A specimen centering device for a split hopkinson pressure bar

Abstract

The utility model discloses a kind of specimen centering devices for split hopkinson pressure bar, including fixing device, positioning device and connecting buckle;The fixing device is by upper disc and lower disc composition;The upper disc is equipped with level recess, slide square hole and connecting ear 1;The lower disc is equipped with guide rail round hole, nut hole and connecting ear 2;The positioning device is by passive component and active component composition;The passive component is by limiting block, slide, four square platform 1 and L type pillar 1 composition;The active component is by half cutting bolt, four square platform 2, L type pillar 2, guide rail column and limit disc composition;The connecting buckle is by sliding component and rotating component composition;The sliding component is equipped with guide rail slider, manual buckle and clamping block;The rotating component is by limit disc, rotating column and rotating ear composition;A kind of specimen centering devices for split hopkinson pressure bar disclosed in the utility model helps to reduce the error of SHPB experiment, improve the accuracy of experiment.

Description

Technical Field

[0001] This utility model relates to the field of specimen alignment in a split Hopkinson test apparatus, and particularly to a specimen alignment device for a split Hopkinson pressure bar. Background Technology

[0002] The Split Hopkinson Bar (SHPB) test technique is a widely used experimental method for studying the dynamic mechanical properties of materials. It is often used to test the stress-strain relationship of materials under high strain rate conditions and has become one of the standard means of studying the dynamic properties of materials.

[0003] In the SHPB experiment, the axial alignment of the specimen has a significant impact on the accuracy and repeatability of the experimental data. If the specimen is not accurately aligned, it can lead to uneven load distribution, distortion of stress wave propagation, and eccentric failure, thus affecting the accuracy of the stress-strain curve and even causing experimental failure. Currently, utility model patent CN223051000 U discloses an SHPB experiment alignment device, but this device needs to be fixed to two rods: an incident rod and a transmission rod. When fixing the specimen, the incident rod needs to be pushed, and since the device is not fixed, it may shift during the pushing process. Secondly, the device does not explain the vertical alignment process. Finally, dynamic tensile testing requires a high-speed camera to capture the end-face failure process, necessitating the placement of the end face perpendicular to the rod end face.

[0004] Therefore, there is an urgent need for a specimen alignment device with a reasonable structure, convenient adjustment, and high alignment accuracy to improve the stability and data reliability of SHPB experiments. Especially in high strain rate and precision testing scenarios, the performance of the alignment device plays a decisive role in the overall experimental results. Summary of the Invention

[0005] To achieve the above objectives, this utility model provides the following solution: This utility model provides a specimen centering device for a split Hopkinson pressure bar, including a fixing device, a positioning device, and a connecting buckle; the fixing device consists of an upper plate (1) and a lower plate (2); the upper plate (1) is provided with a level groove (11), a sliding ruler square hole (12), and a connecting ear 1 (13); the connecting ear 1 (13) is provided with a connecting hole (131) and a retaining groove (132); the lower plate (2) is provided with a guide rail round hole (21), a nut hole (22), and a connecting ear 2 (23); the connecting ear 2 (23) is provided with a fixing hole (231); the positioning device consists of a passive component (3) and an active component (4); the passive component (3) consists of a limiting block (31), a sliding ruler (32), and a square platform 1 (3 4) and L-shaped support 1 (33) are composed of a sliding ruler (32) with a scale 1 (321); the active component (4) is composed of a half-cut bolt (41), a square platform 2 (42), an L-shaped support 2 (43), a guide rail column (44) and a limiting plate (45); the half-cut bolt (41) is provided with a cross groove (411) and a scale 2 (412); the connecting buckle is composed of a sliding component (5) and a rotating component (6); the sliding component (5) is provided with a guide rail slider (51), a manual buckle (52) and a locking block (53); the rotating component (6) is composed of a limiting disc (61), a rotating column (62) and a rotating ear (63); the limiting disc (61) is provided with a buckle groove (611) and a guide rail groove (612).

[0006] Preferably, the fixing device is composed of the upper plate (1) and the lower plate (2), and the inner radius of the formed circle is the same as the radius of the rod (7). This ensures that the entire device can completely fit the rod (7) and ensures the stability of the entire device.

[0007] Preferably, the passive component (3) is an integrated component consisting of a limiting block (31), a sliding ruler (32), a square platform 1 (34), and an L-shaped support column 1 (33). In the active component (4), the square platform 2 (42), the L-shaped support column 2 (43), the guide rail column (44), and the limiting plate (45) form an integrated component, while the half-cut bolt (41) is a separate component. The half-cut bolt (41) is rotated and moved by a screwdriver, which drives the active component (4) to move. The specimen is placed in the middle to play a transmission role, thereby driving the passive component (3) to move.

[0008] Preferably, the height of the sliding ruler (32) and the threaded portion of the half-cut bolt (41) are equal; the height of the square platform 1 (34) and the square platform 2 (42) are equal; and the height of the L-shaped support 1 (33) and the L-shaped support 2 (43) are equal. The positions of the active component (4) and the passive component (3) can be visually reflected by the scale 1 (321) and the scale 2 (412). When the scale 1 (321) and the scale 2 (412) are in the same position, it can be indicated that the specimen is in the center position.

[0009] Preferably, the length of the locking block (53) is such that when the guide rail slider (51) moves to contact the stop groove (132), a part of the locking block (53) must remain in the buckling groove (611), and the entire length of the locking block (53) cannot be greater than the buckling groove (611).

[0010] Preferably, the range and scale of scale 1 (321) and scale 2 (412) are exactly the same.

[0011] Preferably, the level groove (11) is used to place the level bubble, which can ensure that the entire device is in a horizontal state. This prevents the specimen from becoming asymmetrical due to its own weight when placed on the L-shaped support 2 (43) due to the device deflection.

[0012] The beneficial effects of this utility model are: This invention provides a specimen centering device for a split Hopkinson bar. Through the coordinated action of a fixing device, a positioning device, and a connecting buckle, it enables precise adjustment of the specimen in both horizontal and vertical directions, effectively improving the centering accuracy of the specimen and avoiding stress wave distortion and experimental errors caused by eccentric loading, thereby enhancing the accuracy and repeatability of SHPB experimental data. The fixing device adopts an upper and lower plate combination structure that matches the outer diameter of the bar, ensuring stable installation on the device and preventing displacement during sample loading. The positioning device includes a sliding ruler and graduated semi-cut bolts, facilitating intuitive and efficient fine-tuning. The rotating component can adjust the end face angle of the specimen to make it perpendicular to the horizontal plane, meeting the imaging requirements of high-speed photography in dynamic tensile tests. The symmetrical design of each structure of the device provides excellent error compensation capabilities, further enhancing the stability of the experimental process and the reliability of the data. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall design of this utility model.

[0014] Figure 2 This is a diagram of the upper plate.

[0015] Figure 3 This is a diagram of the lower body.

[0016] Figure 4 This is a schematic diagram of the active component.

[0017] Figure 5 This is a schematic diagram of a partially cut bolt.

[0018] Figure 6 This is a schematic diagram of a passive component.

[0019] Figure 7 This is a schematic diagram of the sliding component.

[0020] Figure 8 This is a schematic diagram of the rotating assembly.

[0021] Figure 9 This is a schematic diagram of the dynamic compression test apparatus.

[0022] Figure 10 This is a schematic diagram of the dynamic tensile testing apparatus.

[0023] In the diagram: 1-Upper plate; 11-Level groove; 12-Sliding ruler square hole; 13-Connecting ear 1; 131-Connecting hole; 132-Stop groove; 2-Lower plate; 21-Guide rail round hole; 22-Nut hole; 23-Connecting ear 2; 231-Fixing hole; 3-Passive component; 31-Limit block; 32-Sliding ruler; 321-Scale 1; 33-L-shaped support 1; 34-Square platform 1; 4-Active component; 41-Half-cut bolt ; 411-Cross groove; 412-Scale 2; 42-Square platform 2; 43-L-shaped support 2; 44-Guide rail column; 45-Limiting plate; 5-Sliding component; 51-Guide rail slider; 52-Manual buckle; 53-Clock block; 6-Rotating component; 61-Limiting disc; 611-Snap groove; 612-Guide rail groove; 62-Rotating column; 63-Rotating ear; 7-Ring; 8-Dynamic compressive strength specimen; 9-Dynamic tensile strength specimen. Detailed Implementation

[0024] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] See Figures 1-8A specimen centering device for a split Hopkinson pressure bar includes a fixing device, a positioning device, and a connecting buckle; the fixing device consists of an upper plate (1) and a lower plate (2); the upper plate (1) is provided with a level groove (11), a sliding ruler square hole (12), and a connecting ear 1 (13); the connecting ear 1 (13) is provided with a connecting hole (131) and a stop groove (132); the lower plate (2) is provided with a guide rail round hole (21), a nut hole (22), and a connecting ear 2 (23); the connecting ear 2 (23) is provided with a fixing hole (231); the positioning device consists of a passive component (3) and an active component (4); the passive component consists of a limit block (31), a sliding ruler (32), a square platform 1 (34), and an L-shaped... The support column 1 (33) is composed of a sliding ruler (32) with a scale 1 (321); the active component (4) is composed of a half-cut bolt (41), a square platform 2 (42), an L-shaped support column 2 (43), a guide rail column (44) and a limiting plate (45); the half-cut bolt (41) is provided with a cross groove (411) and a scale 2 (412); the connecting buckle is composed of a sliding component (5) and a rotating component (6); the sliding component (5) is provided with a guide rail slider (51), a manual buckle (52) and a locking block (53); the rotating component (6) is composed of a limiting disc (61), a rotating column (62) and a rotating ear (63); the limiting disc (61) is provided with a buckle groove (611) and a guide rail groove (612). Example 1

[0026] See Figure 9 The usage procedure of this utility model device in the SHPB dynamic compression test is as follows: Move the locking block (53) to the retaining groove (132) by sliding component (5) to lock the rotating component (6) to prevent the rotating component (6) from being misaligned during the installation of the upper and lower plates. Align the upper plate (1) and lower plate (2) and install them on the rod (7). Retract the sliding component (5) into the retaining groove (611). Rotate the rotating ear (63) to drive the entire rotating component (6) to rotate. Lock the rotating ear (63) onto the connecting ear 2 (23) to complete the fixation of the entire device. Finally, level the entire device by placing the bubble level in the groove (11) of the level instrument.

[0027] When installing the specimen, the dynamic compression specimen (8) is first placed parallel to the cross section of the rod (7) above the empty area in the middle of the L-shaped support 2 (43) of the active component (4). The specimen is centered left and right through the symmetry of the structure. The half-cut bolt (41) is adjusted by using a screwdriver on the cross groove (411) to move the entire positioning device up and down. The alignment is judged by the scale 2 (412) on the half-cut bolt (41) and the scale 1 (321) on the slide (32). By achieving the dual symmetry of left and right alignment and up and down alignment, it is ensured that the axis of the dynamic compression specimen (8) is collinear with the axis of the rod (7) during the SHPB dynamic compression test.

[0028] Push the rod (7) to clamp the dynamic compressive strength test specimen (8). After clamping, remove the device by reversing the installation steps and finally enter the experimental stage. Example 2

[0029] See Figure 10 The application process of this device in the SHPB dynamic tensile test is the same as that in the SHPB dynamic compression test described above, consisting of three stages: device installation, specimen installation, and device disassembly. Except for the installation stage, the other two stages remain unchanged.

[0030] The dynamic tensile test requires the end face of the dynamic tensile specimen (9) to be perpendicular to the cross section of the rod (7). When the dynamic tensile specimen (9) is placed above the empty area in the middle of the L-shaped support 2 (43) of the active component (4), the end face will be perpendicular to the rod automatically during the clamping process, and the front and rear symmetry can be achieved naturally without additional adjustment.

[0031] To achieve symmetrical positioning, a ruler was used to measure the distance from the two end faces of the specimen to the plane of the L-shaped support 2 (43). Ensuring that the distances on both sides are consistent indicates that the specimen is symmetrically centered in the horizontal direction. The vertical alignment method is the same as in the dynamic compression experiment. By adjusting the height of the half-cut bolt (41) and combining it with the scale reading, the vertical position of the dynamic tensile specimen (9) was confirmed to be symmetrical, ensuring that the axes are collinear. After alignment, the rod (7) was moved to clamp the specimen.

[0032] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and does not limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A specimen centering device for a split Hopkinson pressure bar, comprising a fixing device, a positioning device, and a connecting buckle; the fixing device consists of an upper plate (1) and a lower plate (2); the upper plate (1) is provided with a level groove (11), a sliding ruler square hole (12), and a connecting ear 1 (13); the connecting ear 1 (13) is provided with a connecting hole (131) and a stop groove (132); the lower plate (2) is provided with a guide rail round hole (21), a nut hole (22), and a connecting ear 2 (23); the connecting ear 2 (23) is provided with a fixing hole (231); the positioning device consists of a passive component (3) and an active component (4); the passive component (3) consists of a limiting block (31), a sliding ruler (32), a square platform 1 (34), and The L-shaped support column 1 (33) is composed of a sliding ruler (32) with a scale 1 (321); the active component (4) is composed of a half-cut bolt (41), a square platform 2 (42), an L-shaped support column 2 (43), a guide rail column (44), and a limiting plate (45); the half-cut bolt (41) is provided with a cross groove (411) and a scale 2 (412); the connecting buckle is composed of a sliding component (5) and a rotating component (6); the sliding component (5) is provided with a guide rail slider (51), a manual buckle (52), and a locking block (53); the rotating component (6) is composed of a limiting disc (61), a rotating column (62), and a rotating ear (63); the limiting disc (61) is provided with a buckle groove (611) and a guide rail groove (612).

2. The specimen centering device for a split Hopkinson pressure bar according to claim 1, characterized in that: The fixing device is composed of the upper plate (1) and the lower plate (2), and the inner circle radius formed is the same as the radius of the rod (7).

3. The specimen centering device for a split Hopkinson pressure bar according to claim 1, characterized in that: The passive component (3) is an integrated component consisting of a limiting block (31), a sliding ruler (32), a square platform 1 (34) and an L-shaped support column 1 (33). The active component (4) consists of a square platform 2 (42), an L-shaped support column 2 (43), a guide rail column (44) and a limiting plate (45). The half-cut bolt (41) is a separate component.

4. A specimen centering device for a split Hopkinson pressure bar according to claim 1, characterized in that: The height of the sliding ruler (32) and the threaded portion of the half-cut bolt (41) are equal; the height of the square platform 1 (34) and the square platform 2 (42) are equal; the height of the L-shaped support 1 (33) and the L-shaped support 2 (43) are equal.

5. A specimen centering device for a split Hopkinson pressure bar according to claim 1, characterized in that: The length of the locking block (53) is such that when the guide rail slider (51) moves to contact the stop groove (132), a part of the locking block (53) must stay in the buckling groove (611), and the entire length of the locking block (53) cannot be greater than the buckling groove (611).

6. A specimen centering device for a split Hopkinson pressure bar according to claim 1, characterized in that: The range and scale of scale 1 (321) and scale 2 (412) are exactly the same.

7. A specimen centering device for a split Hopkinson pressure bar according to claim 1, characterized in that: The level groove (11) is used to place the level bubble.

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