comprehensively describe the mechanical behavior of fresh water ice under different temperature conditions by introducing the temperature-dependent yield criterion, can more accurately simulate the mechanical properties of the contact parts of ice and other media by constructing the contact area expansion model, and can more truly reflect the complexity of actual working conditions by using the random generation method for simulating the random impact load and the stress distribution under the action of temperature gradient. BRIEF DESCRIPTION OF DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. The structure, proportion, size, etc. shown in the specification are only used to cooperate with the content disclosed in the specification, so as to be understood and read by those skilled in the art. Any modification of the structure, change of the proportion relationship or adjustment of the size, which does not affect the effects and purposes that can be achieved by the present application, should still fall within the scope of the technical content disclosed by the present application.

[0046] Fig. 1 The overall flowchart of the method for constructing a constitutive model for simulating the mechanical properties of freshwater ice provided by the embodiments of the present application is shown in the figure.

[0047] Fig. 2 The stress-strain curve of the triaxial compression test of freshwater ice in the embodiments of the present application is shown in the figure. DETAILED DESCRIPTION

[0048] The embodiments of the present application will be described below by specific examples. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in the specification. Obviously, the described embodiments are part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0049] The terms such as "upper", "lower", "left", "right", "middle" and the like cited in the specification are only for the convenience of clear description, and are not used to limit the scope of implementation of the present application. The change or adjustment of the relative relationship without substantial change of the technical content is also regarded as the implementation scope of the present application.

[0050] The embodiments of the present application provide a method and system for constructing a constitutive model for simulating the mechanical properties of freshwater ice, and the specific implementation manner is described in the description of the accompanying drawings. Figs. 1-2 which will be described in detail as follows.

[0051] First, the basic physical and mechanical properties of freshwater ice are obtained according to the experimental design, and the stress-strain relationship is analyzed. The stress-strain curves of freshwater ice under different temperature conditions are obtained through laboratory triaxial compression test and uniaxial tension test, as shown in Fig. 2 , Fig. 2 The mechanical property changes of freshwater ice under different temperature conditions are shown in the figures, in which the abscissa is the strain value, and the ordinate is the stress value, Fig. 2The middle curve represents the typical stress-strain relationship of freshwater ice at a certain temperature. The experimental data record the key parameters such as elastic modulus, compressive strength, tensile strength, and fracture energy, and the data of deviatoric stress and dilatancy angle at different temperatures are also collected, which will serve as the basis for subsequent model parameter setting. For example, at a certain temperature, the elastic modulus is 9.5 GPa, the compressive strength is 3.2 MPa, the tensile strength is 1.4 MPa, and the fracture energy is 0.12 kJ / m 2 . The data of deviatoric stress and dilatancy angle are used to define the shape of the yield surface.

[0052] Next, a geometric model of freshwater ice is constructed based on the actual geometry of the freshwater ice sample, and a contact area expansion model is defined. A computer-aided design software is used to establish the geometric model of freshwater ice, which includes the contact area and its expanded part, where the outer contour size of the contact area is a x b x c, and the expanded outer contour size is A x B x C. The size of the expanded model is calculated according to the formulas A = a · a, B = b · a, and C = c · b, where a is the lateral influence coefficient with a value range of 2 to 3, and b is the longitudinal influence coefficient with a value range of 1.5 to 2. For example, if the original size of the contact area is 100 mm x 50 mm x 20 mm, and a is selected as 2.5 and b is selected as 1.8, the size of the expanded model is 250 mm x 125 mm x 36 mm. The setting of the contact area expansion model can more comprehensively reflect the mechanical properties of the contact area, and provide accurate boundary conditions for subsequent numerical simulation.

[0053] Subsequently, the model parameters are set according to the experimental data and the temperature-dependent yield criterion is defined. The basic physical and mechanical parameters in the model include density of 917 kg / m 3 , elastic modulus of 9.5 GPa, Poisson's ratio of 0.33, tensile strength of 1.4 MPa, compressive strength of 3.2 MPa, and fracture energy of 0.12 kJ / m 2 . The definition of the yield criterion depends on the relationship between the deviatoric stress and the hydrostatic pressure, and its functional form is f(a) = a_m + a(T) · a_d - k(T), where a_m is the hydrostatic pressure, a_d is the deviatoric stress, a(T) is the temperature-dependent deviatoric stress coefficient, and k(T) is the temperature-dependent yield strength. For example, at -10°C, a(T) takes a value of 0.85 and k(T) takes a value of 2.1 MPa; at -20°C, a(T) takes a value of 0.78 and k(T) takes a value of 2.5 MPa. By introducing the temperature-dependent deviatoric stress coefficient and yield strength, the mechanical behavior of ice at different temperatures can be accurately described.

[0054] After the model parameters are set, the finite element analysis software is used to carry out numerical simulation and analyze the mechanical response under complex loading conditions. A simulation impact surface is generated above the fresh water ice, the impact surface is meshed, and the center point of each mesh is taken as the simulation impact point. The impact points are labeled in a sequential numbering manner. 5% of the total number of impact points are selected as actual impact points by a random number generation algorithm. The size of the impact load is randomly generated in the range of 0.5kN to 2.0kN, and the direction is randomly distributed within ±15° of the vertical direction. A temperature field distribution is set in the geometric model of fresh water ice, and the temperature field changes linearly along a certain direction, for example, from -5°C to -20°C. The influence of temperature gradient on deviatoric stress and expansion angle is calculated through thermal-mechanical coupling analysis, and the results are compared and verified with experimental data.

[0055] Finally, the mechanical properties of fresh water ice are analyzed based on the numerical simulation results, and the model parameters are optimized.

[0056] Specifically, the stress-strain curve of the key monitoring point, the fracture energy release behavior, and the influence of temperature on deviatoric stress are extracted, and the simulation results are compared with the experimental data. The deviatoric stress coefficient and yield strength in the yield criterion are adjusted by an iterative optimization method to minimize the error between the simulation results and the experimental data. For example, under a certain temperature condition, the initial deviatoric stress coefficient is 0.85 and the yield strength is 2.1MPa. After three iterations and optimizations, they are adjusted to 0.82 and 2.05MPa respectively, and finally the simulation error is reduced to within 5%. The constitutive model construction system for simulating the mechanical properties of fresh water ice includes a memory and a computer. The memory stores the analysis program designed using the constitutive model construction method, and the computer is pre-installed with computer-aided design software and finite element analysis software. The analysis program is run and automatic analysis is realized. The display is communicatively connected to the computer, displays the simulation analysis process and results, and stores the data in the memory.

[0057] All steps in the above embodiments are executed in sequence, and the coherence of the overall process is realized through data transmission and functional cooperation between components. The size relationship between the geometric model of fresh water ice and the contact area expansion model is clearly defined by a formula, the parameter setting of the yield criterion is based on experimental data and continuously adjusted by an iterative optimization method, and the random impact load and temperature gradient distribution in the numerical simulation process are ensured to be realistic by using a random generation algorithm. The entire system completes the automatic simulation analysis of the mechanical properties of fresh water ice and outputs the results through the collaborative work of the memory, the computer and the display.

[0058] In order to better enable those skilled in the art to fully understand and implement the present application, the specific implementation principles of the present application are further supplemented as follows in conjunction with a specific application scenario.

[0059] In step S1, the basic physical and mechanical properties of freshwater ice are first obtained through laboratory triaxial compression tests and uniaxial tension tests. Fig. 2 As shown in the figure, the stress-strain curve of freshwater ice reflects the changes in mechanical properties under different temperature conditions. During the experiment, the freshwater ice sample needs to be placed in a low-temperature controlled environment and a gradually increasing load is applied to record its stress and strain values. For example, at a certain temperature, the elastic modulus is measured to be 9.5GPa, the compressive strength is 3.2MPa, the tensile strength is 1.4MPa, and the fracture energy is 0.12kJ / m 2 These data provide the basis for subsequent model parameter setting. At the same time, the collected data on the relationship between deviatoric stress and expansion angle are used to define the shape of the yield surface. The reliability of the model establishment is ensured by the accurate recording of experimental data.

[0060] After entering step S2, a geometric model of freshwater ice is constructed based on the actual geometric shape of the freshwater ice sample, and an extended contact area model is defined. The geometric structure of the extended contact area model includes the original contact area size a×b×c and its extended outer contour size A×B×C. The size of the extended model is calculated by the formula A=a·α, B=b·α, C=c·β, where α and β are the lateral and longitudinal influence coefficients, respectively. For example, if the original size of the contact area is 100mm×50mm×20mm, α is selected as 2.5 and β is selected as 1.8, then the size of the extended model is 250mm×125mm×36mm. By setting up the extended model, the mechanical properties of the contact area can be more comprehensively reflected, providing accurate boundary conditions for subsequent numerical simulations. The key to this step is to reasonably select the influence coefficient to ensure that the extended model can cover the actual contact area while avoiding excessive expansion and waste of computing resources.

[0061] Then, in step S3, the model parameters are set according to the experimental data and the temperature-dependent yield criterion is defined. The basic physical and mechanical parameters in the model include a density of 917 kg / m 3 , elastic modulus is 9.5GPa, Poisson's ratio is 0.33, etc. The functional form of the yield criterion is f(σ)=σ_m+α(T)·σ_d-k(T), where α(T) and k(T) are the temperature-related deviatoric stress coefficient and yield strength, respectively. For example, at -10℃, α(T) takes a value of 0.85, and k(T) takes a value of 2.1MPa; at -20℃, α(T) takes a value of 0.78, and k(T) takes a value of 2.5MPa. By introducing temperature-related parameters, the mechanical behavior of ice under different temperature conditions can be accurately described. The core of this step is to adjust the parameters in combination with experimental data to ensure the applicability of the yield criterion.

[0062] In step S4, numerical simulation is carried out using finite element analysis software and the mechanical response under complex loading conditions is analyzed. First, a simulation impact surface is generated above the fresh water ice, and the surface is meshed, with the center point of each mesh serving as a simulation impact point. A random number generation algorithm is used to select 5% of the total number of impact points as actual impact points, with the impact load randomly generated in the range of 0.5 kN to 2.0 kN and the direction randomly distributed within ±15° of the vertical direction. A temperature field distribution is set in the geometric model of the fresh water ice, for example, a linear gradient from -5°C to -20°C. Through thermal-mechanical coupling analysis, the influence of temperature gradient on deviatoric stress and expansion angle is calculated and compared with experimental data for verification. The key to this step is to randomly generate impact points and temperature field distribution to enhance the authenticity of the simulation.

[0063] Finally, in step S5, the mechanical properties of fresh water ice are analyzed and model parameters are optimized based on the results of numerical simulation. The stress-strain curves of key monitoring points, fracture energy release behavior, and the influence of temperature on deviatoric stress are extracted, and the simulation results are compared with experimental data. Through iterative optimization method, the deviatoric stress coefficient and yield strength in the yield criterion are adjusted to minimize the error between the simulation results and the experimental data. For example, under a certain temperature condition, the initial deviatoric stress coefficient is 0.85 and the yield strength is 2.1 MPa, after three iterations, they are adjusted to 0.82 and 2.05 MPa respectively, and finally the simulation error is reduced to within 5%. The core of this step is to continuously adjust the parameters through iterative optimization method to ensure the accuracy of the model.

[0064] The entire system completes the automated simulation analysis of the mechanical properties of fresh water ice and outputs the results through the coordinated work of the memory, computer and display. All steps in the above embodiment are executed in sequence, and the coherence of the overall process is achieved through data transmission and functional cooperation between the components. The size relationship between the geometric model of fresh water ice and the extended model of the contact area is clearly defined by a formula, the parameter setting of the yield criterion is based on experimental data and continuously adjusted through iterative optimization method, and the random impact load and temperature gradient distribution in the numerical simulation process are ensured to be realistic by using a random generation algorithm.

[0065] Although the present application has been described in detail above with general description and specific embodiments, some modifications or improvements can be made on the basis of the present application, which is obvious to those skilled in the art. Therefore, these modifications or improvements made on the basis of not deviating from the spirit of the present application, all belong to the scope of protection claimed by the present application.

Claims

1. A method for constructing a constitutive model for simulating the mechanical properties of freshwater ice, characterized in that: The following steps are involved: Through triaxial compression and uniaxial tension experiments, the stress-strain curves of freshwater ice samples at different temperatures are obtained, their basic physical and mechanical parameters are recorded, and deviatoric stress and expansion angle data are collected to output experimental results; Based on the actual geometric shape of the freshwater ice sample, its geometric model is constructed and the contact area extension model is defined; The basic physical and mechanical parameters recorded in the experiment are used as the basic physical and mechanical parameters of the model, and the temperature-dependent yield criterion is defined; Conduct numerical simulations and analyze mechanical responses under complex loading conditions, using finite element analysis software to simulate random impact loads and stress distribution under temperature gradients; The simulation results were compared and analyzed with the experimental results, and the basic physical and mechanical parameters of the model were optimized. The stress-strain curves of key monitoring points, the fracture energy release behavior, and the influence of temperature on the deviatoric stress were extracted. The deviatoric stress coefficient and yield strength in the yield criterion were adjusted through iterative optimization methods to minimize the error.

2. The constitutive model construction method for simulating the mechanical properties of freshwater ice according to claim 1, characterized in that: The triaxial compression and uniaxial tension experiments are conducted to obtain stress-strain curves of freshwater ice samples at different temperatures, record their basic physical and mechanical parameters, collect deviatoric stress and expansion angle data, and output experimental results, specifically including: The stress-strain curves of freshwater ice at different temperatures are obtained through triaxial compression tests and uniaxial tension tests. The basic physical and mechanical parameters include density, elastic modulus, compressive strength, tensile strength, and fracture energy. The relationship between deviatoric stress and expansion angle is also collected, and the experimental results are output; The construction of the geometric model and definition of the contact area extension model specifically include: A geometric model of freshwater ice is established using computer-aided design software based on the actual geometric shape of the freshwater ice sample. The geometric model includes a contact area extension model. The outer contour dimensions of the contact area extension model are A×B×C, and the outer contour dimensions of the contact area extension model are calculated based on the outer contour dimensions a×b×c of the contact area as A=a·α, B=b·α, and C=c·β, where α is a lateral influence coefficient with a value range of 2 to 3, and β is a longitudinal influence coefficient with a value range of 1.5 to 2.

3. The constitutive model construction method for simulating the mechanical properties of freshwater ice according to claim 1, characterized in that: The basic physical and mechanical parameters recorded in the experiment are used as the basic physical and mechanical parameters of the model, and the temperature-related yield criterion is defined, specifically including: The basic physical and mechanical parameters recorded in the experiment are set as the basic physical and mechanical parameters of the model, and the temperature-dependent yield criterion is defined based on the relationship between deviatoric stress and hydrostatic pressure; The functional form of the yield criterion is f(σ)=σ_m+α(T)·σ_d-k(T); where σ_m is the hydrostatic pressure, σ_d is the deviatoric stress, α(T) is the temperature-dependent deviatoric stress coefficient, and k(T) is the temperature-dependent yield strength.

4. The method for constructing a constitutive model for simulating the mechanical properties of freshwater ice according to claim 1, wherein: The specific method of the random impact load simulation is: A simulated impact surface was generated above the freshwater ice and divided into a grid. The center point of each grid was used as the simulated impact point. The simulated impact points were marked with sequential numbers. 5% of the total impact points were selected as the actual impact points using a random number generation algorithm. The magnitude of the simulated impact load was randomly generated in the range of 0.5 kN to 2.0 kN, and the direction was randomly distributed within the range of ±15° in the vertical direction.

5. The constitutive model construction method for simulating the mechanical properties of freshwater ice according to claim 1, characterized in that: The specific method for simulating stress distribution under the action of the temperature gradient is as follows: A temperature field distribution is set in the geometric model of freshwater ice. The temperature field changes linearly along a certain direction. The influence of temperature gradient on deviatoric stress and expansion angle is calculated through thermal-mechanical coupling analysis.

6. The method for constructing a constitutive model for simulating the mechanical properties of freshwater ice according to claim 1, characterized in that: The temperature range is -20°C to 0°C, and the values ​​of the temperature-dependent deviatoric stress coefficient α(T) and yield strength k(T) are set based on experimental data and adjusted through an iterative optimization method.

7. The method for constructing a constitutive model for simulating the mechanical properties of freshwater ice according to claim 1, characterized in that: The key monitoring points include surface nodes and internal nodes of freshwater ice, and the monitoring data include stress-strain relationship, fracture energy release behavior and the influence of temperature on deviatoric stress.

8. The constitutive model construction method for simulating the mechanical properties of freshwater ice according to claim 1, characterized in that: The iterative optimization method minimizes the error between the simulation results and the experimental data by adjusting the deviatoric stress coefficient and the yield strength in the yield criterion.

9. A constitutive model construction system for simulating the mechanical properties of freshwater ice, characterized in that: The method comprises a memory and a computer, wherein the memory stores an analysis program designed using the constitutive model construction method for simulating the mechanical properties of freshwater ice according to any one of claims 1 to 8, the computer is pre-installed with computer-aided design software and finite element analysis software, the computer is communicatively connected to the memory, runs the analysis program and associates the computer-aided design software and the finite element analysis software to automatically analyze the mechanical properties of freshwater ice, and outputs simulation results and stores them in the memory; The data stored in the memory include experimental data, simulation results and optimized model parameters.

10. The constitutive model construction system for simulating the mechanical properties of freshwater ice according to claim 9, characterized in that: It also includes a display, which is connected to the computer for communication, and the computer controls the display to display the simulation analysis process and simulation analysis results.

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