Hoop tensile test device and hoop tensile test method

Abstract

The present invention discloses a circumferential tensile test device, comprising: a center disk, the center disk is provided with a tensile connection hole; a semicircular rim, the rim is arranged around the center and has elasticity in the circumferential direction; a plurality of spokes, connected and supported between the center disk and the rim; and a length adjustment unit, the length adjustment unit is used to adjust the length of the spokes between the center disk and the rim or the distance between the center disk and the rim in the radial direction. The present invention also relates to a circumferential tensile test method, comprising the steps of: providing the above-mentioned circumferential tensile test device; adjusting the length adjustment unit to adjust the length of the spokes or the distance between the center disk and the rim in the radial direction to change the diameter of the rim and keep the circular curvature of the rim unchanged; and applying a tensile force using a tensile member passing through the tensile connection hole to perform a circumferential tensile test.

Description

Technical Field

[0001] The invention relates to the field of circumferential tensile testing, and in particular to a circumferential tensile testing device and a circumferential tensile testing method. Background Art

[0002] The hoop tensile strength of pipes is an important indicator in pipe production and can be obtained through hoop tensile tests. This test plays a great role in quickly analyzing the hoop compressive strength of pipes. Compared with hydrostatic tests, hoop tensile tests are more convenient and quicker and can provide quantitative data. However, how to ensure the accuracy of hoop tensile test results is a problem that needs to be solved in the prior art. For example, how to improve the accuracy of hoop tensile test results for pipes with different SDR values. The SDR (standard dimension ratio) value of a pipe refers to the standard dimension ratio of the pipe, which is the ratio between the nominal outer diameter and the nominal wall thickness of the pipe. It is often used for plastic pipes whose dimensions are controlled by the outer diameter. It is an important parameter for controlling the wall thickness of the pipe and determining the ability to withstand internal pressure. Summary of the invention

[0003] The present invention is proposed to alleviate or solve at least one aspect of the above-mentioned problems in the prior art.

[0004] According to one aspect of an embodiment of the present invention, a hoop tensile test device is provided, comprising:

[0005] A center disk, wherein the center disk is provided with a stretching connection hole;

[0006] A semicircular rim, which is arranged around the center of the circle and has elasticity in the circumferential direction;

[0007] A plurality of spokes connected and supported between the center disk and the rim; and

[0008] A length adjustment unit is used to adjust the length of the spokes between the center disk and the rim or the distance between the center disk and the rim in the radial direction.

[0009] Optionally, the axis of the spoke extends through the center of the circle.

[0010] Optionally, the spoke center disk is a semicircular center disk, and the wheel rim and the center disk are arranged based on the same center.

[0011] Optionally, one end of the spoke passes through a mounting hole on a side of one of the rim and the center disk, and the other end of the spoke is fixed to or abuts against the other of the rim and the center disk; the end of the spoke passing through the side has a thread; the length adjustment unit includes a length adjustment nut that cooperates with the thread, the length adjustment nut is suitable for abutting against the side and the diameter of the length adjustment nut is larger than the diameter of the mounting hole.

[0012] Optionally, the spoke includes a first section and a second section connected by a length adjustment unit, one end of the first section is fixedly connected to the rim, one end of the second section is fixedly connected to the center disk, the other ends of the first section and the second section are both connected to the length adjustment unit, and the length adjustment unit includes a length adjustment nut, one end of the length adjustment nut is connected to one of the two other ends in an axially fixed and rotatable manner, and the other end of the length adjustment nut is threadedly engaged with the other of the two other ends.

[0013] Optionally, the center disk includes a first disk and a second disk, and a plurality of compression springs connected between the first disk and the second disk; the circumferential tensile test device also includes a spacing adjustment unit for adjusting the distance between the first disk and the second disk; and there is an inclination angle between the spokes and the disk surface of the center disk.

[0014] Optionally, the spacing adjustment unit includes a screw rod and a spacing adjustment nut cooperating with the screw rod, and the screw rod is arranged through the central disk, wherein: based on the threaded cooperation between the spacing adjustment nut and the screw rod, the distance between the first disk and the second disk is adjusted.

[0015] Optionally, the screw is a hollow screw, and the hollow screw is arranged in the stretching connection hole.

[0016] Optionally, an upper wheel rim mounting hole row and a lower wheel rim mounting hole row are provided on the side of the wheel rim; the first disk is an upper disk, the second disk is a lower disk, and both the first disk and the second disk are provided with disk mounting holes; the spokes connected to the disk mounting holes of the upper disk are simultaneously connected to one of the lower wheel rim mounting holes in the row of lower wheel rim mounting holes, and the spokes connected to the disk mounting holes of the lower disk are simultaneously connected to one of the upper wheel rim mounting holes in the row of upper wheel rim mounting holes.

[0017] Optionally, a row of rim mounting holes is provided on the side of the rim, the first plate is an upper plate, the second plate is a lower plate, the first plate and the second plate are both provided with plate mounting holes, the spokes connected to the plate mounting holes of the upper plate are simultaneously connected to one of the rim mounting holes in the row of rim mounting holes, and the spokes connected to the plate mounting holes of the lower plate are simultaneously connected to another rim mounting hole in the row of rim mounting holes.

[0018] Optionally, the vertical plane where each spoke is located passes through the center of the circle.

[0019] Optionally, the center disk includes a first disk and a second disk, and a plurality of compression springs connected between the first disk and the second disk; a radial protrusion is provided between the edges of the first disk and the second disk, and the spokes are connected between the radial protrusion and the rim; the circumferential tensile test device also includes a spacing adjustment unit for adjusting the distance between the first disk and the second disk, and based on the reduction of the distance between the first disk and the second disk, the radial protrusion is suitable for further protruding radially outward to increase the distance between the center disk and the rim in the radial direction.

[0020] According to another aspect of an embodiment of the present invention, another hoop tensile test method is provided, comprising the steps of:

[0021] Providing the above-mentioned hoop tensile test device;

[0022] Adjusting the length adjustment unit to adjust the spoke length to change the diameter of the rim while keeping the circular curvature of the rim unchanged; and

[0023] The hoop tensile test is performed by applying a tensile force using a tensile member passing through the tensile connection hole.

[0024] Optionally, the method further comprises the step of adjusting the distance between the first disk and the second disk to change the inclination angle of the spokes. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The following description and accompanying drawings may better help understand these and other features and advantages of various embodiments disclosed by the present invention, in which the same reference numerals always represent the same components, wherein:

[0026] Figure 1 A schematic top view of a hoop tensile test device according to an exemplary embodiment of the present invention, wherein a rim, a center disk, spokes and an expansion joint are shown;

[0027] Figure 2 According to an exemplary embodiment of the present invention Figure 1 Schematic diagram of the wheel rim in;

[0028] Figure 3 According to an exemplary embodiment of the present invention Figure 1 Schematic diagram of the expansion joint in;

[0029] Figure 4 According to an exemplary embodiment of the present invention Figure 1 A schematic front view of the hoop tensile test apparatus in FIG.

[0030] Figure 5 According to an exemplary embodiment of the present invention Figure 1 A schematic enlarged top view of the lower disk in the central disk of FIG.

[0031] Figure 6 FIG. 4 is a schematic top view of a hoop tensile test device according to another exemplary embodiment of the present invention, wherein a rim, a center disk, spokes and radial protrusions are shown.

[0032] The reference numerals are as follows:

[0033] 1. Rim; 1-2. Mounting hole; 2. Spring; 3-1. Center plate; 3-2. Nut; 3-3. Hollow screw; 3-4. Tensile connection hole; 4. Expansion joint; 4-2. Threaded end of spoke; 4-3. Movable nut; 5. Spoke; 6. Radial protrusion. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further specifically described below by examples and in conjunction with the accompanying drawings. In the specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention and should not be construed as a limitation of the present invention.

[0035] The present invention is proposed to overcome the following problems: in the circumferential tensile test, the inner diameter of the pipe is not uniform due to the large variation range of the wall thickness of the pipe, so that the circumferential tensile separation disk or the circumferential tensile test device cannot fit tightly with the circumferential tensile specimen of the pipe, thereby causing deviation in the experimental data and affecting the stability of the experimental results.

[0036] In the present invention, the hoop tensile test device comprises a central disk, spokes and a rim. The diameter of the rim can be adjusted by adjusting the length of the spokes, thereby adapting to the change of the inner diameter of the pipe.

[0037] In a further solution, there is an inclination angle between the spokes and the disk surface of the center disk, and the center disk includes an upper disk and a lower disk. The change in the rim diameter is further controlled or adjusted by controlling the distance between the upper disk and the lower disk.

[0038] In the present invention, the diameter of the wheel rim can be adjusted according to the inner diameter of the tube circumferential tensile test specimen, so that the tube circumferential tensile test specimen and the wheel rim match each other, thereby increasing the accuracy of the test result.

[0039] Refer to the following Figure 1-5 The hoop tensile test apparatus according to the present invention is exemplarily described.

[0040] Figure 1 It is a schematic top view of a hoop tensile test device according to an exemplary embodiment of the present invention, which shows a rim 1, a center disk 3-1, spokes 5 and an expansion joint 4. The expansion joint 4 corresponds to an adjustment device for the spoke length between the rim 1 and the center disk 3-1.

[0041] Figure 3According to an exemplary embodiment of the present invention Figure 1 Schematic diagram of the telescopic section in FIG. By adjusting the spoke length of the telescopic section 4, the diameter of the rim 1 can be adjusted without substantially changing the circular curvature of the rim 1. As can be understood by those skilled in the art, adjusting the diameter of the rim 1 without substantially changing the circular curvature of the rim 1 indicates that the rim has elasticity in the circumferential direction to facilitate elastic deformation.

[0042] exist Figure 3 In the embodiment, the telescopic joint 4 is a length adjustment nut or a movable nut 4-3 that cooperates with the thread of the spoke end (spoke thread end 4-2), and the length adjustment nut is suitable for abutting the center disk and the diameter of the length adjustment nut is larger than the diameter of the mounting hole of the center disk. As can be understood by those skilled in the art, the center disk includes a side surface, which can be provided with a mounting hole, and the end of the spoke can be inserted into the mounting hole.

[0043] As can be understood, in the case of using an expansion joint, one end of the spoke passes through a mounting hole on the side of one of the rim and the center disk, and the other end of the spoke is fixed to or abuts against the other of the rim and the center disk.

[0044] In the embodiment shown in the present invention, the telescopic section 4 is arranged near the center disk or abuts the side of the center disk. However, the telescopic section as a length adjustment unit is not limited to the form shown in the figure. For example, the telescopic section 4 can also be arranged near the wheel rim or abut the wheel rim. For another example, the spoke includes a first section and a second section connected by a length adjustment unit, one end of the first section is fixedly connected to the wheel rim, one end of the second section is fixedly connected to the center disk, and the other ends of the first section and the second section are both connected to the length adjustment unit, and the length adjustment unit includes a length adjustment nut, one end of the length adjustment nut is connected to one of the two other ends in an axially fixed and rotatable manner, and the other end of the length adjustment nut is threadedly matched with the other of the two other ends. In this way, the distance between the wheel rim and the center disk can be adjusted by rotating the length adjustment nut, thereby adjusting the radius of the wheel rim.

[0045] exist Figure 1 In the embodiment, the center disk is also in the form of a semicircle, so that the wheel rim and the center disk are arranged based on the same center of a circle, but the present invention is not limited thereto. For example, the wheel rim may not be a semicircle, but may be a broken line in which an arc is replaced by a substantially arc-shaped arc.

[0046] In one embodiment of the present invention, the axes of all spokes pass through the center of the rim (when the spokes are substantially parallel to the disk surface of the center disk), or the vertical plane where each spoke is located passes through the center (when, for example, there is an angle between the spokes and the disk surface of the center disk). Figure 4 According to an exemplary embodiment of the present invention Figure 1Schematic front view of the hoop tensile test apparatus in FIG. Figure 4 As shown, the center disk 3-1 includes an upper disk and a lower disk, and a spring 2 is arranged between the upper and lower disks.

[0047] Figure 5 According to an exemplary embodiment of the present invention Figure 1 Schematic enlarged top view of the lower disk of the central disk in FIG. Figure 5 As shown, the center disk 3-1 is provided with a stretching connection hole 3-4. Figure 5 In the embodiment, spring 2 is arranged on the lower plate.

[0048] like Figure 1 and Figure 4 As shown, a hollow screw 3-3 is provided in the stretching connection hole 3-4, and the hollow screw cooperates with the nut 3-2. The position of the nut 3-2 is adjusted by rotating the nut 3-2 to overcome the elastic force of the spring 2 and adjust the distance between the upper plate and the lower plate. The nut 3-2 is a spacing adjustment nut.

[0049] In the present invention, the spring 2 is used as an elastic force providing component. As those skilled in the art will appreciate, other biasing components or structures may replace the spring. The spring in the claims of the present invention includes a biasing component equivalent thereto.

[0050] like Figure 4 As shown, the spoke 5 is connected to the upper plate at one end and to the mounting hole 1-2 located at the lower side in the wheel rim 1 at the other end. Figure 2 As shown), one end is connected to the lower plate and the other end is connected to the mounting hole 1-2 on the upper side of the wheel rim 1. Figure 2 As shown, the side of the rim 1 is provided with an upper rim mounting hole row and a lower rim mounting hole row; accordingly, the upper plate and the lower plate are both provided with a plate mounting hole, and the spoke connected to the plate mounting hole of the upper plate is simultaneously connected to one of the lower rim mounting holes in the lower rim mounting hole row, and the spoke connected to the plate mounting hole of the lower plate is simultaneously connected to one of the upper rim mounting holes in the upper rim mounting hole row. In this way, there is an angle between the spoke 5 and the plate surface of the center plate. In this case, as the spacing between the upper and lower plates increases when the nut 3-2 is loosened, the spoke 5 pulls the rim inward, and as the spacing between the upper and lower plates decreases when the nut 3-2 is tightened, the spoke 5 pushes the rim outward. It should be pointed out that in the present invention, if it is necessary for the end of the spoke to be inserted through or inserted, the plate mounting hole or the rim mounting hole is in the form of a hole; if the end of the spoke only needs to be fixed to the rim or the center plate, the disc mounting hole or the rim mounting hole also includes a component connected to the end of the spoke, which is within the protection scope of the present invention.

[0051] It should be noted that, instead of providing two rows of rim mounting holes, only one row may be provided. In this case, a rim mounting hole row is provided on the side of the rim, and both the upper and lower discs are provided with disc mounting holes, and the spokes connected to the disc mounting holes of the upper disc are simultaneously connected to one of the rim mounting holes in the rim mounting hole row, and the spokes connected to the disc mounting holes of the lower disc are simultaneously connected to another rim mounting hole in the rim mounting hole row.

[0052] It should be noted that the screw for adjusting the spacing between the upper and lower discs is not limited to Figure 4 The arrangement mode or arrangement position shown may also be arranged at a position other than the stretching connection holes 3 - 4 , in which case the screw rod may not be a hollow screw rod.

[0053] The following describes in detail how to perform a tensile test using the above-mentioned circumferential tensile test apparatus.

[0054] The first step is to determine the number of spokes and the matching rims in the hoop tensile test device according to the outer diameter and wall thickness of the hoop tensile test specimen of the tube;

[0055] The second step is to adjust the spoke length in the hoop tensile test device. Each spoke has an expansion joint, which can be used to adjust the length of the spoke so that Figure 2 The rim diameter shown is changed while keeping the circular curvature constant;

[0056] The third step: adjusting the distance between the upper plate and the lower plate of the center plate in the hoop tensile test device, that is, adjusting the distance between the upper plate and the lower plate by tightening and loosening the nut 3-2, so that the relative positions of the center plate, the spokes and the rim are fixed, and the diameter of the rim of the hoop tensile test device is finely adjusted;

[0057] The fourth step is to connect the clamping part of the tensile testing machine to the tensile separation testing device through the center of the through screw in the center disk to perform the circumferential tensile test.

[0058] Figure 6 FIG. 1 is a schematic top view of a hoop tensile test device according to another exemplary embodiment of the present invention, wherein a rim 1, a center disk, spokes 5 and radial protrusions 6 are shown. Figure 6 As shown, the center disk includes a first disk and a second disk, and a plurality of compression springs connected between the first disk and the second disk; a radial protrusion 6 is provided between the edges of the first disk and the second disk, and the spokes are connected between the radial protrusion and the rim; the circumferential tensile test device also includes a spacing adjustment unit for adjusting the distance between the first disk and the second disk, and based on the reduction of the distance between the first disk and the second disk, the radial protrusion is suitable for further protruding radially outward to increase the distance between the center disk and the rim in the radial direction.

[0059] Based on the above, the present invention proposes a more efficient, simple and practical experimental device for circumferential stretching of plastic pipes. Accordingly, the present invention proposes the following technical solutions:

[0060] 1. A hoop tensile test device, comprising:

[0061] A center disk, wherein the center disk is provided with a stretching connection hole;

[0062] A semicircular rim, which is arranged around the center of the circle and has elasticity in the circumferential direction;

[0063] Multiple spokes, connected and supported between the center disc and the rim; hybrid

[0064] A length adjustment unit is used to adjust the length of the spokes between the center disk and the rim or the distance between the center disk and the rim in the radial direction.

[0065] 2. A circumferential tensile test method comprising the steps of:

[0066] Providing the above-mentioned hoop tensile test device;

[0067] Adjusting the length adjustment unit to adjust the spoke length or the distance between the center disk and the rim in the radial direction to change the diameter of the rim while keeping the circular curvature of the rim unchanged; and

[0068] The hoop tensile test is performed by applying a tensile force using a tensile member passing through the tensile connection hole.

[0069] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A hoop tensile test device, comprising: A center disk, wherein the center disk is provided with a stretching connection hole; A semicircular rim, which is arranged around the center of the circle and has elasticity in the circumferential direction; A plurality of spokes connected and supported between the center disk and the rim; and A length adjustment unit, the length adjustment unit is used to adjust the length of the spokes between the center disk and the rim or the distance between the center disk and the rim in the radial direction; The length adjustment unit is arranged at one end of the spoke; or, the spoke includes a first section and a second section connected by the length adjustment unit, one end of the first section is fixedly connected to the rim, one end of the second section is fixedly connected to the center disk, and the other ends of the first section and the second section are both connected to the length adjustment unit.

2. The hoop tensile test device according to claim 1, wherein: The axes of the spokes extend through the center.

3. The hoop tensile test device according to claim 1, wherein: The spoke center disk is a semicircular center disk, and the wheel rim and the center disk are arranged based on the same center.

4. The hoop tensile test device according to claim 1, wherein: One end of the spoke passes through a mounting hole on a side of one of the rim and the center disk, the other end of the spoke is fixed to or abuts against the other of the rim and the center disk, the end of the spoke passing through the side has a thread, the length adjustment unit comprises a length adjustment nut matched with the thread, the length adjustment nut is suitable for abutting against the side and the diameter of the length adjustment nut is larger than the diameter of the mounting hole; or The length adjustment unit comprises a length adjustment nut, one end of which is connected to one of the two other ends in a rotatable manner in an axially fixed position, and the other end of the length adjustment nut is threadably matched with the other of the two other ends.

5. The hoop tensile test device according to claim 1, wherein: The central disk includes a first disk and a second disk, and a plurality of compression springs connected between the first disk and the second disk; The hoop tensile test device further comprises a spacing adjustment unit for adjusting the distance between the first disk and the second disk; and There is an inclination angle between the spokes and the disk surface of the center disk.

6. The hoop tensile test device according to claim 5, wherein: The spacing adjustment unit comprises a screw rod and a spacing adjustment nut matched with the screw rod, wherein the screw rod is arranged through the central disk, wherein: based on the thread matching between the spacing adjustment nut and the screw rod, the distance between the first disk and the second disk is adjusted.

7. The hoop tensile test device according to claim 6, wherein: The screw is a hollow screw, and the hollow screw is arranged in the stretching connection hole.

8. The hoop tensile test device according to any one of claims 5 to 7, wherein: The side of the wheel rim is provided with an upper wheel rim mounting hole row and a lower wheel rim mounting hole row, the first disc is an upper disc, the second disc is a lower disc, the first disc and the second disc are both provided with disc mounting holes, the spokes connected to the disc mounting holes of the upper disc are simultaneously connected to one of the lower wheel rim mounting holes in the row of lower wheel rim mounting holes, and the spokes connected to the disc mounting holes of the lower disc are simultaneously connected to one of the upper wheel rim mounting holes in the row of upper wheel rim mounting holes; or A row of rim mounting holes is provided on the side of the rim, the first plate is an upper plate, the second plate is a lower plate, both the first plate and the second plate are provided with plate mounting holes, the spokes connected to the plate mounting holes of the upper plate are simultaneously connected to one of the rim mounting holes in the row of rim mounting holes, and the spokes connected to the plate mounting holes of the lower plate are simultaneously connected to another rim mounting hole in the row of rim mounting holes.

9. The hoop tensile test device according to claim 5, wherein: The vertical plane where each spoke is located passes through the center of the circle.

10. The hoop tensile test device according to claim 1, wherein: The central disk includes a first disk and a second disk, and a plurality of compression springs connected between the first disk and the second disk; A radial protrusion is provided between the edges of the first disc and the second disc, and the spokes are connected between the radial protrusion and the rim; The circumferential tensile testing device also includes a spacing adjustment unit for adjusting the distance between the first disk and the second disk, and based on the reduction of the distance between the first disk and the second disk, the radial protrusion is suitable for further protruding radially outward to increase the distance between the center disk and the rim in the radial direction.

11. A hoop tensile test method comprising the steps of: Providing a hoop tensile test device according to any one of claims 1 to 4; Adjusting the length adjustment unit to adjust the spoke length or the distance between the center disk and the rim in the radial direction to change the diameter of the rim while keeping the circular curvature of the rim unchanged; and The hoop tensile test is performed by applying a tensile force using a tensile member passing through the tensile connection hole.

12. A hoop tensile test method comprising the steps of: Providing a hoop tensile test device according to any one of claims 5-10; Adjusting the length adjustment unit to adjust the spoke length or the distance between the center disk and the rim in the radial direction to change the diameter of the rim while keeping the circular curvature of the rim unchanged; Conducting a hoop tensile test by applying a tensile force using a tensile member passing through a tensile connection hole; and The distance between the first disk and the second disk is adjusted to change the distance between the center disk and the rim in the radial direction.

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