Acoustic emission sensor installation and protection device

Abstract

The utility model provides an acoustic emission sensor installation and protection device, which is characterized in that an acoustic emission device is installed in a protection assembly, and the protection assembly is installed on an installation base; the mounting base comprises a metal positioning ring and a fixed magnetic ring; the protection assembly comprises a metal sleeve, one end of the metal sleeve is installed on the fixed magnetic ring, and the other end is connected with a top cover. A shielding cushion layer is arranged on the inner wall of the metal sleeve; an elastic unit is arranged in the top cover; the acoustic emission device comprises an acoustic emission sensor, and the acoustic emission sensor is connected with a data transmission line; the front end of the acoustic emission sensor is mounted in the middle of the metal positioning ring and is in direct contact with the rock sample for acoustic emission testing. According to the utility model, the damage possibly caused to the acoustic emission sensor in the rock damage experiment process can be effectively prevented, meanwhile, the interference of static electricity and other interference sources on acoustic emission signal sampling is effectively shielded, the stability in the installation process is improved, and the installation failure of the acoustic emission sensor caused by misoperation is reduced.

Description

Technical Field

[0001] The utility model relates to a rock mechanics experiment monitoring device, in particular to an acoustic emission sensor installation and protection device. Background Technique

[0002] In order to study the dynamic mechanical response characteristics of rock failure under different conditions, it is necessary to use a new type of high-pressure servo dynamic true triaxial rockburst testing machine, electro-hydraulic servo conventional triaxial testing machine, etc. to conduct rock loading experiments. In the experiment, an acoustic emission system can be used to capture the acoustic emission signals released during the crack propagation process when the rock sample is loaded, so as to more intuitively observe and analyze the rock failure process. However, in order to obtain clearer and more accurate acoustic emission signals, the acoustic emission sensor needs to be closely attached to the surface of the rock sample during the experiment. When the rock sample is damaged under pressure, serious ejection may occur, causing certain damage to the acoustic emission sensor. In severe cases, the fixture may fall off, causing a violent impact on the surrounding acoustic emission sensors. Since the acoustic emission sensor is very fragile and expensive, this process may render the acoustic emission sensor unusable and require replacement, resulting in a large economic loss and affecting further experiments. In addition, due to the inconvenient installation of the acoustic emission sensor, it is difficult to ensure that the sensor is closely attached to the rock sample, and abnormal electrostatic signals may interfere with the normal acoustic emission signal sampling. A large amount of time is often wasted during the sample installation process in the early stage of the experiment, greatly reducing the experimental efficiency and the accuracy of acoustic emission signal sampling. At present, there is no installation device that can meet the stability requirements and protection requirements of acoustic emission sensors in rock loading tests under different conditions.

[0003] CN107219122B provides an acoustic emission monitoring device for a true triaxial testing machine and its test method. The relevant acoustic emission protection device can effectively protect the acoustic emission sensor from damage caused by rock debris and can shield some interference signals, but the structure is not easy to install, and it is difficult to achieve the condition of suspending the waveguide rod on other testing machines, so the use conditions are limited; CN105928776B provides an acoustic emission sensor installation device for a true triaxial hydraulic fracturing simulation experiment. The acoustic emission protection device in it is not convenient to install due to its large volume, and the use scenario is relatively limited. Moreover, due to the use of a separated connection between the sensor and the rock sample, the sensor and the rock sample cannot be in direct contact, which to a certain extent reduces the number of acoustic emission signals received by the acoustic emission sensor and is not suitable for rock loading tests where the installation space is limited and the acoustic emission sensor needs to be in direct contact with the surface of the rock sample; CN220473453U provides an acoustic emission monitoring and protection device, which is suitable for acoustic emission signal acquisition in outdoor sites and focuses on the protection function of the acoustic emission sensor and is not suitable for acoustic emission applications during experiments.

[0004] To solve the above problems, it is necessary to establish an acoustic emission sensor protection device in rock loading experiments to prevent damage to the acoustic emission sensor when the rock sample is damaged, reduce the economic losses caused by replacing the acoustic emission sensor, shield the surrounding electromagnetic signals to improve the accuracy of acoustic emission signal sampling, and simplify the installation process of acoustic emission to improve the experimental efficiency.

[0005] In response to the above requirements, an acoustic emission sensor protection device applied to different rock loading experiments is designed, which has quite practical significance in the existing rock loading experiments. Utility Model Content

[0006] The purpose of the present utility model is to provide an acoustic emission sensor installation and protection device, which can effectively prevent damage to the acoustic emission sensor that may occur during the rock destruction experiment, effectively shield the interference of static electricity and other interference sources to the acoustic emission signal sampling, and improve the stability of the installation process, reducing the failure of acoustic emission sensor installation caused by operation errors, thus affecting the experimental results.

[0007] To achieve the above purpose, the present utility model provides an acoustic emission sensor protection device for performing acoustic emission tests on rock specimens; it includes an installation base, a protection component, and an acoustic emission device; the acoustic emission device is installed in the protection component, and the protection component is installed on the installation base;

[0008] The installation base includes a metal positioning ring and a fixed magnetic ring;

[0009] The protection component includes a metal sleeve, one end of the metal sleeve is installed on the fixed magnetic ring, and the other end is connected with a top cover; a shielding cushion layer is provided on the inner wall of the metal sleeve, and an elastic unit is provided in the top cover;

[0010] The acoustic emission device includes an acoustic emission sensor, and the acoustic emission sensor is connected with a data transmission line;

[0011] The front end of the acoustic emission sensor is installed in the middle of the metal positioning ring, directly contacts the rock sample for acoustic emission testing, collects acoustic emission signals and transmits the collected signals to the data recording device through the connected data transmission line; the rear end of the acoustic emission sensor is placed in the metal sleeve, and the data transmission line extends out through the opening of the metal sleeve.

[0012] The metal sleeve, the fixed magnetic ring and the metal positioning ring are connected in a magnetic attraction manner; the metal positioning ring is fixed on the tested rock sample with strong glue and directly contacts the sample; the fixed magnetic ring is installed on the metal positioning ring for fixing the protection component part.

[0013] The contact part between the metal sleeve and the top cover is open, and the opening is U-shaped to allow the data transmission line to pass through; the shielding cushion layer is installed inside the metal sleeve to isolate abnormal signals generated by machine signals and electrostatic interference, which may affect the acquisition results. It also serves as a buffer to provide double protection for the acoustic emission sensor.

[0014] The shielding cushion layer is made of the insulating elastic material silicone.

[0015] The metal positioning ring is a replaceable part.

[0016] The fixed magnetic ring is made of neodymium iron boron strong magnet with a maximum magnetic energy product greater than N35.

[0017] The utility model is convenient for disassembly, avoiding the direct impact on fragile components such as the fixed magnetic ring and the acoustic emission sensor, which may cause damage. The acoustic emission sensor in this device is arranged in the cavity formed by the combination of the metal positioning ring, the fixed magnetic ring and the metal sleeve, greatly reducing the contact with the outside world. This not only reduces the probability of malfunction due to external impact, extends the replacement cycle of the acoustic emission sensor, but also significantly improves the signal-to-noise ratio of the acoustic emission signal and reduces the difficulty of acoustic emission signal processing. Brief Description of the Drawings

[0018] Figure 1 It is a schematic diagram of the overall structure of the device of the utility model;

[0019] Figure 2 It is a schematic diagram of the structures of the various components of the device of the utility model;

[0020] Figure 3 It is a schematic sectional view of the utility model;

[0021] Figure 4 It is an installation schematic diagram of Embodiment 1;

[0022] Figure 5 It is an installation schematic diagram of Embodiment 2;

[0023] Among them, 1 - installation base; 101 - metal positioning ring; 102 - fixed magnetic ring; 2 - protection component; 201 - metal sleeve; 202 - top cover; 203 - shielding cushion layer; 204 - elastic unit; 3 - acoustic emission device; 301 - acoustic emission sensor; 302 - data transmission line. Detailed Embodiment

[0024] The specific technical solution of the utility model will be described in conjunction with the drawings.

[0025] Exemplarily, the preferred embodiments of the present invention will be described in more detail below in conjunction with the accompanying drawings. The specific implementation manners and functional features of the present invention will be more clearly illustrated through the following description. It should be noted that the following drawings are all drawn in non-precise proportions and in a relatively simplified manner, and do not represent real devices, but are only used to clearly and conveniently describe the structure and purpose of the present invention.

[0026] Embodiment 1

[0027] As Figure 1 、 Figure 2 and Figure 3 shown, the present invention provides an acoustic emission sensor installation and protection device for collecting acoustic emission signal data of a rock specimen on a flat surface, including an installation base 1, a protection component 2 is installed on the installation base, and an acoustic emission device 3 is installed in the cavities of the installation base 1 and the protection component 2.

[0028] The installation base 1 includes a metal positioning ring 101 and a fixed magnetic ring 102. One end of the metal positioning ring 101 is fixed on the surface of the rock sample by strong glue or other means, and the other end magnetically attracts and installs the fixed magnetic ring 102.

[0029] The metal positioning ring 101 should be made of a metal with good toughness and magnetism.

[0030] The fixed magnetic ring 102 is made of a magnet with a maximum magnetic energy product above N35.

[0031] The protection component 2 includes a metal sleeve 201. One end of the metal sleeve 201 is U-shaped and open, and the non-open end magnetically attracts and installs on the fixed magnetic ring 102; the inside of the metal sleeve is integrally coated with a shielding cushion layer 203. A bolt is provided at the lower part of the top cover 202, which can be fixed at the nut on the inner side of the upper part of the metal sleeve 201; an elastic unit 204 is fixedly bonded with strong glue on the inner side of the top cover 202.

[0032] In this embodiment, both the shielding cushion layer 203 and the elastic unit 204 are made of highly elastic silicone materials. In this example, after the device is installed, the shielding cushion layer 203 and the elastic unit 204 can isolate the acoustic emission sensor 301 from the metal sleeve 201, thereby absorbing the external impact kinetic energy and isolating the static electricity signals that may appear during the experiment.

[0033] In this embodiment, the thickness of the elastic unit 204 is slightly greater than the distance between the rear end of the acoustic emission sensor 301 and the top cover 202 when the top cover 202 is installed. When the top cover 202 is fixed on the metal sleeve 201, the elastic unit 204 is compressed by force, and at the same time, a reaction force perpendicular to the end face of the sensor is generated to ensure that the acoustic emission sensor 301 is in close contact with the surface of the rock sample.

[0034] It should be noted that when collecting acoustic emission signals during rock fracturing experiments, the acoustic emission sensor 301 is installed in the acoustic emission sensor installation and protection device; during the process of loading the rock sample by the testing machine, the rock sample emits acoustic emission signals, which are collected by the acoustic emission sensor 301 and transmitted to the signal acquisition terminal, such as a computer, through the data transmission line 302 and an amplifier, and the collected acoustic emission signals are analyzed and further processed by the acquisition terminal.

[0035] Specifically, as Figure 4 shown, when using the above-mentioned acoustic emission device 3 to collect acoustic emission signals, the acoustic emission sensor 301 should be in close contact with the surface of the rock sample to reduce signal loss during the acoustic emission signal sampling process. To ensure full contact between the acoustic emission sensor 301 and the surface of the rock sample, when installing the acoustic emission sensor 301, an appropriate amount of coupling agent should be applied to the end face of the acoustic emission sensor 301 to improve the signal-to-noise ratio of signal transmission; at the same time, the thickness of the elastic unit 204 attached to the inner side of the metal top cover 202 should be slightly greater than the distance between the top cover 202 and the end face of the acoustic emission sensor 301. When the top cover 202 is installed on the metal sleeve 201, the elastic unit 204 is compressed to generate a reaction force on the acoustic emission sensor 301, ensuring close fit between the acoustic emission sensor 301 and the surface of the rock sample.

[0036] In this embodiment, the acoustic emission sensor 301 is connected to the data recording device in a wired manner, and the acquired acoustic emission data is transmitted through the data transmission line 302.

[0037] The installation process of the acoustic emission sensor protection device in this embodiment during the rock loading experiment can be as follows: install the rock sample at the designated position on the testing machine, determine the specific position for installing the acoustic emission sensor 301 on the rock sample; fix the metal positioning ring 101 at this position using strong glue; install the fixed magnetic ring 102 on the metal positioning ring 101; install the metal sleeve 201 on the fixed magnetic ring 102; apply an appropriate amount of coupling agent to the end of the acoustic emission sensor 301 and connect the acoustic emission data transmission line 302 to the acoustic emission sensor 301; install the acoustic emission sensor 301 in the cavity formed by the metal positioning ring 101, the fixed magnetic ring 102 and the metal sleeve 201, and pay attention to the close fit between the end of the sensor and the surface of the rock sample during installation; install the top cover 202 at the opening of the metal sleeve 201 and fix it.

[0038] Embodiment 2

[0039] In order to adapt to installations under different-shaped contact surface conditions, the installation conditions for acoustic emission can be met by changing some components in the protection device. Exemplarily, the sensor installation and protection device (i.e., Embodiment 2) after changing the components will be described below with reference to the accompanying drawings.

[0040] In the experiment, there are sometimes cases where the installation surface is a curved surface. In such cases, it is generally difficult to fix the acoustic emission probe installed, and it is easy to fall off. In this embodiment, the shape of the contact surface between the metal positioning ring 101 and the installation surface is mainly changed to increase the degree of fit between the two, providing necessary support and limitation for the acoustic emission probe to ensure the normal acquisition of acoustic emission signals.

[0041] Exemplarily, Figure 5 It is an installation instruction diagram for Embodiment 2. The metal positioning ring 101 improves the degree of fit with the curved installation surface by changing the bottom surface shape and is installed on the installation surface with strong glue. The gap between the acoustic emission probe and the curved surface is filled with a coupling agent.

[0042] Specifically, for an acoustic emission sensor installation and protection device in this embodiment, its installation method and function are basically the same as those in Embodiment 1, and no detailed description will be given in this embodiment.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: within the scope of the technical solutions of the present invention, if some or all of the technical features are equivalently replaced, or the technical solutions recorded in the foregoing embodiments are modified, the essence of the corresponding technical solutions does not deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An acoustic emission sensor installation and protection device, characterized in that, It includes an installation base (1), a protection component (2) and an acoustic emission device (3); the acoustic emission device (3) is installed inside the protection component (2), and the protection component (2) is installed on the installation base (1); The installation base (1) includes a metal positioning ring (101) and a fixed magnetic ring (102); The protection component (2) includes a metal sleeve (201), one end of the metal sleeve (201) is installed on the fixed magnetic ring (102), and the other end is connected with a top cover (202); a shielding cushion layer (203) is arranged on the inner wall of the metal sleeve (201), and an elastic unit (204) is arranged inside the top cover (202); The acoustic emission device (3) includes an acoustic emission sensor (301), and the acoustic emission sensor (301) is connected with a data transmission line (302); The front end of the acoustic emission sensor (301) is installed in the middle of the metal positioning ring (101), directly contacts with the rock sample for acoustic emission testing, collects acoustic emission signals and transmits the collected signals to the data recording device through the connected data transmission line (302); the rear end of the acoustic emission sensor (301) is placed inside the metal sleeve (201), and the data transmission line (302) extends out through the opening of the metal sleeve (201).

2. The acoustic emission sensor installation and protection device according to claim 1, characterized in that The metal sleeve (201), the fixed magnetic ring (102) and the metal positioning ring (101) are connected in a magnetic attraction manner; the metal positioning ring (101) is fixed on the rock sample to be measured with strong glue.

3. The acoustic emission sensor installation and protection device according to claim 1, characterized in that: The shielding cushion layer (203) is made of an insulating elastic material, silicone rubber.

4. The acoustic emission sensor installation and protection device according to claim 1, characterized in that: The metal positioning ring (101) is a replaceable part.

5. The acoustic emission sensor installation and protection device according to claim 1, characterized in that: The fixed magnetic ring (102) is made of neodymium iron boron strong magnet with a maximum magnetic energy product greater than N35.

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