CN106918515A - Particulate matter one-dimension stress wane attenuation effect experimental rig - Google Patents

Abstract

The invention discloses a test device for one-dimensional stress wave attenuation effect of granular matter, which comprises an incident rod (2), a transmission rod (3) and an absorption rod (4) arranged coaxially in sequence along the bullet (1) exit direction, and also includes a sleeve Sleeve (5), the sleeve (5) contains particulate matter (51), one end of the sleeve (5) is loosely fitted on the incident rod (2), and the other end is loosely fitted on the transmission rod (3) . The one-dimensional stress wave attenuation effect test device for granular matter of the present invention has adjustable test piece length and high test efficiency.

Description

Test device for one-dimensional stress wave attenuation effect of particulate matter

technical field

The invention belongs to the technical field of material dynamics test, in particular to a one-dimensional stress wave attenuation effect test device for granular matter with adjustable test piece length and high test efficiency.

Background technique

At present, occasional explosion disasters such as gas explosions and terrorist attacks occur frequently, and the stress waves generated by explosions often cause damage and damage to engineering structures, and even collapse. Particulate matter (such as sand, soil, etc.) is low in cost, easy to obtain, and has the characteristics of being porous and easy to compress, so that the stress wave will obviously attenuate during the process of propagating in it, which makes granular matter often used as a construction project. The protective layer to reduce the possible stress wave impact. However, the current theoretical models used to describe the propagation of stress waves in granular matter are mostly based on continuum mechanics, but in fact the granular matter itself is discontinuous, which makes the theoretical description of the phenomenon inaccurate and requires experimental data to provide support for the theory.

The Split Hopkinson Pressure Bar (SHPB) device is currently the main device for measuring various dynamic mechanical properties of materials, and is generally used to obtain various dynamic mechanical parameters of materials under high strain rates. For example, the Chinese invention patent "SHPB automatic rod impact loading test device under high temperature conditions" (application number: 201310684780.1, publication date: 2014.3.26, authorization announcement date: 2015.12.30). In addition, the device can also be used to measure the attenuation effect of stress wave propagation in materials (such as rocks). By sandwiching the test material between the incident rod and the transmission rod, the test compares the incident wave transmitted wave to analyze the stress wave in the specimen. The attenuation of the test method itself limits the scope of application of the test material to continuous solid materials, and for particulate matter, it is loose and discontinuous, and simple placement cannot guarantee the shape of the test piece, nor can it be fixed. Between the two rods, it is impossible to ensure sufficient contact between the test piece and the end faces of the two rods, so that the test cannot be carried out. Therefore, the existing experimental devices cannot test the attenuation characteristics of the stress wave along the axial direction of the specimen when the particulate matter is subjected to the axial one-dimensional stress wave.

In conclusion, the problem in the prior art is that there is a lack of devices for testing the axial stress wave attenuation characteristics of particulate matter.

Contents of the invention

The object of the present invention is to provide a test device for one-dimensional stress wave attenuation effect of granular matter, with adjustable test piece length and high test efficiency.

The technical solution that realizes the object of the present invention is:

A device for testing the one-dimensional stress wave attenuation effect of particulate matter, comprising an incident rod, a transmission rod, and an absorption rod arranged coaxially in sequence along the ejection direction of the bullet, and a sleeve, the sleeve contains particulate matter, and one end of the sleeve is The loose fit fits over the entrance rod and the other loose fit fits over the transmission rod.

As an improvement, a spacer is provided at both ends of the particulate matter in the sleeve, and the spacer is loosely fitted with the sleeve to encapsulate the particulate matter in the sleeve, one of which is pressed against the incident rod, and the other A spacer is pressed against the transmission rod.

Compared with the prior art, the present invention has the remarkable advantages of:

1. Applicable to granular materials: suitable for stress wave attenuation tests when various materials are laterally restricted, especially for granular materials;

2. The length of the test piece is adjustable: the length of the test piece can be adjusted by changing the position of the pad in the sleeve, without replacing a new sleeve;

3. High test efficiency: less test piece materials are required for the test, saving cost and space, greatly saving test time and improving test efficiency;

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Description of drawings

Fig. 1 is a front view of the device for testing the stress wave attenuation effect of particulate matter in the present invention.

Fig. 2 is an axial sectional view of the sleeve in Fig. 1 .

Fig. 3 is a radial sectional view of the spacer in Fig. 1 .

In the figure, 1 bullet, 2 incident rod, 3 transmission rod, 4 absorption rod, 5 sleeve, 51 particulate matter, 52, 53 spacer, 61 first strain gauge, 62 second strain gauge, 71 first Wheatons Bridge, 72 Second Wheatstone Bridge, 8 Amplifier, 9 Oscilloscope.

detailed description

As shown in Figures 1-3, the test device for the one-dimensional stress wave attenuation effect of particulate matter of the present invention includes an incident rod 2, a transmission rod 3 and an absorption rod 4 arranged coaxially along the direction of bullet 1 emission, and also includes a sleeve 5, The sleeve 5 contains particulate matter 51 , one end of the sleeve 5 is loosely fitted on the incident rod 2 , and the other end is loosely fitted on the transmission rod 3 .

As an improvement, one is provided at both ends of the particulate matter 51 in the sleeve 5, and the pads 52, 53 are loosely fitted with the sleeve 5 to encapsulate the particulate matter 51 in the sleeve 5, and one of the pads 52 It is pressed against the incident rod 2 , and another spacer 53 is pressed against the transmission rod 3 .

As a further improvement, multiple pairs of sleeve screw holes 54 are provided along the axis on the sleeve 5, and each pair of sleeve screw holes 54 is symmetrical about the axis. Hole 54 has the same diameter as spacer screw holes 55,56.

The screw holes 55, 56 of the pads have the same diameter and pitch as the screw holes 54 of the sleeve.

A first strain gauge 61 is pasted on the incident rod 2, and its output end is electrically connected with the amplifier 8 through a first Wheatstone bridge 71; a second strain gauge 62 is pasted on the described transmission rod 3, and its output end is connected through the The second Wheatstone bridge 72 is electrically connected to the amplifier 8 ; said amplifier 8 is electrically connected to the oscilloscope 9 .

The sleeve 5 is cylindrical and made of steel, and its purpose is to ensure the one-dimensional strain state of the test piece during the test.

The pads 52, 53 loosely fit the sleeve 5 to encapsulate the particulate matter 51 in the sleeve 5. The inner diameter of the sleeve 5 is slightly larger than the pads 52, 53, allowing the pads 52, 53 and the rod to rotate freely therein ,slide. Several sections are selected on the sleeve, and each section is provided with a group of screw holes, one group of two, symmetrical to the axial direction, and similarly, a group of screw holes is provided on the spacer. The screw hole and the screw hole of the sleeve have the same diameter and pitch, and the position of the pad in the sleeve is adjusted by tightening the bolt, thereby changing the length of the test piece.

The bullet 1, the incident rod 2, the transmission rod 3, the absorbing rod 4 and the pads 52, 53 are made of the same material, have the same diameter and are coaxial.

One end of the incident rod 2 away from the sleeve 5 faces the bullet 1 coaxial therewith, and the bullet 1 is arranged in the bullet launching mechanism.

The end of the transmission rod 3 away from the sleeve 5 is in contact with the coaxial absorption rod 4 , and the end of the absorption rod 4 away from the transmission rod 3 is connected to the kinetic energy absorbing device.

The experimental operation steps are:

1. Calibrate the rods to ensure that the incident rod 2, the transmission rod 3, and the absorption rod 4 are coaxial and not eccentric;

2. Put a pad 52 into the sleeve 5 to the predetermined position, and screw the bolt into the screw hole to lock it;

3. Weigh the test material with a predetermined weight, and then pour it into the sleeve 5 with the spacer 52 fixed;

4. After the test piece is completely poured in, smooth its upper end, then put the second block 53 into the predetermined position, and lock it with bolts. At this time, the test piece is covered by the sleeve 5 and the two spacers 52, 53 lock;

5. Put the test piece locked by the sleeve 5 and the two pads 52, 53 to the predetermined test position, and push the incident rod 2 and the transmission rod 3 into the sleeve respectively, so that the incident rod 2, the transmission rod 3 and the The pads 52 and 53 fit closely together, and then push the absorbing rod 4 to make it close to the transmitting rod 3;

6. Remove the two pairs of bolts fixing pads 52, 53 and sleeve 5;

7. Turn on the transmitter, launch the bullet 1, and start the high-speed impact experiment;

8. The data collected by the strain gauges 61 and 62 attached to the incident rod 2 and the transmission rod 3 are displayed on the oscilloscope 9 after passing through the Wheatstone bridge 71, 72 and the amplifier 8, and the data on the oscilloscope 9 are preserved, and then carried out Analytical processing.

Claims (5)

1. a kind of particulate matter one-dimension stress wane attenuation effect experimental rig, including sequentially coaxially set along bullet (1) exit direction Incident bar (2), transmission bar (3) and the absorbing rod (4) put, it is characterised in that：

Also include sleeve (5), the built-in particulate matter of the sleeve (5) (51), the sleeve (5) one end loose fit is sleeved on incidence On bar (2), other end loose fit is sleeved on transmission bar (3).

2. experimental rig according to claim 1, it is characterised in that：

A cushion block (52,53), the cushion block (52,53) and set are respectively arranged at the two ends with the sleeve (5) no particulate matter (51) Loosely be encapsulated in particulate matter (51) in sleeve (5) by cylinder (5), and one of cushion block (52) pushes against with incident bar (2), separately One cushion block (53) pushes against with transmission bar (3).

3. experimental rig according to claim 2, it is characterised in that：

Multipair sleeve screw (54) is provided with along axis on the sleeve (5), each pair sleeve screw (54) is symmetric about the axis, Each cushion block (52,53) is provided with and sleeve screw (54) diameter identical cushion block screw (55,56).

4. experimental rig according to claim 3, it is characterised in that：

The cushion block through hole (54,55) is screw, and the diameter of its diameter, pitch and sleeve screw (54), pitch are identical.

5. experimental rig according to claim 1, it is characterised in that：

The first foil gauge (61) is posted on the incident bar (2), its output end passes through this electric bridge (71) of the first Huitong and amplifier (8) electrically connect；

The second foil gauge (62) is posted on the transmission bar (3), its output end passes through this electric bridge (72) of the second Huitong and amplifier (8) electrically connect；

The amplifier (8) electrically connects with oscillograph (9).