Tool and system for testing shear stiffness of corrugated pipe expansion joint under large-displacement working condition

Abstract

The invention relates to a corrugated pipe expansion joint large-displacement working condition shear rigidity testing tool and system, and the tool comprises a fixed end, a movable end which is disposed at one side of the fixed end, and is spaced from the fixed end, so as to form a testing space for installing a to-be-tested model machine; the movable end comprises a shearing loading plate and guide grooves, the guide grooves are formed in the two sides of the shearing loading plate, the extending direction of the guide grooves is perpendicular to the axis of the to-be-tested sample machine, and the shearing loading plate is connected with the guide grooves in a sliding mode. Through the constraint effect of the guide groove, the bending moment is borne by the guide groove, it is ensured that the moving end only generates translational displacement, rotation deformation is avoided, meanwhile, the stress level of key components is reduced, and the accuracy and reliability of a test result are improved.

Description

Technical Field

[0001] The present application relates to the technical field of mechanical equipment performance testing, and in particular to a shear stiffness testing tool and system for a bellows expansion joint under large displacement working conditions. Background Art

[0002] A bellows expansion joint, also known as a bellows compensator, is a device used to absorb stress in piping systems caused by thermal expansion and contraction, vibration, and displacement. The elastic deformation of the bellows absorbs linear and angular displacement of the pipeline, thereby preventing damage caused by excessive stress in the piping system and extending the service life of the pipeline and equipment. To quantitatively and objectively evaluate the ability of a bellows expansion joint to compensate for displacement and deformation in a piping system, it is typically necessary to measure the deformation resistance of a bellows expansion joint prototype, i.e., its stiffness. This stiffness can be further divided into tensile and compressive stiffness and shear stiffness, depending on the direction of deformation.

[0003] In the field of shear stiffness testing of bellows expansion joints, there is still a lack of standardized test fixtures and unified test methods. As the diameter of bellows expansion joints in engineering applications continues to increase, the cost of manufacturing prototypes has increased significantly, and the difficulty of test installation has also increased. To address this situation, the current shear test of large-diameter flexible joints generally adopts a single prototype test solution, that is, fixing the flange at one end of the prototype and applying a shear load to the flange at the other end. However, when the loading end flange is in a free state, the lateral load will cause the prototype to produce obvious bending deformation (such as the attached flange). Figure 1 As shown in the figure, the actual deformation mode deviates from the pure shear deformation, and the test results cannot truly reflect the shear stiffness characteristics of the bellows expansion joint.

[0004] On the other hand, the traditional method drives the radial movement of the bellows expansion joint through the clamping part. The single-point driving structure will cause uneven force on the bellows under large displacement, and asymmetric stress distribution will be generated at the connection between the clamping part and the bellows. When testing large displacement conditions, the reaction force generated by the deformation of the bellows increases sharply, and the combined load of bending moment and shear force borne by the single-point clamping structure increases significantly, resulting in frequent fracture and failure of the clamping part during the test, seriously affecting the accuracy of the shear stiffness test results under large displacement conditions. Summary of the Invention

[0005] An embodiment of the present application provides a shear stiffness test fixture for a bellows expansion joint under large displacement conditions, so as to solve the problem in the related art that the shear stiffness of the bellows expansion joint under large displacement conditions cannot be measured due to bending deformation of the prototype and breakage of the clamping parts.

[0006] When the loading end flange is in a free state, the lateral load will cause the prototype to produce obvious bending deformation, causing the actual deformation mode to deviate from pure shear deformation. The test results cannot truly reflect the shear stiffness characteristics of the bellows expansion joint.

[0007] In a first aspect, a shear stiffness test fixture for a bellows expansion joint under large displacement conditions is provided, comprising: Fixed end, The mobile end is arranged on one side of the fixed end and spaced apart from the fixed end to form a test space for installing the sample to be tested; The movable end includes a shear loading plate and a guide groove, wherein the guide grooves are arranged on both sides of the shear loading plate, the extension direction of the guide grooves is perpendicular to the axis of the prototype to be tested, and the shear loading plate is slidably connected to the guide grooves.

[0008] In some embodiments, the guide groove is a V-shaped groove, and both ends of the shear loading plate are provided with V-shaped guide portions that match the V-shaped groove.

[0009] In some embodiments, rolling bearings are provided on both side inclined surfaces of the V-shaped guide portion.

[0010] In some embodiments, the guide groove is a U-shaped groove, and rollers are installed at both ends of the shear loading plate through a rotating shaft, and the rollers are in rolling contact with the bottom surface of the U-shaped groove.

[0011] In some embodiments, the guide groove is a U-shaped groove, and rollers are rotatably connected to both ends of the shear loading plate, and the rollers are in rolling contact with the side walls of the U-shaped groove.

[0012] In some embodiments, the fixed end is disposed below the test fixture, and the movable end is disposed above the test fixture; Alternatively, the fixed end is arranged above the test fixture, and the movable end is arranged below the test fixture.

[0013] In some embodiments, the invention further comprises fixing seats arranged on both sides of the shear loading plate, and the guide grooves are arranged on the fixing seats.

[0014] In some embodiments, the fixed end is provided with a first flange, and the first flange is used to fix one end of the sample to be tested.

[0015] In some embodiments, the movable end is provided with a second flange, and the second flange is fixedly connected to the shear loading plate.

[0016] In a second aspect, a shear stiffness test system for a bellows expansion joint under large displacement working conditions is provided, including the shear stiffness test fixture for a bellows expansion joint under large displacement working conditions.

[0017] The embodiment of the present application provides a shear stiffness test fixture and system for a bellows expansion joint under large displacement working conditions, wherein one end of the test sample is connected to the fixed end, and the other end is fixedly connected to the shear loading plate of the mobile end. Since the mobile end is provided with a shear loading plate and a guide groove, the extension direction of the guide groove is perpendicular to the axis of the bellows expansion joint. A shear loading force is applied to the shear loading plate from the outside, causing the shear loading plate to move along the direction of the guide groove, thereby achieving shear deformation of the test sample, and then conducting a shear stiffness test of the test sample. Compared with the problem of compound deformation of the test sample under the action of lateral force in traditional testing methods, the present application ensures that the mobile end only produces translational displacement through the constraint effect of the guide groove, avoids the generation of rotational deformation, and improves the accuracy and reliability of the test results.

[0018] Moreover, in the traditional method, the clamping parts are subjected to shear force and bending moment at the same time. However, this solution uses the constraints of the guide groove to make the bending moment borne by the guide groove, which greatly reduces the stress level of key components. It fundamentally solves the problem of high fracture risk of traditional test fixtures under large displacement conditions. It is particularly suitable for high-precision shear stiffness testing of large-diameter bellows expansion joints above DN500, and provides a reliable means for performance evaluation of large deformation compensators in fields such as oil pipelines and nuclear power equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0020] Figure 1 This is a schematic diagram of the deformation of the bellows expansion joint in the prior art of this application; Figure 2 This is a diagram showing the deformation of the bellows expansion joint in this application; Figure 3 Schematic diagram of the shear stiffness test fixture for a bellows expansion joint under large displacement conditions provided in Example 1 of the present application; Figure 4 A schematic diagram of the structure of the shear loading plate and the guide groove provided in Example 1 of the present application; Figure 5 This is a structural diagram of the shear loading plate and the guide groove provided in Example 2 of the present application; Figure 6 This is a structural schematic diagram of the shear loading plate and the guide groove provided in Example 3 of the present application.

[0021] In the figure: 1, fixed end; 101, first flange; 2, movable end; 201, shear loading plate; 202, rolling bearing; 203, roller; 204, second flange; 3, fixed seat; 301, guide groove; 4, prototype to be tested. DETAILED DESCRIPTION

[0022] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0023] An embodiment of the present application provides a shear stiffness test fixture for a bellows expansion joint under large displacement conditions, so as to solve the problem in the related art that the shear stiffness of the bellows expansion joint under large displacement conditions cannot be measured due to bending deformation of the prototype and breakage of the clamping parts.

[0024] Example 1: like Figure 3 As shown, a shear stiffness test fixture for a bellows expansion joint under large displacement conditions comprises: Fixed end 1, The mobile terminal 2 is provided on one side of the fixed terminal 1 and spaced apart from the fixed terminal 1 to form a test space for installing the test sample 4; The mobile end 2 includes a shear loading plate 201 and a guide groove 301. Fixed seats 3 are provided on both sides of the shear loading plate 201. The guide groove 301 is provided on the fixed seat 3. The extension direction of the guide groove 301 is perpendicular to the axis of the prototype 4 to be tested. The shear loading plate 201 is slidably connected to the guide groove 301.

[0025] One end of the test sample 4 is connected to the fixed end 1, and the other end is fixedly connected to the shear loading plate 201 of the mobile end 2. Since the mobile end 2 is provided with the shear loading plate 201 and the guide groove 301, the extension direction of the guide groove 301 is perpendicular to the axis of the test sample 4. The shear loading force is applied to the shear loading plate 201 by the outside, so that the shear loading plate 201 moves along the direction of the guide groove 301, realizing the shear deformation of the test sample 4, and then carrying out the shear stiffness test of the test sample 4. Compared with the problem of compound deformation of the test sample 4 under the action of lateral force in traditional testing methods (such as the Figure 1 As shown in FIG), the present application ensures that the mobile end 2 only produces a translational displacement (as shown in FIG). Figure 2 As shown in the figure, the rotational deformation is avoided and the accuracy and reliability of the test results are improved.

[0026] Specifically, the fixed end 1 is provided with a first flange 101, which is used to fix one end of the test sample 4. The first flange 101 is a blind flange, which is used to seal the bottom of the test sample 4. The blind flange is fixedly connected to the ground of the test site via a fastening device to fix one end of the test sample 4.

[0027] Furthermore, the mobile end 2 is provided with a second flange 204, which is fixedly connected to the shear loading plate 201. The second flange 204 is an end flange, which is connected to the test sample 4 through a fastening device and is also connected to the shear loading plate 201 through the fastening device.

[0028] Further, such as Figure 3 and Figure 4 As shown, the guide groove 301 is a V-shaped groove, and both ends of the shear loading plate 201 are provided with V-shaped guide parts that match the V-shaped groove, and rolling bearings 202 are provided on the inclined surfaces on both sides of the V-shaped guide part.

[0029] Preferably, the angle of the V-shaped groove is 90°, and the angle formed by the two inclined surfaces of the matching V-shaped guide portion is also 90°.

[0030] When the shear stiffness test of the prototype to be tested is carried out, the outside world applies a shear loading force to the shear loading plate 201, causing the shear loading plate 201 to move in the guide groove 301. Since the guide groove 301 is a V-shaped groove, V-shaped guide parts are set at both ends of the shear loading plate 201. During the test, a large shear loading force can be applied to the prototype, and the horizontal and vertical dual limit functions are realized at the same time, which expands the maximum test range of the shear stiffness test of the bellows expansion joint sample.

[0031] When the test sample 4 undergoes shear deformation, the loading force acts directly on the shear loading plate 201. The portion of the test sample 4 moving within the guide groove 301, influenced by the reaction force of its own deformation, experiences a corresponding load, with the load acting in a direction perpendicular to the surface of the guide groove 301. By employing the aforementioned V-shaped groove and providing rolling bearings 202 on both inclined surfaces of the V-shaped guide, the rolling bearings 202 in the V-shaped guide effectively disperse the load within the guide groove 301, raising the upper limit of the loading force, and enabling the device to operate under greater displacement conditions. Furthermore, the V-shaped guide groove 301 effectively disperses the component of the load on the shear loading plate 201 perpendicular to the ground, reducing the likelihood of deformation or even fracture of the shear loading plate 201.

[0032] Furthermore, the entire structure of the test prototype 4 and the shear loading plate 201 is supported as a whole by the fixing base 3 , and the fixing base 3 is fixedly supported by the ground through bottom bolts.

[0033] For the purpose of test stability and ease of operation, in this embodiment, the fixed end 1 is arranged below the test fixture, and the movable end 2 is arranged above the test fixture.

[0034] In some optional embodiments, the fixed end 1 is arranged above the test fixture, and the movable end 2 is arranged below the test fixture.

[0035] Example 2: The difference between it and Example 1 is that: Figure 5 As shown, the guide groove 301 is a U-shaped groove, and rollers 203 are installed at both ends of the shear loading plate 201 through a rotating shaft. The rollers 203 are in rolling contact with the bottom surface of the U-shaped groove.

[0036] Example 3: The difference between it and embodiment 1 is: Figure 6 As shown, the guide groove 301 is a U-shaped groove, and the two ends of the shear loading plate 201 are rotatably connected to rollers 203, and the rollers 203 are in rolling contact with the side walls of the U-shaped groove.

[0037] Through the design of three guiding schemes, the problem that the end flange of the sample cannot move horizontally during the shear stiffness test of the bellows expansion joint is solved. At the same time, by adopting the improved design of the V-shaped guide groove 301 and the rolling bearing 202 of the V-shaped guide part, the situation that the shear stiffness of the sample 4 to be tested is too large and endangers the safety of the test system is effectively avoided. Taking into account the horizontal and vertical dual limit functions, the maximum test range of the shear stiffness test of the bellows expansion joint sample is expanded.

[0038] The bellows expansion joint in this application is specifically designed for large-diameter applications, with a suitable diameter of 500mm and above, far exceeding the conventional 100-300mm specifications. Given the characteristic of metal bellows expansion joints that larger diameters increase the shear force required for the same displacement, conventional products of the same length and diameter exhibit only a 10mm displacement during testing. This product can achieve a displacement of 30-50mm, 3-5 times that of conventional products. This extends the maximum test range for shear stiffness testing of bellows expansion joint specimens.

[0039] The present application also provides a bellows expansion joint large displacement working condition shear stiffness testing system, including a bellows expansion joint large displacement working condition shear stiffness testing tool.

[0040] In the description of this application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0041] It should be noted that, in this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0042] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A shear stiffness test tool for bellows expansion joints under large displacement conditions, characterized in that: It includes: Fixed end (1), A mobile end (2) is arranged on one side of the fixed end (1) and spaced apart from the fixed end (1) to form a test space for installing a test sample (4); The mobile end (2) comprises a shear loading plate (201) and a guide groove (301), wherein the guide groove (301) is arranged on both sides of the shear loading plate (201), and the extension direction of the guide groove (301) is perpendicular to the axis of the prototype to be tested (4), and the shear loading plate (201) is slidably connected to the guide groove (301).

2. The shear stiffness test fixture for a bellows expansion joint under large displacement conditions according to claim 1, characterized in that: The guide groove (301) is a V-shaped groove, and both ends of the shear loading plate (201) are provided with V-shaped guide portions that match the V-shaped groove.

3. The shear stiffness test fixture for a bellows expansion joint under large displacement conditions as claimed in claim 2, characterized in that: Rolling bearings (202) are provided on both side inclined surfaces of the V-shaped guide portion.

4. The shear stiffness test fixture for a bellows expansion joint under large displacement conditions according to claim 1, characterized in that: The guide groove (301) is a U-shaped groove, and rollers (203) are installed at both ends of the shear loading plate (201) via a rotating shaft, and the rollers (203) are in rolling contact with the bottom surface of the U-shaped groove.

5. The shear stiffness test fixture for a bellows expansion joint under large displacement conditions according to claim 1, characterized in that: The guide groove (301) is a U-shaped groove, and rollers (203) are rotatably connected to both ends of the shear loading plate (201), and the rollers (203) are in rolling contact with the side walls of the U-shaped groove.

6. The shear stiffness test fixture for a bellows expansion joint under large displacement conditions according to claim 1, characterized in that: The fixed end (1) is arranged below the test fixture, and the movable end (2) is arranged above the test fixture; Alternatively, the fixed end (1) is arranged above the test fixture, and the movable end (2) is arranged below the test fixture.

7. The shear stiffness test fixture for a bellows expansion joint under large displacement conditions according to claim 1, characterized in that: It also includes fixing seats (3) arranged on both sides of the shear loading plate (201), and the guide groove (301) is arranged on the fixing seats (3).

8. The large displacement shear stiffness test fixture for bellows expansion joints according to claim 1, characterized in that: The fixed end (1) is provided with a first flange (101), and the first flange (101) is used to fix one end of the prototype (4) to be tested.

9. The shear stiffness test fixture for a bellows expansion joint under large displacement conditions according to claim 1, characterized in that: The movable end (2) is provided with a second flange (204), and the second flange (204) is fixedly connected to the shear loading plate (201).

10. A shear stiffness test system for bellows expansion joints under large displacement conditions, characterized by: It comprises the shear stiffness testing tool for the bellows expansion joint under large displacement working conditions as described in any one of claims 1 to 9.

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