A valve-side sleeve core flange stress analysis and cracking risk assessment method and system

Abstract

This invention discloses a method and system for stress analysis and crack risk assessment of a valve-side bushing core flange, relating to the field of valve-side bushing stress analysis technology. The method includes: calculating the heat source power of the valve-side bushing under consideration of harmonic effects based on the heat generation under power frequency current and harmonic heating enhancement coefficient; simulating the temperature field of the valve-side bushing considering heat conduction and heat countermeasures to obtain the temperature field distribution; constructing a mechanical stress field model of the valve-side bushing; using the temperature field distribution as the thermal boundary condition of the mechanical stress field model to simulate the stress field of the valve-side bushing, obtaining the stress field distribution; and assessing the crack risk of the valve-side bushing based on the stress field distribution combined with the material mechanical strength parameters of the valve-side bushing. This invention alleviates the technical problem of inaccurate stress analysis caused by neglecting the influence of temperature on the bushing material in the simulation scheme in existing technologies.

Description

Technical Field

[0001] This invention relates to the field of valve side bushing stress analysis technology, and in particular to a method and system for stress analysis and cracking risk assessment of valve side bushing core flange. Background Technology

[0002] The ±800kV dry-type valve-side bushing core adopts a high aspect ratio structure design, with a cantilever length of up to 10m, and the core itself bears a significant mechanical load. The valve-side bushing carries a large current, but the epoxy resin impregnated paper has poor thermal conductivity. Considering the effects of temperature, the mechanical strength of the epoxy resin impregnated paper material will decrease. Simultaneously, the difference in the coefficients of thermal expansion between the core and flange materials can easily create significant stress at the interface. Especially under extreme environmental temperatures, the core is at risk of cracking, posing a serious threat to the stable operation of the power system.

[0003] The function of the bushing metal flange is to fix the valve-side bushing to the riser seat of the converter transformer tank. As the weak point connecting the bushing and the converter transformer, the flange will bear the weight of the bushing and the alternating stress caused by the transformer vibration at the same time. Under the action of vibration load, fatigue failure and cracking are likely to occur in the stress concentration area.

[0004] In terms of experiments, scholars mainly use shaking tables to test and analyze the seismic performance of transformer bushings. Since the bushing itself does not vibrate, but the vibration of the bushing is caused by the vibration of the transformer itself, a large number of studies focus on the transformer-bushing system as the evaluation object; in addition to transformers, the seismic performance of reactor-bushing systems is also one of the research focuses.

[0005] In simulation, with the improvement of computer performance and the development of finite element algorithms, it has become possible to simulate complex models with detailed structures, strong parametric nonlinearity, and complex physical field coupling. Many scholars have used finite element simulation to identify the stresses experienced by various parts of the casing during earthquakes and the stress distribution under different conditions, and to discover weak points in the casing system by establishing finite element analysis models. Compared with experimental research, simulation research is less costly, more targeted, and can simulate various working conditions, even extreme conditions. Therefore, many scholars use finite element simulation to study casing performance and its influencing factors.

[0006] Although vibration test results are closest to the real situation, they have problems such as few measuring points, difficulty in reflecting the distribution of physical fields inside the bushing, and high cost of test specimens and site fees. Existing simulation studies mainly focus on the seismic performance of bushings, and the vibration load applied to the bushing is a constant load. In addition, the operating environment of the bushing is complex, and the material is affected by temperature, which will cause thermal expansion and temperature changes. Existing simulation studies ignore the influence of temperature on the core and flange. Summary of the Invention

[0007] To address the aforementioned technical problems in the existing technology, embodiments of the present invention provide a method and system for stress analysis and crack risk assessment of valve-side sleeve core flange. The technical solution is as follows: On the one hand, a method for stress analysis and crack risk assessment of valve-side bushing core flange is provided. The method includes: constructing a three-dimensional finite element model based on the mechanical and material parameters of the valve-side bushing to be assessed; calculating the heat source power of the temperature field of the valve-side bushing to be assessed under the consideration of harmonic effects based on the heat generation under the action of power frequency current and the harmonic heating enhancement coefficient; performing temperature field simulation of the valve-side bushing to be assessed considering heat conduction and heat countermeasure based on the three-dimensional finite element model and the heat source power to obtain the temperature field distribution; applying loads to the three-dimensional finite element model and adding thermal expansion constraints to construct a mechanical stress field model of the valve-side bushing to be assessed; using the temperature field distribution as the thermal field boundary condition of the mechanical stress field model to simulate the stress field of the valve-side bushing to be assessed to obtain the stress field distribution; and assessing the crack risk of the valve-side bushing to be assessed based on the stress field distribution and the material mechanical strength parameters of the valve-side bushing to be assessed.

[0008] Optionally, the formula for calculating the harmonic heating enhancement coefficient includes: In the formula, , ; k h The harmonic heating enhancement coefficient is... The heating enhancement coefficient considering the skin effect under harmonic effects. The heating enhancement coefficient considering the skin effect under power frequency current is given. The harmonic angular frequency, ω is the angular frequency of the power frequency current, μ is the permeability of free space, γ is the conductivity of the central conductor, j is the imaginary unit, and I is the angular frequency of the power frequency current. h I is the value of the h-th harmonic current. RMS , where is the effective value of the current spectrum, a and b are the outer and inner diameters of the current-carrying tube, respectively, and K1 is the first and second type of modified Bessel functions of the first order; The formula for calculating the power of the heat source includes: In the formula, P h P is the power of the heat source. RMS The heat generated under the action of the power frequency current.

[0009] Optionally, applying loads to the three-dimensional finite element model includes: operating the valve side sleeve to be evaluated under rated load conditions, applying a vertically downward gravity force to the valve side sleeve to be evaluated, setting the lower end of the oil tank of the valve side sleeve to be evaluated as a fixed constraint, and applying a cantilever load tension to the gas end terminal.

[0010] Optionally, the cracking risk of the valve-side sleeve to be evaluated is assessed based on the stress field distribution and the mechanical strength parameters of the core material of the sleeve to be evaluated, including: calculating the mechanical strength parameters of the core material based on the temperature field distribution; obtaining the mechanical strength parameters of the flange material based on the multi-stress ratio SN curve; the mechanical strength parameters include the tensile strength and compressive strength of the material; determining the principal stresses on the target part of the valve-side sleeve to be evaluated based on the stress field distribution; constructing a cracking risk factor based on the principal stresses and the mechanical strength parameters; and assessing the cracking risk of the target part of the valve-side sleeve to be evaluated based on the cracking risk factor.

[0011] Optionally, the formula for calculating the cracking risk factor includes: In the formula, R is the cracking risk factor. The principal stress, The tensile strength of the material. The compressive strength of the material is given by T, where T represents temperature.

[0012] Optionally, based on the cracking risk factor, assessing the cracking risk of the target location on the valve-side sleeve to be assessed includes: if the absolute value of the cracking risk factor is less than a first preset threshold, then assessing the cracking risk as low risk; if the absolute value of the cracking risk factor is greater than or equal to the first preset threshold and less than a second preset threshold, then assessing the cracking risk as medium risk; the first preset threshold is less than the second preset threshold; if the absolute value of the cracking risk factor is greater than or equal to the second preset threshold, then assessing the cracking risk as high risk.

[0013] On the other hand, a system for stress analysis and cracking risk assessment of valve-side bushing core flange is also provided, used to implement the method for stress analysis and cracking risk assessment of valve-side bushing core flange provided in the embodiments of the present invention; the system includes: a first construction module, a calculation module, a first simulation module, a second construction module, a second simulation module, and an evaluation module; wherein, the first construction module is used to construct a three-dimensional finite element model based on the mechanical and material parameters of the valve-side bushing to be evaluated; the calculation module is used to calculate the heat source power of the temperature field of the valve-side bushing to be evaluated under the consideration of harmonic effects based on the heat generation under the action of power frequency current and the harmonic heating enhancement coefficient; the first simulation module, The first module is used to simulate the temperature field of the valve side sleeve to be evaluated based on the three-dimensional finite element model and the power of the heat source, taking into account heat conduction and heat countermeasure, to obtain the temperature field distribution; the second construction module is used to apply loads to the three-dimensional finite element model and add thermal expansion constraints to construct the mechanical stress field model of the valve side sleeve to be evaluated; the second simulation module is used to simulate the stress field of the valve side sleeve to be evaluated using the temperature field distribution as the thermal field boundary condition of the mechanical stress field model, to obtain the stress field distribution; the evaluation module is used to evaluate the cracking risk of the valve side sleeve to be evaluated based on the stress field distribution and the material mechanical strength parameters of the valve side sleeve to be evaluated.

[0014] Optionally, the evaluation module is further configured to: calculate the mechanical strength parameters of the core material based on the temperature field distribution; obtain the mechanical strength parameters of the flange material based on the multi-stress ratio SN curve; the mechanical strength parameters include the tensile strength and compressive strength of the material; determine the principal stress on the target part of the valve side sleeve to be evaluated based on the stress field distribution; construct a cracking risk factor based on the principal stress and the mechanical strength parameters; and evaluate the cracking risk of the target part of the valve side sleeve to be evaluated based on the cracking risk factor.

[0015] On the other hand, an electronic device is also provided, including: a memory, a processor, and a computer program stored on the memory and running on the processor, wherein the processor executes the computer program to implement the method provided in the embodiments of the present invention.

[0016] On the other hand, a computer-readable storage medium is also provided, which stores computer instructions that, when executed by a processor, implement the method provided in the embodiments of the present invention.

[0017] This invention provides a method and system for stress analysis and crack risk assessment of valve-side bushing core flange. It employs a principle of equivalent heating to obtain the harmonic heating enhancement coefficient of the valve-side bushing, while simultaneously considering heat conduction and convection to calculate the steady-state temperature field during bushing operation. Using a mechanical stress field model considering thermal expansion, it obtains the stress field distribution of the bushing core and flange in accordance with the bushing's operating environment, defines a crack risk coefficient, and obtains the value range of the crack risk coefficient based on a safety factor. By comparing the current crack coefficients of the bushing core / flange, it ultimately assesses the crack risk of the bushing. This invention alleviates the technical problem of inaccurate stress analysis caused by neglecting the influence of temperature on the bushing material in existing simulation schemes. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A flowchart of a method for stress analysis and cracking risk assessment of a valve-side bushing core flange provided in an embodiment of the present invention; Figure 2 A schematic diagram of a three-dimensional model of a valve-side sleeve provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the temperature field distribution of the valve-side sleeve provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of a valve-side bushing core flange stress analysis and cracking risk assessment system provided in an embodiment of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1 Figure 1 This is a flowchart illustrating a method for stress analysis and cracking risk assessment of a valve-side bushing core flange according to an embodiment of the present invention. Figure 1 As shown, the method specifically includes the following steps: Step S102: Based on the mechanical and material parameters of the valve-side sleeve to be evaluated, construct a three-dimensional finite element model.

[0022] Step S104: Based on the heat generation under the action of power frequency current and the harmonic heating enhancement coefficient, calculate the heat source power of the temperature field of the valve side bushing to be evaluated under the consideration of harmonic action.

[0023] Step S106: Based on the three-dimensional finite element model and the power of the heat source, the temperature field of the sleeve on the valve side to be evaluated is simulated, taking into account heat conduction and heat countermeasure, to obtain the temperature field distribution.

[0024] Step S108: Apply loads to the three-dimensional finite element model and add thermal expansion constraints to construct a mechanical stress field model of the valve side sleeve to be evaluated.

[0025] Step S110: The temperature field distribution is used as the thermal field boundary condition of the mechanical stress field model to simulate the stress field of the valve side sleeve to be evaluated, and the stress field distribution is obtained.

[0026] Step S112: Based on the stress field distribution and the material mechanical strength parameters of the valve side sleeve to be evaluated, assess the cracking risk of the valve side sleeve to be evaluated.

[0027] Figure 2 This is a schematic diagram of a three-dimensional model of a valve-side sleeve according to an embodiment of the present invention. Figure 2 As shown, the present invention first uses a three-dimensional model of the structural components of the valve side sleeve, and then constructs a three-dimensional finite element model based on the three-dimensional model for subsequent simulation.

[0028] Preferably, the mechanical parameters of the valve-side bushing to be evaluated include: density, coefficient of thermal expansion, thermal conductivity, specific heat capacity, elastic modulus, and Poisson's ratio; the material parameters include: copper, aluminum alloy, fiberglass, and epoxy resin impregnated paper. Then, based on the actual operating environment of the valve-side bushing to be evaluated, the operating environment temperature and temperature field boundary are determined. The temperature field boundary includes the valve hall temperature, ambient temperature, and room temperature (as a control group).

[0029] Specifically, the calculation process for the heat source power of the valve-side bushing under the consideration of harmonic effects is as follows: First, according to the principle of equivalent heating, the harmonic heating enhancement coefficient k is obtained by taking the first 50 harmonics. h : In the formula, P h P is the power of the heat source. RMS The heat generated under the action of power frequency current, k h The harmonic heating enhancement coefficient, The heating enhancement coefficient considering the skin effect under harmonic effects. I is the heat enhancement coefficient considering the skin effect under power frequency current. hI is the value of the h-th harmonic current. RMS R is the effective value of the current spectrum. h R is the AC resistance under the h-th harmonic current. ac R is the AC resistance under power frequency current. dc This is the DC resistance per unit length of conductor.

[0030] Specifically, when harmonic current flows through the conductive rod, the skin effect occurs, reducing the actual effective cross-sectional area of ​​the conductor, thus increasing resistance and generating more heat. Therefore, the degree of heating in the valve-side bushing varies under different harmonics. It cannot be calculated solely by the effective value of the current spectrum; rather, the "enhancing" effect of the skin effect caused by different harmonic frequencies on heat generation must be considered. Consequently, it is necessary to calculate the harmonic enhancement coefficient.

[0031] Specifically, the formula for calculating the heat enhancement coefficient includes: , ; In the formula, k1 and k2 are intermediate calculation parameters. The harmonic angular frequency, ω is the angular frequency of the power frequency current, μ is the permeability of free space, γ is the conductivity of the central conductor, j is the imaginary unit, a and b are the outer and inner diameters of the current-carrying tube, respectively, and K1 is the first and second kind of modified Bessel functions of the first order. Therefore, the formulas for calculating the power of the heat source can be obtained as follows: The heat transfer in the valve-side bushing mainly occurs through heat conduction between the conductive rod and the core, and heat convection between the bushing and the air. Therefore, the heat transfer method in the simulation must consider both heat conduction and heat convection. By setting the remaining external boundaries as free boundaries, the temperature field distribution can be calculated, as follows: Figure 3 As shown.

[0032] Specifically, applying loads to the three-dimensional finite element model in step S108 includes: operating the valve side sleeve to be evaluated under rated load conditions, applying a vertically downward gravity force to the valve side sleeve to be evaluated, setting the lower end of the oil tank of the valve side sleeve to be evaluated as a fixed constraint, and applying a cantilever load tension to the gas end terminal.

[0033] Specifically, step S112 further includes the following steps: Step S1121: Calculate the mechanical strength parameters of the core material based on the temperature field distribution, and obtain the mechanical strength parameters of the flange material based on the multi-stress ratio SN curve; the mechanical strength parameters include the tensile strength and compressive strength of the material.

[0034] For example, the mechanical strength parameters of the core material under steady-state temperature field conditions include: In the formula, T represents the temperature of the core material. For the tensile strength of the material, This refers to the compressive strength of the material.

[0035] For metal flange materials, the tensile strength and compressive strength of the material can be determined based on the multi-stress ratio SN curve (Stress-Life Curve).

[0036] Step S1122: Based on the stress field distribution, determine the principal stress on the target part of the valve side sleeve to be evaluated.

[0037] Step S1123: Construct cracking risk factors based on principal stress and mechanical strength parameters.

[0038] Specifically, at higher temperatures, the core expands due to heat, and the stress it experiences is primarily compressive stress; at lower temperatures, the core contracts in volume, and due to its adhesion to the flange, the stress it experiences is primarily tensile stress. Correspondingly, in addition to the compressive stress generated by gravity, the flange will also experience compressive or tensile stress due to the expansion and contraction of the core caused by temperature. Therefore, the cracking risk factor R of the core / flange constructed in this embodiment of the invention is: In the formula, R is the cracking risk factor. The principal stress.

[0039] Step S1124: Based on the cracking risk factor, assess the cracking risk of the target location on the valve-side sleeve to be assessed. Specifically, this includes: If the absolute value of the cracking risk factor is less than the first preset threshold, the cracking risk is assessed as low risk. If the absolute value of the cracking risk factor is greater than or equal to the first preset threshold and less than the second preset threshold, the cracking risk is assessed as medium risk; the first preset threshold is less than the second preset threshold. If the absolute value of the cracking risk factor is greater than or equal to the second preset threshold, the cracking risk is assessed as high risk.

[0040] Optionally, Table 1 is a comparison table of cracking risk factors and cracking risk levels provided according to embodiments of the present invention: Table 1 In an optional embodiment of the present invention, the cracking risk R of the core can be calculated separately based on multi-point calculation results. x Risk of flange cracking Rf For example, the cracking risk factor of the part with the highest cracking risk on the core / flange can be taken as the cracking risk factor of the core / flange; then the maximum value R = max{R x ,R f This will be used as an evaluation result.

[0041] As described above, the embodiments of the present invention provide a method and system for stress analysis and crack risk assessment of valve side bushing core flange. It comprehensively considers the influence of temperature on bushing material, and can more accurately perform stress analysis and crack risk assessment on bushing material, thus alleviating the technical problem of inaccurate stress analysis caused by ignoring the influence of temperature on bushing material in the simulation scheme in the prior art.

[0042] Example 2 Figure 4 This is a schematic diagram of a valve-side bushing core flange stress analysis and cracking risk assessment system provided by an embodiment of the present invention. Figure 4 As shown, the system includes: a first building module 10, a calculation module 20, a first simulation module 30, a second building module 40, a second simulation module 50, and an evaluation module 60.

[0043] Specifically, the first construction module 10 is used to construct a three-dimensional finite element model based on the mechanical and material parameters of the valve side sleeve to be evaluated; Calculation module 20 is used to calculate the heat source power of the valve side bushing under the consideration of harmonic effects based on the heat generation under the action of power frequency current and the harmonic heating enhancement coefficient. The first simulation module 30 is used to simulate the temperature field of the valve side sleeve to be evaluated based on a three-dimensional finite element model and the power of the heat source, taking into account heat conduction and heat countermeasure, and to obtain the temperature field distribution. The second construction module 40 is used to apply loads to the three-dimensional finite element model and add thermal expansion constraints to construct a mechanical stress field model of the valve side sleeve to be evaluated. The second simulation module 50 is used to simulate the stress field of the valve side sleeve to be evaluated by using the temperature field distribution as the thermal field boundary condition of the mechanical stress field model, and obtain the stress field distribution. Evaluation module 60 is used to assess the cracking risk of the valve side sleeve based on the stress field distribution and the material mechanical strength parameters of the valve side sleeve to be evaluated.

[0044] Specifically, the evaluation module 60 is also used for: The mechanical strength parameters of the core material are calculated based on the temperature field distribution, and the mechanical strength parameters of the flange material are obtained based on the multi-stress ratio SN curve. The mechanical strength parameters include the tensile strength and compressive strength of the material. Based on the stress field distribution, the principal stresses on the target part of the valve side sleeve to be evaluated are determined. Based on principal stress and mechanical strength parameters, a cracking risk factor is constructed; Based on the cracking risk factor, assess the cracking risk of the target location on the valve-side sleeve to be evaluated.

[0045] The present invention also provides an electronic device, including: a memory, a processor, and a computer program stored on the memory and running on the processor, wherein the processor executes the computer program to implement the method provided in the embodiments of the present invention.

[0046] The present invention also provides a computer-readable storage medium storing computer instructions that, when executed by a processor, implement the method provided in the embodiments of the present invention.

[0047] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0048] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for stress analysis and crack risk assessment of valve-side sleeve core flange, characterized in that, The method includes: A three-dimensional finite element model is constructed based on the mechanical and material parameters of the valve side sleeve to be evaluated. Based on the heat generation under the action of power frequency current and the harmonic heating enhancement coefficient, the heat source power of the temperature field of the valve side bushing to be evaluated under the consideration of harmonic action is calculated. Based on the three-dimensional finite element model and the power of the heat source, the temperature field of the valve side sleeve to be evaluated is simulated considering heat conduction and heat countermeasure, and the temperature field distribution is obtained. A load is applied to the three-dimensional finite element model and a thermal expansion constraint is added to construct a mechanical stress field model of the valve side sleeve to be evaluated; The temperature field distribution is used as the thermal field boundary condition of the mechanical stress field model to simulate the stress field of the valve side sleeve to be evaluated, and the stress field distribution is obtained. Based on the stress field distribution and the material mechanical strength parameters of the valve side sleeve to be evaluated, the cracking risk of the valve side sleeve to be evaluated is assessed.

2. The method according to claim 1, characterized in that: The formula for calculating the harmonic heating enhancement coefficient includes: In the formula, ， ； k h The harmonic heating enhancement coefficient is... The heating enhancement coefficient considering the skin effect under harmonic effects. The heating enhancement coefficient considering the skin effect under power frequency current is given. The harmonic angular frequency, ω is the angular frequency of the power frequency current, μ is the permeability of free space, γ is the conductivity of the central conductor, j is the imaginary unit, and I is the angular frequency of the power frequency current. h I is the value of the h-th harmonic current. RMS , where is the effective value of the current spectrum, a and b are the outer and inner diameters of the current-carrying tube, respectively, and K1 is the first and second type of modified Bessel functions of the first order; The formula for calculating the power of the heat source includes: In the formula, P h P is the power of the heat source. RMS The heat generated under the action of the power frequency current.

3. The method according to claim 1, characterized in that: Applying loads to the three-dimensional finite element model includes: operating the valve side sleeve to be evaluated under rated load conditions, applying a vertically downward gravity force to the valve side sleeve to be evaluated, setting the lower end of the oil tank of the valve side sleeve to be evaluated as a fixed constraint, and applying a cantilever load tension to the gas end terminal.

4. The method according to claim 1, characterized in that: Based on the stress field distribution and the mechanical strength parameters of the core material of the valve-side bushing to be evaluated, the cracking risk of the valve-side bushing to be evaluated is assessed, including: The mechanical strength parameters of the core material are calculated based on the temperature field distribution, and the mechanical strength parameters of the flange material are obtained based on the multi-stress ratio SN curve; the mechanical strength parameters include the tensile strength and compressive strength of the material. Based on the stress field distribution, the principal stresses on the target portion of the valve side sleeve to be evaluated are determined; Based on the principal stress and the mechanical strength parameters, a cracking risk factor is constructed; Based on the cracking risk factor, assess the cracking risk of the target location on the valve-side sleeve to be evaluated.

5. The method according to claim 4, characterized in that: The calculation formula for the cracking risk factor includes: In the formula, R is the cracking risk factor. The principal stress, The tensile strength of the material. The compressive strength of the material is given by T, where T represents temperature.

6. The method according to claim 4, characterized in that: Based on the aforementioned cracking risk factors, the cracking risk of the target location on the valve-side sleeve to be evaluated is assessed, including: If the absolute value of the cracking risk factor is less than the first preset threshold, the cracking risk is assessed as low risk. If the absolute value of the cracking risk factor is greater than or equal to the first preset threshold and less than the second preset threshold, then the cracking risk is assessed as medium risk; the first preset threshold is less than the second preset threshold. If the absolute value of the cracking risk factor is greater than or equal to the second preset threshold, then the cracking risk is assessed as high risk.

7. A system for stress analysis and cracking risk assessment of a valve-side sleeve core flange, characterized in that, This system is used to implement the stress analysis and cracking risk assessment method for a valve side sleeve core flange as described in any one of claims 1-6; the system includes: a first construction module, a calculation module, a first simulation module, a second construction module, a second simulation module, and an evaluation module; wherein, The first construction module is used to construct a three-dimensional finite element model based on the mechanical and material parameters of the valve side sleeve to be evaluated; The calculation module is used to calculate the heat source power of the temperature field of the valve side bushing to be evaluated under the consideration of harmonic effects, based on the heat generation under the action of power frequency current and the harmonic heating enhancement coefficient. The first simulation module is used to simulate the temperature field of the valve side sleeve to be evaluated based on the three-dimensional finite element model and the power of the heat source, taking into account heat conduction and heat countermeasure, and to obtain the temperature field distribution. The second construction module is used to apply loads to the three-dimensional finite element model and add thermal expansion constraints to construct the mechanical stress field model of the valve side sleeve to be evaluated; The second simulation module is used to simulate the stress field of the valve side sleeve to be evaluated by using the temperature field distribution as the thermal field boundary condition of the mechanical stress field model, so as to obtain the stress field distribution. The evaluation module is used to assess the cracking risk of the valve side sleeve based on the stress field distribution and the material mechanical strength parameters of the valve side sleeve to be evaluated.

8. The system according to claim 7, characterized in that: The evaluation module is also used for: The mechanical strength parameters of the core material are calculated based on the temperature field distribution, and the mechanical strength parameters of the flange material are obtained based on the multi-stress ratio SN curve; the mechanical strength parameters include the tensile strength and compressive strength of the material. Based on the stress field distribution, the principal stresses on the target portion of the valve side sleeve to be evaluated are determined; Based on the principal stress and the mechanical strength parameters, a cracking risk factor is constructed; Based on the cracking risk factor, assess the cracking risk of the target location on the valve-side sleeve to be evaluated.

9. An electronic device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor, when executing the computer program, implements the method as claimed in any one of claims 1-6.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed by a processor, implement the method as described in any one of claims 1-6.

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