Device and Method for Measuring Residual Kinetic Energy of Dynamic Rock Fracture Based on Piezoelectric Array

Abstract

This invention discloses a device and method for measuring the residual kinetic energy of dynamically fractured rock based on a piezoelectric array. The device includes an openable cylindrical cavity, a piezoelectric thin film array disposed on the inner wall of the openable cylindrical cavity, an openable circular support disposed inside the openable cylindrical cavity for fixing the rock sample, an incident rod inserted into one end of the openable cylindrical cavity, a transmission rod inserted into the other end of the openable cylindrical cavity, an information processing module disposed outside the openable cylindrical cavity and connected to the piezoelectric thin film array, and a PC disposed outside the openable cylindrical cavity and connected to the information processing module. The method is implemented based on the above device. The advantages of this invention are: simple operation, strong practicality, and the ability to capture the electrical signals generated when fragments impact the inner wall of the cavity in real time, accurately measuring the residual kinetic energy of the fragments.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rock dynamic mechanical property testing, in particular to a rock dynamic breaking residual kinetic energy measuring device and method based on a piezoelectric array. BACKGROUND

[0002] Rock dynamic breaking mechanism research is of great significance in the fields of mine exploitation, tunnel excavation and underground engineering construction. In the above engineering scenarios, rock is frequently subjected to dynamic load, and its breaking process involves complex energy conversion. Residual kinetic energy, as a direct representation of the energy of moving fragments, plays a key role in revealing the energy transfer and dissipation law. The split Hopkinson pressure bar (SHPB) experiment can effectively obtain macroscopic mechanical responses such as dynamic compressive strength and strain rate sensitivity through the three-wave method, but there is still a certain technical gap in measuring the residual kinetic energy of the broken fragments. Since the residual kinetic energy directly reflects the conversion efficiency of stress wave energy to fragment motion, its accurate measurement has important value for perfecting the energy conservation analysis model and establishing the rock mass breaking efficiency evaluation system.

[0003] In the traditional measurement method, the high-speed camera image analysis method usually requires multiple high-frame-rate cameras to be synchronized and equipped with a high-power lighting system. In environments with high dust concentration or insufficient light, the accuracy of this method is not high. In addition, due to the limitations of pixel accuracy of high-speed cameras and the shortcomings of edge detection technology, this method often faces a high risk of missed detection when monitoring small particle size fragments. At the same time, this method requires frame-by-frame analysis of image data, which cannot meet the real-time monitoring demand, and the equipment cost is high, which seriously restricts its applicability. Another strain gauge measurement method indirectly calculates kinetic energy through the combination of an elastic rod and a strain gauge, which is an indirect method. However, the mechanical structure of this method is relatively complex, and the friction loss of the elastic rod and the hinge assembly will reduce the energy transfer efficiency. Especially when monitoring small kinetic energy, due to the insufficient signal-to-noise ratio, it is difficult to accurately capture the data of light fragments, resulting in deviation in energy evaluation. Therefore, it is urgent to develop an economical and efficient residual kinetic energy measuring device that is suitable for complex working conditions, to provide data support for blasting energy utilization rate evaluation, rock mass breaking effect prediction and intelligent construction decision-making. SUMMARY

[0004] The present application aims to overcome the shortcomings of the prior art and provides a rock dynamic breaking residual kinetic energy measuring device and its use method, which is simple to operate and has strong practicality. Through a piezoelectric film array, the electrical signal generated when the fragments hit the inner wall of the cavity is captured in real time, thereby accurately measuring the residual kinetic energy of the fragments, solving the problem of ineffective measurement of the residual kinetic energy of the sample fragments in the split Hopkinson bar experiment.

[0005] To achieve the above purpose, the technical solution adopted by the present application is as follows:

[0006] In one aspect, the application provides a piezoelectric array-based rock dynamic crushing residual kinetic energy measuring device, comprising a openable and closable cylindrical cavity, a piezoelectric film array arranged on the inner wall of the openable and closable cylindrical cavity, an openable and closable circular support arranged in the openable and closable cylindrical cavity for fixing a rock sample, an incident rod inserted into one end of the openable and closable cylindrical cavity and used for completely adhering to one end of the rock sample, a transmission rod inserted into the other end of the openable and closable cylindrical cavity and used for completely adhering to the other end of the rock sample, an information processing module arranged outside the openable and closable cylindrical cavity and connected with the piezoelectric film array, and a PC arranged outside the openable and closable cylindrical cavity and connected with the information processing module.

[0007] Further, the openable and closable cylindrical cavity comprises an upper semicircular cavity and a lower semicircular cavity, and the upper semicircular cavity and the lower semicircular cavity are locked together by two buckle locks arranged on the left and right sides of the openable and closable cylindrical cavity.

[0008] Further, each of the buckle locks comprises a lock body fixed on the outer wall of the upper semicircular cavity and a clasp fixed on the outer wall of the lower semicircular cavity and matched with the lock body.

[0009] Further, the piezoelectric film array comprises a plurality of upper piezoelectric films arranged on the inner wall of the upper semicircular cavity and a plurality of lower piezoelectric films arranged on the inner wall of the lower semicircular cavity.

[0010] Further, the openable and closable circular support comprises an upper U-shaped support arranged at the center of the inner wall of the upper semicircular cavity and a lower U-shaped support arranged at the center of the inner wall of the lower semicircular cavity.

[0011] Further, a protective layer is arranged on the surface of each of the upper piezoelectric films and the lower piezoelectric films, the protective layer is fixed on the surface of the upper piezoelectric film or the lower piezoelectric film by an adhesive, the protective layer is made of wear-resistant material and is used for protecting the upper piezoelectric film and the lower piezoelectric film from direct impact of rock fragments, and the adhesive is fast-drying epoxy resin.

[0012] Further, an insulating layer is arranged between each of the upper piezoelectric films and the inner wall of the upper semicircular cavity and between each of the lower piezoelectric films and the inner wall of the lower semicircular cavity, the insulating layer is made of polytetrafluoroethylene and is used for isolating the upper piezoelectric film and the lower piezoelectric film from direct contact with the inner wall of the upper semicircular cavity and the inner wall of the lower semicircular cavity, and preventing the electric signals generated by the upper piezoelectric film and the lower piezoelectric film from being disturbed by external interference.

[0013] Further, each of the upper piezoelectric film and the lower piezoelectric film is connected with a flexible lead wire, and the end of each flexible lead wire is connected with a connector, and each connector is connected with the information processing module.

[0014] The upper semicircular cavity body and the lower semicircular cavity body are both provided with a plurality of reserved holes for penetrating the flexible lead wires, and the plurality of reserved holes provided on the upper semicircular cavity body correspond to the plurality of upper piezoelectric films provided on the inner wall of the upper semicircular cavity body one by one, and the plurality of reserved holes provided on the lower semicircular cavity body correspond to the plurality of lower piezoelectric films provided on the inner wall of the lower semicircular cavity body one by one.

[0015] Further, the information processing module comprises a PCB circuit board, a charge amplifier, a data acquisition card, a calculation unit, a lead wire interface and a signal line interface arranged on the PCB circuit board, the charge amplifier is connected with the data acquisition card, the calculation unit and the lead wire interface respectively, the data acquisition card and the calculation unit are connected with the signal line interface, the signal line interface is connected with a PC, and the lead wire interface is connected with the connector.

[0016] On the other hand, the application also provides a use method of the rock dynamic breaking residual kinetic energy measuring device based on the piezoelectric array, which comprises the following steps:

[0017] S1, a calibration projectile is launched to hit the openable cylindrical cavity body, and a voltage signal is recorded , a calibration coefficient is calculated , and is stored in a database; wherein, Herein, is the mass of the calibration projectile, is the launch speed of the calibration projectile;

[0018] S2, the rock material to be studied is processed into a standard cylindrical rock sample with a parallelism of ≤0.05mm between the upper and lower end faces, a flatness of ≤0.02mm of the end faces, a diameter of 50mm and a height of 35mm according to the ISMR test procedure;

[0019] S3, the openable cylindrical cavity body is opened, the standard cylindrical rock sample prepared in step S2 is placed on the lower U-shaped support, the incident rod and the transmission rod are moved to ensure that the incident rod and the transmission rod are completely aligned with the two ends of the standard cylindrical rock sample, and then the openable cylindrical cavity body is closed to completely fix the standard cylindrical rock sample;

[0020] S4, the lead wires of the piezoelectric film array are led out from the reserved holes on the openable cylindrical cavity body and connected with the information processing module;

[0021] S5, start the Hopkinson bar impact test, make the standard cylindrical rock sample break in the openable cylindrical cavity, and generate rock fragments;

[0022] S6, receive the impact of the rock fragments through the piezoelectric film array on the inner wall of the openable cylindrical cavity, when the rock fragments hit the piezoelectric film array on the inner wall of the openable cylindrical cavity, the piezoelectric film array is forced to generate an electric signal and transmit the electric signal to the signal processing module through flexible wires;

[0023] S7, process and analyze the electric signal received by the signal processing module, calculate the kinetic energy of the rock fragments, and display the experimental results;

[0024] S8, open the openable cylindrical cavity, take out the fragments of the rock sample, and clean and recycle.

[0025] Compared with the prior art, the rock dynamic breaking residual kinetic energy measuring device and method based on the piezoelectric array have the following advantages and beneficial effects:

[0026] (1) The piezoelectric film array is uniformly arranged on the inner wall of the cylindrical openable cavity, which can capture the electric signal generated when the rock fragments hit the inner wall of the cavity in real time, so as to calculate and output the residual kinetic energy distribution cloud of the rock fragments, and solve the problem that the Hopkinson bar test cannot effectively measure the residual kinetic energy of the rock sample fragments.

[0027] (2) The openable cylindrical cavity design is convenient for installation and disassembly of the rock sample, easy to operate, and improves the test efficiency. After the cylindrical cavity is closed, a sealed space is formed, and the flying energy of the rock fragments is completely absorbed by the inner wall sensor. Compared with the traditional high-speed camera image analysis method, the present application has extremely low miss rate when detecting small fragments. After the test is completed, the cavity is opened to directly recycle 100% of the fragments, solving the cleaning problem of the traditional device.

[0028] (3) The piezoelectric film array axially covers the inner wall of the cavity, and a three-dimensional measurement space is constructed, realizing effective decoupling in the direction. In this space, a single impact event can be synchronously and accurately captured by multiple piezoelectric films, which greatly eliminates the influence of the flying direction of the fragments on the measurement results. In addition, there is no physical contact between the present method and the fragments, thereby avoiding potential interference with the motion trajectory of the fragments.

[0029] (4) The present application is based on the voltage square integral method, which effectively weakens the noise interference and improves the signal-to-noise ratio. At the same time, the time domain threshold filtering and spatial trajectory tracking method are combined to eliminate the interference of multiple rebound signals, so that the measurement result is more accurate and reliable.

[0030] (5) The signal processing module of the present application is highly integrated, and integrates multiple functions such as charge amplification, data acquisition and integral calculation, and can output the residual kinetic energy value in a very short time after the test is completed. Compared with the image analysis method and the traditional strain gauge method, the processing efficiency is significantly improved. In addition, compared with the high-speed camera method which requires at least two cameras arranged at multiple angles, the hardware complexity of the device of the present application is greatly reduced, the cost is more economical, and there is no need to accurately calibrate the camera position and set the harsh optical environment. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creating laborious work.

[0032] Figure 1 is a structural schematic diagram of a rock dynamic breaking residual kinetic energy measuring device based on a piezoelectric array related to the embodiments of the present application;

[0033] Figure 2 is a cross-sectional schematic diagram of an openable and closable cylindrical cavity related to the embodiments of the present application;

[0034] Figure 3 is a structural schematic diagram of an openable and closable cylindrical cavity related to the embodiments of the present application Figure 1 ;

[0035] Figure 4 is a structural schematic diagram of an openable and closable cylindrical cavity related to the embodiments of the present application Figure 2 ;

[0036] Figure 5 is a structural schematic diagram of an information processing module related to the embodiments of the present application;

[0037] BRIEF DESCRIPTION OF DRAWINGS: 1, openable and closable cylindrical cavity; 101, upper half cylindrical cavity; 102, lower half cylindrical cavity; 103, buckle type lock; 104, reserved hole; 2, piezoelectric film array; 201, upper piezoelectric film; 202, lower piezoelectric film; 3, openable and closable circular support; 301, upper U-shaped support; 302, lower U-shaped support; 303, rubber pad; 4, incident rod; 5, transmission rod; 6, flexible wire; 7, connector; 8, information processing module; 801, PCB circuit board; 802, charge amplifier; 803, data acquisition card; 804, calculation unit; 805, wire interface; 806, signal line interface; 9, PC; 10, rock sample. DETAILED DESCRIPTION

[0038] The technical means, creative features, purposes and effects of the present application are described below in conjunction with the drawings and specific embodiments to make it easier to understand how the present application is implemented.

[0039] As shown in Figure 1 , the embodiment of the present application provides a rock dynamic crushing residual kinetic energy measuring device based on a piezoelectric array, which comprises an openable and closable cylindrical cavity body 1, a piezoelectric film array 2 arranged on the inner wall of the openable and closable cylindrical cavity body 1, an openable and closable circular support 3 arranged in the interior of the openable and closable cylindrical cavity body 1 and used for fixing a rock sample 10, an incident rod 4 inserted into one end of the openable and closable cylindrical cavity body 1 and used for completely adhering to one end of the rock sample 10, a transmission rod 5 inserted into the other end of the openable and closable cylindrical cavity body 1 and used for completely adhering to the other end of the rock sample 10, an information processing module 8 arranged outside the openable and closable cylindrical cavity body 1 and connected with the piezoelectric film array 2, and a PC 9 arranged outside the openable and closable cylindrical cavity body 1 and connected with the information processing module 8. The openable and closable cylindrical cavity body 1 is made of a steel material with low elongation and high strength, such as alloy steel, high carbon steel and stainless steel, and can change little in shape under the condition of long-term use or large load, which is helpful to maintain the geometric precision and stability of the openable and closable cylindrical cavity body 1.

[0040] Specifically, in the embodiment of the present application, as shown in Figure 2 , the openable and closable cylindrical cavity body 1 comprises an upper semicircular cavity body 101 and a lower semicircular cavity body 102, and the upper semicircular cavity body 101 and the lower semicircular cavity body 102 are locked together by two buckle type locks 103 arranged on the left and right sides of the openable and closable cylindrical cavity body 1, forming a cylindrical cavity body structure that can be opened and closed.

[0041] Specifically, in the embodiment of the present application, as shown in Figure 2 , each buckle type lock 103 is composed of a lock body 103a fixed on the outer wall of the upper semicircular cavity body 101 and a buckle ring 103b fixed on the outer wall of the lower semicircular cavity body 102 and matched with the lock body 103a. By buckling the lock body 103a and the buckle ring 103b, the closure of the upper semicircular cavity body 101 and the lower semicircular cavity body 102 can be achieved, thereby forming a cylindrical cavity body structure that can be opened and closed.

[0042] Specifically, in the embodiment of the present application, as shown in Figure 1As shown, the piezoelectric film array 2 is composed of a plurality of upper piezoelectric films 201 arranged on the inner wall of the upper semicircular cavity 101 and a plurality of lower piezoelectric films 202 arranged on the inner wall of the lower semicircular cavity 102. It should be noted that the shape, size and number of the upper piezoelectric films 201 and the lower piezoelectric films 202 are optimized according to the geometric size of the inner wall of the openable and closable cylindrical cavity 1, so as to ensure that the piezoelectric films can cover most of the area of the inner wall of the openable and closable cylindrical cavity 1, thereby improving the sensitivity and accuracy of the device.

[0043] Specifically, in the embodiment of the present application, as shown in Figure 3 The openable and closable cylindrical support 3 is composed of an upper U-shaped support 301 arranged at the center of the inner wall of the upper semicircular cavity 101 and a lower U-shaped support 302 arranged at the center of the inner wall of the lower semicircular cavity 102. The materials of the upper U-shaped support 301 and the lower U-shaped support 302 are preferably aluminum alloy, which has good strength and lightness, can effectively fix the rock sample 10, and ensure the stability and reliability of the test.

[0044] In order to protect the piezoelectric film array 2 from direct impact of rock fragments, based on the above-mentioned embodiment of the rock dynamic crushing residual kinetic energy measuring device based on the piezoelectric array, the present application provides an improved example 1: a protective layer (not shown in the figure) is arranged on the surface of each upper piezoelectric film 201 and lower piezoelectric film 202, and the protective layer is fixed on the surface of the upper piezoelectric film 201 or lower piezoelectric film 202 by adhesive.

[0045] Specifically, in the present improved example 1, the protective layer is made of wear-resistant material, and the thickness is preferably 0.5mm; the adhesive is fast-drying epoxy resin, which has high strength and high temperature resistance after curing.

[0046] In order to prevent the electric signal generated by the piezoelectric film array 2 from being disturbed by external interference, based on the above-mentioned embodiment of the rock dynamic crushing residual kinetic energy measuring device based on the piezoelectric array, the present application provides an improved example 2: an insulating layer (not shown in the figure) is arranged between each upper piezoelectric film 201 and the inner wall of the upper semicircular cavity 101, and between each lower piezoelectric film 202 and the inner wall of the lower semicircular cavity 102.

[0047] Specifically, in the present improved example 2, the insulating layer is made of polytetrafluoroethylene, and the thickness is preferably 0.2mm. Polytetrafluoroethylene has good insulation performance and high temperature resistance, and can effectively isolate the direct contact between the upper piezoelectric film 201 and the inner wall of the upper semicircular cavity 101 and between the lower piezoelectric film 202 and the inner wall of the lower semicircular cavity 102, thereby preventing the electric signal generated by the upper piezoelectric film 201 and the lower piezoelectric film 202 from being disturbed by external interference.

[0048] In order to reduce the additional impact on the rock sample during the experiment, on the basis of the above-mentioned piezoelectric array-based rock dynamic crushing residual kinetic energy measuring device, the application provides an improved example 3: that is, as shown in the figure, the inner surfaces of the upper U-shaped support 301 and the lower U-shaped support 302 are provided with rubber pads 303. Figure 4

[0049] Specifically, in the present improved example 3, the thickness of the rubber pad 303 is preferably 1.0mm.

[0050] In order to ensure the stability of the rock sample 10 during the impact process, on the basis of the above-mentioned improved example 3, the application makes further improvements, that is, the inner surface of the openable and closeable circular support 3 is provided with anti-skid texture, which is used to increase the friction between the rock sample 10 and the openable and closeable circular support 3, so as to ensure the stability of the rock sample 10 during the impact process.

[0051] Specifically, in the above-mentioned embodiments and improved examples 1-3, in order to facilitate the timely transmission of the electric signal generated by the piezoelectric film array 2 to the external information processing module 8, each of the upper piezoelectric film 201 and the lower piezoelectric film 202 is connected with a flexible wire 6, the end of each flexible wire 6 is connected with a connector 7, and each connector 7 is used to connect with the information processing module 8; a plurality of reserved holes 104 for passing the flexible wire 6 are formed on the upper semicircular cavity body 101 and the lower semicircular cavity body 102; wherein the plurality of reserved holes 104 formed on the upper semicircular cavity body 101 correspond to the plurality of upper piezoelectric films 201 arranged on the inner wall of the upper semicircular cavity body 101; the plurality of reserved holes 104 formed on the lower semicircular cavity body 102 correspond to the plurality of lower piezoelectric films 202 arranged on the inner wall of the lower semicircular cavity body 102. When all the flexible wires 6 of the piezoelectric films are led out from the corresponding reserved holes 104, they are gathered at one end of the openable and closeable cylindrical cavity body 1 and connected with the information processing module 8 through the connectors 7 respectively.

[0052] Specifically, in the above-mentioned embodiments and improved examples 1-3, in order to ensure the reliability of the flexible wire 6, each flexible wire 6 is fixed at the center position of the corresponding upper piezoelectric film 201 or lower piezoelectric film 202 by welding. The material of the flexible wire 8 is preferably silver-plated copper wire, which has good conductivity and flexibility, can effectively prevent interference in the signal transmission process, and ensure the stability and reliability of the signal transmission.

[0053] Specifically, in the above-mentioned embodiments and improved examples 1-3, as shown in the figure, Figure 5 ​As shown, the information processing module 8 comprises a PCB circuit board 801 and a charge amplifier 802, a data acquisition card 803, a computing unit 804, a wire interface 805 and a signal line interface 806 arranged on the PCB circuit board 801, the charge amplifier 802 is connected with the data acquisition card 803, the computing unit 804 and the wire interface 805 respectively, the data acquisition card 803 and the computing unit 804 are connected with the signal line interface 806, the signal line interface 806 is connected with a PC 9, and the wire interface 805 is connected with the connector 7; wherein the wire interface 805 is used for receiving the charge signal generated when the piezoelectric film is impacted by the rock fragments, and transmitting the charge signal to the charge amplifier 802, the charge amplifier 802 is used for converting the received charge signal into voltage data and transmitting the voltage data to the computing unit 804 for calculation, the data acquisition card 803 is used for recording the voltage data converted by the charge amplifier 802, and the signal line interface 806 is used for transmitting the data recorded by the data acquisition card 803 and the calculation result of the computing unit 804 to the PC 9 for display. Wherein the data acquisition card 803 is used for recording the voltage data at a sampling rate of 1.0MHz, and a reasonable time window (such as 0.1ms) is set, for example, if the same piezoelectric film triggers multiple times within the window, it is considered as the continuous rebound of the same fragment, and only the first impact signal is recorded; the computing unit 804 is used for executing the voltage square integral algorithm (V2dt) ), to obtain the residual kinetic energy of the fragments, wherein, is a calibration coefficient, which is determined by calibration experiment, is the voltage data.

[0054] In the use process of the rock dynamic breaking residual kinetic energy measuring device based on the piezoelectric array provided by the application, first, the rock sample 10 is placed on the lower U-shaped support 302 inside the lower semicircular cavity body 102, and then the upper semicircular cavity body 101 is closed after ensuring that the end faces of the incident rod 4 and the projection rod 5 are completely coincided with the two ends of the rock sample 10, so that the rock sample 10 is completely fixed, and then the Hopkinson bar impact test is started, so that the rock sample 10 is broken in the openable and closable cylindrical cavity body 1, when the sample fragments hit the piezoelectric film on the inner wall of the openable and closable cylindrical cavity body 1, the piezoelectric film generates an electric signal under force and transmits the electric signal to the signal processing module 8 through the flexible wire 6, then the signal processing module 8 processes and analyzes the electric signal, calculates the kinetic energy of the fragments, and finally obtains the experimental result. After the test is completed, all the fragments can be conveniently taken out by opening the openable and closable cylindrical cavity body 1, the operation is simple, the kinetic energy of the fragments can be measured in real time during the test process, and the problem that the residual kinetic energy of the fragments cannot be accurately measured in the prior art is effectively solved.

[0055] On the basis of the above-mentioned embodiment of the application, the application further provides a use method of the rock dynamic breaking residual kinetic energy measuring device based on the piezoelectric array, which specifically comprises the following steps:

[0056] S1, record the voltage signal when the calibration projectile hits the openable cylindrical cavity body 1 , calculate the calibration coefficient , and store it in the database; wherein, Here, is the mass of the calibration projectile, is the launch speed of the calibration projectile;

[0057] S2, according to the ISMR test procedure, the rock material to be studied is processed into a standard cylindrical rock sample with a parallelism of ≤0.05mm between the upper and lower end faces, a flatness of ≤0.02mm on the end faces, a diameter of 50mm and a height of 35mm;

[0058] S3, open the openable cylindrical cavity body 1, place the standard cylindrical rock sample prepared in step S2 on the lower U-shaped support, move the incident rod 4 and the transmission rod 5 to ensure that the incident rod 4 and the transmission rod 5 are completely aligned with the two ends of the standard cylindrical rock sample, then close the openable cylindrical cavity body 1 to completely fix the standard cylindrical rock sample;

[0059] S4, the flexible lead wire 6 of the piezoelectric film array 2 is led out from the reserved hole 10 on the openable cylindrical cavity body 1 and connected with the information processing module 8;

[0060] S5, start the Hopkinson bar impact test to make the standard cylindrical rock sample break in the openable cylindrical cavity body 1 and generate rock fragments;

[0061] S6, the piezoelectric film array 2 on the inner wall of the openable cylindrical cavity body 1 receives the impact of the rock fragments, when the rock fragments hit the piezoelectric film array 2 on the inner wall of the openable cylindrical cavity body 1, the piezoelectric film array 2 generates an electric signal under stress and transmits the electric signal to the signal processing module 8 through the flexible lead wire 8;

[0062] S7, the signal processing module 8 processes and analyzes the received electric signal to calculate the kinetic energy of the rock fragments and display the experimental results;

[0063] S8, open the openable cylindrical cavity body 1, take out the fragments of the rock sample, clean and recycle.

[0064] Finally, it is pointed out that the above description is only an embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent flow transformation made by using the content of the specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for using a piezoelectric array-based rock dynamic crushing residual kinetic energy measuring device, the device comprising an openable and closable cylindrical cavity body (1), a piezoelectric film array (2) arranged on the inner wall of the openable and closable cylindrical cavity body (1), an openable and closable circular support (3) arranged inside the openable and closable cylindrical cavity body (1) and used for fixing a rock sample (10), an incident rod (4) inserted into one end of the openable and closable cylindrical cavity body (1) and used for completely adhering to one end of the rock sample (10), a transmission rod (5) inserted into the other end of the openable and closable cylindrical cavity body (1) and used for completely adhering to the other end of the rock sample (10), an information processing module (8) arranged outside the openable and closable cylindrical cavity body (1) and connected with the piezoelectric film array (2), and a PC (9) arranged outside the openable and closable cylindrical cavity body (1) and connected with the information processing module (8), characterized in that, The method comprises the following steps: S1, the impact of the calibration projectile on the openable cylindrical cavity (1), record the voltage signal , calculate the calibration coefficient , and store to the database; wherein, , The mass of the calibration projectile is, The launch speed of the calibration projectile; S2, the rock material to be studied is processed into a standard cylindrical rock sample with parallel upper and lower end faces ≤0.05mm, end face flatness ≤0.02mm, diameter 50mm and height 35mm according to ISRM test procedures; S3, open the openable cylindrical cavity (1), place the standard cylindrical rock sample prepared in step S2 on the lower U-shaped support, move the incident rod (4) and the transmission rod (5), ensure that the incident rod (4) and the transmission rod (5) are completely aligned with the two ends of the standard cylindrical rock sample, then close the openable cylindrical cavity (1), and completely fix the standard cylindrical rock sample; S4, the lead wire of the piezoelectric film array (2) is led out from the reserved hole on the openable cylindrical cavity (1) and connected with the information processing module (8); S5, start the Hopkinson bar impact test, make the standard cylindrical rock sample break in the openable cylindrical cavity (1), and generate rock fragments; S6, the piezoelectric film array (2) on the inner wall of the openable cylindrical cavity (1) receives the impact of the rock fragments, when the rock fragments hit the piezoelectric film array (2) on the inner wall of the openable cylindrical cavity (1), the piezoelectric film array (2) generates an electric signal under stress and transmits the electric signal to the information processing module (8) through the flexible lead wire (6); S7, process and analyze the electric signal connected to the information processing module (8), calculate the kinetic energy of the rock fragments, and display the experimental results; S8, open the openable cylindrical cavity (1), take out the rock sample fragments, clean and recycle.

2. The method of using a piezoelectric array based rock dynamic breakage residual kinetic energy measuring device according to claim 1, characterized in that: The openable cylindrical cavity (1) comprises an upper semicircular cavity (101) and a lower semicircular cavity (102), and the upper semicircular cavity (101) and the lower semicircular cavity (102) are locked together through two buckle locks (103) arranged on the left and right sides of the openable cylindrical cavity (1).

3. The method of using a piezoelectric array based rock dynamic breakage residual kinetic energy measuring device according to claim 2, characterized in that: Each buckle lock (103) is composed of a lock body (103a) fixed on the outer wall of the upper semicircular cavity (101) and a buckle ring (103b) fixed on the outer wall of the lower semicircular cavity (102) and matched with the lock body (103a).

4. The method of using a piezoelectric array based rock dynamic breakage residual kinetic energy measuring device of claim 2, wherein: The piezoelectric film array (2) is composed of a plurality of upper piezoelectric films (201) arranged on the inner wall of the upper semicircular cavity (101) and a plurality of lower piezoelectric films (202) arranged on the inner wall of the lower semicircular cavity (102).

5. The method of using a piezoelectric array based rock dynamic breakage residual kinetic energy measuring device of claim 2, wherein: The openable cylindrical support (3) is composed of an upper U-shaped support (301) arranged at the center position of the inner wall of the upper semicircular cavity (101) and the lower U-shaped support (302) arranged at the center position of the inner wall of the lower semicircular cavity (102).

6. The method of using a piezoelectric array based rock dynamic breakage residual kinetic energy measuring device of claim 4, wherein: The surface of each of the upper piezoelectric film (201) and the lower piezoelectric film (202) is provided with a protective layer, the protective layer is fixed on the surface of the upper piezoelectric film (201) or the lower piezoelectric film (202) through an adhesive, the protective layer is made of wear-resistant material, and is used for protecting the upper piezoelectric film (201) and the lower piezoelectric film (202) from direct impact of rock fragments.

7. The method of using a piezoelectric array based rock dynamic breakage residual kinetic energy measuring device of claim 4, wherein: An insulating layer is arranged between each of the upper piezoelectric film (201) and the inner wall of the upper semicircular cavity (101) and between each of the lower piezoelectric film (202) and the inner wall of the lower semicircular cavity (102), the insulating layer is made of polytetrafluoroethylene, and is used for isolating the direct contact between the upper piezoelectric film (201) and the inner wall of the upper semicircular cavity (101) and between the lower piezoelectric film (202) and the inner wall of the lower semicircular cavity (102), and preventing the electric signals generated by the upper piezoelectric film (201) and the lower piezoelectric film (202) from being disturbed by the outside.

8. The method of using a piezoelectric array based rock dynamic breakage residual kinetic energy measuring device of claim 4, wherein: Each of the upper piezoelectric film (201) and the lower piezoelectric film (202) is connected with a flexible wire (6), the end of each flexible wire (6) is connected with a connector (7), and each connector (7) is connected with an information processing module (8). A plurality of reserved holes (104) for penetrating the flexible wire (6) are arranged on the upper semicircular cavity (101) and the lower semicircular cavity (102), the plurality of reserved holes (104) arranged on the upper semicircular cavity (101) correspond to the plurality of upper piezoelectric films (201) arranged on the inner wall of the upper semicircular cavity (101) in a one-to-one manner, and the plurality of reserved holes (104) arranged on the lower semicircular cavity (102) correspond to the plurality of lower piezoelectric films (202) arranged on the inner wall of the lower semicircular cavity (102) in a one-to-one manner.

9. The method of using a piezoelectric array based rock dynamic breakage residual kinetic energy measuring device according to claim 8, characterized in that: The information processing module (8) comprises a PCB circuit board (801), a charge amplifier (802), a data acquisition card (803), a calculation unit (804), a wire interface (805) and a signal line interface (806) arranged on the PCB circuit board (801), the charge amplifier (802) is connected with the data acquisition card (803), the calculation unit (804) and the wire interface (805), the data acquisition card (803) and the calculation unit (804) are connected with the signal line interface (806), the signal line interface (806) is connected with a PC (9), and the wire interface (805) is connected with the connector (7).

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