Clamping device for axial tensile test of composite material pipe
By improving the clamping device design and utilizing the combined clamping mechanism of the split expansion sleeve and contraction sleeve, the problem of unstable clamping in the existing device was solved, and the stability and data accuracy of the axial tensile test of composite material tubes were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- BEIJING GLASS STEEL INST TESTING CENT CO LTD
- Filing Date
- 2025-05-28
- Publication Date
- 2026-04-17
AI Technical Summary
In existing composite material tube axial tensile testing clamping devices, the petal-shaped friction inner sleeve is prone to falling off, failing to effectively clamp the sample and leading to unstable testing.
The clamping device is designed with a core rod, a split expansion sleeve, and a split contraction sleeve. The expansion of the tapered section and the cooperation of the contraction sleeve are used to clamp the sample from the inside and outside by using the contact surface and the abutment platform. Combined with the tightening operation of the inner and outer jacking screw sleeves, the clamping and fixing are ensured.
This effectively prevented the clamping device from falling off during the experiment, ensuring the stable clamping of the sample and guaranteeing the accuracy of the experimental data.
Smart Images
Figure CN224137034U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of composite material tensile testing fixtures, and in particular to a clamping device for axial tensile testing of composite material tubes. Background Technology
[0002] The pipe axial tensile test clamping device is used in the laboratory to determine the axial tensile properties of pipes. It is fixed on the tensile testing machine and its function is to clamp both ends of the test pipe and apply axial load to the test pipe through the tensile testing machine.
[0003] like Figure 1 , Figure 2 As shown, the existing tooling for axial tensile testing of composite material tubes consists of a mandrel 901, a preload nut 902, a rigid outer sleeve 903, and a petal-shaped friction inner sleeve 904. The clamping force on the sample is achieved by the expansion and movement of the petal-shaped friction inner sleeve 904 on the mandrel 901. However, the petal-shaped friction inner sleeve inside the sample tube is prone to detachment, and the clamping only provides external clamping; the external friction force is insufficient to meet the testing requirements.
[0004] Therefore, in order to address the above problems, this utility model urgently needs to provide a clamping device for axial tensile testing of composite material tubes. Summary of the Invention
[0005] The purpose of this invention is to provide a clamping device for axial tensile testing of composite material tubes. The structural design of the clamping device for axial tensile testing of composite material tubes solves the technical problem in the prior art where the petal-shaped friction inner sleeve of the clamping sample is prone to falling off.
[0006] This utility model provides a clamping device for axial tensile testing of composite material tubes, comprising a mandrel, at least two segmented expansion sleeves, and at least two segmented contraction sleeves. The mandrel includes a connecting section, an intermediate section, and a tapered section connected in sequence for connection to a universal testing machine. The diameter of the tapered section gradually increases outward from one end adjacent to the intermediate section. A limiting platform is provided at the connection between the tapered section and the second intermediate section. The inner wall of each segmented expansion sleeve is provided with a mating surface that matches the outer wall of the tapered section, and an abutment platform that abuts against the limiting platform. The outer wall of the segmented expansion sleeve is provided with an external protrusion; each segmented shrink sleeve has an inwardly extending overlapping plate at one end, and after the segmented shrink sleeve is assembled with one end of the sample, there is a shrinkage gap between two adjacent segmented shrink sleeves; an outer sleeve is tightly fitted outside the segmented shrink sleeve, and the inner diameter of the outer sleeve gradually decreases from the end close to the segmented shrink sleeve upward; an inner jacking screw sleeve is screwed to the middle section and is used to push the segmented expansion sleeve towards the sample; an outer jacking screw sleeve is screwed to the inner jacking screw sleeve and is used to push the outer sleeve towards the sample.
[0007] Furthermore, the outer shell is made of a rigid material.
[0008] Furthermore, a locking ring is screwed onto the connecting section for connection with the universal testing machine.
[0009] Furthermore, one end of the connecting section is provided with a connecting hole for connecting to a universal testing machine.
[0010] Furthermore, it includes two segmented shrink sleeves.
[0011] Furthermore, it includes two segmented expansion sleeves, each segmented expansion sleeve having threads on its outer wall.
[0012] Furthermore, the inner jacking sleeve includes an inner jacking nut and an inner jacking annular sleeve integral with the inner jacking nut, with threads on both the inner and outer walls of the inner jacking annular sleeve.
[0013] Furthermore, the external jacking sleeve includes an external jacking nut and an external jacking annular sleeve integral with the external jacking nut, the inner wall of which is threaded.
[0014] Furthermore, the core rod, the segmented expansion sleeve, the segmented contraction sleeve, the outer sleeve, the inner jacking screw sleeve, the outer jacking screw sleeve, and the locking ring are all made of metal.
[0015] Furthermore, the intermediate section includes a first segment and a second segment, with a stepped platform between the first segment and the second segment. One end of the segmented expansion sleeve abuts against the stepped platform, and the width of the stepped platform is less than the wall thickness of the segmented expansion sleeve.
[0016] The clamping device for axial tensile testing of composite material tubes provided by this utility model has the following advantages compared with the prior art:
[0017] This utility model provides a clamping device for axial tensile testing of composite material tubes. Two clamping devices are used to hold the two ends of the sample. The segmented expansion sleeves in the clamping devices are assembled with the mandrel via a mating surface and abutment platform. The two segmented expansion sleeves cover the mandrel, and the mandrel and the two segmented expansion sleeves are inserted into the sample together. The segmented contraction sleeves are assembled with the sample via an overlap plate, and the outer sleeve is fitted onto the segmented contraction sleeve, thus connecting the mandrel and the sample. An inner jacking screw is fitted onto the mandrel, and an outer jacking screw is fitted onto the inner jacking screw. The inner jacking screw is tightened first with a wrench, and the inner jacking screw pushes the segmented expansion sleeves. Because the conical section of the core rod is conical, the segmented expansion sleeve expands outward during the jacking process. The segmented expansion sleeve exerts an outward force on the inner wall of the sample. By tightening the outer jacking screw with a wrench, the outer sleeve is jacked towards the sample. Since the inner diameter of the outer sleeve gradually decreases from the end close to the segmented contraction sleeve upward, the outer sleeve provides an inward pushing force to the segmented contraction sleeve, which can clamp the segmented contraction sleeve. The segmented contraction sleeve exerts an inward force on the outer wall of the sample. The segmented contraction sleeve and the segmented contraction sleeve clamp the sample from the inside and outside, thereby achieving clamping and fixing of the sample, effectively preventing the segmented contraction sleeve and the segmented expansion sleeve from falling off during the experiment, ensuring the smooth progress of the experiment, and obtaining accurate data. Attached Figure Description
[0018] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in 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 utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0019] Figure 1 A schematic diagram (perspective view) of a conventional tooling structure for axial tensioning of existing composite material tubes.
[0020] Figure 2 A schematic diagram (three-dimensional view) of the existing petal-shaped friction inner sleeve.
[0021] Figure 3 This is a schematic diagram (assembly drawing) of the clamping device for axial tensile testing of composite material tubes described in this utility model.
[0022] Figure 4 This is a schematic diagram (front view) of the core rod structure described in this utility model.
[0023] Figure 5 This is a schematic diagram (three-dimensional view) of the segmented expansion sleeve described in this utility model.
[0024] Figure 6This is a schematic diagram (three-dimensional view) of the structure of the segmented shrink sleeve described in this utility model;
[0025] Figure 7 This is a schematic diagram (perspective view) of the outer casing described in this utility model.
[0026] Figure 8 This is a schematic diagram (three-dimensional view) of the structure of the inner jacking annular sleeve, the outer jacking screw sleeve, and the locking ring described in this utility model.
[0027] Explanation of reference numerals in the attached figures:
[0028] 1. Core rod; 101. Connecting section; 102. Middle section; 1021. First segment; 1022. Second segment; 103. Conical section; 104. Limiting platform; 2. Split-type expansion sleeve; 201. Contact surface; 202. Abutment platform; 203. Outer boss; 3. Split-type contraction sleeve; 31. Overlap plate; 4. Outer sleeve; 5. Inner jacking screw sleeve; 51. Inner jacking nut; 52. Inner jacking annular sheath; 6. Outer jacking screw sleeve; 61. Outer jacking nut; 62. Outer jacking annular sheath; 7. Locking ring; 8. Sample. Detailed Implementation
[0029] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.
[0030] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0031] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0032] like Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 As shown, the clamping device for axial tensile testing of composite material tubes provided in this embodiment includes a core rod 1. The core rod 1 includes a connecting section 101 for connection with a universal testing machine, an intermediate section 102, and a tapered section 103 connected in sequence. The diameter of the tapered section 103 gradually increases outward from the end close to the intermediate section 102. A limiting platform 104 is provided at the connection between the tapered section 103 and the second intermediate section 102. It also includes a segmented expansion sleeve 2 and a segmented contraction sleeve 3. The inner wall of each segmented expansion sleeve 2 is provided with a fitting surface 201 that matches the outer wall of the tapered section, and a contact surface 201 that abuts against the limiting platform 104. The abutment platform 202 has an outer protrusion 203 on the outer wall of the segmented expansion sleeve; each segmented shrink sleeve 3 has an inwardly extending overlapping plate 31 on one end of its circumference. After the segmented shrink sleeve 3 is assembled with one end of the sample, there is a shrinkage gap between two adjacent segmented shrink sleeves 3; the outer sleeve 4 is tightly fitted on the segmented shrink sleeve 3, and the inner diameter of the outer sleeve gradually decreases from the end close to the segmented shrink sleeve 3 upward; the inner push-in screw sleeve 5 is screwed to the middle section 102 and is used to push the segmented expansion sleeve 2 towards the sample; the outer push-in screw sleeve 6 is screwed to the inner push-in screw sleeve 5 and is used to push the outer sleeve 4 towards the sample.
[0033] The present invention provides a clamping device for axial tensile testing of composite material tubes. Two clamping devices for axial tensile testing of composite material tubes are clamped at both ends of the sample 8. The segmented expansion sleeves 2 in the clamping devices are assembled with the core rod 1 through the mating surface 201 and the abutment platform 202. The two segmented expansion sleeves 2 cover the core rod 1. The core rod 1 and the two segmented expansion sleeves 2 are inserted into the sample together. The segmented contraction sleeve 3 is assembled with the sample 1 through the overlapping plate 31. The outer sleeve 4 is fitted onto the segmented contraction sleeve 3 to connect the core rod 1 and the sample. The inner push-in screw sleeve 5 is screwed onto the core rod 1, and the outer push-in screw sleeve 6 is screwed onto the inner push-in screw sleeve 5. The inner push-in screw sleeve 5 is tightened first with a wrench. The inner push-in screw sleeve 5 is tightened onto the segmented expansion sleeve 1. The expansion sleeve 2 is pushed forward. Since the tapered section 103 of the core rod 1 is tapered, the split expansion sleeve 2 expands outward during the pushing process. The split expansion sleeve 2 exerts an outward force on the inner wall of the sample. The outer push-in screw sleeve 6 is tightened by a wrench, and the outer sleeve 4 is pushed towards the sample. Since the inner diameter of the outer sleeve 4 gradually decreases from the end close to the split shrink sleeve 4 upward, the outer sleeve 4 provides an inward pushing force to the split shrink sleeve 4, which can clamp the split shrink sleeve 3. The split shrink sleeve 3 exerts an inward force on the outer wall of the sample. The split shrink sleeve 4 and the split shrink sleeve 3 clamp the sample from the inside and outside, thereby achieving clamping and fixing of the sample, effectively preventing the split shrink sleeve 3 and the split expansion sleeve 2 from falling off during the experiment, ensuring the smooth progress of the experiment and obtaining accurate data.
[0034] The outer casing 4 of this utility model is made of rigid material.
[0035] like Figure 3 As shown, in this embodiment, a locking ring 7 is screwed onto the connecting section 101 for connecting with the universal testing machine, which is used to connect with the universal testing machine and achieve locking and fixing with the universal testing machine.
[0036] like Figure 3 As shown, one end of the connecting section 101 in this embodiment is provided with a connecting hole for connecting to a universal testing machine, which facilitates connection and fixation.
[0037] This utility model includes two split-type shrink sleeves 3.
[0038] This utility model includes two segmented expansion sleeves 2.
[0039] like Figure 8 As shown, the inner jacking screw sleeve 5 in this embodiment includes an inner jacking nut 51 and an inner jacking annular sleeve 52 which is integral with the inner jacking nut 51. The inner wall and outer wall of the inner jacking annular sleeve 52 are both provided with threads.
[0040] like Figure 8As shown, the external jacking screw sleeve 6 in this embodiment includes an external jacking nut 61 and an external jacking annular sleeve 62 which is integral with the external jacking nut 61. The inner wall of the external jacking annular sleeve 62 is provided with threads.
[0041] The core rod 1, the segmented expansion sleeve 2, the segmented contraction sleeve 3, the outer sleeve 4, the inner jacking screw sleeve 5, the outer jacking screw sleeve 6, and the locking ring 7 of this utility model are made of metal.
[0042] like Figure 4 As shown, the middle section 102 of this embodiment includes a first segment 1021 and a second segment 1022. A stepped platform is provided between the first segment 1021 and the second segment 1022. One end of the split expansion sleeve 2 abuts against the stepped platform. The width of the stepped platform is less than the wall thickness of the split expansion sleeve 2, which facilitates the installation of the split expansion sleeve 2.
[0043] 1. Core rod; 101. Connecting section; 102. Middle section; 1021. First segment; 1022. Second segment; 103. Conical section; 104. Limiting platform; 2. Split-type expansion sleeve; 201. Contact surface; 202. Abutment platform; 203. Outer boss; 3. Split-type contraction sleeve; 31. Overlap plate; 4. Outer sleeve; 5. Inner jacking screw sleeve; 51. Inner jacking nut; 52. Inner jacking annular sheath; 6. Outer jacking screw sleeve; 61. Outer jacking nut; 62. Outer jacking annular sheath; 7. Locking ring; 8. Sample.
[0044] Assembly process of clamping device and specimen (composite material tube) for axial tensile testing of composite material tubes:
[0045] 1. First, assemble a set of clamping devices for axial tensile testing of composite tubes with one end of the specimen. Specifically, assemble two split expansion sleeves with the core rod 1. After assembly, the split expansion sleeves and the core rod 1 extend into the specimen. Then, assemble the split contraction sleeve 3 with the specimen and the outer sleeve 4 with the split contraction sleeve 3.
[0046] 2. Thread the inner jacking screw sleeve 5 to the core rod 1, and thread the split shrink sleeve 6 to the inner jacking screw sleeve 5. First, tighten the inner jacking screw sleeve 5 to push the split expansion sleeve to move towards the sample. Then, tighten the outer jacking screw sleeve to push the split shrink sleeve 3 to move towards the sample.
[0047] 3. Following steps 1 and 2, assemble another set of clamping devices for axial tensile testing of composite tubes with the specimen.
[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.
Claims
1. A clamping device for axial tensile testing of composite material tubes, characterized in that: It includes a core rod (1), at least two split expansion sleeves (2) and at least two split contraction sleeves (3). The core rod (1) includes a connecting section (101), an intermediate section (102) and a tapered section (103) connected in sequence for connection with a universal testing machine. The diameter of the tapered section (103) gradually increases from one end close to the intermediate section (102) outward. A limiting platform (104) is provided at the connection between the tapered section (103) and the second intermediate section (102). Each segmented expansion sleeve (2) has an inner wall with a mating surface (201) that matches the outer wall of the conical section (103) and an abutting platform (202) that abuts against the limiting platform (104). The outer wall of the segmented expansion sleeve (2) has an outer protrusion (203). Each segmented shrink sleeve (3) has an inwardly extending overlapping plate (31) at one end. After the segmented shrink sleeve (3) is assembled with one end of the sample, a shrinkage gap is provided between two adjacent segmented shrink sleeves (3). An outer sleeve (4) is tightly fitted outside the split-type shrink sleeve (3), and the inner diameter of the outer sleeve (4) gradually decreases upward from the end close to the split-type shrink sleeve (3); The inner push-in sleeve (5) is screwed to the middle section (102) and is used to push the split expansion sleeve (2) towards the sample direction; The outer jacking screw sleeve (6), which is screwed to the inner jacking screw sleeve (5), is used to push the outer sleeve (4) towards the sample direction.
2. The clamping device for axial tensile testing of composite material tubes according to claim 1, characterized in that: The outer jacket (4) is made of rigid material.
3. The gripping device for axial tensile testing of composite tubes according to claim 1, characterized in that: A locking ring (7) is screwed onto the connecting section (101) for connection with the universal testing machine.
4. The gripping device for axial tensile testing of composite tubes according to claim 1, characterized in that: One end of the connecting section (101) is provided with a connecting hole for connecting to a universal testing machine.
5. The gripping device for axial tensile testing of composite tubes of claim 1, wherein: Includes two split-type shrink sleeves (3).
6. The gripping device for axial tensile testing of composite tubes of claim 1, wherein: It includes two split expansion sleeves (2), and each split expansion sleeve (2) has threads on its outer wall.
7. The gripping device for axial tensile testing of composite tubes according to claim 1, characterized in that: The inner jacking screw sleeve (5) includes an inner jacking nut (51) and an inner jacking annular sleeve (52) which is integral with the inner jacking nut (51). The inner wall and outer wall of the inner jacking annular sleeve (52) are both threaded.
8. The gripping device for axial tensile testing of composite tubes according to claim 1, characterized in that: The external jacking screw sleeve (6) includes an external jacking nut (61) and an external jacking annular sleeve (62) which is integral with the external jacking nut (61). The inner wall of the external jacking annular sleeve (62) is provided with threads.
9. The gripping device for axial tensile testing of composite tubes according to claim 1, characterized in that: The core rod (1), the split expansion sleeve (2), the split contraction sleeve (3), the outer sleeve (4), the inner jacking screw sleeve (5), the outer jacking screw sleeve (6), and the locking ring (7) are made of metal.
10. The gripping device for axial tensile testing of composite tubes of claim 1, wherein: The middle section (102) includes a first segment (1021) and a second segment (1022). A stepped platform is provided between the first segment (1021) and the second segment (1022). One end of the split expansion sleeve (2) abuts against the stepped platform. The width of the stepped platform is less than the wall thickness of the split expansion sleeve (2).