Acoustic emission probe fixing device and method for rock mechanical test

Abstract

The invention belongs to the technical field of rock mechanics tests, and particularly relates to an acoustic emission probe fixing device and method for a rock mechanics test, the device adopts the design of multi-direction movement adjustment, elastic clamping buffering, negative pressure fitting and pressure closed-loop control, and positioning is achieved through a three-stage movement device; the clamping device has radial elastic clamping, axial pre-compression buffering and negative pressure adsorption functions and is matched with dynamic adjustment of a pressure sensor and a negative pressure generator to ensure that the probe is attached to a rock test piece; the method follows the processes of test piece pretreatment, precise positioning, clamping buffering, negative pressure fitting and pressure calibration, reliable fixing can be achieved without a coupling agent, full-dimension positioning is achieved through a three-stage moving device, the clamping device integrates the two-way elastic buffering and negative pressure adsorption functions, real-time monitoring and dynamic adjustment are achieved in cooperation with a pressure sensor, and the working efficiency is improved. The stable attachment of the acoustic emission probe and the rock test piece is ensured, and the accuracy and reliability of acoustic signal acquisition are remarkably improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of rock mechanics test, and particularly relates to a rock mechanics test acoustic emission probe fixing device and method. BACKGROUND

[0002] In the rock mechanics test, the acoustic emission technology is a core means for monitoring the internal damage evolution and crack expansion of the rock, and the acoustic emission probe, as a key component for signal collection, directly determines the accuracy and reliability of signal collection. In the current prior art, the acoustic emission probe fixing mode has two core technical defects: Firstly, the traditional fixing mode relies on manual positioning and a single clamping structure, and it is difficult to realize accurate adjustment in all dimensions, resulting in low alignment accuracy of the probe and the detection surface of the rock specimen, and lacking effective adhesion strengthening mechanism, and the test vibration easily causes gaps between the probe and the specimen, causing serious attenuation of the acoustic signal, and even missing the micro-damage signal; secondly, the high-frequency vibration generated in the rock mechanics test and the specimen crushing debris easily impact the probe, and the existing device lacks a buffer structure, and only relies on a simple shell or a single spring buffer, which cannot effectively disperse the impact stress; the adhesion pressure of the probe and the specimen cannot be monitored and dynamically adjusted in real time, and excessive pressure easily damages the specimen, and insufficient pressure leads to loose contact, further affecting the signal collection quality.

[0003] In view of the above technical problems, a rock mechanics test acoustic emission probe fixing device and method are needed to break through the bottleneck of the prior art. SUMMARY

[0004] In view of the above deficiencies in the prior art, the application provides a rock mechanics test acoustic emission probe fixing device and method to solve the problems in the background art.

[0005] In order to solve the above technical problems, the application adopts the following technical scheme: A rock mechanics test acoustic emission probe fixing method, comprising the following steps: S1: polishing the detection surface of the rock specimen, and marking the adhesion area on the detection surface according to the detection requirement; S2: moving the acoustic emission probe by moving and cooperatively adjusting the fixing device, so that the acoustic emission probe is aligned with the detection surface of the rock specimen; S3: placing the acoustic emission probe in the clamping device, applying clamping force to the acoustic emission probe by the clamping device, and providing buffer protection by the buffer assembly; S4: tightly adhering the acoustic emission probe to the detection surface; monitoring the adhesion pressure by the pressure sensor, adjusting the negative pressure value to keep the adhesion pressure stable, and completing the fixing.

[0006] Further, the detection surface of the rock test piece is polished by using multi-gauge sandpaper to polish the detection surface step by step, and the surface dust, protrusions and loose particles are removed.

[0007] Further, the mobile cooperative adjustment realizes the multi-directional mobile adjustment, and the mobile devices are locked after positioning.

[0008] Further, the sealing cavity is formed between the fitting part on the clamping device and the detection surface, and the negative pressure is formed by extracting the air in the sealing cavity to realize the fitting.

[0009] Further, the control is formed by the pressure sensor and the negative pressure generator, and the air extraction amount is adjusted to stabilize the negative pressure value.

[0010] An acoustic emission probe fixing device for rock mechanics test, comprising a base, a first moving device fixed on the base, a second moving device fixed on the first moving device, a third moving device fixed on the second moving device, and a clamping device connected to the third moving device.

[0011] Further, the clamping device comprises a buffer shell, a stress guide groove is arranged on the buffer shell, an installation part is arranged in the buffer shell, a first spring is arranged on the inner side of the installation part in a circumferential direction, a clamping plate is arranged on the first spring, the clamping plate is arranged on the acoustic emission probe in a circumferential direction, a second spring is arranged at the bottom end of the acoustic emission probe, a rubber ring is arranged at the other end of the acoustic emission probe, a fitting part is arranged on the upper side of the rubber ring, a pressure sensor is connected to one side of the fitting part, a negative pressure interface is arranged on one side of the pressure sensor, the negative pressure interface penetrates through a fixed cover at one end, and the fixed cover is arranged at the bottom end of the buffer shell.

[0012] Further, a plurality of first springs are arranged in a circumferential direction, the clamping plate is in an arc structure, a friction plate is arranged on the clamping plate, and the friction plate is connected to the acoustic emission probe.

[0013] Further, the rubber ring is sleeved on the fitting end of the acoustic emission probe, the rubber ring is made of elastic wear-resistant material, the second spring is in a pre-compressed state, one end of the second spring is connected to the fixed cover, and the other end is connected to the bottom end of the acoustic emission probe.

[0014] Further, the negative pressure interface is connected to a negative pressure generator, the negative pressure interface penetrates through the fitting part, and the pressure sensor is electrically connected to the negative pressure generator.

[0015] Compared with the prior art, the present application has the following advantages: 1. The tertiary mobile device realizes full-dimensional mobile adjustment, cooperates with the detection surface mark positioning to ensure the accurate alignment of the probe and the detection surface; the sealed cavity formed by the negative pressure adsorption makes the probe and the detection surface closely adhere, and then the closed-loop control of the pressure sensor and the negative pressure generator dynamically maintains the stable adhesion pressure, solves the problems of large positioning deviation and signal attenuation caused by contact gap in the traditional fixed mode, and improves the accuracy of sound signal acquisition; 2. The stress guide groove of the buffer shell disperses the impact stress, the first spring provides radial elastic clamping and buffering, the second spring provides axial pre-compression buffering, and the rubber ring assists in buffering and sealing, forming a multiple buffering protection structure, effectively absorbing test vibration and debris impact energy, and avoiding fatigue failure of the piezoelectric element of the probe; 3. The combination structure of the first spring and the arc-shaped clamping plate can adapt to acoustic emission probes of different diameters through elastic deformation, without the need to replace clamping parts; the fixed process is clear, and the positioning, clamping, adhesion and calibration operations are simple, without the need to rely on the experience of operators, reducing the operation difficulty, improving the test efficiency, and being suitable for various rock mechanics test scenes. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a sectional view of the acoustic emission probe fixing device for rock mechanics test of the application; Figure 2 It is a three-dimensional structural schematic view of the acoustic emission probe clamping device and the negative pressure adhesion unit; Figure 3 It is Figure 2 It is a local enlarged view of A in FIG. 4; The reference signs in the drawings of the specification include: 1, first mobile device; 2, second mobile device; 3, clamping device; 4, third mobile device; 5, base; 301, buffer shell; 302, mounting; 303, fixed cover; 304, acoustic emission probe; 305, second spring; 306, first spring; 307, clamping plate; 308, stress guide groove; 309, negative pressure interface; 310, adhesion piece; 311, rubber ring; 312, pressure sensor. DETAILED DESCRIPTION

[0017] In order for those skilled in the art to better understand the present application, the technical solutions of the present application are further described below in combination with the drawings and examples.

[0018] Among them, the drawings are only used for exemplary description, and the representation is only a schematic diagram, not a physical diagram, and cannot be understood as a limitation on the present application; in order to better illustrate the embodiments of the present application, some components in the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0019] The same or similar reference numerals in the drawings of the embodiments of the present application correspond to the same or similar components; in the description of the present application, it is understood that if the terms "upper", "lower", "left", "right", "inner", "outer" and the like indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the terms describing the positional relationship in the drawings are only used for exemplary illustration, and cannot be understood as a limitation of the present application, for those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0020] In the description of the present application, unless otherwise explicitly specified and limited, if the term "connection" and the like indicating the connection relationship between components appears, the term should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two components or the interaction relationship between two components. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0021] Embodiment one: As Figures 1-3 shown, the present application is a rock mechanics test acoustic emission probe fixing method, comprising the following steps: S1: polishing treatment of the detection surface of the rock test piece, marking the bonding area on the detection surface according to the detection requirement; Specifically, the polishing treatment of the detection surface of the rock test piece adopts multi-mesh sandpaper to polish the detection surface step by step, removes the surface dust, protrusions and loose particles, and ensures that the detection surface is flat and free of impurities; according to the test detection requirement, mark the bonding area on the treated detection surface with a marker pen, the area of the marked area is slightly larger than the area of the bonding end of the acoustic emission probe 304, which provides a clear reference for subsequent probe positioning and avoids positioning deviation.

[0022] S2: moving and cooperatively adjusting the fixing device to drive the acoustic emission probe 304 to move, so that the acoustic emission probe 304 is aligned with the detection surface of the rock test piece; Specifically, the mobile cooperative adjustment respectively realizes the multi-directional mobile adjustment, locks each mobile device after positioning, fixes the base 5 of the fixed device on the test table, ensures the stable installation of the whole device, cooperatively adjusts the first mobile device 1, the second mobile device 2 and the third mobile device 4, respectively realizes the movement in the X-axis, Y-axis and Z-axis directions, drives the synchronous movement of the clamping device 3 and the internal acoustic emission probe 304, accurately aligns the contact end of the acoustic emission probe 304 with the marked area of the rock specimen detection surface, locks the locking mechanism of each mobile device after positioning, prevents the position deviation caused by vibration during the test, and guarantees the positioning accuracy S3: Place the acoustic emission probe 304 in the clamping device 3, apply clamping force to the acoustic emission probe 304 through the clamping device 3, and simultaneously provide buffer protection through the buffer assembly; Specifically, open the fixed cover 303 of the clamping device 3, place the acoustic emission probe 304 into the installation piece 302, make the probe bottom end contact with the second spring 305, and align the probe contact end with the contact piece 310 after the rubber ring 311 is sleeved; the first spring 306 distributed on the inner side of the installation piece 302 is pushed to shrink towards the center of the probe under the action of elastic force, uniformly clamps the acoustic emission probe 304 in the radial direction, and realizes the stable fixation of the probe; at the same time, the second spring 305 in the pre-compressed state applies a continuous axial buffer force to the probe, cooperates with the stress guiding groove of the buffer shell 301, effectively absorbs the test vibration and impact energy, and avoids the damage of the probe caused by excessive clamping force or the loosening of the probe caused by vibration.

[0023] S4: Make the acoustic emission probe 304 tightly contact with the detection surface; monitor the contact pressure through the pressure sensor, adjust the negative pressure value to keep the contact pressure stable, and complete the fixation.

[0024] Specifically, the control is formed by the pressure sensor and the negative pressure generator, the air extraction amount is adjusted to stabilize the negative pressure value. After the contact piece 310 is aligned with the detection surface of the rock specimen, the rubber ring 311 and the contact piece 310 jointly form a sealed cavity; start the negative pressure generator, extract the air in the sealed cavity through the negative pressure interface 309 to generate negative pressure, under the action of negative pressure suction force, the contact end of the acoustic emission probe 304 tightly contacts with the detection surface, and the small gap between the contact surfaces is eliminated; the pressure sensor monitors the contact pressure data in real time and transmits it to the negative pressure generator, forms a closed loop control, adjusts the air extraction amount to stabilize the negative pressure value, keeps the contact pressure stable at all times, guarantees the tightness of the contact, avoids the damage of the specimen caused by excessive pressure, and completes the whole fixation process.

[0025] An acoustic emission probe fixing device for rock mechanics test, comprising a base 5, a first mobile device 1 fixed on the base 5, a second mobile device 2 fixed on the first mobile device 1, a third mobile device 4 fixed on the second mobile device 2, and a clamping device 3 connected to the third mobile device 4.

[0026] Specifically, the base 5 is the installation basis of the whole device, which is made of high-strength metal material, so that the deformation of the base caused by test vibration can be avoided; a plurality of fixing holes are arranged on the base, so that the base can be fixedly connected with a test table through bolts or expansion screws, and the installation requirements of different specifications of test tables can be met. The first moving device 1 of the three moving devices is fixed on the base, the second moving device 2 is fixed on the moving end of the first moving device, and the third moving device 4 is fixed on the moving end of the second moving device, so that the three moving devices can realize full-dimensional movement adjustment in X-axis, Y-axis and Z-axis directions; each moving device is provided with a locking mechanism, so that the moving end position can be fixed after adjustment through friction force, vibration displacement can be prevented, and positioning accuracy and reliability can be ensured.

[0027] Further, the clamping device 3 comprises a buffer shell 301, a stress guide groove 308 is arranged on the buffer shell 301, an installation piece 302 is arranged in the buffer shell 301, a first spring 306 is arranged on the inner side of the installation piece 302 in a circumferential direction, a clamping plate 307 is arranged on the first spring 306, the clamping plate 307 is arranged on the acoustic emission probe 304 in a circumferential direction, a second spring 305 is arranged at the bottom end of the acoustic emission probe 304, a rubber ring 311 is arranged at the other end of the acoustic emission probe 304, a fitting piece 310 is arranged on the upper side of the rubber ring 311, a pressure sensor 312 is connected to one side of the fitting piece 310, a negative pressure interface 309 is arranged on one side of the pressure sensor 312, one end of the negative pressure interface 309 penetrates through a fixed cover 303, and the fixed cover 303 is arranged at the bottom end of the buffer shell 301.

[0028] Specifically, the buffer shell 301 is made of high-strength wear-resistant material, and a stress guide groove 308 is arranged on the outer wall, so that external impact stress can be dispersed and conducted along the guide groove, and deformation or damage of the probe caused by stress concentration can be avoided; the installation piece 302 is fixed in the buffer shell and has a cylindrical structure, and a first spring mounting groove is arranged on the inner side for fixing the circumferentially distributed first spring 306, so that the clamping force can be ensured to be symmetrical and uniform.

[0029] Further, a plurality of first springs 306 are arranged in a circumferential direction, the clamping plate 307 has an arc-shaped structure, a friction plate is arranged on the clamping plate 307, and the friction plate is connected with the acoustic emission probe 304. Specifically, a plurality of first springs 306 are arranged in a circumferential direction, one end of each first spring 306 is connected with the installation piece, the other end of each first spring 306 is fixed with the arc-shaped clamping plate 307, the friction plate on the inner side of the clamping plate is fitted with the outer wall of the acoustic emission probe 304, the clamping friction force is enhanced, the probe is prevented from sliding, and the surface of the probe is prevented from being damaged.

[0030] Further, the rubber ring 311 is sleeved on the bonding end of the acoustic emission probe 304, the rubber ring 311 is made of elastic wear-resistant material, the second spring 305 is in a pre-compressed state, one end of the second spring 305 is connected with the fixed cover 303, and the other end is connected with the bottom end of the acoustic emission probe 304. Specifically, the second spring 305 is made of spring steel material with an elastic coefficient adapted to the pre-compressed state, one end of the second spring 305 is connected with the fixed cover 303, and the other end is in abutment with the bottom end of the acoustic emission probe, thereby providing axial buffer protection; the rubber ring 311 is made of elastic wear-resistant material, is sleeved on the outside of the bonding end of the probe, and plays an auxiliary sealing and buffering role.

[0031] Further, the negative pressure interface 309 is connected with the negative pressure generator, the negative pressure interface 309 penetrates through the bonding piece 310, and the pressure sensor 312 is electrically connected with the negative pressure generator. Specifically, the bonding piece 310 is made of elastic sealing material and can be deformed when being in contact with the detection surface, thereby enhancing the sealing performance of the sealed cavity; the pressure sensor 312 can be a thin film pressure sensor and is installed on the bonding piece to monitor the bonding pressure in real time; the negative pressure interface 309 penetrates through the bonding piece and the fixed cover and is sealingly connected with the negative pressure generator, and is used for extracting air inside the sealed cavity to form negative pressure; the fixed cover 303 is fixedly connected with the bottom end of the buffer shell and is detachable, thereby facilitating the installation and replacement of the acoustic emission probe and providing installation support for the second spring.

[0032] Key component working principle: The linear guide rail sliding table of the first and second moving devices adopts ball screw transmission to ensure accurate positioning in the horizontal direction; the third moving device 4 adopts a screw lifting sliding table to realize height fine adjustment, cooperates with a locking mechanism, effectively avoids position deviation caused by vibration during the test, and guarantees the alignment accuracy of the probe and the detection surface.

[0033] The first spring 306 (radial) is self-adaptable to acoustic emission probes 304 with different diameters through elastic deformation, can realize clamping without replacing components, and has soft and uniform clamping force, thereby avoiding damage to the probe; the second spring 305 (axial) is in a pre-compressed state, can provide continuous axial pre-tightening force, can also absorb axial impact energy generated by test vibration, cooperates with the stress guide groove of the buffer shell 301, forms multi-dimensional buffer protection, and significantly reduces the risk of probe damage.

[0034] The bonding piece 310 cooperates with the rubber ring 311 to form a sealed cavity, the negative pressure generator generates negative pressure by extracting air inside the cavity, makes the probe tightly bond with the detection surface, and eliminates micro gaps; the pressure sensor monitors the bonding pressure in real time, forms a closed loop control with the negative pressure generator, dynamically adjusts the air extraction state to stabilize the negative pressure value, ensures that the pressure is always in the optimal bonding range, guarantees the acoustic signal transmission efficiency, and avoids damage to the test piece or the probe.

[0035] The above is only an embodiment of the present application, and relates to circuits and electronic components and modules, which are all prior art. Those skilled in the art can implement the present application without further description. The present application does not involve improvement of software and methods. Commonly known specific structures and characteristics in the scheme are not described in detail herein. Those skilled in the art know all common technical knowledge in the technical field of the present application before the filing date or the priority date, can know all prior art in the field, and have the ability to apply conventional experimental means before the date. Those skilled in the art can perfect and implement the present scheme based on their own ability under the guidance of the present application. Some typical known structures or known methods should not be an obstacle for those skilled in the art to implement the present application. It should be pointed out that, for those skilled in the art, a number of modifications and improvements can be made without departing from the structure of the present application. These should also be considered as the protection scope of the present application, and these will not affect the implementation effect and practicality of the patent.

Claims

1. A method for fixing an acoustic emission probe in a rock mechanics test, characterized in that: Includes the following steps: S1: Grind the test surface of the rock specimen and mark the mating area on the test surface according to the test requirements; S2: By adjusting the movement of the fixed device, the acoustic emission probe is moved so that it is aligned with the detection surface of the rock specimen; S3: Place the acoustic emission probe in the clamping device, apply clamping force to the acoustic emission probe through the clamping device, and provide buffer protection using the buffer assembly; S4: Ensure the acoustic emission probe fits tightly against the detection surface; monitor the bonding pressure using a pressure sensor, adjust the negative pressure value to maintain a stable bonding pressure, and complete the fixation.

2. The method for fixing an acoustic emission probe in a rock mechanics test as described in claim 1, characterized in that: The testing surface of the rock specimen was polished by grinding the surface with multi-grit sandpaper in stages to remove surface dust, protrusions and loose particles.

3. The method for fixing an acoustic emission probe in a rock mechanics test as described in claim 1, characterized in that: The coordinated movement adjustment enables movement in multiple directions, and each moving device is locked after positioning is completed.

4. The method for fixing an acoustic emission probe in a rock mechanics test as described in claim 1, characterized in that: The clamping device and the detection surface form a sealed cavity, and the fit is achieved by drawing air out of the sealed cavity to create negative pressure.

5. The method for fixing an acoustic emission probe in a rock mechanics test as described in claim 1, characterized in that: A closed-loop control system is formed by a pressure sensor and a negative pressure generator to adjust the air extraction volume and stabilize the negative pressure value.

6. A device for fixing an acoustic emission probe in a rock mechanics test, characterized in that: Includes a base (5), on which a first moving device (1) is fixed, on which a second moving device (2) is fixed, on which a third moving device (4) is fixed, and on which a clamping device (3) is inherently connected.

7. The acoustic emission probe fixing device for rock mechanics testing as described in claim 6, characterized in that: The clamping device (3) includes a buffer housing (301), a stress guiding groove (308) on the buffer housing (301), an installation part (302) inside the buffer housing (301), a first spring (306) circumferentially arranged on the inner side of the installation part (302), a clamping plate (307) on the first spring (306), the clamping plate (307) circumferentially arranged on the acoustic emission probe (304), a second spring (305) at the bottom end of the acoustic emission probe (304), a rubber ring (311) at the other end of the acoustic emission probe (304), a fitting part (310) on the upper side of the rubber ring (311), a pressure sensor (312) connected to one side of the fitting part (310), a negative pressure interface (309) on one side of the pressure sensor (312), a fixed cover (303) penetrating one end of the negative pressure interface (309), and a fixed cover (303) at the bottom end of the buffer housing (301).

8. The acoustic emission probe fixing device for rock mechanics testing as described in claim 7, characterized in that: The first spring (306) has multiple circumferential springs, and the clamping plate (307) has an arc-shaped structure. The clamping plate (307) is provided with friction plates, which are connected to the acoustic emission probe (304).

9. The acoustic emission probe fixing device for rock mechanics testing as described in claim 7, characterized in that: The rubber ring (311) is fitted on the contact end of the acoustic emission probe (304). The rubber ring (311) is made of elastic and wear-resistant material. The second spring (305) is in a pre-compressed state. One end of the second spring (305) is connected to the fixed cover (303), and the other end is connected to the bottom end of the acoustic emission probe (304).

10. The acoustic emission probe fixing device for rock mechanics testing as described in claim 7, characterized in that: The negative pressure interface (309) is connected to the negative pressure generator, the negative pressure interface (309) passes through the fitting (310), and the pressure sensor (312) is electrically connected to the negative pressure generator.

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