CN209311212U - A separate Hopkinson pressure bar positioning device suitable for multi-size specimens - Google Patents

Abstract

The utility model discloses a separated Hopkinson pressure bar positioning device suitable for multi-size test pieces, the structure of which comprises a detachable clamping device and a side positioning piece. The detachable clamping device is composed of an upper sleeve and a lower sleeve. One side of the upper sleeve and the lower sleeve are connected as a whole through a loose-leaf hinge. Fix the upper and lower side sleeves with bolts on the other side. The side positioning piece is placed on the lower sleeve, and the curved surface of the side positioning piece is used to position the test piece to ensure that the center of the test piece is on a straight line with the centers of the incident rod and the transmission rod. The utility model has a simple structure, can realize accurate positioning of test pieces, and has corresponding side positioning pieces to match test pieces of different sizes, and has strong applicability. At the same time, its structure is convenient for installation and disassembly, and the operation is simple and convenient.

Description

A separate Hopkinson pressure bar positioning device suitable for multi-size specimens

technical field

The utility model relates to the field of testing and researching the dynamic mechanical properties of materials, in particular to a separate Hopkinson pressure bar positioning device suitable for multi-size test pieces.

Background technique

When solving many practical problems in engineering technology and military technology, people often encounter dynamic loads such as various impacts and explosions. The mechanical response of most materials under dynamic loads is very different from that of static loads. In order to further study the mechanical response of materials under dynamic loads, a series of dynamic loading instruments have been designed and improved since the 19th century.

In 1872, J.Hopkinson completed the first impact tensile test using iron wire and drop weight. In 1914, B.Hopkinson used Hopkinson compression rod to measure the pressure-time relationship when explosives explode or bullets shoot at the rod end. In 1949, Kolsky first turned the Hopkinson compression bar into a separate type and used it to study the dynamic mechanical behavior of materials under high strain rates. Then the split Hopkinson pressure bar (SHPB) is widely used in the test experiment of the dynamic performance of the material.

The widely used Hopkinson pressure bar experimental system is composed of a bullet launcher, a wave shaper, an incident bar, a transmission bar, a buffer (generally a buffered transmission bar or a damping device, etc.), a waveform amplifier, and a digital oscilloscope. In the material impact compression test, the specimen is clamped between the incident rod and the transmission rod, and then the firing device launches the impact bullet under a certain blow pressure, and the incident wave is generated when it collides with the end surface of the incident rod, and the incident wave travels When reaching the end faces of the incident rod and the test piece, reflected waves are generated due to the difference in impedance, and transmitted waves are generated at the end faces of the test piece and the transmission rod. The incident wave, reflected wave and transmitted wave are transmitted into the digital oscilloscope through the strain gauges and wires pasted on the incident rod and the transmitted rod.

When using the Hopkinson compression bar to test the impact compression performance of the specimen, the one-dimensional stress wave assumption and the assumption of stress balance at both ends of the specimen must be complied with, otherwise the test results will not accurately reflect the dynamic mechanical properties of the specimen.

The separate Hopkinson rod test technique is now recognized as the most important and reliable experimental method for studying the mechanical properties of materials at medium and high strain rates. Using the Hopkinson rod can simulate the strain rate conditions similar to the field, and its application fields are also From the initial metal and metal materials to on-site measurement of a series of new materials such as rocks, concrete, ceramics, polymers, and composite materials.

However, the existing separated Hopkinson pressure bar system has the following deficiencies in the actual operation process:

1. The existing separated Hopkinson rod does not have a corresponding supporting device after the specimen is placed between the incident rod and the transmission rod. Since the end of the specimen is usually coated with lubricants such as Vaseline to reduce end friction and affect the measurement results Therefore, the specimen may slip from between the incident rod and the transmission rod before starting the test, causing damage to the specimen.

2. When the diameter of the test piece is different from that of the Hopkinson pressure bar, the coaxial placement of the center of the test piece and the center of the Hopkinson pressure bar cannot be accurately realized, and it is easy to cause the bending of the pressure bar during the impact test , affecting the assumption of one-dimensional stress wave propagation, which brings errors to the measurement of the test waveform and reduces the accuracy of the test.

Utility model content

The purpose of this utility model is to provide a separate Hopkinson pressure bar positioning device suitable for multi-size test pieces with simple structure, convenient operation and wide application range, so as to overcome the existing separate Hopkinson pressure bar The test device cannot provide reliable support for the specimen clamped between the incident rod and the transmission rod, and at the same time cannot realize the coaxial and precise positioning of the center of the specimen and the center of the pressure rod.

In order to achieve the above object, the utility model adopts the following technical solutions:

A separate Hopkinson pressure bar positioning device suitable for multi-size test pieces, characterized in that it includes a detachable clamping device and a side positioning piece that matches the difference between the diameter of the sample and the diameter of the incident rod; The detachable clamping device is composed of the upper sleeve wall and the lower sleeve wall. One side of the upper sleeve wall and the lower sleeve wall is connected as a whole through a hinge, and the other side can be opened and closed according to needs and set. There is a connection structure; the inner diameters of the upper sleeve wall and the lower sleeve wall are equal to the diameter of the incident rod, and the lower sleeve wall is provided with a support structure supporting the side positioning piece; the side The side positioning piece is provided with a surface matching with the support structure and a specimen positioning circular arc surface in contact with the specimen.

Preferably, the upper sleeve wall and the lower sleeve wall in the detachable clamping device are both semi-cylindrical tubular, and at one end where the test piece is located, the lower sleeve wall protrudes from the upper sleeve wall and as the supporting structure.

Preferably, the thickness of the upper sleeve wall and the lower sleeve wall are both 1 mm, the length of the upper sleeve wall is 5 cm, and the length of the lower sleeve wall is 7.5 cm.

Preferably, the connection structure includes: a flange at the free edge of the upper sleeve and the lower sleeve, the flanges are parallel to each other when the upper and lower sleeves are closed, and two identical flanges are located at the same position of the upper and lower flanges The size of the threaded hole for the insertion of bolts for connection.

Preferably, the materials of the detachable clamping device and the side positioning parts are all stainless steel.

Preferably, the side positioning member is in the shape of a semicircle, the width along the length direction of the incident rod is 2.5 cm, and the thickness along the radial direction of the incident rod is related to the size of the matched test piece, and its thickness=(Hopkinson incident Rod diameter D-test piece diameter d)/2.

The beneficial effects of the utility model are reflected in:

1) The detachable clamping device has a simple structure and low manufacturing cost, which is conducive to mass production and popularization.

2) Installation and disassembly are easy to operate, and at the same time, the positioning accuracy of the device can be guaranteed.

3) The use of side positioning parts with different radial thicknesses can meet the positioning requirements of test pieces of different sizes, and has a wide range of applications.

4) This device is an auxiliary device other than the Hopkinson bar test platform, which is convenient for regular maintenance and replacement after damage.

Description of drawings

Fig. 1 is a three-dimensional structure schematic diagram of the utility model.

Fig. 2 is a front view of the utility model.

Fig. 3 is a side view of the utility model.

Fig. 4 is an apparatus view of a test piece with a diameter of 80 mm.

Fig. 5 is an apparatus view of a test piece with a diameter of 75 mm.

Fig. 6 is an apparatus view of a test piece with a diameter of 50 mm.

In the figure, 1-Hopkinson incident rod, 2-upper sleeve wall, 3-lower sleeve wall, 30-support structure, 4-flange, 5-connecting bolt, 6-nut, 7-side Side positioning piece, 8-test piece, 9-leaf hinge, transmission rod-10.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is further described.

A separate Hopkinson pressure bar positioning device suitable for multi-size test pieces, as shown in Figures 1 and 2, includes a detachable clamping device and a side positioning piece 7. The detachable clamping device is composed of an upper sleeve wall 2 and a lower sleeve wall 3, both of which are semi-cylindrical and made of stainless steel. 1 have the same diameter and a thickness of 1 mm, the upper sleeve wall 2 is 5 cm long, and the lower sleeve wall 3 is provided with a support structure 30 protruding from the upper sleeve wall 2 at the end where the test piece 8 is located. In order to support the side positioning part 7, the length of the lower sleeve wall 3 is 7.5 cm. One side of the upper side sleeve wall 2 and the lower side sleeve wall 3 are connected as a whole through a hinge 9, and the other side can be opened and closed as required.

When in use, first put the upper and lower sleeve walls on the end where the incident rod is in contact with the test piece, so that the rightmost end of the upper sleeve wall coincides with the rightmost end of the incident rod, and then close the upper and lower sleeve walls 2 and 3 so that The flanges 4 of the upper and lower sleeve walls are parallel to each other, insert the connecting bolt 5 on the upper side of the corresponding two bolt holes, and tighten the nut 6 on the lower side, so as to fix the upper and lower sleeve walls 2 and 3 at the incident on pole 1.

The side positioning part 7 is a semi-circular ring-shaped stainless steel member, and its outer diameter is the same as the inner diameter of the lower side sleeve wall 3, as a surface that cooperates with the support structure 30, and its inner side is a test piece positioning arc surface in contact with the test piece . The size of the side positioning parts used for different diameters of the test piece is different. The width along the length direction of the incident rod is 2.5cm, and the height is half of the diameter of the incident rod. The thickness is adjusted according to the diameter of the test piece:

When the diameter of the incident rod is 100mm and the diameter of the test piece is 80mm, a side positioning piece with a thickness of 10mm can be used, as shown in Figure 3;

When the diameter of the incident rod is 100 mm and the diameter of the test piece is 75 mm, a side positioning piece with a thickness of 12.5 mm can be used, as shown in Figure 4;

When the diameter of the incident rod is 100 mm and the diameter of the test piece is 50 mm, a side positioning piece with a thickness of 25 mm can be used, as shown in Figure 5;

Put the corresponding side positioning piece 7 into the end of the lower sleeve 3 protruding from the upper sleeve wall 2, and make the left side of the side support close to the right end surface of the incident rod 1, and then on the side Place the test piece 8 above the positioning piece, push the transmission rod 10 to the left, so that the left end surface of the transmission rod 10 is in close contact with the right end surface of the test piece 8, then loosen the nut 6, and take out the connecting bolt 5 from the screw hole , so that the upper and lower side sleeves and side positioning parts are taken out from the Hopkinson pressure bar device. At this time, the specimen 8 clamped between the incident rod 1 and the transmission rod 10 has been accurately positioned to ensure that the center of the specimen 8 It is on a straight line with the center of incident rod 1 and transmission rod 10 .

The above is only a specific embodiment of the utility model, but the structural features of the utility model are not limited thereto, and any changes or modifications made by those skilled in the art within the scope of the utility model are covered by the utility model. In the new protection scope.

Claims (6)

1. a kind of split hopkinson press bar positioning device suitable for more size test specimens, which is characterized in that including detachable Formula clamping device and the side tabs to match with specimen finish and incident bar diameter difference；The removable holding device It being made of upper sleeve wall, lower sleeve wall, upper sleeve wall and being connected by a hinge on one side for lower sleeve wall become whole, Another side can be opened and closed as needed and be provided with connection structure；The upper sleeve wall, lower sleeve wall internal diameter with enter The diameter for penetrating bar is equal, and the lower sleeve wall is provided with the support construction for supporting the side tabs；The side is fixed Position part, which is provided with, positions arc surface with the face of support construction cooperation and the test specimen contacted with test specimen.

2. a kind of split hopkinson press bar positioning device suitable for more size test specimens according to claim 1, It is characterized in that, upper sleeve wall and lower sleeve wall are semicolumn tubulose in the removable holding device, in test specimen institute The one end at place, lower sleeve wall protrude from upper sleeve wall and as the support constructions.

3. a kind of split hopkinson press bar positioning device suitable for more size test specimens according to claim 1, It is characterized in that, the thickness of the upper sleeve wall and lower sleeve wall is 1mm, the long 5cm of upper sleeve wall, and lower sleeve wall is long 7.5cm。

4. a kind of split hopkinson press bar positioning device suitable for more size test specimens according to claim 1, It is characterized in that, the connection structure includes: to have a flange at the free margins of upper sleeve and lower sleeve respectively, when upper and lower sides set The flange is parallel to each other when cylinder closure, and the screwed hole of two same sizes, is used at upper lower flange same position Insertion bolt is attached.

5. a kind of split hopkinson press bar positioning device suitable for more size test specimens according to claim 1, It is characterized in that, the material of the removable holding device and side tabs is stainless steel.

6. a kind of split hopkinson press bar positioning device suitable for more size test specimens according to claim 1, It is characterized in that, the side tabs are semi-annular shape, and the width along incident bar length direction is 2.5cm, along incident bar diameter To thickness it is related with the sample dimensions to match, thickness=(Hopkinson incidence shank diameter D- test specimen diameter d)/2.