Test method and test device suitable for determining the fatigue life of bellows

Abstract

Embodiments of the present application relate to the technical field of expansion joint performance testing, and particularly relate to a test method and a test device suitable for determining the fatigue life of a bellows. The test method provided by the embodiments of the present application can ensure that the bellows subjected to the applied force remains the same predetermined time in each execution process, thereby achieving precise control over the time length of each stage of the test. Since the bellows in the actual service environment usually does not reset immediately after deformation, but remains for a certain period of time, the above operation can take into account the influence of high-temperature creep effect on the service life of the bellows, and can also ensure the consistency and repeatability of the test conditions, thereby determining the actual allowable fatigue number according to the predetermined cycle number, and achieving the purpose of predicting the fatigue life of the bellows.

Description

Technical Field

[0001] The embodiments of this application relate to the field of expansion joint performance testing technology, specifically to a test method and test apparatus suitable for determining the fatigue life of bellows. Background Technology

[0002] The statements herein are provided merely as background information in connection with this application and do not necessarily constitute prior art.

[0003] The medium inside the main loop piping of a fast reactor is typically liquid sodium, which operates at a relatively high temperature, resulting in a large thermal displacement in the piping. If a conventional π-bend layout is used for the piping, the stress level of the piping will be relatively high, the total length of the piping will be relatively long, the nuclear island building will have a large footprint, and the process rooms will be crowded, which will lead to a higher overall cost for the fast reactor.

[0004] As the power output of fast reactors increases, the impact of piping layout on the overall economics of fast reactors becomes more pronounced. Therefore, it is necessary to optimize the layout of process rooms and reduce the footprint of the nuclear island building during the piping process. Currently, most methods absorb thermal displacement by arranging expansion joint structures on the main piping to reduce the footprint of the nuclear island building. Among these, the bellows is a key component affecting the lifespan of the expansion joint, so determining the lifespan of the bellows is extremely important. Summary of the Invention

[0005] A brief overview of this application is provided below to offer a basic understanding of certain aspects thereof. It should be understood that this overview is not an exhaustive summary of the application. It is not intended to identify key or essential parts of the application, nor is it intended to limit its scope. Its purpose is merely to present certain concepts in a simplified form as a prelude to the more detailed description that follows.

[0006] In a first aspect, embodiments of this application provide a test method suitable for determining the fatigue life of a bellows, comprising the following steps: S1, determining the bellows to be tested; S2, installing the bellows on a test mounting component of a test apparatus; S3, determining the test conditions of the test apparatus; S4, under the test conditions determined in step S3, applying a force to the bellows using the test apparatus and holding it for a predetermined time; S5, stopping the application of force and waiting for the bellows to reset; S6, repeating steps S4 and S5 until a predetermined number of cycles is reached; S7, determining the fatigue life of the bellows based on the test conditions determined in step S3, the predetermined time in step S4, and the predetermined number of cycles determined in step S6.

[0007] The test method provided in the embodiments of this application applies a force to the bellows and holds it for a predetermined time. After the bellows resets, this operation is repeated until a predetermined number of cycles is reached. This ensures that the bellows under force is held for the same predetermined time during each execution, thereby achieving precise control over the duration of each stage of the test. Since the bellows in actual service environments usually do not reset immediately after deformation but are held for a certain period of time, the above operation can take into account the impact of high-temperature creep on the life of the bellows and also ensure the consistency and repeatability of the test conditions. Thus, the actual allowable number of fatigue cycles can be determined based on the predetermined number of cycles, thereby achieving the purpose of predicting the fatigue life of the bellows.

[0008] Secondly, embodiments of this application also provide a test method suitable for determining the fatigue life of a bellows, comprising the following steps: S10, determining multiple bellows to be tested; S20, installing one bellows onto a test mounting component of a test apparatus; S30, determining the test conditions of the test apparatus; S40, under the test conditions determined in step S30, applying a force to the bellows using the test apparatus and holding it for a predetermined time; S50, stopping the application of force and waiting for the bellows to reset; S60, repeating steps S40 and S50 until a predetermined number of cycles is reached; S70, determining the fatigue life of the bellows based on the test conditions determined in step S30, the predetermined time in step S40, and the predetermined number of cycles determined in step S60; S80, removing the bellows from step S20, and installing another of the multiple bellows onto the test mounting component of the test apparatus, repeating steps S30 to S70 to determine the fatigue life of each bellows.

[0009] The test method provided in the embodiments of this application applies a force to the bellows and holds it for a predetermined time. After the bellows resets, this operation is repeated until a predetermined number of cycles is reached. This ensures that the bellows under force is held for the same predetermined time during each execution, thereby achieving precise control over the duration of each stage of the test. Since the bellows in actual service environments usually do not reset immediately after deformation but are held for a certain period of time, the above operation can take into account the impact of high-temperature creep on the life of the bellows and also ensure the consistency and repeatability of the test conditions. Thus, the actual allowable number of fatigue cycles can be determined based on the predetermined number of cycles, thereby achieving the purpose of predicting the fatigue life of the bellows.

[0010] Thirdly, embodiments of this application also provide a testing apparatus suitable for determining the fatigue life of a bellows, comprising: a test mounting component configured to mount a bellows; a test operation component configured to apply a force to the bellows to deform it; a test timing component configured to start timing after the bellows deforms, so that the bellows remains in a predetermined time; a test condition holding component configured to keep the bellows under test conditions that meet the service requirements of the bellows; a controller configured to: control the test operation component to apply a force to the bellows and hold it for a predetermined time; control the test operation component to stop applying the force, and after the bellows is reset, repeat the steps of "controlling the test operation component to apply a force to the bellows and holding it for a predetermined time, and then controlling the test operation component to stop applying the force" until a predetermined number of cycles is reached; and a processor configured to: determine the fatigue life of the bellows based on the test conditions, the predetermined time, and the predetermined number of cycles.

[0011] The testing apparatus provided in the embodiments of this application applies a force to the bellows using a testing operation component and holds it for a predetermined time. After the bellows resets, the controller controls the testing operation component to repeat this operation until a predetermined number of cycles is reached. This ensures that the bellows under force is held for the same predetermined time during each execution. By setting a testing timing device to determine the holding time after the bellows deforms, errors caused by manual timing are avoided, thereby achieving precise control of the duration of each stage of the test. Since the bellows in actual service environments usually do not reset immediately after deformation but are held for a certain period of time, the above operation can take into account the impact of high-temperature creep on the bellows' lifespan and also ensure the consistency and repeatability of the test conditions. Thus, the actual allowable number of fatigue cycles is determined based on the predetermined number of cycles, achieving the purpose of predicting the fatigue life of the bellows.

[0012] These and other advantages of this application will become more apparent from the following detailed description of preferred embodiments in conjunction with the accompanying drawings. Attached Figure Description

[0013] To further illustrate the above and other advantages and features of this application, the specific embodiments of this application will be described in more detail below with reference to the accompanying drawings. The drawings, together with the following detailed description, are included in and form a part of this specification. Elements having the same function and structure are indicated by the same reference numerals. It should be understood that these drawings only depict typical examples of this application and should not be considered as limiting the scope of this application.

[0014] Figure 1 This is a schematic flowchart of the test method according to an embodiment of this application.

[0015] It should be noted that the accompanying drawings are not necessarily drawn to scale, but are shown only in a schematic manner without affecting the reader's understanding. Detailed Implementation

[0016] Exemplary embodiments of this application will be described below with reference to the accompanying drawings. For clarity and brevity, not all features of actual implementations are described in the specification. However, it should be understood that many implementation-specific decisions must be made in the development of any such actual embodiment to achieve the developer's specific goals, such as complying with constraints related to the system and business, and these constraints may vary depending on the implementation. Furthermore, it should be understood that while development work can be very complex and time-consuming, such development work is merely a routine task for those skilled in the art who benefit from the content of this application.

[0017] It should also be noted that, in order to avoid obscuring this application with unnecessary details, only the equipment structure and / or processing steps closely related to the solution according to this application are shown in the accompanying drawings, while other details that are not closely related to this application are omitted.

[0018] It should be noted that, unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning as understood by a person with ordinary skills in the field to which this application pertains.

[0019] In the description of the embodiments of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0020] In related technologies, expansion joint structures are often arranged on the main pipeline to absorb thermal displacement and reduce the footprint of the nuclear island building. Among these, the bellows is a key component affecting the lifespan of the expansion joint. The inventors of this application have discovered that currently, most methods for calculating the fatigue life of bellows are based on a temperature lower than the material's creep temperature. However, the operating temperature of the main pipeline in a fast reactor is relatively high, reaching approximately 530°C, which far exceeds the creep temperature of the 316H bellows material. Current calculation methods are not applicable in this case. Furthermore, conventional bellows fatigue life tests can only verify whether the number of fatigue cycles meets the design requirements, but cannot determine the actual allowable number of fatigue cycles.

[0021] To address the aforementioned technical problems, embodiments of this application provide a test method suitable for determining the fatigue life of bellows, which may include at least the following steps S1 to S7.

[0022] In some embodiments, S1, determine the bellows to be tested; S2, install the bellows on the test mounting part of the test apparatus; S3, determine the test conditions of the test apparatus; S4, under the test conditions determined in step S3, apply a force to the bellows using the test apparatus and hold it for a predetermined time; S5, stop applying the force and wait for the bellows to reset; S6, repeat steps S4 and S5 until a predetermined number of cycles is reached; S7, determine the fatigue life of the bellows based on the test conditions determined in step S3, the predetermined time in step S4, and the predetermined number of cycles determined in step S6.

[0023] The test method provided in the embodiments of this application applies a force to the bellows and holds it for a predetermined time. After the bellows resets, this operation is repeated until a predetermined number of cycles is reached. This ensures that the bellows under force is held for the same predetermined time during each execution, thereby achieving precise control over the duration of each stage of the test. Since the bellows in actual service environments usually do not reset immediately after deformation but are held for a certain period of time, the above operation can take into account the impact of high-temperature creep on the life of the bellows and also ensure the consistency and repeatability of the test conditions. Thus, the actual allowable number of fatigue cycles can be determined based on the predetermined number of cycles, thereby achieving the purpose of predicting the fatigue life of the bellows.

[0024] In some embodiments, the test methods provided in this application can be applied to the high-temperature fatigue life of bellows designed for temperatures exceeding the material creep temperature. In such embodiments, the high temperature can be 500-600°C, i.e., the temperature of the bellows' service environment, such as 530°C, 540°C, or 550°C.

[0025] In some embodiments, the corrugated pipe used in the test method provided in the embodiments of this application can be a real corrugated pipe in service, or it can be a small-sized corrugated pipe designed separately with the same material as the real corrugated pipe in service. This application does not limit this.

[0026] In some embodiments, in step S3, the test conditions include at least the total stress range of the bellows and a predetermined time for the bellows to remain in a deformed state. In step S4, the specific steps are as follows: S41, under the test conditions determined in step S3, a force is applied to the bellows using a test device to bring the stress of the bellows within the total stress range; S42, when the stress of the bellows is within the total stress range, the test device is controlled to continue applying a force to the bellows and maintain it for a predetermined time.

[0027] The test method provided in the embodiments of this application predetermines the test conditions, which enables the stress of the bellows during the test to be within the total stress range. This helps the test conditions to closely approximate the actual service environment of the bellows, thereby improving the reliability of the final test results.

[0028] In some embodiments, step S41 specifically includes the following steps: under test conditions, using a test device, applying a force to the bellows to compress or stretch the bellows; after the bellows is compressed or stretched to a predetermined position, determining that the stress of the bellows is within the total stress range.

[0029] The test method provided in the embodiments of this application determines that the stress of the bellows is within the total stress range after the bellows is compressed or stretched to a predetermined position. This helps to determine whether the test device has reached the target position, thereby ensuring that the degree of deformation of the bellows can meet the test requirements.

[0030] In some embodiments, after the corrugated pipe has deformed to a predetermined length, it can be determined that the corrugated pipe has been compressed or stretched to a predetermined position. It is understood that those skilled in the art can determine the specific value of the predetermined length based on experience, and this application does not impose any limitations on this.

[0031] In some embodiments, in step S1, the number of bellows is four. Among the four bellows, the first bellows and the second bellows have the same design parameters, the third bellows and the fourth bellows have the same design parameters, and / or the total stress range of the first bellows and the second bellows differs from the total stress range of the third bellows and the fourth bellows by a first predetermined multiple, and / or the predetermined time corresponding to the first bellows and the second bellows differs from the predetermined time corresponding to the third bellows and the fourth bellows by a second predetermined multiple.

[0032] In some embodiments, the first predetermined multiple may be greater than or equal to 2 times, for example, it may be 2 times, 3 times, 4 times, 5 times, etc., and this application does not limit it.

[0033] In some embodiments, the second predetermined multiple may be greater than or equal to 100 times, such as 100 times, 150 times, 200 times, etc., and this application does not limit it.

[0034] In some embodiments, after step S7, the following step is further included: S8, installing another of the plurality of bellows on the test mounting, repeating steps S3 to S7, and determining the fatigue life of each bellows.

[0035] The test method provided in the embodiments of this application can ensure that the total stress range and the holding time after being subjected to force meet the test requirements when testing another bellows.

[0036] In some embodiments, in step S3, the test conditions further include: test temperature and test pressure that meet the service requirements of the bellows, so that the test environment can be closer to the actual service environment of the bellows, thereby ensuring the reliability of the bellows fatigue life obtained by the test.

[0037] In some embodiments, step S6 further includes the following steps: detecting the state of the bellows; determining the actual number of cycles to be repeated in steps S4 and S5 when the bellows develops a crack; wherein, in step S7, the fatigue life of the bellows is determined based on the test conditions determined in step S3, the predetermined time in step S4, and the actual number of cycles determined in step S6.

[0038] The test method provided in the embodiments of this application determines the current actual number of cycles when a crack is detected in the bellows, and uses the actual number of cycles, the test conditions determined in the previous embodiments, and a predetermined time to determine the fatigue life of the bellows. This helps to determine the actual number of fatigue cycles of the bellows and ensures the accuracy of the fatigue life obtained from the test.

[0039] Embodiments of this application also provide a test method suitable for determining the fatigue life of a bellows, the test method may include at least the following steps S10 to S80.

[0040] In some embodiments, S10, determine a plurality of bellows to be tested; S20, install one bellows on the test mounting part of the test apparatus; S30, determine the test conditions of the test apparatus; S40, under the test conditions determined in step S30, apply a force to the bellows using the test apparatus and hold it for a predetermined time; S50, stop applying the force and wait for the bellows to reset; S60, repeat steps S40 and S50 until a predetermined number of cycles is reached; S70, determine the fatigue life of the bellows based on the test conditions determined in step S30, the predetermined time in step S40, and the predetermined number of cycles determined in step S60; S80, remove the bellows from step S20, and install another of the plurality of bellows on the test mounting part of the test apparatus, repeat steps S30 to S70, and determine the fatigue life of each bellows.

[0041] The test method provided in the embodiments of this application applies a force to the bellows and holds it for a predetermined time. After the bellows resets, this operation is repeated until a predetermined number of cycles is reached. This ensures that the bellows under force is held for the same predetermined time during each execution, thereby achieving precise control over the duration of each stage of the test. Since the bellows in actual service environments usually do not reset immediately after deformation but are held for a certain period of time, the above operation can take into account the impact of high-temperature creep on the life of the bellows and also ensure the consistency and repeatability of the test conditions. Thus, the actual allowable number of fatigue cycles can be determined based on the predetermined number of cycles, thereby achieving the purpose of predicting the fatigue life of the bellows.

[0042] In some embodiments, in step S30, the test conditions include at least the total stress range of the bellows and a predetermined time for the bellows to remain in a deformed state. Specifically, step S40 includes the following steps: S401, under the test conditions determined in step S30, applying a force to the bellows using a test device to bring the stress of the bellows within the total stress range; S402, when the stress of the bellows is within the total stress range, controlling the test device to continue applying a force to the bellows and maintaining it for a predetermined time.

[0043] The test method provided in the embodiments of this application predetermines the test conditions, which enables the stress of the bellows during the test to be within the total stress range. This helps the test conditions to closely approximate the actual service environment of the bellows, thereby improving the reliability of the final test results.

[0044] Embodiments of this application also provide a testing apparatus suitable for determining the fatigue life of bellows. The testing apparatus may include at least a test mounting component, a test operation component, a test timing component, a test condition holding component, a controller, and a processor.

[0045] In some embodiments, a test mounting component is configured to mount a bellows; a test operation component is configured to apply a force to the bellows to deform it; a test timing component is configured to start timing after the bellows is deformed to keep the bellows in place for a predetermined time; a test condition holding component is configured to keep the bellows under test conditions that meet the service requirements of the bellows; a controller is configured to: control the test operation component to apply a force to the bellows and hold it for a predetermined time; control the test operation component to stop applying the force, and after the bellows is reset, repeat the steps of "controlling the test operation component to apply a force to the bellows and holding it for a predetermined time, and then controlling the test operation component to stop applying the force" until a predetermined number of cycles is reached; and a processor is configured to: determine the fatigue life of the bellows based on the test conditions, the predetermined time, and the predetermined number of cycles.

[0046] The testing apparatus provided in the embodiments of this application applies a force to the bellows using a testing operation component and holds it for a predetermined time. After the bellows resets, the controller controls the testing operation component to repeat this operation until a predetermined number of cycles is reached. This ensures that the bellows under force is held for the same predetermined time during each execution. By setting a testing timing device to determine the holding time after the bellows deforms, errors caused by manual timing are avoided, thereby achieving precise control of the duration of each stage of the test. Since the bellows in actual service environments usually do not reset immediately after deformation but are held for a certain period of time, the above operation can take into account the impact of high-temperature creep on the bellows' lifespan and also ensure the consistency and repeatability of the test conditions. Thus, the actual allowable number of fatigue cycles is determined based on the predetermined number of cycles, achieving the purpose of predicting the fatigue life of the bellows.

[0047] Regarding the embodiments of this application, it should also be noted that, without conflict, the embodiments of this application and the features in the embodiments can be combined with each other to obtain new embodiments.

[0048] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. The scope of protection of this application shall be determined by the scope of the claims.

Claims

1. A test method suitable for determining the fatigue life of bellows, characterized in that, It includes the following steps: S1. Determine the bellows to be tested; S2. Install the corrugated pipe onto the test mounting component of the test device; S3. Determine the test conditions for the test apparatus; S4. Under the test conditions determined in step S3, apply a force to the bellows using the test device and hold it for a predetermined time. S5. Stop applying the force and wait for the bellows to reset; S6. Repeat steps S4 and S5 until the predetermined number of cycles is reached; S7. Determine the fatigue life of the bellows based on the test conditions determined in step S3, the predetermined time in step S4, and the predetermined number of cycles determined in step S6.

2. The test method according to claim 1, characterized in that, In step S3, the test conditions include at least the total stress range of the bellows and a predetermined time for the bellows to remain in a deformed state. Specifically, step S4 includes the following steps: S41. Under the test conditions determined in step S3, the test device is used to apply a force to the bellows so that the stress of the bellows is within the total stress range. S42. When the stress of the bellows is within the total stress range, control the test device to continue applying force to the bellows and maintain it for the predetermined time.

3. The test method according to claim 2, characterized in that, Step S41 specifically includes the following steps: Under the test conditions, the test device is used to apply a force to the bellows so that the bellows is compressed or stretched. After the bellows is compressed or stretched to a predetermined position, it is determined that the stress of the bellows is within the total stress range.

4. The test method according to claim 2, characterized in that, In step S1, the number of bellows is four. Of the four bellows, the first bellows and the second bellows have the same design parameters, the third bellows and the fourth bellows have the same design parameters, and / or The total stress range of the first and second bellows differs from the total stress range of the third and fourth bellows by a first predetermined multiple, and / or The predetermined time corresponding to the first corrugated pipe and the second corrugated pipe differs from the predetermined time corresponding to the third corrugated pipe and the fourth corrugated pipe by a second predetermined multiple.

5. The test method according to claim 4, characterized in that, Following step S7, the following steps are also included: S8. Install another of the plurality of bellows onto the test mounting, and repeat steps S3 to S7 to determine the fatigue life of each bellows.

6. The test method according to any one of claims 1-5, characterized in that, In step S3, the test conditions also include: test temperature and test pressure that meet the service requirements of the bellows.

7. The test method according to any one of claims 1-5, characterized in that, Step S6 also includes the following steps: Detect the state of the bellows; When the bellows develops a crack, determine the actual number of times steps S4 and S5 are repeated. In step S7, the fatigue life of the bellows is determined based on the test conditions determined in step S3, the predetermined time in step S4, and the actual number of cycles determined in step S6.

8. A test method suitable for determining the fatigue life of bellows, characterized in that, It includes the following steps: S10. Identify the multiple bellows to be tested; S20. Install one of the bellows pipes onto the test mounting component of the test apparatus; S30. Determine the test conditions for the test apparatus; S40. Under the test conditions determined in step S30, apply a force to the bellows using the test device and hold it for a predetermined time. S50. Stop applying the force and wait for the bellows to reset. S60. Repeat steps S40 and S50 until the predetermined number of cycles is reached; S70. Determine the fatigue life of the bellows based on the test conditions determined in step S30, the predetermined time in step S40, and the predetermined number of cycles determined in step S60. S80. Remove the bellows from step S20 and install another of the multiple bellows on the test mounting piece of the test device. Repeat steps S30 to S70 to determine the fatigue life of each bellows.

9. The test method according to claim 8, characterized in that, In step S30, the test conditions include at least the total stress range of the bellows and a predetermined time for the bellows to remain in a deformed state. Specifically, step S40 includes the following steps: S401. Under the test conditions determined in step S30, the test device is used to apply a force to the bellows so that the stress of the bellows is within the total stress range. S402. When the stress of the bellows is within the total stress range, control the test device to continue applying force to the bellows and maintain it for the predetermined time.

10. A testing apparatus suitable for determining the fatigue life of bellows, characterized in that, It includes: Test installation components, configured to accommodate bellows; A test operation component configured to apply a force to the bellows to deform it; A test timing device is configured to start timing after the bellows is deformed, so that the bellows remains for a predetermined time; A test condition holding component is configured to subject the bellows to test conditions that meet the service requirements of the bellows. The controller is configured to: control the test operation component to apply a force to the bellows and maintain it for a predetermined time; control the test operation component to stop applying the force, and after the bellows is reset, repeat the steps of "controlling the test operation component to apply a force to the bellows and maintaining it for the predetermined time, and then controlling the test operation component to stop applying the force" until a predetermined number of cycles is reached; The processor is configured to determine the fatigue life of the bellows based on the test conditions, the predetermined time, and the predetermined number of cycles.

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