Fatigue failure probability evaluation method of high-temperature molten salt tank welding structure and related device

Abstract

The invention discloses a fatigue failure probability evaluation method of a high-temperature molten salt tank welding structure and a related device, and relates to the technical field of high-temperature molten salt tank risk assessment and inspection. Molten salt liquid level change data is processed by using a rain flow counting method to obtain a plurality of liquid level change intervals; and the occurrence frequency corresponding to each liquid level change interval is determined. And calculating the equivalent structure stress change amplitude of the high-temperature molten salt tank welding structure in each liquid level change interval, and calculating the theoretical cycle index distribution of the high-temperature molten salt tank welding structure by taking the equivalent structure stress change amplitude as input. Based on the stress-strength interference model theory, the cumulative failure probability of the high-temperature molten salt tank welding structure in each liquid level change interval is calculated by combining the occurrence frequency and theoretical cycle index distribution corresponding to each liquid level change interval, and the high-temperature fatigue failure probability multiplication factor of the high-temperature molten salt tank welding structure is determined; and carrying out fatigue reliability and risk evaluation on the welding structure of the high-temperature molten salt tank.

Description

Technical Field

[0001] The present application relates to the technical field of risk assessment and inspection of high-temperature molten salt tanks, and in particular to a fatigue failure probability evaluation method and related device for a high-temperature molten salt tank welded structure based on a stress-strength interference model theory. Background Art

[0002] Molten salt energy storage technology is an important supporting technology in the fields of solar thermal power generation storage, utilization of waste electricity from new energy sources, and peak load regulation of power grids. Among them, high-temperature molten salt tanks are key equipment for molten salt energy storage technology. In order to achieve long-term stable power generation, high-temperature molten salt tanks need to operate for a long time at high temperatures. During alternating day and night operation, the welded structure on the tank body of the high-temperature molten salt tank will be fatigued due to the action of cyclic loads, and the risk of fatigue cracking is high under long-term operation. Accurately evaluating the risks of high-temperature molten salt tanks and conducting effective inspections on high-risk areas are one of the key means to ensure the safety of high-temperature molten salt tanks in service.

[0003] At present, the commonly used risk-based inspection method (GB / T-26610) has been successfully applied in the equipment inspection and integrity management of petrochemical and coal chemical industries. However, the risk-based inspection method cannot be applied to the field of molten salt energy storage. The main reasons include: 1) The current high-temperature molten salt tank is put into use in small quantities and has a short operating time. The failure probability data of the high-temperature molten salt tank and its structural parts are insufficient, so it is impossible to obtain the basic failure probability of the high-temperature molten salt tank based on statistical data; 2) High-temperature fatigue is a key factor affecting the failure of the welded structure of the high-temperature molten salt tank. There is currently a lack of correction factors that can evaluate the failure probability of the welded structure of the high-temperature molten salt tank. In response to this problem, this application proposes a fatigue failure probability evaluation method for the welded structure of a high-temperature molten salt tank to provide technical support for the application of risk-based inspection methods in the field of molten salt energy storage. Summary of the invention

[0004] The purpose of this application is to provide a fatigue failure probability evaluation method and related devices for the welding structure of a high-temperature molten salt tank, which can evaluate the fatigue failure probability of the welding structure of a high-temperature molten salt tank, solve the problem of the lack of effective failure probability evaluation technology in the risk assessment of the high-temperature molten salt tank under high-temperature fatigue, and provide technical support for the application of risk-based inspection methods in the field of molten salt energy storage.

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] In a first aspect, the present application provides a method for evaluating the fatigue failure probability of a high-temperature molten salt tank welded structure, the method comprising:

[0007] Acquire the molten salt level change data of the high-temperature molten salt tank in a preset time period; the molten salt level change data includes the molten salt level at each moment in the preset time period;

[0008] The molten salt liquid level change data is processed by using a rain flow counting method to obtain a plurality of liquid level change intervals; the liquid level change interval is an interval consisting of a liquid level lower limit and a liquid level upper limit;

[0009] Determine the occurrence frequency corresponding to each of the liquid level change intervals based on the molten salt liquid level change data;

[0010] For each of the liquid level change intervals, the equivalent structural stress change amplitude of the high-temperature molten salt tank welding structure in the liquid level change interval is calculated, and the equivalent structural stress change amplitude is used as input to calculate the theoretical cycle number distribution of the high-temperature molten salt tank welding structure, and obtain the theoretical cycle number distribution corresponding to the liquid level change interval;

[0011] For each of the liquid level change intervals, the theoretical cycle number distribution is used as input, and based on the stress-strength interference model theory, the cumulative failure probability that the theoretical cycle number is less than the design cycle number in the liquid level change interval is calculated to obtain the cumulative failure probability corresponding to the liquid level change interval;

[0012] Based on the occurrence frequency and cumulative failure probability corresponding to each of the liquid level change intervals, the average failure probability of the high-temperature molten salt tank welding structure is solved, and the high-temperature fatigue failure probability multiplication factor of the high-temperature molten salt tank welding structure is further determined. According to the high-temperature fatigue failure probability multiplication factor, the fatigue reliability and risk evaluation of the high-temperature molten salt tank welding structure is carried out.

[0013] In a second aspect, the present application provides a computer device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-mentioned method for evaluating fatigue failure probability of a high-temperature molten salt tank welded structure.

[0014] In a third aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-mentioned method for evaluating fatigue failure probability of a high-temperature molten salt tank welded structure.

[0015] In a fourth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the steps of the above-mentioned fatigue failure probability evaluation method for a high-temperature molten salt tank welded structure.

[0016] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0017] The present application provides a fatigue failure probability evaluation method and related device for a high-temperature molten salt tank welding structure. The molten salt level change data is processed by the rain flow counting method to obtain several level change intervals, and the frequency of occurrence corresponding to each level change interval is determined. The equivalent structural stress change amplitude of the high-temperature molten salt tank welding structure in each level change interval is calculated, and the equivalent structural stress change amplitude is used as input to calculate the theoretical cycle number distribution of the high-temperature molten salt tank welding structure, and the theoretical cycle number distribution corresponding to each level change interval is obtained. According to the frequency of occurrence and theoretical cycle number distribution corresponding to each level change interval, the cumulative failure probability of the high-temperature molten salt tank welding structure is calculated based on the stress-strength interference model theory, and the high-temperature fatigue failure probability multiplication factor of the high-temperature molten salt tank welding structure is determined, and the fatigue reliability and risk evaluation of the high-temperature molten salt tank welding structure is performed. The present application can determine the high-temperature fatigue failure probability multiplication factor of the high-temperature molten salt tank, so that the failure probability of the high-temperature molten salt tank welding structure can be evaluated, and the problem of the lack of effective failure probability evaluation technology in the risk assessment of the high-temperature molten salt tank under high-temperature fatigue is solved, and the application of risk-based inspection methods in the field of molten salt energy storage is provided. Technical support. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 This is an application environment diagram of a fatigue failure probability evaluation method for a high-temperature molten salt tank welding structure provided in Example 1 of the present application.

[0020] Figure 2 A schematic flow chart of a fatigue failure probability evaluation method for a high-temperature molten salt tank welding structure provided in Example 1 of the present application.

[0021] Figure 3 This is a schematic diagram of the temperature change data provided in Example 1 of the present application.

[0022] Figure 4 A schematic diagram of the molten salt level change data provided in Example 1 of the present application.

[0023] Figure 5 A schematic diagram of the structural dimensions of the connecting pipe weld provided in Example 1 of the present application.

[0024] Figure 6 Schematic diagram of the numerical model of the connecting pipe weld provided in Example 1 of the present application.

[0025] Figure 7 A schematic diagram of the functional modules of a failure probability assessment device for a high-temperature molten salt tank welding structure provided in Example 2 of the present application.

[0026] Figure 8 for Figure 7 Schematic diagram of the detailed functional modules of the analysis system.

[0027] Fig. 9 A schematic diagram of the structure of a computer device provided in Example 3 of the present application. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0029] Example 1

[0030] The fatigue failure probability evaluation method of the high-temperature molten salt tank welding structure provided in the embodiment of the present application can be applied to Figure 1 In the application environment shown. Among them, the terminal communicates with the server through the network. The data storage system can store the data that the server needs to process. The data storage system can be set up separately, integrated on the server, or placed on the cloud or other servers. The terminal can send the molten salt level change data to be processed to the server. After the server receives the molten salt level change data to be processed, the server uses the rain flow counting method to process the molten salt level change data to obtain several level change intervals; based on the molten salt level change data, the occurrence frequency corresponding to each level change interval is determined; for each level change interval, the equivalent structural stress change amplitude of the high-temperature molten salt tank welding structure in the level change interval is calculated, and the equivalent structural stress change amplitude is used as input to calculate the theoretical cycle number distribution of the high-temperature molten salt tank welding structure to obtain the level change interval. The theoretical number of cycles distribution corresponding to the interval; for each liquid level change interval, the theoretical number of cycles distribution is used as input, based on the stress-strength interference model theory, the cumulative failure probability of the theoretical number of cycles under the liquid level change interval is calculated to obtain the cumulative failure probability corresponding to the liquid level change interval; based on the occurrence frequency and cumulative failure probability corresponding to each liquid level change interval, the average failure probability of the high-temperature molten salt tank welding structure is solved, and the high-temperature fatigue failure probability multiplication factor of the high-temperature molten salt tank welding structure is further determined. According to the high-temperature fatigue failure probability multiplication factor, the fatigue reliability and risk evaluation of the high-temperature molten salt tank welding structure is performed. The server can feedback the evaluation results to the terminal.

[0031] In addition, in some embodiments, the fatigue failure probability evaluation method of the high-temperature molten salt tank welding structure can also be implemented independently by a server or a terminal. For example, the terminal can directly process the molten salt level change data to be processed, or the server can obtain the molten salt level change data to be processed from the data storage system and process the molten salt level change data to be processed.

[0032] The terminal may be, but is not limited to, various desktop computers, laptop computers, smart phones, tablet computers, IoT devices, and portable wearable devices. The server may be implemented as an independent server or a server cluster consisting of multiple servers, or may be a cloud server.

[0033] like Figure 2 As shown, the embodiment of the present application provides a method for evaluating the fatigue failure probability of a high-temperature molten salt tank welding structure. The method is executed by a computer device, and can be executed by a computer device such as a terminal or a server alone, or can be executed by a terminal and a server together. In the embodiment of the present application, the method is applied to Figure 1 Taking the server in the example as an example, the fatigue failure probability evaluation method of the high-temperature molten salt tank welding structure includes the following steps:

[0034] S1: Obtaining molten salt level change data of a high-temperature molten salt tank in a preset time period; the molten salt level change data includes the molten salt level at each moment in the preset time period.

[0035] S2: Processing the molten salt liquid level change data using a rain flow counting method to obtain a plurality of liquid level change intervals; the liquid level change interval is an interval consisting of a liquid level lower limit and a liquid level upper limit.

[0036] S3: Determine the occurrence frequency corresponding to each of the liquid level change intervals based on the molten salt liquid level change data.

[0037] S4: For each of the liquid level change intervals, the equivalent structural stress change amplitude of the high-temperature molten salt tank welding structure in the liquid level change interval is calculated, and the equivalent structural stress change amplitude is used as input to calculate the theoretical cycle number distribution of the high-temperature molten salt tank welding structure, and obtain the theoretical cycle number distribution corresponding to the liquid level change interval.

[0038] S5: For each of the liquid level change intervals, the theoretical cycle number distribution is used as input, and based on the stress-strength interference model theory, the cumulative failure probability that the theoretical cycle number is less than the design cycle number in the liquid level change interval is calculated to obtain the cumulative failure probability corresponding to the liquid level change interval.

[0039] S6: Based on the occurrence frequency and cumulative failure probability corresponding to each of the liquid level change intervals, the average failure probability of the high-temperature molten salt tank welding structure is solved, and the high-temperature fatigue failure probability multiplication factor of the high-temperature molten salt tank welding structure is further determined. According to the high-temperature fatigue failure probability multiplication factor, the fatigue reliability and risk evaluation of the high-temperature molten salt tank welding structure is performed.

[0040] By implementing the above-mentioned steps S1 to S6, the embodiment of the present application can determine the high-temperature fatigue failure probability multiplication factor considering the fatigue failure of the high-temperature molten salt tank, so as to evaluate the fatigue failure probability of the welding structure of the high-temperature molten salt tank, solve the problem of the lack of effective failure probability evaluation technology in the risk assessment of the high-temperature molten salt tank under high-temperature fatigue, and provide technical support for the application of risk-based inspection methods in the field of molten salt energy storage.

[0041] S1 is a basic data collection step, which can specifically read the molten salt level from the molten salt tank monitoring system or DCS system (Distributed Control System). By continuously reading the preset time period, the molten salt level change data of the high-temperature molten salt tank in the preset time period can be obtained. The molten salt level change data includes the molten salt level at each moment in the preset time period.

[0042] The fatigue failure probability evaluation method of the high-temperature molten salt tank welding structure of the embodiment of the present application also includes:

[0043] (1) Obtaining temperature change data of the high-temperature molten salt tank welding structure in a preset time period, wherein the temperature change data includes the temperature at each moment in the preset time period.

[0044] In the embodiment of the present application, a temperature sensor is arranged at the welding structure on the tank body of the high-temperature molten salt tank (i.e., the welding structure of the high-temperature molten salt tank). The temperature sensor is used to collect the temperature at the welding structure. The collected temperature is sent to the data collector through the temperature transmitter, and the temperature value is obtained through digital-to-analog conversion. The temperature is continuously collected for a preset time period to obtain the temperature change data of the welding structure of the high-temperature molten salt tank in the preset time period. The temperature change data includes the temperature at each moment in the preset time period.

[0045] In addition, if a temperature acquisition system has been arranged on the tank wall of the high-temperature molten salt tank, the temperature at the welding structure of the high-temperature molten salt tank can be directly read from the temperature acquisition system through the software interface. By continuously reading for a preset time period, the temperature change data of the welding structure of the high-temperature molten salt tank in the preset time period can be obtained. The temperature change data includes the temperature at each moment in the preset time period.

[0046] (2) Calculate the maximum value T in the temperature change data s and minimum value T d and determine whether the difference is less than a preset threshold; if not, the evaluation ends.

[0047] Determine the maximum and minimum values ​​in the temperature change data, calculate the difference between the maximum and minimum values, and further determine whether the difference is less than the preset threshold value. If it is less than the preset threshold value, it means that the temperature change is within the normal range, and the molten salt level change data within the preset time period is retained to prepare for the next step of analysis, and the evaluation continues, and steps S2-S6 are executed; otherwise, that is, it is not less than the preset threshold value, and it is considered that the high-temperature molten salt tank needs to be shut down for maintenance, then the molten salt level change data is not included in the high-temperature fatigue failure analysis, and the evaluation ends, and steps S2-S6 are no longer executed. Through this process, only the molten salt level change data generated when the high-temperature molten salt tank is in a normal working state can be analyzed to improve efficiency.

[0048] In the embodiment of the present application, the preset threshold value may be 50° C., and the condition for continuing the evaluation is: |T s -T d |<50℃, where T s is the maximum value of the monitored temperature of the molten salt tank, T d Minimum value for monitoring temperature of the molten salt tank.

[0049] In S2, the molten salt liquid level change data is processed using the rain flow counting method to obtain a number of liquid level change intervals, and the liquid level change interval is an interval consisting of a liquid level lower limit and a liquid level upper limit.

[0050] The rain flow counting method is an existing mature method for counting loads. In the embodiment of the present application, the liquid level is used as the load, and the rain flow counting method is used to obtain the load spectrum of the liquid level change. The load spectrum includes several liquid level change intervals (also called typical loads, which are represented by liquid level changes). Each liquid level change interval ΔH i Both have a lower limit of liquid level H l,i and liquid level upper limit H u,i , liquid level change interval ΔH i The lower limit of the liquid level H l,i and liquid level upper limit H u,i The interval composed of.

[0051] In S3, each liquid level change interval ΔH is determined based on the molten salt liquid level change data. i The corresponding frequency P i .

[0052] In the embodiment of the present application, a plurality of liquid level change intervals ΔH are determined. i Afterwards, the occurrence frequency P of different liquid level change intervals is further counted i , i=1,...,M, M is the total number of liquid level change intervals.

[0053] S3 specifically includes:

[0054] (1) According to the operation cycle of the high-temperature molten salt tank, the preset time period is divided into a plurality of continuous unit times, and the unit time is the same as the time of one operation cycle.

[0055] Generally, one operation cycle is one day. If the preset time period includes multiple days, the preset time period is divided into multiple days.

[0056] (2) For each unit time, the molten salt level at each moment in the unit time is determined based on the molten salt level change data, and the maximum and minimum values ​​of the molten salt level at each moment in the unit time are determined to obtain the maximum and minimum values ​​corresponding to each unit time.

[0057] (3) For each unit time, if the error between the maximum value corresponding to the unit time and the upper limit of the liquid level in the liquid level change interval is within the first error range, and the error between the minimum value corresponding to the unit time and the lower limit of the liquid level in the liquid level change interval is within the second error range, then the unit time belongs to the liquid level change interval, and the number of unit times belonging to each liquid level change interval is obtained.

[0058] The first error range can be ±0.5m (i.e. -0.5m to 0.5m), and the second error range can be ±0.5m. If the error between the maximum value corresponding to the unit time and the upper limit of the liquid level in the liquid level change interval is ±0.5m, and the error between the minimum value corresponding to the unit time and the lower limit of the liquid level in the liquid level change interval is ±0.5m, then the unit time belongs to the liquid level change interval.

[0059] (4) For each liquid level change interval, calculate the ratio of the number of unit times belonging to the liquid level change interval to the total number of unit times to obtain the occurrence frequency corresponding to the liquid level change interval.

[0060] Through the above process, each liquid level change interval ΔH can be statistically obtained i The corresponding frequency P i .

[0061] In this embodiment, the uncertainty parameters such as size, load, material, etc. of the high-temperature molten salt tank welding structure are randomized, and the uncertainty parameters are used as input to calculate the equivalent structural stress change amplitude of the high-temperature molten salt tank welding structure in each liquid level change interval.

[0062] As an optional implementation, in S4, calculating the equivalent structural stress change amplitude of the high-temperature molten salt tank welding structure in the liquid level change range specifically includes:

[0063] (1) Calculate the liquid level change range ΔH of the high-temperature molten salt tank welding structure i The lower limit of liquid level H l,i The first stress set of each position point is calculated to calculate the high-temperature molten salt tank welding structure working in the liquid level change range ΔH iThe upper limit of liquid level H u,i The second stress set at each position point is the first stress set including the first structural stress σ sl,i , the first bending stress σ bl,i and the first membrane stress σ ml,i , the second stress set includes the second structural stress σ su,i , the second bending stress σ bu,i and the second membrane stress σ mu,i .

[0064] Structural stress σ of high temperature molten salt tank welding structure s,i is the bending stress σ b,i and membrane stress σ m,i The sum is calculated as:

[0065]

[0066] In formula (1), f y,i is the moment in the y direction; t is the thickness of the flat plate of the welded structure; m x,i is the bending moment in the x direction. y,i and m x,i Based on the lower limit of liquid level H l,i and liquid level upper limit H u,i Sure.

[0067] Using formula (1), this embodiment can calculate the first structural stress σ of each position point of the high-temperature molten salt tank welding structure: sl,i , the first bending stress σ bl,i , the first membrane stress σ ml,i , the second structural stress σ su,i , the second bending stress σ bu,i and the second membrane stress σ mu,i The first structural stress σ sl,i = first bending stress σ bl,i +First membrane stressσ ml,i , the second structural stress σ su,i = Second bending stress σ bu,i + Second membrane stress σ mu,i .

[0068] In order to further improve the calculation efficiency, this embodiment uses a simulation method to calculate the first stress set and the second stress set at each position point of the high-temperature molten salt tank welding structure. Specifically, a numerical model of the high-temperature molten salt tank welding structure is established, with the lower limit H of the liquid level as l,i As input, the first structural stress σ at each position of the high-temperature molten salt tank welding structure is obtained through numerical model simulation calculation. sl,i , the first bending stress σ bl,i and the first membrane stress σ ml,i , with the upper limit of liquid level Hu,i As the input, the secondary structural stress σ at each position point of the welded structure of the high-temperature molten salt tank is obtained through numerical model simulation calculation su,i , the secondary bending stress σ bu,i and the secondary membrane stress σ mu,i .

[0069] (2) Based on the first stress set and the second stress set at each position point of the welded structure of the high-temperature molten salt tank, calculate the equivalent structural stress amplitude ΔS of the welded structure of the high-temperature molten salt tank ess,i .

[0070] In the stress cycle, the change amplitude ΔS of the equivalent structural stress considering the non-linear effect of the notch stress ess,i is calculated by the formula:

[0071]

[0072] In formula (2), Δσ s,i is the change amplitude of the structural stress, that is, the difference between the first structural stress σ sl,i and the second structural stress σ su,i , Δσ s,i =σ su,i -σ sl,i ; t ess is the effective thickness of the structural stress. When t ≤ 16 mm, t ess = 16 mm; when t ≥ 150 mm, t ess = 150 mm; when 16 mm < t < 150 mm, t ess = t; m ss is a constant, which can be taken as 3.6; is the shape coefficient; f M is the mean stress correction coefficient, σ max and σ min are the peak and valley values of the structural stress respectively. The peak value is the larger value of the first structural stress and the second structural stress, and the valley value is the smaller value of the first structural stress and the second structural stress.

[0073]

[0074] In formula (3), R b is the correction coefficient used in the structural stress evaluation, Δσ b,i is the change amplitude of the bending stress, that is, the difference between the first bending stress σ bl,i and the second bending stress σ bu,i , Δσ b,i =σ bu,i -σ bl,i , Δσm,i is the variation amplitude of membrane stress, that is, the first membrane stress σ ml,i and the second membrane stress σ mu,i The difference, Δσ m,i =σ mu,i -σ ml,i .

[0075] For each position point of the high-temperature molten salt tank welding structure, the equivalent structural stress change amplitude of each position point is calculated using formula (2), and the maximum value of the equivalent structural stress change amplitude of all position points is selected as the equivalent structural stress change amplitude ΔS of the high-temperature molten salt tank welding structure ess,i .

[0076] When the shear stress of the structure cannot be ignored, another implementation method is selected to calculate the equivalent structural stress change amplitude. In S4, the equivalent structural stress change amplitude of the high-temperature molten salt tank welding structure in the liquid level change range is calculated, specifically including:

[0077] (1) Calculate the liquid level change range ΔH of the high-temperature molten salt tank welding structure i The lower limit of liquid level H l,i The third stress set of each position point is calculated to calculate the high-temperature molten salt tank welding structure working in the liquid level change range ΔH i The upper limit of liquid level H u,i The fourth stress set at each position point is σ, and the third stress set includes the first structural stress σ sl,i , the first bending stress σ bl,i , the first membrane stress σ ml,i , the first shear stress τ sl,i , the bending component of the first shear stress τ bl,i and the membrane component of the first shear stress τ ml,i , the fourth stress set includes the second structural stress σ su,i , the second bending stress σ bu,i , the second membrane stress σ mu,i , the second shear stress τ su,i , the bending component of the second shear stress τ bu,i and the membrane component of the second shear stress τ mu,i .

[0078] In order to further improve the calculation efficiency, this embodiment uses a simulation method to calculate the third stress set and the fourth stress set at each position point of the high-temperature molten salt tank welding structure. Specifically, a numerical model of the high-temperature molten salt tank welding structure is established with the lower limit H of the liquid level. l,i As input, the first structural stress σ at each position of the high-temperature molten salt tank welding structure is obtained through numerical model simulation calculation. sl,i , the first bending stress σ bl,i , the first membrane stress σml,i , the first shear stress τ sl,i , the bending component of the first shear stress τ bl,i and the membrane component of the first shear stress τ ml,i , with the upper limit of liquid level H u,i As input, the second structural stress σ at each position of the high-temperature molten salt tank welding structure is obtained through numerical model simulation calculation su,i , the second bending stress σ bu,i , the second membrane stress σ mu,i , the second shear stress τ su,i , the bending component of the second shear stress τ bu,i and the membrane component of the second shear stress τ mu,i The first shear stress τ sl,i = bending component τ of the first shear stress bl,i + membrane component of the first shear stress τ ml,i , the second shear stress τ su,i = bending component τ of the second shear stress bu,i + membrane component of the second shear stress τ mu,i .

[0079] (2) Based on the third stress set and the fourth stress set at each position of the high-temperature molten salt tank welding structure, the equivalent structural stress amplitude ΔS of the high-temperature molten salt tank welding structure is calculated. ess,i .

[0080] When uniaxial loading causes a multiaxial stress state in the weld, the shear stress τ cannot be ignored. Considering the equivalent structural stress change amplitude ΔS of the shear stress ess,i The calculation formula is:

[0081]

[0082] In formula (4), Δτ s,i is the amplitude of shear stress change, that is, the difference between the first shear stress and the second shear stress, Δτ s,i =τ su,i -τ sl,i ;m ess is a constant, which can be 5.0; is the shape factor.

[0083]

[0084] In formula (5), R bt is the correction factor used in structural stress assessment, Δτ b,i is the variation amplitude of the bending component of the shear stress, that is, the difference between the bending component of the first shear stress and the bending component of the second shear stress, Δτ b,i =τbu,i -τ bl,i , Δτ m,i is the variation amplitude of the membrane component of the shear stress, that is, the difference between the membrane component of the first shear stress and the membrane component of the second shear stress, Δτ m,i =τ mu,i -τ ml,i .

[0085] For each position point of the high-temperature molten salt tank welding structure, the equivalent structural stress change amplitude of each position point is calculated using formula (4), and the maximum value of the equivalent structural stress change amplitude of all position points is selected as the equivalent structural stress change amplitude ΔS of the high-temperature molten salt tank welding structure ess,i .

[0086] Through the above process, for a certain welding structure, each typical load ΔH can be calculated i The equivalent structural stress change amplitude ΔS under ess,i .

[0087] In S4, the equivalent structural stress change amplitude is used as input to calculate the theoretical cycle number distribution of the high-temperature molten salt tank welding structure, specifically including: taking the equivalent structural stress change amplitude ΔS ess,i As input, using the theoretical number of cycles N i The calculation formula is used to calculate the theoretical cycle number distribution of the high-temperature molten salt tank welding structure.

[0088] The main SN curve parameter C value in the ASME BPVC.VIII.2-2023 fatigue life model is randomized and considered to obey the standard normal distribution. Based on the fatigue life model, the fatigue life of the high-temperature molten salt tank welding structure is calculated, that is, the calculation formula of the theoretical cycle number is:

[0089]

[0090] In formula (6), i is the serial number of the liquid level change interval; N i is the theoretical cycle number of the high-temperature molten salt tank welding structure under the i-th liquid level change interval, that is, the fatigue life; f I is the structural stress correction factor, ΔS ess,i is the equivalent structural stress variation amplitude of the high-temperature molten salt tank welding structure under the i-th liquid level variation interval, C usm is the conversion factor. When stress is expressed in ksi, C usm =1.0, when stress is in MPa, C usm =14.15; f E is the environmental correction factor; f MT are material and temperature correction factors, ET is the elastic modulus at room temperature, E ACS is the elastic modulus at service temperature; C0 is a constant; Δ e is a constant; d is a random variable that obeys the normal distribution; h is a constant.

[0091] d obeys the standard normal distribution. The Latin hypercube sampling method is used to sample d. At each value, the theoretical number of cycles is calculated using formula (6). The theoretical number of cycles at all values ​​constitutes the theoretical number of cycles distribution, and the typical load ΔH can be calculated. i Fatigue life distribution under .

[0092] In S5, the theoretical cycle number distribution is used as input, and based on the stress-strength interference model theory, the cumulative failure probability that the theoretical cycle number is less than the design cycle number under the liquid level change range is calculated, specifically including: for each liquid level change range ΔH i , with the liquid level change interval ΔH i The corresponding theoretical cycle number distribution is used as input, and the liquid level change interval ΔH is calculated using the cumulative failure probability calculation formula i The cumulative failure probability when the theoretical number of cycles is less than the designed number of cycles is obtained, and the liquid level change interval ΔH is obtained. i The corresponding cumulative failure probability F i .

[0093] In this embodiment, the cumulative failure probability calculation formula is proposed based on the stress-strength interference model theory, that is, the stress-strength interference model is used to calculate the fatigue failure probability of the high-temperature molten salt tank welding structure, that is, the cumulative failure probability calculation formula is:

[0094]

[0095] In formula (7), F i is the cumulative failure probability corresponding to the i-th liquid level change interval; G(x i ) is the limit state function of the high temperature molten salt tank welding structure, x i is the random variable of the ith liquid level variation interval; N0 is the number of design cycles; is the average value of the logarithm of the theoretical cycle number distribution corresponding to the ith liquid level change interval; N i is the theoretical cycle number; is the variance of the logarithm of the theoretical cycle number distribution corresponding to the i-th liquid level change interval.

[0096] The limit state function is defined as:

[0097] G(x i )=Ln(N i )-Ln(N0)(8)

[0098] In S6, based on the occurrence frequency and cumulative failure probability corresponding to each liquid level change interval, the average failure probability of the high-temperature molten salt tank welding structure is solved, and the high-temperature fatigue failure probability multiplication factor of the high-temperature molten salt tank welding structure is further determined. According to the high-temperature fatigue failure probability multiplication factor, the fatigue reliability and risk evaluation of the high-temperature molten salt tank welding structure is carried out, including:

[0099] (1) Based on each liquid level change interval ΔH i The corresponding frequency P i and the cumulative failure probability F i The average failure probability F of the high-temperature molten salt tank welding structure is calculated using the average failure probability calculation formula.

[0100] The average failure probability calculation formula is:

[0101]

[0102] In formula (9), F is the average failure probability, that is, the average failure probability of the welded structure to serve to the life N0; M is the total number of liquid level change intervals; F i is the cumulative failure probability corresponding to the i-th liquid level change interval; P i is the occurrence frequency corresponding to the i-th liquid level change interval.

[0103] Based on the above formula (9), the average failure probability under various typical loads can be calculated.

[0104] (2) Calculate the average failure probability F and the average failure probability F of similar equipment G The ratio of the high temperature fatigue failure probability multiplication factor F of the high temperature molten salt tank is determined according to the ratio TEM , according to the high temperature fatigue failure probability multiplication factor F TEM Determine the fatigue failure possibility level to conduct fatigue reliability and risk assessment on the welded structure of high-temperature molten salt tank.

[0105] High temperature fatigue failure probability multiplication factor F TEM The calculation formula is as follows:

[0106]

[0107] In formula (10), F G is the average failure probability of similar equipment, and the default value is F G =1×10 -4 .

[0108] The high temperature fatigue failure probability multiplication factor F of the high temperature molten salt tank welding structure can be calculated by the above formula (10): TEM , in determining the high temperature fatigue failure probability multiplication factor F of the high temperature molten salt tankTEM Then, according to the high temperature fatigue failure probability multiplication factor F TEM , check the fatigue failure possibility level classification table (i.e. Table 1 below) to determine the fatigue failure possibility level, so as to conduct fatigue reliability and risk evaluation on the high-temperature molten salt tank welding structure.

[0109] Table 1 Fatigue failure probability classification

[0110] Fatigue failure probability level <![CDATA[F TEM ]]> 1 <![CDATA[F TEM ≤3 <!-- 9 -->]]> 2 <![CDATA[3<F TEM ≤10]]> 3 <![CDATA[10<F TEM ≤100]]> 4 <![CDATA[100<F TEM ≤1000]]> 5 <![CDATA[F TEM >1000]]>

[0111] Here, the fatigue failure probability evaluation method of the high-temperature molten salt tank welding structure of this embodiment is introduced through a specific example:

[0112] (1) The temperature data of the high-temperature molten salt tank is collected every day in a certain month, and the obtained temperature change data is as follows Figure 3 As shown in the figure, the molten salt level of the high-temperature molten salt tank is read from the molten salt tank monitoring system or DCS system every day of a month, and the molten salt level change data obtained is as follows Figure 4 shown.

[0113] (2) Based on the temperature change data, it can be determined that the maximum value is 276°C and the minimum value is 266°C. The temperature change is within the normal range (i.e. |T s -T d |<50℃), at this time, continue the evaluation to prepare for the next step of analysis.

[0114] (3) Figure 4 The molten salt level change data shown in the figure is used as input, and the load spectrum of the level change is obtained according to the rain flow counting method, and the frequency of occurrence of different level change intervals is counted. The level change interval is ΔH i , the frequency of occurrence is P i , i = 1, ..., M, M is the total number of liquid level change intervals. The load spectrum obtained by the rain flow counting method and the frequency of occurrence of each liquid level change interval are shown in Table 2 below.

[0115] Table 2 High temperature molten salt tank level change range and frequency

[0116] Working conditions <![CDATA[Liquid level change interval ΔH i / m]]> <![CDATA[Frequency of occurrence n i > <![CDATA[Occurrence frequency P i > Condition 1 1.5484～12.3872 3 0.0952 Condition 2 1.5484～11.1485 6 0.1905 Condition 3 1.5484～10.5291 3 0.0952 Condition 4 1.5484～9.2904 4 0.1429 Condition 5 1.5484～8.0517 4 0.1429 Condition 6 3.0969～9.9098 10 0.3333

[0117] (4) For the welding structure of the high-temperature molten salt tank, this example selects the pipe weld as the welding structure for research. The structural dimensions of the pipe weld are as follows: Figure 5 As shown in Figure 2, the numerical model of the pipe weld is established. Figure 6 As shown in the figure, the stress set of the nozzle weld (i.e., structural stress, bending stress, membrane stress, shear stress, bending component of shear stress, and membrane component of shear stress) is calculated using ABAQUS software. ess =44mm,m ss=3.6, m ess =5.0, is about 1.263, About 1.238, R b =0.99, f M =0.95, calculate different liquid level change intervals H i The equivalent structural stress change amplitude under various working conditions is shown in Table 3.

[0118] Table 3 Equivalent structural stress amplitude

[0119] Working conditions <![CDATA[Equivalent structural stress amplitude ΔS ess / MPa]]> Condition 1 374.44 Condition 2 331.65 Condition 3 310.25 Condition 4 267.46 Condition 5 224.66 Condition 6 235.36

[0120] (5) Select C usm =14.15, f E =10,f MT =0.957, E T =203GPa, E ACS =194.2GPa, C0=11577.6, Δ e =1.72, h=-0.3195, d is a random variable, d~N(0,1), calculate the theoretical number of cycles N of the pipe weld i The failure probability evaluation model of the pipe weld cycle to N0 = 2000 times was established, and the cumulative failure probability F of the pipe weld under different working conditions was calculated. i . Structural stress correction factor f for improved fatigue of nozzle welds I , theoretical cycle numbers and cumulative failure probability are shown in Table 4.

[0121] Table 4 Structural stress correction factor, theoretical cycle number and cumulative failure probability

[0122]

[0123]

[0124] (6) Under actual working conditions, the molten salt level of the high-temperature molten salt tank is cycled once a day. According to the principle of 6-year inspection of high-temperature molten salt tanks, the design fatigue times (i.e., design cycles) of the high-temperature molten salt tanks are 2000 times. i And the cumulative failure probability F shown in Table 4 i , the average failure probability F = 0.0576 of the taking-over weld that can serve to the service life N0 = 2000 under various working conditions is calculated.

[0125] (7) The average failure probability F = 0.0576 under various working conditions is calculated, and combined with the ratio calculation formula, we get: F TEM =0.0576 / (1×10 -4)=576, look up Table 1 and get 100<F TEM ≤1000, fatigue failure possibility level is 4.

[0126] The fatigue failure probability evaluation method of the high-temperature molten salt tank welded structure based on the stress-strength interference model provided in the embodiment of the present application includes the following steps: (1) reading the daily changes in the molten salt liquid level and temperature from the molten salt tank monitoring system or DCS system and the temperature sensor. (2) analyzing the temperature change range, and the temperature difference greater than 50°C is not included in the failure probability analysis. (3) obtaining the load spectrum of the liquid level change according to the rain flow counting method, and statistically analyzing the occurrence frequency of different typical loads. (4) randomizing the uncertainty parameters such as the size, load, and material of the high-temperature molten salt tank welded structure, and calculating the equivalent structural stress change amplitude under the typical load according to the liquid level change. (5) calculating the fatigue life under different typical loads according to the equivalent structural stress change amplitude and the randomized parameter C value of the main SN curve in the fatigue life model, and using the stress-strength interference model to calculate the cumulative failure probability of the structure cycling to the specified fatigue life under different loads. (6) calculating the average failure probability of the structural component cycling to the specified fatigue life under the coupling of multiple typical loads. (7) calculating the high-temperature fatigue failure probability multiplication factor of the high-temperature molten salt tank according to the average failure probability of the structural component. (8) Based on the high-temperature fatigue failure probability multiplication factor, the possibility of high-temperature fatigue failure of the high-temperature molten salt tank is evaluated.

[0127] Compared with the prior art, the embodiments of the present application have the following beneficial effects: quantitatively calculating the average life and average failure probability of the high-temperature molten salt tank welding structure, evaluating the fatigue resistance of the high-temperature molten salt tank welding structure, proposing a high-temperature fatigue failure probability multiplication factor, shortening the evaluation cycle, improving work efficiency, and reducing costs.

[0128] Example 2

[0129] Based on the same inventive concept, the embodiment of the present application also provides a fatigue failure probability evaluation device for a high-temperature molten salt tank welded structure for implementing the fatigue failure probability evaluation method for the high-temperature molten salt tank welded structure involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in the embodiment of the fatigue failure probability evaluation device for a high-temperature molten salt tank welded structure provided below can refer to the limitations of the fatigue failure probability evaluation method for a high-temperature molten salt tank welded structure above, and will not be repeated here.

[0130] like Figure 7 As shown, an embodiment of the present application provides a fatigue failure probability evaluation device for a high-temperature molten salt tank welding structure, including: a data acquisition system and an analysis system.

[0131] The data acquisition system collects the temperature change data and molten salt level change data of the high-temperature molten salt tank.

[0132] The analysis system receives the temperature change data and the molten salt liquid level change data collected by the data acquisition system, and stores the temperature change data and the molten salt liquid level change data in a database.

[0133] like Figure 8 As shown, the data receiving module receives the temperature change data and the molten salt level change data collected by the data acquisition system, and the data processing module performs preliminary processing on the temperature change data to evaluate the data with large noise. If the temperature difference of the temperature change data exceeds a certain error, it is considered that the equipment is shut down and the evaluation is stopped; the fatigue life analysis module calculates the fatigue life based on the molten salt level change data to obtain the fatigue life; the failure probability analysis module performs failure probability analysis based on the molten salt level change data to obtain the cumulative failure probability; the fatigue performance evaluation module evaluates the fatigue performance of the structural parts based on the fatigue life and the cumulative failure probability, that is, evaluates the failure probability.

[0134] Example 3

[0135] In an exemplary embodiment, a computer device is provided. The computer device may be a server or a terminal. The internal structure diagram thereof may be as follows: Fig. 9 As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store molten salt level change data and temperature change data. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a fatigue failure probability evaluation method for a high-temperature molten salt tank welded structure is implemented.

[0136] Those skilled in the art will understand that Fig. 9 The structure shown in the figure is only a block diagram of a part of the structure related to the present application scheme, and does not constitute a limitation on the computer device to which the present application scheme is applied. The specific computer device may include Fig. 9 More or fewer components may be shown, or certain components may be combined, or may have a different arrangement of components.

[0137] In an exemplary embodiment, a computer device is also provided, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the fatigue failure probability evaluation method for the high-temperature molten salt tank welded structure described in Example 1.

[0138] Example 4

[0139] An embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the fatigue failure probability evaluation method for the high-temperature molten salt tank welding structure described in Example 1 are implemented.

[0140] Example 5

[0141] An embodiment of the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the steps of the fatigue failure probability evaluation method for a high-temperature molten salt tank welded structure described in Example 1.

[0142] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0143] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A fatigue failure probability evaluation method for a high-temperature molten salt tank welding structure, characterized in that: The fatigue failure probability evaluation method of the high-temperature molten salt tank welding structure includes: Acquire the molten salt level change data of the high-temperature molten salt tank in a preset time period; the molten salt level change data includes the molten salt level at each moment in the preset time period; The molten salt liquid level change data is processed by using a rain flow counting method to obtain a plurality of liquid level change intervals; the liquid level change interval is an interval consisting of a liquid level lower limit and a liquid level upper limit; Determine the occurrence frequency corresponding to each of the liquid level change intervals based on the molten salt liquid level change data; For each of the liquid level change intervals, the equivalent structural stress change amplitude of the high-temperature molten salt tank welding structure in the liquid level change interval is calculated, and the equivalent structural stress change amplitude is used as input to calculate the theoretical cycle number distribution of the high-temperature molten salt tank welding structure, and obtain the theoretical cycle number distribution corresponding to the liquid level change interval; For each of the liquid level change intervals, the theoretical cycle number distribution is used as input, and based on the stress-strength interference model theory, the cumulative failure probability that the theoretical cycle number is less than the design cycle number in the liquid level change interval is calculated to obtain the cumulative failure probability corresponding to the liquid level change interval; Based on the occurrence frequency and cumulative failure probability corresponding to each of the liquid level change intervals, the average failure probability of the high-temperature molten salt tank welding structure is solved, and the high-temperature fatigue failure probability multiplication factor of the high-temperature molten salt tank welding structure is further determined. According to the high-temperature fatigue failure probability multiplication factor, the fatigue reliability and risk evaluation of the high-temperature molten salt tank welding structure is carried out.

2. The fatigue failure probability evaluation method of the high-temperature molten salt tank welding structure according to claim 1 is characterized in that: Before processing the molten salt level change data by using the rain flow counting method, the fatigue failure probability evaluation method of the high-temperature molten salt tank welding structure also includes: Acquire temperature change data of the high-temperature molten salt tank welding structure in a preset time period; the temperature change data includes the temperature at each moment in the preset time period; Calculate the difference between the maximum value and the minimum value in the temperature change data, and determine whether the difference is less than a preset threshold; if not, end the evaluation.

3. The fatigue failure probability evaluation method of the high-temperature molten salt tank welding structure according to claim 1 is characterized in that: Determining the occurrence frequency corresponding to each of the liquid level change intervals based on the molten salt liquid level change data specifically includes: According to the operation cycle of the high-temperature molten salt tank, the preset time period is divided into a plurality of continuous unit times; the unit time is the same as the time of one operation cycle; For each of the unit time, determine the molten salt level at each moment in the unit time based on the molten salt level change data, and determine the maximum and minimum values ​​of the molten salt level at each moment in the unit time, to obtain the maximum and minimum values ​​corresponding to each of the unit time; For each of the unit time, if the error between the maximum value corresponding to the unit time and the upper limit of the liquid level of the liquid level change interval is within a first error range, and the error between the minimum value corresponding to the unit time and the lower limit of the liquid level of the liquid level change interval is within a second error range, then the unit time belongs to the liquid level change interval, and the number of unit times belonging to each of the liquid level change intervals is obtained; For each of the liquid level change intervals, the ratio of the number of unit times belonging to the liquid level change interval to the total number of unit times is calculated to obtain the occurrence frequency corresponding to the liquid level change interval.

4. The fatigue failure probability evaluation method of the high-temperature molten salt tank welding structure according to claim 1 is characterized in that: Calculating the equivalent structural stress variation amplitude of the high-temperature molten salt tank welding structure in the liquid level variation range includes: Calculate the first stress set of each position point when the high-temperature molten salt tank welding structure works at the lower limit of the liquid level in the liquid level change range, and calculate the second stress set of each position point when the high-temperature molten salt tank welding structure works at the upper limit of the liquid level in the liquid level change range; the first stress set includes the first structural stress, the first bending stress and the first membrane stress, and the second stress set includes the second structural stress, the second bending stress and the second membrane stress; Based on the first stress set and the second stress set at each position point of the high-temperature molten salt tank welding structure, the equivalent structural stress change amplitude of the high-temperature molten salt tank welding structure is calculated; Alternatively, a third stress set is calculated for each position point when the high-temperature molten salt tank welding structure operates at the lower limit of the liquid level in the liquid level variation interval, and a fourth stress set is calculated for each position point when the high-temperature molten salt tank welding structure operates at the upper limit of the liquid level in the liquid level variation interval; the third stress set includes a first structural stress, a first bending stress, a first membrane stress, a first shear stress, a bending component of the first shear stress, and a membrane component of the first shear stress, and the fourth stress set includes a second structural stress, a second bending stress, a second membrane stress, a second shear stress, a bending component of the second shear stress, and a membrane component of the second shear stress; Based on the third stress set and the fourth stress set at each position point of the high-temperature molten salt tank welding structure, the equivalent structural stress change amplitude of the high-temperature molten salt tank welding structure is calculated.

5. The fatigue failure probability evaluation method of the high-temperature molten salt tank welding structure according to claim 1 is characterized in that: Taking the equivalent structural stress change amplitude as input, the theoretical cycle number distribution of the high-temperature molten salt tank welding structure is calculated, specifically including: The equivalent structural stress change amplitude is used as input, and the theoretical cycle number distribution of the high-temperature molten salt tank welding structure is calculated using the calculation formula of the theoretical cycle number; Wherein, the calculation formula of the theoretical number of cycles is: Among them, N i is the theoretical number of cycles of the high-temperature molten salt tank welding structure under the i-th liquid level change interval; f I is the structural stress correction factor; f E is the environmental correction factor; ΔS ess,i is the equivalent structural stress variation amplitude of the high-temperature molten salt tank welding structure under the i-th liquid level variation interval; f MT is the material and temperature correction factor; C0 is a constant; Δ e is a constant; d is a random variable that obeys the normal distribution; h is a constant.

6. The fatigue failure probability evaluation method of the high-temperature molten salt tank welding structure according to claim 1 is characterized in that: Taking the theoretical cycle number distribution as input, based on the stress-strength interference model theory, the cumulative failure probability that the theoretical cycle number is less than the design cycle number in the liquid level change range is calculated, specifically including: Taking the theoretical cycle number distribution as input, the cumulative failure probability that the theoretical cycle number is less than the designed cycle number in the liquid level variation range is calculated using the cumulative failure probability calculation formula; The cumulative failure probability calculation formula is proposed based on the stress-strength interference model theory, and the cumulative failure probability calculation formula is: Among them, F i is the cumulative failure probability corresponding to the i-th liquid level change interval; G(x i ) is the limit state function of the high temperature molten salt tank welding structure, x i is the random variable of the ith liquid level change interval; N0 is the number of design cycles; μ Ln(Ni) is the average value of the logarithm of the theoretical cycle number distribution corresponding to the ith liquid level change interval; N i is the theoretical cycle number; σ Ln(Ni) is the variance of the logarithm of the theoretical cycle number distribution corresponding to the i-th liquid level change interval; G(x i )=Ln(N i )-Ln(N0)。 7. The fatigue failure probability evaluation method of the high-temperature molten salt tank welding structure according to claim 1 is characterized in that: Based on the occurrence frequency and cumulative failure probability corresponding to each of the liquid level change intervals, the average failure probability of the high-temperature molten salt tank welding structure is solved, and the high-temperature fatigue failure probability multiplication factor of the high-temperature molten salt tank welding structure is further determined. According to the high-temperature fatigue failure probability multiplication factor, the fatigue reliability and risk evaluation of the high-temperature molten salt tank welding structure is carried out, specifically including: Based on the occurrence frequency and cumulative failure probability corresponding to each of the liquid level change intervals, the average failure probability of the high-temperature molten salt tank welding structure is calculated using the average failure probability calculation formula; Calculate the ratio of the average failure probability to the average failure probability of similar equipment, and determine the high-temperature fatigue failure probability multiplication factor of the high-temperature molten salt tank welding structure according to the ratio; determine the fatigue failure possibility level according to the high-temperature fatigue failure probability multiplication factor, so as to perform fatigue reliability and risk evaluation on the high-temperature molten salt tank welding structure; The average failure probability calculation formula is: Among them, F is the average failure probability; M is the total number of liquid level change intervals; F i is the cumulative failure probability corresponding to the i-th liquid level change interval; P i is the occurrence frequency corresponding to the i-th liquid level change interval.

8. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the fatigue failure probability evaluation method for a high-temperature molten salt tank welded structure according to any one of claims 1 to 7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the fatigue failure probability evaluation method for the high-temperature molten salt tank welded structure according to any one of claims 1 to 7 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the fatigue failure probability evaluation method for the high-temperature molten salt tank welded structure according to any one of claims 1 to 7 is implemented.

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