Thermal compensation design and implementation method for near-net-shape molding of thermoset composite component and based on temperature field and cure degree field

Abstract

The present application relates to the field of fiber-reinforced resin matrix composite molding, and in particular to a thermal compensation design and implementation method for the near-net-shape molding of a thermoset composite component and based on a temperature field and a cure degree field. The method comprises: establishing a minimum symmetric unit model on the basis of the size of a component, the size of a mold, and an ambient temperature; establishing a cure kinetics model and a heat transfer model; incorporating a molding temperature profile into a subprogram; on the basis of an obtained temperature field and an obtained cure degree field, performing simulated thermal compensation on regions where the temperature is lower than a molding temperature and the temperature difference from the molding temperature is greater than or equal to 5% of the molding temperature, until the difference between the temperature of each region and the current molding temperature is lower than 5% of the molding temperature; then, performing stimulated thermal compensation on regions where the cure degree is less than or equal to 0.9; and assembling a thermal compensation apparatus on the basis of a thermal compensation design scheme, performing experimental validation, and when the difference between an actually measured temperature value and a simulated value is less than 5% and the cure degree exceeds 0.9, obtaining a thermal compensation scheme and a thermal compensation method. The blindness of traditional molding that relies on experience is reduced.

Description

Design and implementation method of near-net-shape thermal compensation for thermosetting composite parts based on temperature field and curing degree field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application number 202410071351.5, filed with the Patent Office of China on January 18, 2024, entitled “Design and Implementation Method for Near-Net Shape Thermal Compensation of Thermosetting Composite Parts Based on Temperature Field and Curing Degree Field,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to the field of fiber-reinforced resin-based composite material molding, and in particular to a near-net-shape molding thermal compensation design and implementation method for thermosetting composite parts based on temperature field and curing degree field. Background Art

[0004] Fiber-reinforced resin-based composites are composed of resins (such as epoxy resins, phenolic resins, polyimide resins, and cyanate resins) and fibers (such as glass fiber, carbon fiber, and ultra-high molecular weight fiber). Due to their high specific strength and specific stiffness, they have been widely used in many fields that require good mechanical properties and weight reduction. The strength and integrity of the final composite parts depend to a large extent on the uniformity of the temperature field and the degree of cure field during the curing process. Therefore, the huge demand for fiber-reinforced resin-based composites in national defense and the national economy urgently requires research on the distribution of the temperature field and the degree of cure field of such materials during the curing process, and then through effective control, obtain high-quality near-net-shape parts.

[0005] Currently, the molding of fiber-reinforced resin-based composites primarily utilizes semi-empirical pure resin curing processes. For complex or thick parts, the temperature field distribution during the molding process is uneven. Temperature differences can lead to variations in the thermal strain and curing shrinkage strain of the composite material, ultimately causing curing deformation and performance degradation of the resulting part. Existing technologies primarily address temperature field differences on the mold surface caused by heat exchange with the external ambient temperature. However, research on temperature field distribution during composite molding is limited. Therefore, optimizing the internal temperature field of composite materials through thermal compensation is an important research direction.

[0006] In summary, the development of an economical and efficient thermal compensation design method for fiber-reinforced resin-based composites has important practical significance and application value.

[0007] Summary of the Invention

[0008] In order to make up for the defect of the existing technology that lacks the uniformity of the temperature field and curing degree field inside the composite material during the molding process through thermal compensation design, the present invention provides a near-net molding thermal compensation design and implementation method for thermosetting composite parts based on temperature field and curing degree field.

[0009] The present invention is achieved through the following technical solutions: a design and implementation method for near-net-shape thermal compensation of thermosetting composite parts based on temperature field and curing degree field, wherein the thermosetting composite material is composed of a thermosetting resin matrix and a fiber reinforcement phase;

[0010] The thermal compensation design and implementation method comprises the following steps:

[0011] S1. Establish a minimum symmetrical unit model based on the workpiece and mold dimensions and ambient temperature;

[0012] S2. Perform non-isothermal testing on the thermosetting resin matrix using a differential scanning calorimeter. Based on the change in heat flow, establish the relationship between the reaction rate and temperature during the curing process of the thermosetting resin matrix, and then establish a curing kinetics model.

[0013] S3. Test the parameters required for heat transfer analysis and establish a heat transfer model during the molding process;

[0014] S4. Incorporating the molding temperature curve into a subroutine, using the molding process temperature curve of the resin matrix in the first calculation, and using the molding process temperature curve with the thermal compensation design incorporated into the compensation region, i.e., the corrected molding process temperature curve of the resin matrix, in subsequent thermal compensation scheme design.

[0015] S5. Perform thermal-chemical coupling analysis on thermosetting composites to obtain the evolution of the composite temperature field and curing degree field during the molding process;

[0016] S6. Based on the temperature field and curing degree field distribution obtained in S5, simulated thermal compensation is performed on the area below the molding temperature and with a temperature difference from the molding temperature greater than or equal to 5% of the molding temperature, and steps S4 and S5 are repeated based on the corrected molding process temperature curve of the resin matrix until the temperature difference between all areas and the current molding temperature is less than 5% of the current molding temperature, which meets the design requirements and the temperature field distribution is considered uniform. At this time, if the curing degree of the thermosetting composite material in the simulated thermal compensation scheme is less than or equal to 0.9, further optimization of the simulated thermal compensation scheme is required based on the curing degree field, and the curing degree of the thermosetting composite material is increased by increasing the temperature of the thermal compensation area until the curing degree is greater than 0.9, which meets the design requirements. A thermal compensation design scheme that satisfies both the temperature field and the curing degree field is obtained.

[0017] S7, assembling a thermal compensation device according to the thermal compensation design scheme obtained in step S6, and measuring the temperature evolution of the compensation area during the molding process by an embedded temperature sensor;

[0018] S8. When the difference between the measured temperature value and the simulated temperature value is greater than or equal to 5%, the thermal compensation device needs to be further optimized until the difference between the measured temperature value and the simulated temperature value is less than 5%. The thermal compensation device is effective, and the final thermal compensation scheme and thermal compensation device based on the temperature field and the curing degree field are obtained.

[0019] As a further improvement of the technical solution of the present invention, in step S2, when establishing the curing kinetics model, a curing kinetics phenomenological model is adopted. The general form of the curing kinetics phenomenological model is:

[0020] Where: α is the degree of cure, K(T) is the curing rate constant of the resin matrix, and f(α) is the curing mechanism function;

[0021] The curing rate constant K(T) of the resin matrix is ​​usually expressed using the Arrhenius equation:

[0022] Where: A0 is the pre-exponential factor, E is the activation energy constant, R is the universal gas constant, and T is the absolute temperature;

[0023] The expression of the curing degree of the resin matrix during the molding process is: α=∫ t K(T)f(α)d(t).

[0024] As a further improvement of the technical solution of the present invention, in step S3, establishing a heat transfer model includes the following steps:

[0025] (1) The heat exchange mode between the thermosetting composite and the environment is the third type of temperature boundary condition; the heat exchange mode between the thermosetting composite and the mold is heat conduction;

[0026] (2) The parameters required for the test include the density ρ, specific heat capacity c, heat transfer coefficient k, convection heat transfer coefficient and thermal radiation coefficient of the thermosetting composite;

[0027] (3) Heat transfer analysis is performed using the three-dimensional nonlinear heat transfer equation, which is:

[0028] Where: ρ and c are the density and specific heat capacity of the thermosetting composite, respectively; k x 、k y 、k z are the heat transfer coefficients in the x, y, and z directions respectively; Q is the heat released by the resin curing reaction, which is defined as:

[0029] Where: v f is the volume fraction of the fiber reinforcement phase; ρ r is the resin density; H RIt is the heat released by the curing reaction of unit mass of resin matrix.

[0030] As a further improvement of the technical solution of the present invention, in step S4, the subroutine is a program written for secondary development of the Abaqus finite element method.

[0031] As a further improvement to the technical solution of the present invention, in step S5, performing the thermal-chemical coupling analysis further includes meshing the thermosetting composite part and the mold model. The mesh size in the length and width directions of the part should be less than or equal to 2% of the total size of the thermosetting composite part, and the meshing in the thickness direction should be no less than 10 layers.

[0032] As a further improvement to the technical solution of the present invention, in step S6, based on the temperature of each region in the thermal-chemical coupling analysis results, a Python script is used to calculate the difference between the temperature of each region of the thermosetting composite and the molding temperature, and the regions where the difference is greater than or equal to 5% of the molding temperature are screened for simulated thermal compensation design.

[0033] As a further improvement of the technical solution of the present invention, the thermosetting resin matrix in the thermosetting composite material is one of epoxy resin, phenolic resin, and unsaturated polyester resin, or a mixture of any of them.

[0034] As a further improvement of the technical solution of the present invention, the fiber reinforcement phase in the thermosetting composite is selected from one or a combination of any of carbon fiber, quartz fiber, glass fiber, basalt fiber, aramid fiber, ultra-high molecular weight polyethylene fiber, and poly(p-phenylene benzobisoxazole) fiber.

[0035] As a further improvement of the technical solution of the present invention, in step S7, the assembled thermal compensation device uses thermocouples as heat sources for compensation in areas where thermal compensation is required on the mold surface, or / and uses thin-film resistors as heat sources for compensation in areas where thermal compensation is required between the mold and the workpiece, or / and adds thermally conductive fillers to the areas between the workpiece layers corresponding to the areas where thermal compensation is required to construct a thermal conductive network.

[0036] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0037] (1) Due to the influence of heat released by the resin curing reaction and environmental heat exchange, the temperature field distribution of the thermosetting composite during the molding process is uneven. The difference in temperature distribution will lead to differences in the curing reaction rate of the thermosetting composite, and ultimately lead to differences in thermal strain, curing shrinkage strain, etc., resulting in residual stress and affecting the quality of the obtained parts. The present invention simulates and analyzes the temperature field and curing degree field during the thermosetting composite molding process, performs thermal compensation on areas with large temperature differences, and then performs thermal compensation on areas where the curing degree does not meet the requirements, thereby obtaining high-quality thermosetting composite near-net-shape parts.

[0038] (2) The present invention effectively combines the curing heat release inside the thermosetting composite material with the external heat exchange with the environment, which makes up for the defects of the existing temperature field analysis method that does not consider the internal heat generation during the thermosetting composite molding process.

[0039] (3) The present invention designs a thermal compensation scheme and its implementation method based on the distribution of temperature field and curing degree field, which can reduce the blindness and dependence of the traditional experience-based method currently commonly used in thermosetting composite molding, and reduce the trial and error costs of experiments and production. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0042] FIG1 is a flow chart of a method for designing and implementing near-net-shape thermal compensation for thermosetting composite parts based on temperature field and curing degree field according to the present invention.

[0043] FIG2 is a thermosetting composite part model and its boundary conditions according to Example 1 of the present invention.

[0044] FIG3 is a temperature curve of the thermosetting composite molding process according to Example 1 of the present invention.

[0045] FIG. 4 shows the temperature changes in the maximum temperature region and the minimum temperature region during the heat conduction process of Example 1 of the present invention.

[0046] FIG5 is a schematic diagram of experimental verification in Example 1 of the present invention. DETAILED DESCRIPTION

[0047] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0048] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all the embodiments.

[0049] The present invention provides a specific embodiment of a method for designing and implementing near-net-shape thermal compensation for a thermosetting composite part based on a temperature field and a curing degree field. The thermosetting composite is composed of a thermosetting resin matrix and a fiber reinforcement phase, and includes the following steps:

[0050] S1. Establish a minimum symmetrical unit model based on the workpiece and mold dimensions and ambient temperature;

[0051] S2. Perform non-isothermal testing on the thermosetting resin matrix using a differential scanning calorimeter. Based on the change in heat flow, establish the relationship between the reaction rate and temperature during the curing process of the thermosetting resin matrix, and then establish a curing kinetics model.

[0052] S3. Test the parameters required for heat transfer analysis and establish a heat transfer model during the molding process;

[0053] S4. Incorporating the molding temperature curve into a subroutine, using the molding process temperature curve of the resin matrix in the first calculation, and using the molding process temperature curve with the thermal compensation design incorporated into the compensation region, i.e., the corrected molding process temperature curve of the resin matrix, in subsequent thermal compensation scheme design.

[0054] S5. Perform thermal-chemical coupling analysis on thermosetting composites to obtain the evolution of the composite temperature field and curing degree field during the molding process;

[0055] S6. Based on the temperature field and curing degree field distribution obtained in S5, simulated thermal compensation is performed on the area below the molding temperature and with a temperature difference from the molding temperature greater than or equal to 5% of the molding temperature, and steps S4 and S5 are repeated based on the corrected molding process temperature curve of the resin matrix until the temperature difference between all areas and the current molding temperature is less than 5% of the current molding temperature, which meets the design requirements and the temperature field distribution is considered uniform. At this time, if the curing degree of the thermosetting composite material in the simulated thermal compensation scheme is less than or equal to 0.9, further optimization of the simulated thermal compensation scheme is required based on the curing degree field, and the curing degree of the thermosetting composite material is increased by increasing the temperature of the thermal compensation area until the curing degree is greater than 0.9, which meets the design requirements. A thermal compensation design scheme that satisfies both the temperature field and the curing degree field is obtained.

[0056] S7, assembling a thermal compensation device according to the thermal compensation design scheme obtained in step S6, and measuring the temperature evolution of the compensation area during the molding process by an embedded temperature sensor;

[0057] S8. When the difference between the measured temperature value and the simulated temperature value is greater than or equal to 5%, the thermal compensation device needs to be further optimized until the difference between the measured temperature value and the simulated temperature value is less than 5%. The thermal compensation device is effective, and the final thermal compensation scheme and thermal compensation device based on the temperature field and the curing degree field are obtained.

[0058] In one embodiment provided by the present invention, in step S2, when establishing the curing kinetics model, a curing kinetics phenomenological model is used. The general form of the curing kinetics phenomenological model is:

[0059] Where: α is the degree of cure, K(T) is the curing rate constant of the resin matrix, and f(α) is the curing mechanism function;

[0060] The curing rate constant K(T) of the resin matrix is ​​usually expressed using the Arrhenius equation:

[0061] Where: A0 is the pre-exponential factor, E is the activation energy constant, R is the universal gas constant, and T is the absolute temperature;

[0062] The expression of the curing degree of the resin matrix during the molding process is: α=∫ t K(T)f(α)d(t).

[0063] In another embodiment provided by the present invention, in step S3, establishing a heat transfer model includes the following steps:

[0064] (1) The heat exchange mode between the thermosetting composite and the environment is the third type of temperature boundary condition; the heat exchange mode between the thermosetting composite and the mold is heat conduction;

[0065] (2) The parameters required for the test include the density ρ, specific heat capacity c, heat transfer coefficient k, convection heat transfer coefficient and thermal radiation coefficient of the thermosetting composite;

[0066] (3) Heat transfer analysis is performed using the three-dimensional nonlinear heat transfer equation, which is:

[0067] Where: ρ and c are the density and specific heat capacity of the thermosetting composite, respectively; k x 、k y 、k z are the heat transfer coefficients in the x, y, and z directions respectively; Q is the heat released by the resin curing reaction, which is defined as:

[0068] Where: v f is the volume fraction of the fiber reinforcement phase; ρ r is the resin density; H R It is the heat released by the curing reaction of unit mass of resin matrix.

[0069] In one embodiment provided by the present invention, in step S4, the subroutine is a program written for secondary development of the Abaqus finite element method.

[0070] In another embodiment provided by the present invention, in step S5, performing the thermal-chemical coupling analysis further includes meshing the thermosetting composite part and the mold model. The mesh size in the length and width directions of the part should be less than or equal to 2% of the total size of the thermosetting composite part, and the meshing in the thickness direction should be no less than 10 layers.

[0071] In one embodiment provided by the present invention, in step S6, based on the temperature of each region in the thermal-chemical coupling analysis results, a Python script is used to calculate the difference between the temperature of each region of the thermosetting composite and the molding temperature, and the regions where the difference is greater than or equal to 5% of the molding temperature are screened for simulated thermal compensation design.

[0072] In another embodiment provided by the present invention, the thermosetting resin matrix in the thermosetting composite material is one of epoxy resin, phenolic resin, and unsaturated polyester resin, or a mixture of any of them.

[0073] In one embodiment provided by the present invention, the fiber reinforcement phase in the thermosetting composite is selected from one or a combination of carbon fiber, quartz fiber, glass fiber, basalt fiber, aramid fiber, ultra-high molecular weight polyethylene fiber, poly(p-phenylene benzobisoxazole) fiber.

[0074] In another embodiment provided by the present invention, in step S7, the assembled thermal compensation device uses thermocouples as heat sources for compensation in areas where thermal compensation is required on the mold surface, or / and uses thin-film resistors as heat sources for compensation in areas where thermal compensation is required between the mold and the workpiece, or / and adds thermally conductive fillers to corresponding areas where thermal compensation is required between the workpiece layers to construct a thermal conductive network.

[0075] The specific embodiments of the present invention are described in detail below.

[0076] Example 1

[0077] A method for designing and implementing near-net-shape thermal compensation for thermosetting composite parts based on temperature field and curing degree field, comprising the following steps:

[0078] S1. The thermosetting resin matrix of the thermosetting composite is E-51 epoxy resin, and the fiber reinforcement phase is carbon fiber cloth. The molding process is adopted, and the mold size is 300*300*6mm. According to its symmetrical structure, 1 / 8 area is selected to establish a three-dimensional solid model (150*150*3mm) as the minimum symmetrical unit model.

[0079] S2. Non-isothermal testing of the epoxy resin matrix was performed using a differential scanning calorimeter. By testing the change in the heat of the epoxy curing reaction at different heating rates (5°C / min, 10°C / min, 15°C / min, and 20°C / min), a curing kinetics model of the epoxy resin was established. A curing kinetics phenomenological model was used. The general form of the curing kinetics phenomenological model is: Where: α is the degree of curing, K(T) is the curing rate constant of epoxy resin, and f(α) is the curing mechanism function;

[0080] Where: k1, k2, k3 are epoxy curing reaction constants, R is the gas constant, A i is the pre-exponential factor (A1=1.98*10 9 , A2=-2.35*10 9 , A3=2.21*10 5 ), ΔE is the activation energy constant (7.12*10 4 ), R is the universal gas constant, and T is the absolute temperature.

[0081] Expression for change of epoxy resin curing degree:

[0082] Where: α t It represents the degree of solidification at time t, and Δt represents the time of each incremental step.

[0083] S3. Test the parameters required for heat transfer analysis and establish a heat transfer model during the molding process, including the following steps:

[0084] (1) The heat exchange mode between the epoxy / carbon fiber cloth composite and the environment is the third type of temperature boundary condition, and the heat exchange mode between the epoxy / carbon fiber cloth composite and the mold is heat conduction;

[0085] (2) The parameters required for the test are: the density of the epoxy / carbon fiber cloth composite is ρ 1680 kg / m 3 , epoxy resin ρ r The density is 1210kg / m 3 , the specific heat capacity c is 918J / (kg·K), the volume fraction of carbon fiber cloth v f is 60%, the heat transfer coefficient k x 、k y 、k z They are 4.3W / (K·m), 4.3W / (K·m), and 0.4W / (K·m), respectively, and the heat convection heat transfer coefficient is 5W / (m 2 ·k).

[0086] (3) Heat transfer analysis is performed using the three-dimensional nonlinear heat transfer equation, which is:

[0087] Where: ρ and c are the density and specific heat capacity of epoxy / carbon fiber cloth composite respectively; k x 、k y 、k z are the heat transfer coefficients in the x, y, and z directions, respectively; Q is the heat released by the resin curing reaction;

[0088] Where: v f is the volume fraction of carbon fiber cloth; ρ r is the density of epoxy resin; H R It is the heat released by the curing reaction of unit mass of epoxy resin matrix.

[0089] According to calculation, the heat released by the curing reaction of unit mass epoxy resin matrix H R The heat transfer coefficient between the mold and the epoxy / carbon fiber composite is 10 5 W / (m 2 .k).

[0090] S4. During the first calculation, the epoxy resin molding process temperature curve is compiled into the Abaqus subroutine.

[0091] S5. Perform a thermochemical coupling analysis on the epoxy / carbon fiber cloth composite to obtain the evolution of the composite temperature field and curing degree field during the molding process. In the thermochemical coupling analysis, set the mesh size of the epoxy / carbon fiber cloth composite part to 0.5 mm in the length and width directions and 0.005 mm in the thickness direction.

[0092] S6. Based on the temperature and cure field distributions obtained in S5, during the molding process, the maximum temperature difference between the corners and the center of the epoxy / carbon fiber composite part was 15.6°C (exceeding 5% of the molding process temperature). Therefore, the corners were selected for simulated thermal compensation. The simulated temperature compensation range was 10-20°C, and the simulated compensation area was 20 x 20 mm, as shown in Figure 4. Steps S4 and S5 were repeated again. In subsequent iterations, the corrected epoxy matrix molding process temperature curve was incorporated into the subroutine for the areas requiring thermal compensation. The temperature curves for the remaining areas remained the epoxy resin molding process temperature curve. After simulated thermal compensation, the maximum temperature difference between all areas and the current molding temperature dropped to 4.7°C. The temperature difference in all areas was less than 5% of the current molding temperature, meeting the design requirements, and the temperature field distribution was considered uniform. At this point, the cure degree of the epoxy / carbon fiber composite in the thermal compensation scheme was 0.98 to 1, meeting the design requirements. Therefore, a thermal compensation design scheme that satisfies both the temperature and cure fields was obtained.

[0093] S7. Assemble a thermal compensation device according to the thermal compensation design scheme obtained in step S6. The thermal compensation device is a thin-film resistor (20*20 mm). Place it in the eight corner areas of the upper and lower surfaces of the epoxy / carbon fiber cloth composite part. Embed temperature sensors in the corner areas and the center to test temperature changes during the molding process.

[0094] S8. The difference between the measured temperature value and the simulated temperature value is within 1°C and less than 5% of the simulated temperature value. The thermal compensation range is determined to be 10-20°C and the compensation area is 20*20mm as the final thermal compensation solution. In the areas where thermal compensation is required, 20*20mm thin-film resistance thermal compensation devices are installed in the eight corner areas on the upper and lower surfaces of the epoxy / carbon fiber cloth composite parts as the final thermal compensation implementation plan.

[0095] The above description is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Although detailed descriptions have been made with reference to the aforementioned embodiments, those skilled in the art should understand that they may still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents; and such modifications or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the technical solutions of the embodiments, and they should all be included in the scope of protection of the claims.

Claims

1. A near-net shaping thermal compensation design and implementation method for thermoset composite parts based on temperature field and degree of cure field, characterized in that the thermoset composite consists of a thermosetting resin matrix and a fiber reinforcement phase; The thermal compensation design and implementation method includes the following steps: S1. Establish a minimum symmetric unit model according to the part and mold dimensions and the ambient temperature; S2. Perform non-isothermal tests on the thermosetting resin matrix using a differential scanning calorimeter. According to the change in heat flow, establish the relationship between the reaction rate and temperature during the curing process of the thermosetting resin matrix, and then establish a curing kinetics model; S3. Test the parameters required for heat transfer analysis and establish a heat transfer model during the forming process; S4. Incorporate the forming temperature curve into a subroutine. In the first calculation, use the forming process temperature curve of the resin matrix. In the subsequent thermal compensation scheme design, use the forming process temperature curve with thermal compensation design added in the compensation area, that is, the modified forming process temperature curve of the resin matrix; S5. Conduct thermo-chemical coupling analysis on the thermoset composite to obtain the evolution of the temperature field and degree of cure field of the composite during the forming process; S6. Based on the temperature field and degree of cure field distributions obtained in S5, perform simulated thermal compensation on the area where the temperature is lower than the forming temperature and the temperature difference from the forming temperature is greater than or equal to 5% of the forming temperature. Repeat steps S4 and S5 based on the modified forming process temperature curve of the resin matrix until the temperature difference between all areas and the current forming temperature is lower than 5% of the current forming temperature, meeting the design requirements and considering the temperature field distribution to be uniform; At this time, if the degree of cure of the thermoset composite in the simulated thermal compensation scheme is less than or equal to 0.9, further optimization of the simulated thermal compensation scheme is required based on the degree of cure field. By increasing the temperature in the thermal compensation area, the degree of cure of the thermoset composite is increased until the degree of cure is greater than 0.9, meeting the design requirements; Obtain a thermal compensation design scheme that simultaneously meets the temperature field and degree of cure field; S7. Assemble the thermal compensation device according to the thermal compensation design scheme obtained in step S6, and measure the temperature evolution in the compensation area during the forming process through buried temperature sensors; S8. When the difference between the measured temperature value and the simulated temperature value is greater than or equal to 5%, the thermal compensation device needs to be further optimized until the difference between the measured temperature value and the simulated temperature value is less than 5%, the thermal compensation device is effective, and the final thermal compensation scheme and thermal compensation device based on the temperature field and degree of cure field are obtained.

2. A near-net shaping thermal compensation design and implementation method for thermosetting composite parts based on temperature field and degree of cure field according to claim 1, characterized in that, in step S2, when establishing the curing kinetics model, a phenomenological model of curing kinetics is adopted, and the general form of the phenomenological model of curing kinetics is: Where: α is the degree of cure, K(T) is the curing rate constant of the resin matrix, and f(α) is the curing mechanism function; The curing rate constant K(T) of the resin matrix is usually expressed by the Arrhenius equation: Where: A0 is the pre-exponential factor, E is the activation energy constant, R is the universal gas constant, and T is the absolute temperature; The expression for the degree of cure of the resin matrix during the forming process is: α = ∫ t K(T)f(α)d(t).

3. The near-net shaping thermal compensation design and implementation method for thermoset composite parts based on temperature field and degree of cure field according to claim 1, characterized in that in step S3, establishing the heat transfer model includes the following steps: (1) The heat exchange mode between the thermoset composite and the environment is the third kind of temperature boundary condition; the heat exchange mode between the thermoset composite and the mold is heat conduction; (2) Test the parameters to be input, including the density ρ, specific heat capacity c, heat transfer coefficient k, convective heat transfer coefficient, and thermal radiation coefficient of the thermosetting composite material. (3) Thermal transfer analysis is carried out using a three-dimensional non-linear heat transfer equation, and the equation is as follows: where ρ and c are the density and specific heat capacity of the thermosetting composite material, respectively; k x , k y , k z are the heat transfer coefficients in the x, y, and z axis directions, respectively; Q is the heat released by the resin curing reaction, defined as: where: v f is the volume fraction of the fiber-reinforced phase; ρ r is the resin density; H R is the heat released by the curing reaction of the resin matrix per unit mass.

4. A near-net shape thermal compensation design and implementation method for thermosetting composite parts based on temperature field and degree of cure field according to claim 1, characterized in that in step S4, the subroutine is a program written by secondary development of Abaqus finite element.

5. A near-net shape thermal compensation design and implementation method for thermosetting composite parts based on temperature field and degree of cure field according to claim 1, characterized in that in step S5, performing thermo-chemical coupling analysis further includes meshing the thermosetting composite part and the mold model. The mesh size in the length and width directions of the part should be less than or equal to 2% of the total size of the thermosetting composite part, and the meshing in the thickness direction should have no less than 10 layers of meshes.

6. A near-net shape thermal compensation design and implementation method for thermosetting composite parts based on temperature field and degree of cure field according to claim 1, characterized in that in step S6, according to the temperatures of each region in the thermo-chemical coupling analysis results, use Python script to calculate the difference between the temperatures of each region of the thermosetting composite material lower than the forming temperature, and screen the regions where the difference is greater than or equal to 5% of the forming temperature for simulated thermal compensation design.

7. A near-net shape thermal compensation design and implementation method for thermosetting composite parts based on temperature field and degree of cure field according to claim 1, characterized in that the thermosetting resin matrix in the thermosetting composite material is one or a mixture of any several of epoxy resin, phenolic resin, and unsaturated polyester resin.

8. A near-net shape thermal compensation design and implementation method for thermosetting composite parts based on temperature field and degree of cure field according to claim 1, characterized in that the fiber reinforcement phase is selected from one or any combination of carbon fiber, quartz fiber, glass fiber, basalt fiber, aramid fiber, ultra-high molecular weight polyethylene fiber, and poly(p-phenylene benzobisoxazole) fiber.

9. A near-net shape thermal compensation design and implementation method for thermosetting composite parts based on temperature field and degree of cure field according to claim 1, characterized in that in step S7, the assembled thermal compensation device compensates using a thermocouple as a heat source in the area on the mold surface that requires thermal compensation, and / or compensates using a thin-film resistor as a heat source in the area between the mold and the part that requires thermal compensation, and / or adds a heat-conducting filler in the corresponding area between the layers of the part to construct a heat-conducting network.

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