Acoustic emission probe fixing device preparation process based on MAE material

Abstract

The invention relates to the technical field of acoustic emission probes for rock mechanics tests, and particularly discloses a preparation process of an acoustic emission probe fixing device based on an MAE material, which comprises the following steps: designing a female die according to the shape of an acoustic emission sensor, printing the female die by using a 3D printing technology, pouring an MAE mixed solution into the female die, and carrying out ultrasonic treatment on the MAE mixed solution to obtain the MAE material fixing device. The sensor fixing device obtains initial magnetism through an excitation device, and a simple magnetic field is provided nearby when the sensor fixing device is used, so that the viscosity of the sensor fixing device is controlled. The acoustic emission sensor fixing device manufactured through the method is good in bonding effect in the using process, signal receiving loss caused by poor contact can be avoided, the acoustic emission sensor fixing device is easy to disassemble and can be repeatedly used, the using cost is reduced, and the using effect is good. The damage to the surface of the sensor caused by sticking the probe on the rock by using glue and the harm to human health caused by cleaning the glue by using an acetone solution are avoided.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of acoustic emission sensors, in particular to a preparation process of an acoustic emission probe fixing device based on MAE materials. BACKGROUND

[0002] Acoustic emission (AE) technology utilizes the ultrasonic wave information radiated by internal cracking and frictional sliding between crack surfaces during rock deformation, continuously observing the dynamic evolution of internal micro-cracking of rock materials. This technology can reveal the micro-process of rock deformation and failure, and is crucial for understanding the mechanical properties and variation laws of rocks. The acoustic emission sensor is an important part of the acoustic emission detection system. The acoustic emission sensor is in close contact with the monitored object. When the piezoelectric ceramic is subjected to the action of sound waves, it will deform, thereby causing the accumulation of electric charges. This process converts sound waves into electrical signals, thereby realizing the detection of internal damage of the structure.

[0003] In rock triaxial tests, the acoustic emission sensor is generally fixed on the outer wall of the triaxial chamber by using a ferromagnetic suction seat. For uniaxial compression tests, Brazilian splitting tests, shear tests and other working conditions, a bandage, adhesive tape, or adhesive is often used. However, these methods mostly have problems such as poor fixation, signal attenuation, or complex operation. In particular, the use of high-strength glue can cause many problems: (1) introducing a third medium between the rock and the acoustic emission sensor can affect the transmission of acoustic emission signals, leading to distortion of the received signals, thereby affecting the accuracy and reliability of the signals; (2) using glue to bond the sensor can make the test operation more complex and time-consuming, and precise control of the amount of glue and the bonding process is required to ensure that the sensor is in close contact with the rock surface; (3) in addition, the cleaning and removal of the glue can be difficult, increasing the cleaning work after the test, and the piezoelectric ceramic on the surface of the sensor can be irreversibly damaged during the cleaning process, affecting the service life of the sensor; (4) the cleaning of the glue can involve acetone solution, posing a risk to the environment and the health of the operator; (5) the glue can leave residues on the surface of the sensor, affecting its bonding with the rock in the next test, or affecting the performance of the sensor. SUMMARY

[0004] The purpose of the present application is to provide a preparation process of an acoustic emission probe fixing device based on MAE materials, which aims to solve the technical problem that in the prior art, the bonding of the sensor with the surface of the rock test piece can affect the signal reception of the sensor, thereby affecting the test results, and after the test is completed, the sensor needs to be removed and the residual glue thereon needs to be cleaned, which process can irreversibly damage the piezoelectric ceramic on the surface of the sensor, affecting the service life of the sensor.

[0005] To achieve the above object, the application adopts a preparation process of an acoustic emission probe fixing device based on MAE material, which comprises the following steps: Designing a master mold according to the shape of the acoustic emission sensor; Printing the master mold designed above by using a 3D printer; Polishing and polishing burrs of the master mold by using polishing tools; Soaking the master mold in anhydrous ethanol for ultrasonic cleaning to remove residual resin, and drying the master mold; Preparing an MAE mixed solution added with soft magnetic material, pouring the MAE mixed solution into the master mold, and curing at 70°C for 60 min to prepare a sensor fixing device; Placing the fixing device in an energized excitation device to make the iron powder particles in the fixing device directionally arranged to form a chain structure, thereby having a magnetic pole feature; Constructing a simple controllable magnetic field near the sensor fixing device to control the viscosity of the material, thereby controlling the bonding degree between the sensor fixing device and the acoustic emission sensor and the rock.

[0006] In the step of designing the master mold, the master mold is designed according to the shape and size of the acoustic emission sensor, the upper surface of the master mold is designed with a biomimetic structure containing a polygonal or circular unit array and a nano-sized hemispherical microstructure, the designed master mold is adjusted in size, the model data is checked to avoid errors or incompleteness in the model to ensure correct printing, and the model is decomposed into slices, each slice representing a side to be printed on the printer; In the step of polishing the master mold, cutting tools or polishers are used to remove the support structure of the mold, sandpaper is used to polish the surface of the mold to remove burrs and impurities, and polishing cloth is used to polish the surface of the mold; In the step of curing the MAE material, the state of the thermostat is detected, the thermostat is powered on, the temperature of the thermostat is adjusted to 50°C for 2 min, the temperature inside the thermostat is preheated, the temperature of the thermostat is adjusted to 70°C, the fixing device is placed in the thermostat, and the MAE material is constant temperature dried for 60 min to make the MAE material cured; The sensor fixing device controls the viscosity of the MAE material through a magnetic field, the fixing device is placed in an energized excitation device, the iron particles in the fixing device are regularly distributed to form a chain, thereby having a magnetic pole feature in a macroscopic sense; The sensor fixing device controls the viscosity of the MAE material by using a magnetic field, and when rock mechanics tests are carried out, two rectangular current-carrying coils are arranged near the acoustic emission sensor and the fixing device, so that the opposite magnetic poles are opposite, at this time, a specific magnetic field distribution rule can be generated, so as to realize the function of controlling the fixing device to bond the acoustic emission sensor to the surface of the rock.

[0007] The preparation process of the acoustic emission probe fixing device based on the MAE material has the following beneficial effects: 1. The fixing device prepared by the method has good adhesion with the rock surface during use, and can avoid the loss of acoustic emission signal reception caused by poor contact; 2. The spacing between the plurality of fixing devices can be automatically adjusted according to the deformation of the test piece, avoiding the damage of the device, the interference of the test piece or the distortion of the information caused by the non-adjustable spacing of the rigid clamp; 3. The surface profile of the fixing device can be flexibly designed according to the shape of the test piece, and the application range is wide; 4. The operation is simpler and the adjustment is more flexible. By adjusting the magnetic field strength, the device can be easily disassembled, avoiding the use of glue to paste the sensor on the rock, reducing the damage to the surface sensitive material of the sensor caused by pasting and degumming, prolonging the service life of the sensor, and avoiding the harm to human health caused by using acetone solution for cleaning; 5. Promote the use of recycled design and sustainable materials, reduce material waste, and prolong the service life of the acoustic emission sensor. BRIEF DESCRIPTION OF DRAWINGS

[0008] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0009] Figure 1 It is a method step flow chart of the preparation process of the acoustic emission probe fixing device based on the MAE material of the present application.

[0010] Figure 2 It is a schematic diagram of the excitation device of the acoustic emission sensor fixing device based on the MAE material of the present application.

[0011] Figure 3 It is a front view of the fixing device of the preparation process of the acoustic emission probe fixing device based on the MAE material of the present application.

[0012] Figure 4This is a schematic diagram of the adsorption surface of the fixing device in the fabrication process of an acoustic emission probe fixing device based on MAE material according to the present invention.

[0013] Figure 5 This is a schematic diagram of a controllable magnetic field for a MAE-based acoustic emission sensor fixing device according to the present invention. Detailed Implementation

[0014] Please see Figures 1 to 5 This invention provides a fabrication process for an acoustic emission probe fixing device based on MAE material, comprising the following steps: S1: Design the master mold based on the shape of the acoustic emission sensor; S2: Use a 3D printer to print the master mold of the above design; S3: Use a grinding tool to grind and polish the burrs on the master mold; S4: Immerse the master mold in anhydrous ethanol for ultrasonic cleaning for 20 minutes to remove residual resin, and then dry the master mold. S5: Prepare a MAE mixture with added soft magnetic material, pour the MAE mixture into the master mold, and cure it at 70℃ for 60 min to obtain the sensor fixing device. S6: Place the above-mentioned fixing device into the excitation device, so that the iron powder particles inside the fixing device are oriented and form a chain structure, thereby having magnetic pole characteristics; S7: Construct a simple and controllable magnetic field near the sensor fixing device to control the viscosity of the material, thereby controlling the degree of adhesion between the sensor fixing device and the acoustic emission sensor and the rock.

[0015] Furthermore, in the process of designing the master mold: the master mold is designed according to the shape and size of the acoustic emission sensor. A biomimetic structure is designed on the upper surface of the master mold, including polygonal or circular unit arrays and nanoscale hemispherical microstructures. The size of the designed master mold is adjusted, and the model data is checked to avoid errors or incompleteness in the model, so as to ensure that it can be printed correctly. The model is also decomposed into thin slices, each slice representing the side to be printed on the printer.

[0016] Furthermore, in the step of polishing the master mold: the supporting structure of the mold is removed using a cutting tool or a polishing machine, the surface of the mold is polished with sandpaper to remove burrs and impurities, and then the surface of the mold is polished with a polishing cloth.

[0017] Furthermore, in the step of curing MAE material: the status of the constant temperature chamber is checked, and the constant temperature chamber is powered on. The temperature of the constant temperature chamber is adjusted to 50°C and held for 2 minutes to preheat the internal temperature of the constant temperature chamber. Then the temperature of the constant temperature chamber is adjusted to 70°C. The fixing device is placed in the constant temperature chamber and the MAE material is dried at a constant temperature for 60 minutes to cure the MAE material. Furthermore, the sensor fixing device controls the viscosity of the MAE material through a magnetic field. The fixing device is placed in an energized excitation device, causing the iron powder particles inside to be regularly distributed to form a chain shape, thus exhibiting magnetic pole characteristics on a macroscopic scale. At the same time, a biomimetic structure is designed on the contact surface between the fixing device and the rock, which can increase the adhesion of the material. Furthermore, when conducting rock mechanics tests, a constant magnetic field can be constructed near the acoustic emission sensor and the fixing device. This can be achieved by having two magnets with opposite magnetic poles facing each other to generate a constant magnetic field. At the same time, the fixing device and the acoustic emission sensor can be placed inside the magnetic field, ensuring that the opposite magnetic poles are also facing each other. This allows the fixing device to be controlled by the magnetic field to adsorb the acoustic emission sensor onto the rock surface. Furthermore, after the magnetic field is weakened or removed, the viscosity of the MAE material will decrease, and the device will also detach from the acoustic emission sensor and the rock due to changes in the microstructure of its surface.

[0018] The advantages of this invention are: good adhesion to the sensor and rock surface during use, avoiding loss of acoustic emission signal reception due to poor contact; automatic adjustment of the spacing between multiple fixing devices as the specimen deforms, avoiding device damage, specimen interference, or information distortion caused by rigid clamps that cannot adjust the spacing; flexible design of the fixing device surface contour to suit the specimen shape, with a wide range of applications; easy disassembly of the device by adjusting the magnetic field strength, avoiding the traditional use of glue to attach the sensor to the rock, reducing damage to the sensitive material of the sensor surface during adhesion and detachment, improving sensor lifespan, and avoiding the health hazards of cleaning with acetone solution; and reusability, reducing usage costs.

[0019] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A fabrication process for an acoustic emission probe fixing device based on MAE material, characterized in that, Includes the following steps: Design the master mold based on the shape of the acoustic emission sensor; The master mold of the above design was printed using a 3D printer; The master mold is deburred and polished using a grinding tool; The master mold was immersed in anhydrous ethanol for ultrasonic cleaning to remove residual resin, and then the master mold was dried. A MAE mixture with added soft magnetic material was prepared and poured into a master mold. The mixture was then cured at 70°C for 60 min to obtain a sensor fixing device. The aforementioned fixing device is placed inside an energized excitation device, causing the iron powder particles inside the fixing device to align in a direction and form a chain-like structure, thereby exhibiting magnetic pole characteristics. A simple, controllable magnetic field is constructed near the sensor fixing device to control the viscosity of the material, thereby controlling the degree of adhesion between the sensor fixing device and the acoustic emission sensor and the rock.

2. The fabrication process of the acoustic emission probe fixing device based on MAE material as described in claim 1, characterized in that, In the process of designing the master mold: the master mold is designed according to the shape and size of the acoustic emission sensor. The upper surface of the master mold is designed with a biomimetic structure, including polygonal or circular unit arrays and nanoscale hemispherical microstructures. The size of the designed master mold is adjusted, and the model data is checked to avoid errors or incompleteness in the model, so as to ensure that it can be printed correctly. The model is also decomposed into thin slices, each slice representing the side to be printed on the printer.

3. The fabrication process of the acoustic emission probe fixing device based on MAE material as described in claim 2, characterized in that, In the step of polishing the master mold: the supporting structure of the mold is removed by using a cutting tool or a polishing machine, the surface of the mold is polished with sandpaper to remove burrs and impurities, and then the surface of the mold is polished with a polishing cloth.

4. The fabrication process of the acoustic emission probe fixing device based on MAE material as described in claim 3, characterized in that, In the step of curing MAE material: check the status of the constant temperature chamber, turn on the constant temperature chamber, adjust the temperature of the constant temperature chamber to 50°C for 2 minutes to preheat the internal temperature of the constant temperature chamber, then adjust the temperature of the constant temperature chamber to 70°C, put the fixing device into the constant temperature chamber, and dry the MAE material at a constant temperature for 60 minutes to cure the MAE material.

5. The fabrication process of the acoustic emission probe fixing device based on MAE material as described in claim 4, characterized in that, The sensor fixing device controls the viscosity of the MAE material through a magnetic field. The fixing device is placed inside an energized excitation device, causing the iron particles inside to be regularly distributed to form a chain shape, thus exhibiting magnetic pole characteristics on a macroscopic scale.

6. The fabrication process of the acoustic emission probe fixing device based on MAE material as described in claim 5, characterized in that, The sensor fixing device utilizes a magnetic field to control the viscosity of the MAE material, constructing two rectangular current-carrying coils near the acoustic emission sensor and the fixing device so that opposite magnetic poles are opposite each other. At this time, a specific magnetic field distribution pattern can be generated, thereby achieving the function of controlling the fixing device to bond the acoustic emission sensor to the rock surface.

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