Hydrogen prying block overall sealing equivalence evaluation method, device, equipment and medium

Abstract

The application relates to the technical field of sealing performance analysis, and discloses a hydrogen pry block overall sealing performance equivalent evaluation method, device, equipment and medium, wherein the method comprises the following steps: obtaining stress response data, and screening out, from types, a pipeline joint with the largest cumulative fatigue damage value as a test sample for any type of pipeline joint; performing frequency spectrum analysis on the stress response data of the test sample to determine a test loading frequency, and reversely generating an equivalent loading displacement amplitude; based on the test loading frequency and the equivalent loading displacement amplitude, performing a vibration loading test on the test sample into which high-pressure hydrogen is introduced, and collecting a leakage rate of the test sample; based on the leakage rate of the test sample, the cumulative fatigue damage value of the test sample and the cumulative fatigue damage values of the pipeline joints of various types, determining an overall equivalent leakage rate of the hydrogen pry block, so as to evaluate the sealing performance of the hydrogen pry block. The technical scheme provided by the application can take into account the overall test evaluation efficiency and precision of the hydrogen pry block.

Description

Technical Field

[0001] This application relates to the field of sealing performance analysis technology, and in particular to a method, apparatus, equipment and medium for equivalent evaluation of the overall sealing performance of a hydrogen skid. Background Technology

[0002] Hydrogen fuel cells are a core technology for the green transformation of ships. As the core integrated equipment for ship hydrogen transportation, the high-pressure hydrogen transmission skid has weak sealing at its pipeline joints. Under the combined action of alternating vibration and high-pressure hydrogen, it is prone to fatigue failure. In addition, hydrogen is flammable and explosive, and leakage will greatly increase the risk of explosion. Therefore, the reliability of joint sealing under vibration load is the core requirement of skid design.

[0003] Currently, the industry commonly uses integral skid vibration testing to test sealing performance, but this method has significant drawbacks: it only provides the total leakage volume and cannot pinpoint individual joint faults; different skid specifications require the construction of new test benches, resulting in poor versatility; the use of inert gas instead of hydrogen medium is insufficiently equivalent due to safety restrictions; it cannot monitor dynamic changes in leakage in real time; and disassembly and repair costs are extremely high in case of abnormalities. Although a few single-pipe unit tests have been attempted, they suffer from insufficient damage equivalence and crude evaluation logic, and the results cannot adequately replace the integral test.

[0004] Therefore, how to balance the overall testing and evaluation efficiency and accuracy of hydrogen skids is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] This application provides a method, apparatus, equipment, and medium for equivalent evaluation of the overall sealing performance of a hydrogen skid, which achieves a technical effect that balances the efficiency and accuracy of the overall test evaluation of the hydrogen skid.

[0006] To achieve the above objectives, the main technical solutions adopted in this application include: In a first aspect, embodiments of this application provide an equivalent evaluation method for the overall sealing performance of a hydrogen skid, the method comprising: The stress response data of all pipe joints in the hydrogen skid under vibration load are obtained, the pipe joints are classified, and for any type of pipe joint, the pipe joint with the largest cumulative fatigue damage value is selected as the test sample. Spectral analysis is performed on the stress response data of the test samples to determine the test loading frequency, and the equivalent loading displacement amplitude is then calculated. Based on the test loading frequency and the equivalent loading displacement amplitude, a vibration loading test was conducted on the test sample with high-pressure hydrogen gas introduced, and the leakage rate of the test sample was collected. Based on the leakage rate of the test sample, the cumulative fatigue damage value of the test sample, and the cumulative fatigue damage value of each type of pipe joint, the overall equivalent leakage rate of the hydrogen skid is determined to evaluate the sealing performance of the hydrogen skid.

[0007] In one embodiment, the step of selecting the pipe joint with the highest cumulative fatigue damage value from any type of pipe joint as the test sample includes: For any type of pipe joint, modal contribution analysis is performed on the stress response data, and stress response data with modal contribution values ​​lower than the modal contribution value threshold are removed to obtain the target stress response data; Based on the target stress response data, fatigue load spectrum is extracted, and combined with the preset material fatigue characteristic model, the cumulative fatigue damage value of each pipeline joint is determined. The pipe joint with the largest cumulative fatigue damage value was selected as the test sample.

[0008] In one embodiment, performing spectral analysis on the stress response data of the test sample to determine the test loading frequency includes: Based on the stress response data of the test sample, obtain the power spectral density curve of stress amplitude as a function of frequency; Identify the peak points in the power spectral density curve and take the frequency corresponding to the peak points as the dominant frequency component; The dominant frequency component is determined as the test loading frequency.

[0009] In one implementation, generating the equivalent loading displacement amplitude includes: The cumulative fatigue damage value of the test sample is used as the target fatigue damage value; Using the test loading frequency as a reference, an initial displacement amplitude is set, and the equivalent fatigue damage value of the test sample under the initial displacement amplitude is determined. The initial displacement amplitude is iteratively adjusted until the equivalent fatigue damage value equals the target fatigue damage value, and the adjusted initial displacement amplitude is determined as the equivalent loading displacement amplitude.

[0010] In one embodiment, determining the overall equivalent leakage rate of the hydrogen skid based on the leakage rate of the test sample, the cumulative fatigue damage value of the test sample, and the cumulative fatigue damage value of each type of pipe joint includes: For any type of pipe joint, the cumulative fatigue damage value of each pipe joint in that type is compared with the cumulative fatigue damage value of the test sample to obtain the vibration severity correction coefficient for each pipe joint. The total leakage rate of the type is obtained by multiplying the leakage rate of the test sample with the sum of the vibration severity correction coefficients of all pipe joints in the type. The overall equivalent leakage rate of the hydrogen skid is obtained by summing up the total leakage rates of all types within the hydrogen skid.

[0011] In one embodiment, the sealing evaluation of the hydrogen skid includes: Determine whether the leakage rate of the test sample is less than a preset leakage rate threshold, and whether the maximum stress value of the test sample in the vibration loading test has not reached the yield strength of the material; If the determination is yes, then the overall sealing performance of the hydrogen skid is determined based on the overall equivalent leakage rate. If the result is negative, the sealing performance evaluation of the hydrogen skid is deemed unqualified.

[0012] In one embodiment, determining the overall sealing performance of the hydrogen skid based on the overall equivalent leakage rate includes: Obtain the preset threshold for hydrogen skid sealing compliance; The overall equivalent leakage rate is compared with the sealing performance qualification threshold. When the overall equivalent leakage rate is less than or equal to the sealing performance qualification threshold, the sealing performance evaluation result of the hydrogen skid is determined to be qualified. When the overall equivalent leakage rate is greater than the sealing performance qualification threshold, the sealing performance evaluation result of the hydrogen skid is determined to be unqualified.

[0013] Secondly, embodiments of this application provide an equivalent evaluation device for the overall sealing performance of a hydrogen skid, the device comprising: The sample screening unit is used to acquire stress response data of all pipe joints in the hydrogen skid under vibration load, classify the pipe joints, and select the pipe joint with the largest cumulative fatigue damage value from the type of pipe joint for any given type as the test sample. The parameter back-calculation unit is used to perform spectral analysis on the stress response data of the test sample to determine the test loading frequency and back-calculate the equivalent loading displacement amplitude. The vibration test unit is used to conduct a vibration loading test on a test sample with high-pressure hydrogen gas introduced, based on the test loading frequency and the equivalent loading displacement amplitude, and to collect the leakage rate of the test sample. The sealing evaluation unit is used to determine the overall equivalent leakage rate of the hydrogen skid based on the leakage rate of the test sample, the cumulative fatigue damage value of the test sample, and the cumulative fatigue damage value of each type of pipeline joint, so as to evaluate the sealing performance of the hydrogen skid.

[0014] Thirdly, embodiments of this application provide a computer device, including: The system includes a memory and a processor, which are interconnected. The memory stores computer instructions, and the processor executes these computer instructions to perform the aforementioned method for evaluating the overall sealing performance of the hydrogen skid.

[0015] Fourthly, embodiments of this application provide a computer-readable storage medium storing computer instructions, which are used to cause a computer to execute the above-described hydrogen skid overall sealing equivalence evaluation method.

[0016] The technical solutions provided by one or more embodiments of this application scientifically classify hundreds or thousands of pipe joints within a hydrogen skid according to their joint type, specifications, and connection functions. This ensures that joints of the same type have similar mechanical responses and fatigue damage evolution patterns under vibration loads. Furthermore, the joints with the highest cumulative fatigue damage values ​​in each category are selected as test samples. This significantly simplifies the problem of testing a massive number of pipe joints into a verification problem targeting a few critical, worst-case samples. While significantly reducing the number of physical test samples and testing costs, it ensures that the evaluation results cover the sealing safety boundaries of all joints. Secondly, by performing spectral analysis on the stress response data of the test samples to accurately identify the dominant resonant frequency band most prone to fatigue failure under actual working conditions, and by inversely calculating the equivalent loading displacement amplitude, the excitation conditions of the laboratory vibration table highly match the actual service conditions in both frequency coverage and damage equivalence dimensions. Furthermore, under high... Physical tests were conducted under the coupled loading environment of compressed hydrogen and directional reciprocating mechanical vibration, and leakage rates were collected in real time. This directly reflects the sealing structure's resistance to fretting wear and its sealing retention capability under the equivalent fatigue damage accumulation, providing core measured data support for assessing the sealing safety boundary and verifying the critical state of sealing failure. Finally, using the cumulative fatigue damage values ​​of various types of joints as weighting coefficients, the leakage rate data of individual test samples were weighted and superimposed to derive the overall equivalent leakage rate of the hydrogen skid. This achieved a leap from individual sample verification to system-level overall sealing performance evaluation. By comprehensively considering the differences in fatigue damage of different joint types and their contribution weight to the total leakage, the limitations of single measurement point data were eliminated. This allows for a more comprehensive and objective quantitative assessment of the sealing reliability of the entire hydrogen skid under complex vibration and high-pressure coupled environments, providing a scientific and quantitative evaluation basis for determining whether it meets safe service standards and predicting the remaining sealing life. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 A flowchart illustrating an equivalent evaluation method for the overall sealing performance of a hydrogen skid, provided in this application embodiment; Figure 2 A flowchart of step S1 provided in the embodiments of this application; Figure 3 A flowchart for determining the test loading frequency provided in this application embodiment; Figure 4 A flowchart for generating the equivalent loading displacement amplitude provided in this application embodiment; Figure 5 A flowchart for determining the overall equivalent leakage rate of a hydrogen skid provided in this application embodiment; Figure 6 A block diagram of an equivalent evaluation device for the overall sealing performance of a hydrogen skid provided in this application embodiment; Figure 7 This is a schematic diagram of the structure of a computer device provided in an embodiment of this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] Hydrogen fuel cell power systems are a core technological path for the current green transformation of ships. High-pressure hydrogen transmission skids, as the core integrated equipment for marine hydrogen transportation, consist of internal pipelines, connectors, valves, pipes, and other components connected in series. The sealing performance directly determines the operational safety of the entire power system and is one of the core assessment indicators for marine hydrogen energy equipment.

[0021] During actual service, ships are subjected to tilting, rolling, and impact loads, as well as long-term broadband random vibrations caused by main engine operation and wave excitation. Pipeline joints, as the weakest point in the piping system's sealing, are prone to micro-deformation and fatigue accumulation on the sealing surface under the combined effects of long-term alternating vibration loads and high-pressure hydrogen media. This leads to a decrease in contact stress and ultimately seal failure. Furthermore, hydrogen molecules are small, flammable, and explosive; leaks can accumulate rapidly in the compartment, significantly increasing the risk of explosion. Therefore, the sealing reliability of joints under vibration loads is a core requirement in the design of marine hydrogen skids.

[0022] Currently, the sealing performance test of marine gas transmission equipment generally adopts the overall skid vibration test scheme: the entire gas transmission skid is fixed on the vibration platform, the inside is filled with inert gas to the rated working pressure, and a fixed frequency and fixed amplitude vibration test is carried out according to the set parameters. After the vibration is completed, the overall sealing performance of the equipment is determined by helium mass spectrometry leak detection. This technical solution has several inherent flaws: First, the evaluation granularity is coarse, only able to obtain the total overall leakage amount, unable to quantitatively evaluate the leakage level of individual joints or valves, making fault location and problem diagnosis extremely difficult; second, it has poor versatility, requiring the reconstruction of test benches for different structures and specifications of gas transmission skids, resulting in long iteration and optimization cycles and low efficiency; third, the medium equivalence is insufficient, limited by the safety characteristics of hydrogen, the overall test often uses inert gases such as nitrogen and helium to replace hydrogen medium, which cannot truly reflect the sealing leakage characteristics under small molecule hydrogen medium; fourth, the process monitoring capability is lacking, the dynamic changes in leakage amount cannot be monitored in real time during the test, it is difficult to capture the decay law of sealing performance with vibration cycle, and it cannot support the assessment of seal fatigue life; fifth, the verification cost is high, if leakage or structural abnormality occurs in the overall skid test, on-site disassembly and repair are difficult, and the cost of problem location and optimization verification is extremely high.

[0023] To address the drawbacks of overall testing, a few attempts have been made in the field of single-pipeline unit vibration testing. However, these generally suffer from two core technical limitations: First, the damage equivalence is insufficient. They simply reproduce the vibration displacement or acceleration of the pipeline without grasping the essence that "fatigue accumulation of the sealing surface is the core cause of vibration leakage." The damage equivalence relationship between random vibration and constant amplitude loading is unclear, and the test results deviate significantly from actual working conditions. Second, the sample selection and evaluation logic is crude. Pipelines with the largest displacement are usually selected directly as test samples without distinguishing the different contributions of rigid body displacement, axial displacement, and bending displacement to sealing failure. The overall evaluation is simply a superposition of "single joint leakage rate × number," resulting in either overly conservative or unreliable results.

[0024] Due to the aforementioned limitations, a technical bias has generally formed in this field that "single-pipeline unit test results are distorted, cannot be equivalent to overall skid tests, and cannot be used for quantitative evaluation of overall sealing performance." This has led to the industry's long-term reliance on high-cost overall test solutions, making it difficult to balance evaluation efficiency and accuracy.

[0025] In conclusion, how to balance the overall testing and evaluation efficiency and accuracy of hydrogen skids is a technical problem that urgently needs to be solved.

[0026] According to an embodiment of this application, an embodiment of an equivalent evaluation method for the overall sealing performance of a hydrogen skid is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0027] This embodiment provides an equivalent evaluation method for the overall sealing performance of a hydrogen skid. Figure 1 A flowchart illustrating an equivalent evaluation method for the overall sealing performance of a hydrogen skid, as provided in this application embodiment, is shown below. Figure 1 As shown, the process includes the following steps: Step S1: Obtain stress response data of all pipe joints in the hydrogen skid under vibration load, classify the pipe joints, and for any type of pipe joint, select the pipe joint with the largest cumulative fatigue damage value as the test sample.

[0028] Specifically, based on the type of connector (e.g., compression fittings, flared fittings, welded fittings, etc.), dimensions (e.g., pipe diameter), and connection function (e.g., main pipe connection, branch pipe connection, valve connection, etc.), the hundreds or thousands of pipe fittings inside the hydrogen skid are divided into several mutually exclusive categories (e.g., Category A - high-pressure compression fittings, Category B - medium-pressure flared fittings, etc.). The purpose of this classification is to ensure that pipe fittings within the same category have similar mechanical response characteristics and fatigue damage evolution patterns under the same vibration load, thereby ensuring the scientific validity of the subsequent selection of representative samples.

[0029] Stress response data can be obtained using finite element simulation or actual measurement. In this embodiment, finite element simulation is preferred. A three-dimensional finite element model containing all pipelines and pipe joints is established based on the engineering drawings of the hydrogen skid, and corresponding material properties and boundary conditions are assigned. Subsequently, the broadband random vibration loads (including mechanical vibrations caused by main engine operation and low-frequency swaying caused by wave excitation) in the actual service environment of the ship are converted into power spectral density (PSD) curves in the frequency domain, which are then applied as excitation sources to the base or mounting flange of the finite element model to conduct random vibration response analysis.

[0030] In the post-processing stage, stress response data of all pipe joint sealing surfaces (such as sealing cone surfaces, thread roots, and other areas prone to fatigue failure) in the model are extracted. Stress response data includes, but is not limited to, stress-time data of the pipe joint sealing surface as a function of time, typically represented as a time-varying stress tensor or stress component sequence; the total stress on the pipe joint sealing surface at each mode (or frequency band); and the stress amplitude and corresponding cycle number for each stress cycle.

[0031] The stress response data of each pipeline joint were mapped, categorized, and stored according to the classification system established in the first step, forming a structured database containing "joint type - joint number - stress response data". This database not only provides basic data support for the subsequent screening of test samples with the largest cumulative fatigue damage values, but also ensures the traceability and integrity of the evaluation process.

[0032] For each type of pipe joint, the cumulative fatigue damage value of each joint calculated in the previous steps is retrieved and compared within that type. The pipe joint with the largest cumulative fatigue damage value (i.e., the most severely damaged and highest risk) is selected as the test sample for that type. The scientific basis of this selection strategy is that the joint with the largest cumulative fatigue damage value represents the weakest link or ultimate state of that type of joint under vibration load. If this most unfavorable joint can pass the subsequent vibration loading test and meet the sealing requirements (i.e., no leakage and a leakage rate below the threshold), then other joints with smaller cumulative damage values ​​in that type will also necessarily meet the sealing requirements. In this way, this embodiment simplifies the problem of testing a massive number of pipe joints into a verification problem for a few key worst-case samples. This ensures that the evaluation results can cover the sealing safety boundary of all joints, while greatly reducing the number of physical test samples and testing costs, achieving an optimal balance between evaluation efficiency and accuracy.

[0033] Step S3: Perform spectral analysis on the stress response data of the test sample to determine the test loading frequency, and then reverse-engineer the equivalent loading displacement amplitude.

[0034] Specifically, the stress response data of the test samples under actual working conditions are analyzed to identify the peak frequency that dominates the stress response of the pipe joints, and this peak frequency is determined as the test loading frequency. This step ensures that the frequency excited by the laboratory vibration table accurately covers the resonant frequency band most prone to fatigue failure in the actual service environment. Subsequently, using this test loading frequency as a reference, an initial reciprocating vibration displacement amplitude is set on the vibration test bench, and the equivalent stress amplitude of the sealing surface is calculated. Based on this, the equivalent fatigue damage value generated under the current initial displacement amplitude is derived using the Miner linear cumulative damage criterion. By continuously comparing the currently calculated equivalent fatigue damage value with the target fatigue damage value until they completely converge within the allowable error range, the equivalent loading displacement amplitude is obtained by reverse calculation.

[0035] Step S5: Based on the test loading frequency and equivalent loading displacement amplitude, a vibration loading test is conducted on the test sample with high-pressure hydrogen gas introduced, and the leakage rate of the test sample is collected.

[0036] Specifically, the test sample is installed on a vibration test bench and filled with high-pressure hydrogen at a specified pressure to establish an internal back pressure environment. Then, the test bench is driven to apply directional reciprocating mechanical vibration strictly according to the frequency and amplitude, so that the joint sealing surface generates a dynamic response under the coupling effect of external high-frequency vibration and internal high-pressure gas. At the same time, a high-precision detection device is used to collect the leakage rate data of the test sample in real time. This step accurately reproduces the mechanical load and medium load under actual working conditions by constructing a real physical verification environment. It can intuitively reflect the anti-fretting wear capability and sealing retention capability of the pipeline joint sealing structure under equivalent fatigue damage accumulation, thus providing core measured data support for evaluating the sealing safety boundary of the hydrogen skid pipeline joint and verifying the critical state of sealing failure.

[0037] Step S7: Based on the leakage rate of the test sample, the cumulative fatigue damage value of the test sample, and the cumulative fatigue damage value of each type of pipeline joint, determine the overall equivalent leakage rate of the hydrogen skid to evaluate the sealing performance of the hydrogen skid.

[0038] Specifically, based on the distribution quantity of each type of pipe joint in the skid and its corresponding cumulative fatigue damage value, a weighted superposition algorithm is used. The cumulative fatigue damage value of each type of joint is used as a weighting coefficient to calculate the local leakage contribution value of each pipe joint under the corresponding fatigue damage. The local leakage contribution values ​​of all pipe joints are then summed to derive the overall equivalent leakage rate characterizing the sealing performance of the entire hydrogen skid under complex vibration and high-pressure coupling environment. This step realizes the leap from individual sample test data to system-level overall performance. By comprehensively considering the differences in fatigue damage of different joint types and their contribution weight to the total leakage, the limitations of single measurement point data are eliminated. This allows for a more comprehensive and objective quantitative evaluation of the overall sealing reliability of the hydrogen skid, providing a scientific and quantitative evaluation basis for determining whether the skid meets the safe service standards and predicting its remaining sealing life.

[0039] This embodiment provides a method for evaluating the overall sealing performance of a hydrogen skid. By scientifically classifying hundreds or thousands of pipe joints within the hydrogen skid according to their type, size, and function, it ensures that similar joints exhibit similar mechanical responses and fatigue damage evolution under vibration loads. The method then selects the joint with the highest cumulative fatigue damage value from each category as the test sample. This significantly simplifies the problem of testing a massive number of pipe joints into a verification problem targeting a few critical, worst-case samples. While significantly reducing the number of physical test samples and testing costs, it ensures that the evaluation results cover the sealing safety boundaries of all joints. Secondly, by performing spectral analysis on the stress response data of the test samples, the dominant resonant frequency band most prone to fatigue failure under actual operating conditions is accurately identified, and the equivalent loading displacement amplitude is inferred. This ensures that the excitation conditions of the laboratory vibration table highly match the actual service conditions in both frequency coverage and damage equivalence dimensions. Furthermore... Physical tests conducted under the coupled loading environment of high-pressure hydrogen and directional reciprocating mechanical vibration, along with real-time leakage rate acquisition, can directly reflect the sealing structure's resistance to fretting wear and its sealing retention capability under equivalent fatigue damage accumulation. This provides core measured data support for assessing the sealing safety boundary and verifying the critical state of sealing failure. Finally, using the cumulative fatigue damage values ​​of various types of joints as weighting coefficients, the leakage rate data of individual test samples are weighted and superimposed to derive the overall equivalent leakage rate of the hydrogen skid. This achieves a leap from individual sample verification to system-level overall sealing performance evaluation. By comprehensively considering the differences in fatigue damage of different joint types and their contribution weight to the total leakage, the limitations of single-point measurement data are eliminated. This allows for a more comprehensive and objective quantitative assessment of the sealing reliability of the entire hydrogen skid under complex vibration and high-pressure coupled environments, providing a scientific and quantitative evaluation basis for determining whether it meets safe service standards and predicting the remaining sealing life.

[0040] Figure 2 The flowchart for step S1 provided in the embodiments of this application may include the following steps: Step S11: For any type of pipe joint, perform modal contribution analysis on the stress response data, remove stress response data with modal contribution values ​​lower than the modal contribution value threshold, and obtain the target stress response data.

[0041] Specifically, modal contribution analysis is performed on the acquired stress response data. First, the contribution percentage C of the r-th mode to the total stress on the sealing surface of the pipe joint is calculated. r The calculation formula is as follows: in, The stress squared is the stress corresponding to the r-th mode. This is the sum of the squared stresses of all modes (from order 1 to order N), where N is the total modal order. Then, a modal contribution threshold C is set. th (For example, set to 5%). If the C of a certain mode... r <C th If the contribution of this mode to fatigue damage is weak (usually low-frequency rigid body motion or high-frequency weak vibration), the corresponding stress response data is discarded; C is retained. r ≥C th The modal stress response data of each order are superimposed to obtain the target stress response data for subsequent fatigue assessment.

[0042] Step S13: Extract the fatigue load spectrum based on the target stress response data, and determine the cumulative fatigue damage value of each pipeline joint by combining it with the preset material fatigue characteristic model.

[0043] Specifically, the target stress response data is first statistically analyzed using the rainflow counting method to extract m stress cycles, thus obtaining the fatigue load spectrum (including the stress amplitude S of the h-th cycle). h and the number of loops n h Subsequently, based on the pre-defined material fatigue characteristic model (i.e., the SN curve model), the fatigue damage caused by each cycle is calculated. The single-cycle damage d caused by the h-th cycle is... h The calculation formula is: Where, N f,h The stress amplitude S h The number of cycles required for the material to fail, C s and b are the SN curve constant parameters of the pipe joint material, respectively. Finally, according to Miner's linear cumulative damage rule, the damage of this type of pipe joint under all stress cycles is linearly accumulated to obtain the cumulative fatigue damage value D of the pipe joint. The calculation formula is: Step S15: Select the pipe joint with the largest cumulative fatigue damage value and determine it as the test sample.

[0044] Specifically, after calculating the cumulative fatigue damage value D for all pipe joints of the same type, an automatic comparison is performed to identify the pipe joint with the largest cumulative fatigue damage value in that category, i.e., the one that satisfies: D max =max(D1,D2,...,D p ), where p is the total number of pipe joints of this type. The one with the maximum cumulative fatigue damage value D... max The pipe joint was selected as the representative test sample for this type. Because this joint experiences the greatest vibration severity and the fastest fatigue evolution, it best represents the sealing failure risk boundary of this type of joint under vibration environment. Using it as the test sample can minimize the number of physical test samples while ensuring the accuracy of the evaluation.

[0045] This embodiment performs modal contribution analysis on stress response data, calculates the contribution ratio of each mode to the total stress of the sealing surface, and removes weak contributing modes below a set threshold (usually low-frequency rigid body motion or high-frequency weak vibration). Only the modal data that plays a dominant role in fatigue damage are retained for superposition, thereby effectively filtering out noise interference and non-fatigue-related vibration components, significantly improving the data quality and computational efficiency of subsequent fatigue assessment. On this basis, a fatigue load spectrum containing stress amplitude and cycle number is extracted from the target stress response data, and combined with a preset material fatigue characteristic model, the complex random vibration stress response is transformed into a quantifiable cumulative fatigue damage value, realizing a scientific and quantitative characterization of the fatigue evolution law of pipeline joints under vibration load. Finally, by traversing and screening all pipeline joints of the same type, the joint with the largest cumulative fatigue damage value is selected as the test sample, so that the sample can represent the sealing failure risk boundary of this type of joint under vibration environment. While ensuring the evaluation accuracy, the number of samples required for physical testing is minimized, achieving the optimal balance between evaluation efficiency and accuracy.

[0046] Figure 3 The flowchart for determining the test loading frequency provided in this application embodiment may include the following steps: Step S311: Based on the stress response data of the test sample, obtain the power spectral density curve of stress amplitude as a function of frequency.

[0047] Specifically, a Fast Fourier Transform (FFT) was performed on the stress response data of the test samples under complex working conditions to convert the time-domain signal into a frequency-domain signal. The auto power spectral density (PSD) was calculated to obtain the power spectral density curve showing the stress amplitude as a function of frequency. This curve reflects the energy distribution of the pipe joint under vibration excitation at different frequencies.

[0048] Step S313: Identify the peak points in the power spectral density curve and take the frequency corresponding to the peak points as the dominant frequency component.

[0049] Step S315: Determine the main frequency component as the test loading frequency.

[0050] Specifically, while the random vibrations experienced by ship piping systems contain broadband energy, actual fatigue damage is often dominated by a few resonant frequencies. Therefore, peak search of the power spectral density curve is necessary. An energy identification threshold G is set. th (For example, take 10% of the maximum peak value of the curve), traverse all frequency points on the curve, and filter out those that satisfy G. xx (f)≥G th The local maximum point of G xx (f) represents the stress power spectral density at frequency f. These local maxima are identified as peak points, and the frequencies corresponding to these peak points are assigned to f. p The dominant frequency component that plays a leading role in the stress response of the pipe joint was identified. In this embodiment, to ensure that the experiment can fully induce fatigue damage in the pipe joint, the component with the strongest energy (i.e., G) on the power spectral density curve was selected. xx The frequency corresponding to the peak point of (f) with the largest value is taken as the main frequency component.

[0051] This embodiment uses Fast Fourier Transform (FFT) on the stress response data of the test samples to obtain the power spectral density curve of stress amplitude as a function of frequency. This transforms the complex time-domain vibration signal into a clear frequency-domain energy distribution characterization, intuitively revealing the stress energy distribution characteristics of the pipe joint under different frequency excitations. Subsequently, by setting an energy identification threshold, peak search is performed on the power spectral density curve to accurately screen out local maxima that meet the threshold conditions and identify their corresponding frequencies as the dominant frequency components. This effectively distinguishes the resonant frequencies that play a dominant role in fatigue damage from irrelevant frequency components with weak energy and minimal contribution in the broadband, significantly improving the targeting and accuracy of frequency identification. Finally, the strongest dominant frequency component is determined as the test loading frequency, ensuring that the excitation frequency of the laboratory vibration table can accurately cover the dominant resonant frequency band that is most likely to cause fatigue failure in the actual service environment. This makes the test loading conditions highly consistent with the real working conditions in the frequency dimension, thereby ensuring the efficiency and equivalence of subsequent vibration loading tests in inducing fatigue damage in the pipe joint.

[0052] Figure 4 The flowchart for generating the equivalent loading displacement amplitude provided in this application embodiment may include the following steps: Step S331: Use the cumulative fatigue damage value of the test sample as the target fatigue damage value.

[0053] Specifically, the cumulative fatigue damage value of the test sample calculated based on actual complex sea conditions in step S13 is directly set as the target fatigue damage value D0 for iterative solution in this step. This value represents the actual vibration fatigue damage boundary that the pipeline joint experiences during its actual service life.

[0054] Step S333: Using the test loading frequency as a reference, set the initial displacement amplitude and determine the equivalent fatigue damage value of the test sample under the initial displacement amplitude.

[0055] Specifically, using the test loading frequency f test As a benchmark, an initial reciprocating displacement amplitude x0 is set on the vibration test bench. It is important to emphasize that the loading direction of this reciprocating vibration must be consistent with the principal direction of the bending stress on the sealing surface to realistically simulate the stress state of the sealing surface. Under this initial displacement amplitude x0, the equivalent stress amplitude S of the sealing surface of the test sample at the corresponding displacement is calculated. eq Specifically, the stress-displacement transfer coefficient (or equivalent bending stiffness) K at the sealing surface of the pipe joint is extracted through finite element simulation or preliminary calibration tests. The physical meaning of this coefficient K is: the equivalent stress value (usually in MPa / mm) generated on the sealing surface when a unit displacement (e.g., 1 mm) occurs at the root of the pipe joint. After setting the initial reciprocating vibration displacement amplitude x0 on the vibration test bench, the equivalent stress amplitude S of the sealing surface is directly calculated using the following formula based on the principle of linear superposition. eq :S eq =K×x0, where x0 is the set initial displacement amplitude, and K is the stress-displacement transfer coefficient obtained in the previous iteration. As the displacement amplitude x0 increases during subsequent iterations... old The continuous adjustments will be made in real time according to S eq =K×x new Update the equivalent stress amplitude.

[0056] Subsequently, using Miner's linear cumulative damage criterion, the fatigue damage value D per unit time under this initial displacement amplitude was derived. t The calculation formula is as follows: Among them, f test The test loading frequency (i.e., the number of vibration cycles per second), T test For the preset target test time, Nf C represents the number of cycles required for the material to fail at this equivalent stress amplitude. s and b are the SN curve constant parameters of the pipe joint material, respectively. The calculated fatigue damage value D per unit time is then used. t This serves as the equivalent fatigue damage value under the current initial displacement amplitude.

[0057] Step S335: Iteratively adjust the initial displacement amplitude until the equivalent fatigue damage value equals the target fatigue damage value, and determine the adjusted initial displacement amplitude as the equivalent loading displacement amplitude.

[0058] Specifically, since the initial displacement amplitude x0 is often difficult to accurately match the actual damage in one iteration, an iterative algorithm is needed for correction. An allowable error range ε ​​(e.g., 1%) is set. In each iteration, the currently calculated equivalent fatigue damage value D is... t Compare with the target fatigue damage value D0. When D t When the value is equal to D0, the equivalent fatigue damage value is determined to be equal to the target fatigue damage value. The corresponding displacement amplitude at this time is the final equivalent loading displacement amplitude.

[0059] If D t If x ≠ D0, then adjust the displacement amplitude according to the deviation scaling rule. The new displacement amplitude x new The update formula is: x new =x old ×(D t / D0) 1 / b , where x old Let x be the displacement amplitude used in the previous iteration, and b be the slope parameter of the SN curve. new The new initial displacement amplitude is substituted into step S333 for recalculation, and the process is repeated iteratively. The iteration stops when the difference between the fatigue damage calculated in two consecutive iterations is less than the error range ε. The finally converged displacement amplitude is determined as the equivalent loading displacement amplitude x. eq .

[0060] By using the aforementioned iterative reverse calculation algorithm and strictly maintaining the loading direction consistent with the principal direction of bending stress on the sealing surface, the complex random vibration under actual working conditions was successfully transformed into a fixed-amplitude reciprocating vibration, ensuring the equivalence of fatigue damage between physical tests and actual service conditions.

[0061] This embodiment directly sets the cumulative fatigue damage value of the test sample as the target fatigue damage value, clarifying the true fatigue damage boundary that the physical test needs to reproduce, and ensuring the consistency between the test target and the actual service conditions. Subsequently, the initial displacement amplitude is set based on the test loading frequency, and the displacement amplitude is converted into the equivalent stress amplitude of the sealing surface using the stress-displacement transfer coefficient. The loading direction is strictly kept consistent with the principal direction of the bending stress of the sealing surface, thereby realistically simulating the stress state of the sealing surface under actual conditions. Then, the equivalent fatigue damage value is calculated, and the complex random vibration under actual conditions is converted into fixed-amplitude reciprocating vibration for damage equivalence. Finally, when the equivalent fatigue damage value converges to the target fatigue damage value within the allowable error range, the equivalent loading displacement amplitude is determined, ensuring a high degree of equivalence between the laboratory physical test and the actual service conditions in the fatigue damage dimension, and providing accurate and quantifiable loading parameters for subsequent vibration loading tests.

[0062] Figure 5 The flowchart for determining the overall equivalent leakage rate of a hydrogen skid provided in this application embodiment may include the following steps: Step S711: For any type of pipe joint, the cumulative fatigue damage value of each pipe joint in the type is calculated by comparing it with the cumulative fatigue damage value of the test sample to obtain the vibration severity correction coefficient for each pipe joint.

[0063] Specifically, since the test samples selected in the previous steps are the pipe units with the greatest fatigue damage and the most severe operating conditions among this type of pipe joint, their cumulative fatigue damage value is denoted as D. i,max For the j-th pipe joint in this type (the i-th type), obtain its cumulative fatigue damage value D. i,j The vibration severity correction factor k for this pipe joint is calculated using ratio calculation. i,j The calculation formula is as follows: Because of D i,max This is the largest cumulative fatigue damage value in this type, therefore the correction factor k i,j The range of values ​​always satisfies 0 ≤ k i,j ≤1. This coefficient objectively reflects the relative fatigue severity of the joint under the current vibration environment.

[0064] Step S713: Multiply the leakage rate of the test sample by the sum of the vibration severity correction coefficients of all pipe joints in the type to obtain the total leakage rate of the type.

[0065] Specifically, the leakage rate of the test sample (i.e., the joint with the greatest damage) is measured through physical vibration testing and denoted as q. i Meanwhile, the total number of type i connectors within the skid is N.i The vibration severity correction factors for all joints of this type are summed, and then multiplied by the leakage rate of the test sample to obtain the total leakage rate Q of the i-th type of joint. i The calculation formula is as follows: This formula reasonably maps the leakage test results of a single test sample to all joint groups of this type.

[0066] Step S715: The total leakage rates of all types within the hydrogen skid are summed to obtain the overall equivalent leakage rate of the hydrogen skid.

[0067] Specifically, iterate through all n types of pipe joints within the hydrogen skid and calculate the total leakage rate Q for all types. i By performing linear accumulation, the overall equivalent leakage rate of the skid is obtained. The calculation formula is as follows: The calculated overall equivalent leakage rate Q total By comparing the performance with the allowable leakage threshold for marine equipment, it can be determined whether the overall sealing performance of the skid meets the standard.

[0068] This embodiment calculates the vibration severity correction coefficient by comparing the cumulative fatigue damage value of each pipe joint in each type with the maximum cumulative fatigue damage value of the test sample of that type. This establishes a fatigue damage mapping relationship from the worst-case sample to all joints of the same type, objectively quantifying the relative fatigue severity of each joint under the current vibration environment. Subsequently, the leakage rate of the test sample measured by physical tests is multiplied by the sum of the vibration severity correction coefficients of all pipe joints of that type. The leakage test results of a single test sample are reasonably extrapolated to the entire group of joints of that type, realizing an equivalent extension from individual measured data to the group leakage contribution. Finally, by linearly summing the total leakage rates of all types within the hydrogen skid, the overall equivalent leakage rate is obtained and compared with the allowable leakage threshold. This achieves a leapfrog integration from the group leakage contribution of various joints to the overall sealing performance of the skid, eliminating the limitations of single measurement point data and providing a scientific basis for the quantitative evaluation and compliance determination of system-level sealing reliability.

[0069] In a preferred embodiment, the sealing performance evaluation of the hydrogen skid includes: determining whether the leakage rate of the test sample is less than a preset leakage rate threshold, and whether the maximum stress value of the test sample in the vibration loading test has not reached the yield strength of the material; if the determination is yes, the overall sealing performance of the hydrogen skid is determined based on the overall equivalent leakage rate; if the determination is no, the sealing performance evaluation result of the hydrogen skid is determined to be unqualified.

[0070] Specifically, to ensure that the overall equivalent leakage rate calculated in the preceding steps has engineering reference value, it is essential to guarantee that the test samples are within a safe and effective testing range during the vibration loading test. This step must simultaneously meet the following two conditions: Condition 1 (Sealing Effectiveness Verification): Obtain the measured leakage rate q of the test sample after the vibration loading test. i And determine whether it is less than the preset leakage rate threshold q. th (This threshold is typically set according to the design specifications or national standards for hydrogen skids). If q i th This indicates that the test sample did not experience macroscopic sealing failure or structural damage during the test, and the measured leakage rate data truly reflects the sealing performance of the pipeline joint during the elastic vibration stage.

[0071] Condition 2 (Mechanical State Verification): Obtain the maximum stress value σ that the test sample experiences during the vibration loading test. max And determine whether it is less than the yield strength σ of the pipe joint material. y (i.e. σ) max <σ y If the yield strength is not reached, it indicates that the test sample remained in the elastic deformation stage throughout the entire vibration process, without plastic yielding or material tearing.

[0072] The joint does not leak and the leakage rate q is satisfied only if both conditions are met simultaneously (i.e., after being loaded to the preset number of cycles, the joint does not leak and the leakage rate q is satisfied). i <1×10 -8 (The vibration loading test was deemed valid when the pipe stress did not reach the yield strength, and the test was conducted at mbar·L / s). At this point, the overall sealing performance of the hydrogen skid was determined based on the overall equivalent leakage rate.

[0073] If any condition is not met (i.e., leakage occurs at the joint during loading, or the pipeline stress reaches the yield threshold), the joint is deemed unqualified for sealing, and consequently, the sealing performance evaluation of the hydrogen skid is deemed unqualified. Furthermore, after being determined to be unqualified, the causes of failure are analyzed simultaneously. For example, if leakage occurs, the causes of wear on the sealing surface or insufficient contact stress are analyzed; if the yield strength is reached, the causes of structural stiffness or localized stress concentration are analyzed. This failure analysis provides direct data support for joint structure optimization and material selection.

[0074] ​In this embodiment, a dual verification mechanism combining leakage rate threshold and material yield strength is established to synchronously determine the sealing effectiveness and mechanical state of the test sample during the vibration loading test. It is ensured that only when the test sample has no macroscopic sealing failure (leakage rate is lower than the preset threshold) and is always in the elastic deformation stage (the maximum stress does not reach the material yield strength), the vibration loading test is deemed valid and the overall equivalent leakage rate is evaluated accordingly. This ensures that the test data based on which the overall equivalent leakage rate is calculated truly reflects the sealing performance of the pipe joint in the elastic vibration stage, significantly improving the engineering reference value and reliability of the evaluation result; on the contrary, if any condition is not met, the sealing evaluation result of the hydrogen skid is directly determined as unqualified, and failure cause analysis (such as sealing surface wear, insufficient contact stress, structural stiffness defect or local stress concentration, etc.) is carried out synchronously, which provides direct data support for joint structure optimization and material selection, and realizes the closed-loop technical effect from sealing performance evaluation to failure attribution feedback.

[0075] In a preferred embodiment, determining the overall sealing performance of the hydrogen skid according to the overall equivalent leakage rate includes: obtaining a preset qualified threshold for hydrogen skid sealing performance; comparing the overall equivalent leakage rate with the qualified sealing threshold; when the overall equivalent leakage rate is less than or equal to the qualified sealing threshold, determining that the sealing evaluation result of the hydrogen skid is qualified; when the overall equivalent leakage rate is greater than the qualified sealing threshold, determining that the sealing evaluation result of the hydrogen skid is unqualified.

[0076] Specifically, before determining the overall sealing performance of the skid, it is necessary to preset an allowable maximum leakage standard, that is, the qualified sealing threshold of the hydrogen skid (recorded as Q limit ). This threshold is usually determined comprehensively by the design specification of the hydrogen skid, relevant national safety standards (such as the leakage rate standard for hydrogen energy storage and transportation equipment) or the safety margin requirements of actual working conditions. This threshold represents the ultimate safety boundary that can ensure no dangerous leakage of hydrogen during the long-term service of the skid.

[0077] The calculated overall equivalent leakage rate is compared in terms of numerical value with the preset qualified sealing threshold of the hydrogen skid Q limit .

[0078] If the comparison result shows that Q total ≤ Q limit , it indicates that the total leakage risk of all types of pipe joints in the hydrogen skid under the equivalent vibration load is within a safe and controllable range. At this time, the sealing evaluation result of the hydrogen skid is determined as qualified, the skid meets the vibration working condition service standard required by the design, and can enter the next production or assembly process.

[0079] This embodiment establishes a quantitative evaluation benchmark characterizing the ultimate safety boundary by setting a pre-defined hydrogen skid sealing performance qualification threshold. Subsequently, the calculated overall equivalent leakage rate is numerically compared with the qualification threshold, realizing the transformation from quantitative calculation of system-level leakage to qualitative judgment of sealing performance. When the overall equivalent leakage rate is less than or equal to the qualification threshold, it indicates that the total leakage risk of all types of pipeline joints in the hydrogen skid under equivalent vibration load is within a safe and controllable range, and it is determined that it meets the vibration condition usage standard required by the design and can enter the subsequent production or assembly process. Conversely, when the overall equivalent leakage rate is greater than the qualification threshold, the leakage risk exceeding the safety boundary is promptly identified and judged as unqualified, thus providing a standardized and quantifiable judgment basis for the sealing safety of the hydrogen skid, effectively supporting production quality control and safe service decision-making.

[0080] The specific implementation of this invention is described below with reference to a specific application scenario. In this specific application scenario, a 316L stainless steel high-pressure pipeline and G1 / 2 threaded joint in a marine hydrogen skid are used as the evaluation objects, and an equivalent evaluation of sealing performance is carried out through the following steps: Step S1001: Overall Finite Element Modal Analysis of the Skid Block and Selection of Test Samples A general-purpose CAE analysis software was used to perform overall finite element analysis on the target marine hydrogen skid. Geometric modeling and mesh generation were completed, and excitation boundary conditions were set based on the random vibration load spectrum of ship navigation, followed by solution processing. For all G1 / 2 threaded joints, the contribution ratio of bending stress on the sealing surface was calculated for each joint, filtering out those with a contribution ratio below 5%. Based on the effective stress time history results, the stress cycle distribution was statistically analyzed using the rainflow counting method, and the cumulative fatigue damage value of each joint was calculated using the Miner criterion. Finally, the pipe joint with the largest cumulative fatigue damage value was selected as the test sample for this type. The calculated parameters for this test sample were: dominant vibration frequency 10Hz, equivalent stress amplitude on the sealing surface 120MPa, and the pipe support type being simply supported at both ends.

[0081] Step S1002: Setup of Single Pipe Joint Sealing Test System A 316L stainless steel high-pressure pipe with specifications identical to that inside the skid was selected, and G1 / 2 threaded connectors to be evaluated were installed at both ends. Matching PTFE sealing gaskets were used, and assembly was performed to standard torque to ensure initial sealing performance. The pipe was fixed at both ends in a simply supported beam configuration to replicate the actual support state inside the skid. The middle section of the pipe was reliably connected to the reciprocating vibration displacement loading device, and the pipe alignment was calibrated to ensure no loosening or assembly deviation. Strain gauges were attached near the joint sealing surfaces, and pressure sensors, acceleration sensors, and laser displacement sensors were installed on the pipe. A high-precision hydrogen concentration sensor was placed in the sealed test chamber. The data acquisition system was connected and debugged, and the acquisition frequency was set to 20Hz.

[0082] Step S1003: Calculation of equivalent loading parameters for fatigue damage Based on the stress time history of the sealing surface of the test sample obtained in step S1001, the target fatigue damage value of the sealing surface per unit time is obtained through rainflow counting and Miner's criterion. A dominant frequency of 10Hz is selected as the test loading frequency. The bending stress amplitude of the joint sealing surface under different displacement amplitudes is derived using mechanical formulas, and the corresponding damage per unit time is calculated. Through iterative calculation, when the reciprocating vibration displacement amplitude is 1.1mm, the equivalent stress amplitude of the test pipeline joint sealing surface is 120MPa, and the corresponding damage per unit time is exactly equal to the target fatigue damage value. Therefore, the equivalent loading parameters are determined as follows: equivalent loading displacement amplitude 1.1mm, test loading frequency 10Hz, and loading direction is vertically upwards and downwards along the pipeline axis. The hydrogen pressure in the test pipeline is set to 4MPa, the preset vibration cycle number is 106, and the hydrogen concentration alarm threshold is set to a volume fraction of 0.4%.

[0083] Step S1004: Equivalent vibration loading and data acquisition High-pressure hydrogen gas was slowly introduced into the pipe joint, and the pressure was increased to 4 MPa before stopping the introduction. The pressure was maintained for 30 minutes to confirm the initial seal was qualified. The reciprocating vibration displacement loading device was then activated, continuously applying a reciprocating vibration load according to the parameters of an equivalent loading displacement amplitude of 1.1 mm and a test loading frequency of 10 Hz. During the loading process, the data acquisition system simultaneously collected data on strain, displacement, acceleration, pipe pressure, and chamber hydrogen concentration, generating corresponding change curves in real time. Strain and displacement monitoring verified that the equivalent stress amplitude, vibration frequency, and equivalent conversion parameters of the joint sealing surface remained consistent throughout the test, and the loading accuracy met the requirements. After 106 cycles of loading, no leakage alarm occurred at the joint, and the pipe stress did not reach the yield strength of 316L stainless steel. Loading was stopped after meeting the termination conditions.

[0084] Step S1005: Comprehensive evaluation of the overall sealing performance of the skid block (1) Performance judgment of single-pipe joint After 106 cycles of loading in this test, there was no leakage and the stress did not exceed the standard. It was determined that the G1 / 2 threaded joint was qualified in terms of sealing performance under the corresponding vibration conditions and could meet the usage requirements of the skid. The leakage rate of the test sample under this condition was obtained by data fitting.

[0085] (2) Calculation of overall leakage of skid Eight G1 / 2 threaded joints were found inside the skid. Based on finite element analysis, the cumulative fatigue damage value of each joint was calculated. Using the maximum cumulative fatigue damage value as a benchmark, the vibration severity correction coefficients for the eight joints were obtained as follows: 1.000, 0.800, 0.700, 0.600, 0.600, 0.500, 0.400, and 0.300. The total leakage rate of this type of joint was calculated as: Qtotal = (Test sample leakage rate) × (1.000 + 0.800 + 0.700 + 0.600 + 0.600 + 0.500 + 0.400 + 0.300).

[0086] All other types of joints within the skid were tested and calculated using the same method described above. The total leakage rates of all joint types were then summed to obtain the overall equivalent leakage rate of the skid. Upon comparison, this overall equivalent leakage rate was found to be lower than the allowable leakage threshold for marine hydrogen equipment, thus confirming that the overall sealing performance of the skid met the standards.

[0087] To verify the equivalent accuracy of this method, a comprehensive vibration test was conducted using a skid of the same specification as a control, and the overall leakage rate was measured. The deviation between the calculated results of this method and the measured values ​​of the comprehensive test was 7.2% (<10%), which meets the accuracy requirements for engineering evaluation and proves the reliability and accuracy of the equivalent method. In addition, since the test sample selected in this embodiment is the pipeline unit with the largest cumulative fatigue damage value and the most severe operating conditions among similar joints, the overall evaluation results are conservative and have sufficient safety margin.

[0088] Accordingly, please refer to Figure 6 A block diagram of an equivalent evaluation device for the overall sealing performance of a hydrogen skid provided in this application embodiment, the device comprising: The sample screening unit 101 is used to acquire stress response data of all pipe joints in the hydrogen skid under vibration load, classify the pipe joints, and select the pipe joint with the largest cumulative fatigue damage value from the types of pipe joints for any type as the test sample. The parameter back-calculation unit 103 is used to perform spectral analysis on the stress response data of the test sample to determine the test loading frequency and back-calculate the equivalent loading displacement amplitude. The vibration test unit 105 is used to conduct vibration loading tests on test samples with high-pressure hydrogen gas introduced based on the test loading frequency and equivalent loading displacement amplitude, and to collect the leakage rate of the test samples. The sealing evaluation unit 107 is used to determine the overall equivalent leakage rate of the hydrogen skid based on the leakage rate of the test sample, the cumulative fatigue damage value of the test sample, and the cumulative fatigue damage value of each type of pipeline joint, so as to evaluate the sealing performance of the hydrogen skid.

[0089] In some optional implementations, the sample screening unit 101 includes: For any type of pipe joint, modal contribution analysis is performed on the stress response data, and stress response data with modal contribution values ​​lower than the modal contribution value threshold are removed to obtain the target stress response data; The fatigue load spectrum is extracted based on the target stress response data, and the cumulative fatigue damage value of each pipeline joint is determined by combining it with the preset material fatigue characteristic model. The pipe joint with the highest cumulative fatigue damage value was selected as the test sample.

[0090] In some alternative implementations, the parameter back-calculation unit 103 includes: Based on the stress response data of the test samples, obtain the power spectral density curve of stress amplitude as a function of frequency; Identify the peak points in the power spectral density curve and take the frequency corresponding to the peak points as the dominant frequency component; The main frequency component was determined as the test loading frequency.

[0091] In some optional implementations, the parameter back-calculation unit 103 includes: The cumulative fatigue damage value of the test sample is used as the target fatigue damage value; Using the test loading frequency as a benchmark, the initial displacement amplitude is set, and the equivalent fatigue damage value of the test sample under the initial displacement amplitude is determined. The initial displacement amplitude is iteratively adjusted until the equivalent fatigue damage value equals the target fatigue damage value. The adjusted initial displacement amplitude is then determined as the equivalent loading displacement amplitude.

[0092] In some alternative implementations, the sealing evaluation unit 107 includes: For any type of pipe joint, the cumulative fatigue damage value of each pipe joint in the type is compared with the cumulative fatigue damage value of the test sample to obtain the vibration severity correction coefficient for each pipe joint. The total leakage rate of the type is obtained by multiplying the leakage rate of the test sample by the sum of the vibration severity correction factors of all pipe joints in the type. The total leakage rate of all types within the hydrogen skid is summed to obtain the overall equivalent leakage rate of the hydrogen skid.

[0093] In some alternative implementations, the sealing evaluation unit 107 includes: Determine whether the leakage rate of the test sample is less than the preset leakage rate threshold, and whether the maximum stress value of the test sample in the vibration loading test has not reached the yield strength of the material. If the determination is yes, then the overall sealing performance of the hydrogen skid is judged based on the overall equivalent leakage rate; If the result is negative, the sealing performance evaluation of the hydrogen skid is deemed unqualified.

[0094] In some alternative implementations, the sealing evaluation unit 107 includes: Obtain the preset threshold for hydrogen skid sealing compliance; The overall equivalent leakage rate is compared with the sealing performance qualification threshold; When the overall equivalent leakage rate is less than or equal to the sealing performance qualification threshold, the sealing performance evaluation result of the hydrogen skid is deemed qualified. When the overall equivalent leakage rate is greater than the sealing performance qualification threshold, the sealing performance evaluation result of the hydrogen skid is deemed unqualified.

[0095] Further functional descriptions of the above modules and units are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0096] In this embodiment, the hydrogen skid overall sealing performance equivalent evaluation device is presented in the form of a functional unit. Here, a unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that execute one or more software or fixed programs, and / or other devices that can provide the above functions.

[0097] Please see Figure 7 , Figure 7 This application provides a schematic diagram of the structure of a computer device, as shown in the embodiment of the present application. Figure 7 As shown, the computer device includes one or more processors 10, memory 20, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. The components communicate with each other via different buses and can be mounted on a common motherboard or otherwise installed as needed. The processors can process instructions executed within the computer device, including instructions stored in or on memory to display graphical information of a GUI on external input / output devices (such as display devices coupled to the interfaces). In some alternative implementations, multiple processors and / or multiple buses can be used with multiple memories and multiple memory modules, if desired. Similarly, multiple computer devices can be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system). Figure 7 Take a processor 10 as an example.

[0098] Processor 10 may be a central processing unit, a network processor, or a combination thereof. Processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The programmable logic device may be a complex programmable logic device (CAMP), a field-programmable gate array (FPGA), a general-purpose array logic (GDA), or any combination thereof.

[0099] The memory 20 stores instructions executable by at least one processor 10 to cause the at least one processor 10 to perform the method shown in the above embodiments.

[0100] The memory 20 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the computer device. Furthermore, the memory 20 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some alternative embodiments, the memory 20 may optionally include memory remotely located relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0101] The memory 20 may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as flash memory, hard disk or solid-state drive; the memory 20 may also include a combination of the above types of memory.

[0102] The computer device also includes a communication interface 30 for communicating with other devices or communication networks.

[0103] This application also provides a computer-readable storage medium. The methods described in this application can be implemented in hardware or firmware, or implemented as recordable on a storage medium, or implemented as computer code downloaded over a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and subsequently stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code. When the software or computer code is accessed and executed by the computer, processor, or hardware, the methods shown in the above embodiments are implemented.

[0104] The apparatus and units described in the above embodiments can be implemented by a computer chip or physical entity, or by a product with a certain function. A typical implementation device is a computer. Specifically, a computer can be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smartphone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or any combination of these devices.

[0105] For ease of description, the above devices are described separately by function as various units. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware.

[0106] Those skilled in the art will understand that the embodiments of this application can be provided as methods or apparatus. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0107] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus, and devices according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0108] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0109] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0110] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0111] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the apparatus embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0112] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

[0113] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for evaluating the overall sealing performance of a hydrogen skid, characterized in that, The method includes: The stress response data of all pipe joints in the hydrogen skid under vibration load are obtained, the pipe joints are classified, and for any type of pipe joint, the pipe joint with the largest cumulative fatigue damage value is selected as the test sample. Spectral analysis is performed on the stress response data of the test samples to determine the test loading frequency, and the equivalent loading displacement amplitude is then calculated. Based on the test loading frequency and the equivalent loading displacement amplitude, a vibration loading test was conducted on the test sample with high-pressure hydrogen gas introduced, and the leakage rate of the test sample was collected. Based on the leakage rate of the test sample, the cumulative fatigue damage value of the test sample, and the cumulative fatigue damage value of each type of pipe joint, the overall equivalent leakage rate of the hydrogen skid is determined to evaluate the sealing performance of the hydrogen skid.

2. The method according to claim 1, characterized in that, For any type of pipe joint, the pipe joint with the highest cumulative fatigue damage value is selected as the test sample from the types, including: For any type of pipe joint, modal contribution analysis is performed on the stress response data, and stress response data with modal contribution values ​​lower than the modal contribution value threshold are removed to obtain the target stress response data; Based on the target stress response data, fatigue load spectrum is extracted, and combined with the preset material fatigue characteristic model, the cumulative fatigue damage value of each pipeline joint is determined. The pipe joint with the largest cumulative fatigue damage value was selected as the test sample.

3. The method according to claim 1, characterized in that, The step of performing spectral analysis on the stress response data of the test sample to determine the test loading frequency includes: Based on the stress response data of the test sample, obtain the power spectral density curve of stress amplitude as a function of frequency; Identify the peak points in the power spectral density curve and take the frequency corresponding to the peak points as the dominant frequency component; The dominant frequency component is determined as the test loading frequency.

4. The method according to claim 1, characterized in that, The generation of the equivalent loading displacement amplitude includes: The cumulative fatigue damage value of the test sample is used as the target fatigue damage value; Using the test loading frequency as a reference, an initial displacement amplitude is set, and the equivalent fatigue damage value of the test sample under the initial displacement amplitude is determined. The initial displacement amplitude is iteratively adjusted until the equivalent fatigue damage value equals the target fatigue damage value, and the adjusted initial displacement amplitude is determined as the equivalent loading displacement amplitude.

5. The method according to claim 1, characterized in that, The determination of the overall equivalent leakage rate of the hydrogen skid based on the leakage rate of the test samples, the cumulative fatigue damage value of the test samples, and the cumulative fatigue damage value of each type of pipe joint includes: For any type of pipe joint, the cumulative fatigue damage value of each pipe joint in that type is compared with the cumulative fatigue damage value of the test sample to obtain the vibration severity correction coefficient for each pipe joint. The total leakage rate of the type is obtained by multiplying the leakage rate of the test sample with the sum of the vibration severity correction coefficients of all pipe joints in the type. The overall equivalent leakage rate of the hydrogen skid is obtained by summing up the total leakage rates of all types within the hydrogen skid.

6. The method according to claim 1, characterized in that, The sealing evaluation of the hydrogen skid includes: Determine whether the leakage rate of the test sample is less than a preset leakage rate threshold, and whether the maximum stress value of the test sample in the vibration loading test has not reached the yield strength of the material; If the determination is yes, then the overall sealing performance of the hydrogen skid is determined based on the overall equivalent leakage rate. If the result is negative, the sealing performance evaluation of the hydrogen skid is deemed unqualified.

7. The method according to claim 6, characterized in that, The determination of the overall sealing performance of the hydrogen skid based on the overall equivalent leakage rate includes: Obtain the preset threshold for hydrogen skid sealing compliance; The overall equivalent leakage rate is compared with the sealing performance qualification threshold. When the overall equivalent leakage rate is less than or equal to the sealing performance qualification threshold, the sealing performance evaluation result of the hydrogen skid is determined to be qualified. When the overall equivalent leakage rate is greater than the sealing performance qualification threshold, the sealing performance evaluation result of the hydrogen skid is determined to be unqualified.

8. A device for evaluating the overall sealing performance of a hydrogen skid, characterized in that, The device includes: The sample screening unit is used to acquire stress response data of all pipe joints in the hydrogen skid under vibration load, classify the pipe joints, and select the pipe joint with the largest cumulative fatigue damage value from the type of pipe joint for any given type as the test sample. The parameter back-calculation unit is used to perform spectral analysis on the stress response data of the test sample to determine the test loading frequency and back-calculate the equivalent loading displacement amplitude. The vibration test unit is used to conduct a vibration loading test on a test sample with high-pressure hydrogen gas introduced, based on the test loading frequency and the equivalent loading displacement amplitude, and to collect the leakage rate of the test sample. The sealing evaluation unit is used to determine the overall equivalent leakage rate of the hydrogen skid based on the leakage rate of the test sample, the cumulative fatigue damage value of the test sample, and the cumulative fatigue damage value of each type of pipeline joint, so as to evaluate the sealing performance of the hydrogen skid.

9. A computer device, characterized in that, include: A memory and a processor are interconnected, the memory stores computer instructions, and the processor executes the computer instructions to perform the equivalent evaluation method for the overall sealing performance of the hydrogen skid as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing the computer to execute the hydrogen skid overall sealing equivalence evaluation method according to any one of claims 1 to 7.

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