CN118533676A - Freeze thawing cycle and power disturbance coupling loading SHPB testing device and method - Google Patents
Freeze thawing cycle and power disturbance coupling loading SHPB testing device and method Download PDFInfo
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Abstract
The invention provides a freeze thawing cycle and power disturbance coupling loading SHPB testing device and method. The testing device comprises a one-dimensional Hopkinson pressure bar system based on hydraulic propulsion on two sides, a freeze thawing cycle confining pressure loading system, a controllable high-frequency pendulum striking system based on a pressure sensor and a data acquisition and analysis system. The method utilizes gravitational potential energy of the pendulum bob to design a controllable high-frequency pendulum bob beating system based on a pressure sensor, and the pendulum bob beating device comprises a supporting structure, a second main control system and a beating structure, can set beating frequency, height and period, can realize automatic control in a test period, and performs high-frequency power disturbance on a sample by beating the tail end of a transmission rod during test so as to simulate real working conditions of bearing the high-frequency power disturbance by rocks in the mining resource exploitation process. According to the invention, through automatically controlling the striking frequency and the striking height of the pendulum bob, the high-frequency high Zhou Di amplitude power disturbance on the rock bearing the freezing-thawing circulation effect is directly realized.
Description
Technical Field
The invention belongs to the field of high-end equipment manufacturing, relates to the field of rock dynamics research, and particularly relates to a Hopkinson pressure bar testing device for researching dynamic mechanical properties and breaking mechanisms of rocks in cold regions after high-frequency low-amplitude dynamic disturbance.
Background
Split hopkinson struts (split Hopkinson pressure bar, SHPB).
The meaning of some common words in the present application and some common sense in life are different, and are specifically described herein as follows:
Frequencies of low and high frequencies: frequency refers to the strike time: time required for a single power disturbance, wherein the low frequency: the time of primary power disturbance is more than 3min; high frequency: the time of one power disturbance is <10s.
The weeks of low and high weeks: and the power disturbance period refers to the number of times of power disturbance on the sample, wherein the period is lower than the period: the number of impacts required to break the sample is < 100; high week: refers to the number of times the sample is impacted >10000 times before damage or no damage occurs.
Amplitude in high amplitude and low amplitude: amplitude value: the intensity of the impact. Wherein, high amplitude: the incident stress intensity of the striking is more than 100MPa, and the amplitude is low: the incident stress intensity of the striking is <50MPa.
The drilling and blasting method is a main method for exploiting various mineral resources all the time by virtue of the advantages of low excavation cost, high construction speed, relatively mature technology and the like. The stress wave generated in the drilling and blasting process carries out high-amplitude dynamic loading on the rock close to the rock, and along with the gradual attenuation of the stress wave, the rock far away from the rock is subjected to low-amplitude dynamic disturbance, so that the rock in a mining area is often subjected to tens of thousands of times of high-frequency low-amplitude dynamic disturbance before the high-amplitude dynamic rock is broken. In addition, partial areas in China are in cold areas, the areas are often greatly influenced by factors such as rainfall, snowfall and temperature difference, so that rocks in mining areas are subjected to long-time freeze-thawing cycle action, the mechanical properties of the rocks are gradually deteriorated, the bearing capacity of the rocks is reduced, and therefore the freeze-thawing cycle action must be considered in researching the dynamic mechanical properties of the rocks in the cold areas. Meanwhile, with the increasing exhaustion of shallow mineral resources, the trend of deep mining resources is increasingly remarkable, the stress field of deep rock engineering is different from that of shallow layers, and the deep rock engineering is generally subjected to larger dead weight stress and structural stress, so that the influence of three-dimensional static load on the dynamic mechanical properties of rock is necessary to consider when deep mining is carried out.
In summary, in order to perfect the rock dynamics basic theory related to mining resources exploitation in cold regions, research on freeze thawing cycle-three-dimensional static load-dynamic disturbance-dynamic impact coupling test needs to be carried out on rocks, so that potential threats to safe production and long-life healthy operation of mining regions in severe cold regions are eliminated. Therefore, it is important to define the influence of the coupling damage of freeze thawing cycle and dynamic disturbance on the dynamic mechanical property of rock.
In reality, considering the actual working condition that the rock in the cold region bears the action of the freeze-thawing cycle, the rock bears the action of the load while bearing the action of the freeze-thawing cycle. The current rock cyclic impact research mainly focuses on low frequency (the time required by single impact is more than 3 min), low cycle (the time required by the damage of a sample is more than 100 times), high amplitude (the incident stress is more than 100 MPa) loading, the rock is macroscopically damaged under tens of times of impact, but surrounding rock in real engineering can bear power disturbance from mechanical vibration, blasting impact and running load for tens of thousands times, which involves high frequency (the primary power disturbance is more than 10 s), high cycle (> 10000 times, even tens of thousands times), low amplitude loading (the incident stress is more than 50 MPa), and the damage evolution rule of the rock in the situation can be different from the low frequency, low cycle and high amplitude loading.
The application provides a testing device, which can be used for carrying out dynamic mechanical property testing of rock under the coupling effect of freeze thawing cycle, three-dimensional static load and dynamic disturbance, wherein the dynamic disturbance has the characteristics of high frequency, high circumference and low amplitude loading, so that theoretical basis is provided for research on strength characteristics, damage and destruction and the like of engineering rock mass in cold regions, theoretical basis and technical support are provided for design, construction, support, stability evaluation and the like of geotechnical engineering in cold regions, and the support refers to one of construction steps.
Disclosure of Invention
The controllable high-frequency pendulum hammer striking device based on the pressure sensor mainly comprises a supporting structure, a second main control system and a striking structure, the striking frequency, the height and the period can be set, automatic control can be realized in the test period, and the high-frequency power disturbance is carried out on the sample by striking the tail end of the transmission rod during the test so as to simulate the real working condition that the rock bears the high-frequency power disturbance in the mining resource exploitation process. The data acquisition and analysis system mainly comprises a high-performance computer, a multichannel high-speed synchronous recorder, a strain gauge, a Wheatstone bridge and a strain signal amplifier, and plays a role in real-time monitoring, complete recording and storage of test signals. In conclusion, the dynamic mechanical property test of the rock after the freeze thawing cycle-three-dimensional static load-dynamic disturbance coupling loading is realized through the mutual connection cooperation among the systems.
In order to solve the problems in the prior art, the invention provides a freeze thawing cycle and power disturbance coupled loading SHPB testing device, which comprises a one-dimensional Hopkinson pressure bar system based on oil pressure propulsion at two sides, a freeze thawing cycle confining pressure loading system, a controllable high-frequency pendulum striking system based on a pressure sensor and a data acquisition and analysis system; the freeze-thawing cycle confining pressure loading system comprises a confining pressure loading device, a freeze-thawing cycle device and a second main control system, and simulates the working condition that rocks in cold areas bear freeze-thawing cycle-confining pressure loading; the controllable high-frequency pendulum striking system based on the pressure sensor comprises a supporting structure, a control system and a striking structure; the striking structure is a pendulum; the one-dimensional Hopkinson pressure bar system based on hydraulic propulsion on two sides comprises a plurality of supports arranged on a supporting platform, wherein an incident bar and a transmission bar are arranged on the supports; the hydraulic cylinder is provided with two side pushing hydraulic cylinders; a seventh support in the supports is fixedly connected with two side pushing oil pressure cylinders, the tail end of the transmission rod extends out of the center position of the seventh support, and a controllable high-frequency pendulum striking system based on a pressure sensor is arranged on one side of the tail end of the transmission rod; the pendulum in the controllable high-frequency pendulum striking system based on the pressure sensor directly strikes the tail end of the transmission rod, and the tail end is the end far away from the sample.
As a further improvement of the invention, the incident beam is provided with a thick diameter of the incident beam, and a thick diameter portion of the thick diameter of the incident beam is abutted against a first one of the holders.
As a further improvement of the present invention, the transmission rod is provided with a transmission rod thick diameter, and a thick diameter portion of the transmission rod thick diameter abuts against a sixth one of the holders.
As a further improvement of the invention, the one-dimensional Hopkinson pressure bar system based on hydraulic propulsion at two sides further comprises a high-pressure air chamber, a gun barrel and a bullet, wherein the high-pressure air chamber is connected with the gun barrel, and the bullet is arranged in the gun barrel.
As a further improvement of the invention, the controllable high-frequency pendulum striking system based on the pressure sensor sequentially comprises a support base, a screw rod support, a hammer body, a hammer head, a pendulum rod, a fixed cross rod, a double-gear embedded central cross shaft, a left servo motor, a right servo motor, a double-gear transmission shaft, a first main control system, a pressure data processing device and an angle sensor from bottom to top; the lead screw pillar is connected on the pillar base, fixed horizontal pole is connected on the lead screw pillar, the embedded central cross axle of dual gear is connected with fixed horizontal pole through bearing rotor, angle sensor installs in fixed horizontal pole front side and highly keeps unanimous with the embedded central cross axle central plane of dual gear, the pendulum pole is connected with the embedded central cross axle of dual gear, the tup setting is on the pendulum pole, simultaneously pressure sensor embeds at the tup front end, left side servo motor, right side servo motor, first master control system, pressure data processing apparatus sets up in fixed horizontal pole top, dual gear transmission shaft welding and passes left side servo motor), right side servo motor's rotor.
As a further improvement of the invention, the four screw rod struts on two sides can adjust the length; one surface of the base, which is clung to the ground, is covered with a coating.
As a further improvement of the invention, the freeze-thawing cycle device comprises a cold air inlet, a cold air outlet, a thermocouple power line, a thermocouple, a cold air circulation pipeline and a freeze-thawing cycle control device; the cold air inlet and the cold air outlet are connected with the freezing and thawing cycle control device from the upper part, the thermocouple power line is connected with the freezing and thawing cycle control device from the upper part, the cold air is sent into the cold air circulation pipeline from the cold air inlet and then discharged from the cold air outlet, the cold air compressor and the second main control system are arranged in the freezing and thawing cycle control device, and the thermocouple is heated by the second main control system.
The method for testing the SHPB by coupling the freeze-thawing cycle and the power disturbance comprises the step of testing by using the SHPB testing device by coupling the freeze-thawing cycle and the power disturbance; before the test, the sample is placed between the incident rod and the transmission rod in parallel along the height direction, the freeze-thawing cycle confining pressure loading system seals the sample in the sample for freeze-thawing cycle and confining pressure loading, the two-side propulsion oil pressure cylinders are utilized for providing the sample with shaft pressure of a preset magnitude, during the test, the striking structure of the controllable high-frequency pendulum striking system based on the pressure sensor strikes the transmission rod under the power driving action, and when the controllable high-frequency pendulum striking system based on the pressure sensor strikes the one-dimensional Hopkinson pressure bar system based on the hydraulic propulsion of the two sides, the time of one-time power disturbance is less than 10s; the number of times of impact required by the sample to be destroyed is more than 10000 times; the incident stress intensity of the striking is less than 50Mpa.
As a further improvement of the invention, the dynamic disturbance is ended, the impact rock breaking is carried out, the final dynamic mechanical property of the sample is calculated, and an incident stress wave is generated at the incident rod end and at the wave speedPropagating forward, E e is the elastic modulus of the rod body,The density of the rod body is the density of the rod body, and reflected stress waves and transmitted stress waves are respectively generated in the incident rod and the transmission rod after the rod body is contacted with the sample; measurement of incident Strain Signal Using Strain gauge attached to incident rodAnd a reflected strain signalThe strain gauge stuck on the transmission rod measures the transmission strain signal; The stress, strain and strain rate time course curve of the sample is calculated by the following formula:
Wherein: a e is the cross-sectional area of the compression bar, m 2;As is the cross-sectional area of the sample, m 2;Ls is the length of the sample, m; c e and E e are respectively the longitudinal wave velocity and the elastic modulus, m/s and GPa of the elastic rod.
As a further improvement of the invention, after the power disturbance of the preset period is finished, the high-pressure air stored in the high-pressure air chamber in the one-dimensional Hopkinson pressure bar system based on oil pressure propulsion at two sides is used for driving the bullet to strike the incident bar, the high-amplitude incident stress can realize the rock breaking by striking, and the power disturbance and dynamic impact test data are recorded to the oscilloscope and the high-performance computer through the strain gauge and are used for researching the dynamic mechanical response of the surrounding rock of the submarine tunnel after the coupling damage of the seawater corrosion and the high-frequency power disturbance.
The beneficial effects of the invention are as follows:
The application designs a controllable high-frequency pendulum striking system based on a pressure sensor by utilizing gravitational potential energy of a pendulum, and the system directly realizes high-frequency high Zhou Di amplitude dynamic disturbance on rocks bearing the action of freeze thawing circulation by automatically controlling the striking frequency and the height of the pendulum. In addition, the application designs a freeze-thawing cycle confining pressure loading system, and realizes that the freeze-thawing cycle and confining pressure loading are carried out on the sample at the same time.
(1) The freeze-thawing cycle-three-dimensional static load-power disturbance coupling Hopkinson pressure bar testing device designs a controllable high-frequency pendulum striking system based on a pressure sensor in a modularized concept, can realize uniform, rapid and accurate controllable high-frequency power disturbance on a sample, and solves the technical problems that the incident stress amplitude generated when a traditional Hopkinson pressure bar bullet is impacted is large and repeated high-frequency impact cannot be carried out.
(2) The freezing-thawing cycle-three-dimensional static load-power disturbance coupling Hopkinson pressure bar testing device applies axial force to a sample by adopting a double-oil-pressure cylinder pushing mode at two sides, and meanwhile, a cushion block for transmitting axial pressure in the traditional Hopkinson pressure bar is removed, so that the problem of power disturbance manufactured from the tail end of a transmission rod by utilizing a pendulum is solved, the stress uniformity of the sample is facilitated, and errors caused by eccentric stress are reduced. In addition, the invention can maintain the axial pressure and the confining pressure to be relatively stable in the power disturbance process, and overcomes the defect that the axial pressure and the confining pressure in the traditional Hopkinson pressure bar can not be relatively stable in the repeated impact process.
(3) The device for testing the freezing and thawing cycle-three-dimensional static load-power disturbance coupling Hopkinson pressure bar can develop high-frequency power disturbance for the rock under the action of the three-dimensional static load and the freezing and thawing cycle, realize dynamic impact test after the coupling action of the freezing and thawing cycle-three-dimensional static load-power disturbance, the method solves the technical problem that the existing dynamic mechanical test of rock based on the Hopkinson pressure bar device can not simulate freeze thawing cycle-three-dimensional static load-power disturbance multi-field coupling in the test process, and enables the test process to be closer to the real stress environment of rock mass in cold mining areas, so that the test result is more reliable and accurate.
The specific detail effects are supplemented as follows:
In order to realize high-frequency power disturbance on the sample 107 from the tail end of the Hopkinson pressure bar, the invention improves a conventional oil pressure cylinder body with central propulsion into bilateral symmetrical propulsion so that the tail end of the transmission rod can extend from the central position.
In the conventional hopkinson bar device, the axial pressure applied to the sample 107 is transmitted through the cushion block at the front end of the incident bar 105 and the tail end of the transmission bar 106, but in consideration of the fact that tens of thousands of high-frequency power disturbance can cause the contact condition between the cushion block and the bar to change, the error can be caused in stress wave transmission, therefore, when the incident bar 105 and the transmission bar 106 are processed, the diameter of the bar is properly increased at a proper position from any end surface of the bar, such as the thick incident bar diameter 1051 in fig. 3A and the thick transmission bar diameter 1061 in fig. 3B, the processing aims are that the thick diameter part of the thick incident bar diameter 1051 can bear against the first support 111, the thick diameter part of the transmission bar diameter 1061 can bear against the sixth support 116, and the axial pressure is gradually applied to the sample 107 along with the pushing of the pushing oil cylinders 108 at both sides.
Drawings
FIG. 1 is a three-dimensional diagram of a freeze-thaw cycle-three-dimensional static load-dynamic disturbance coupling Hopkinson pressure bar testing device;
FIG. 2A is a front view of a freeze-thaw cycle-three-dimensional static load-dynamic disturbance coupled Hopkinson pressure bar testing device;
FIG. 2B is a side view of a freeze-thaw cycle-three-dimensional static load-dynamic disturbance coupled Hopkinson pressure bar testing device;
FIG. 2C is a top view of a freeze-thaw cycle-three-dimensional static load-dynamic disturbance coupled Hopkinson pressure bar testing device;
FIG. 3A is a three-dimensional view of a one-dimensional Hopkinson pressure bar system based on hydraulic propulsion on two sides;
FIG. 3B is another angular view of the left-hand enlarged view of FIG. 3A;
FIG. 4 is a three-dimensional view of a freeze-thaw cycle confining pressure loading system;
FIG. 5A is a front view of a freeze-thaw cycle confining pressure loading system;
FIG. 5B is a side view of a freeze-thaw cycle confining pressure loading system;
FIG. 5C is a top view of a freeze-thaw cycle confining pressure loading system;
FIG. 6 is an internal cross-sectional view of a freeze thawing cycle confining pressure loading system;
FIG. 7 is an elevation view of a freeze thawing cycle confining pressure loading system in section;
FIG. 8 is a three-dimensional view of a controllable high frequency pendulum impact system based on pressure sensors;
FIG. 9A is a front view of a pressure sensor based controllable high frequency pendulum impact system;
FIG. 9B is a side view of a pressure sensor based controllable high frequency pendulum impact system;
Fig. 9C is a top view of a pressure sensor based controllable high frequency pendulum impact system.
The reference numbers correspond to the component designations as follows:
One-dimensional Hopkinson pressure bar system 1 based on oil pressure propulsion on two sides, freeze thawing cycle confining pressure loading system 2 and controllable high-frequency pendulum striking system 3 based on pressure sensors;
The device comprises a supporting platform 100, a guide rail 101, a high-pressure air chamber 102, a gun barrel 103, a bullet 104, an incidence rod 105, an incidence rod thick diameter 1051, a transmission rod 106, a transmission rod thick diameter 1061, a sample 107, a two-side pushing hydraulic cylinder 108, a ninth support 109, a tenth support 110, a first support 111, a second support 112, a third support 113, a fourth support 114, a fifth support 115, a sixth support 116, a seventh support 117 and a strain gauge 118;
the device comprises a confining pressure loading cylinder base 200, a confining pressure loading cylinder upper end fixing frame 201, a confining pressure cylinder body 202, a pressure gauge 203, an oil inlet 204, an oil outlet 205, a cold air inlet 206, a cold air outlet 207, a thermocouple power line 208, a thermocouple 209, a cold air circulation pipeline 210, a confining pressure loading rubber sleeve 211 and a freezing and thawing circulation control device 212;
The device comprises a support base 300, a screw rod support 301, a hammer body 302, a hammer head 303, a pendulum rod 304, a fixed cross rod 305, a double-gear embedded central cross shaft 306, a left servo motor 307, a right servo motor 308, a double-gear transmission shaft 309, a first main control system 310, a pressure data processing device 311 and an angle sensor 312.
Detailed Description
The invention is further described below with reference to the accompanying drawings.
The theoretical basis of the invention is as follows: the split Hopkinson pressure bar is suitable for dynamic testing of various rock materials, and the testing process is usually completed in microsecond time, so that high-amplitude dynamic impact can be provided. In general, the rocks in cold regions are not only subjected to freeze-thawing cycle action, but also subjected to high-frequency and low-amplitude power disturbance from mechanical vibration, explosion shock waves, driving loads and the like. Therefore, the dynamic mechanical characteristics of the explored rock after the freeze thawing cycle and the dynamic disturbance coupling damage can be used for more comprehensively evaluating the impact damage resistance performance of the cold region rock engineering. The dynamic impact test utilizes the existing one-dimensional stress wave theory to calculate the damage rule and the dynamic characteristics. The specific principle is as follows:
two basic assumptions: (1) One-dimensional assumption, also called planar assumption, assumes that the system is strictly in one-dimensional stress state, and each cross section in the rod remains planar all the time when a stress wave propagates in the elongated elastic rod. (2) Stress uniformity assumes that the stress wave is equal at both ends of the specimen and at the internal stress locations along the loading direction after multiple back and forth reflections within the specimen.
The calculation formula is as follows: before testing, the rock sample was placed in parallel in the height direction between the incident rod and the transmission rod. During test, the punch head impacts the incident rod under the action of power drive to produce one incident stress wave at the incident rod end(E e is the elastic modulus of the rod body,Rod density) and generates reflected and transmitted stress waves in the incident and transmitted rods, respectively, upon contact with the specimen. Measurement of incident Strain Signal Using Strain gauge attached to incident rodAnd a reflected strain signalThe strain gauge stuck on the transmission rod measures the transmission strain signal. The stress, strain and strain rate time course curve of the sample is calculated by the following formula:
Wherein: a e is the cross-sectional area of the compression bar, m 2;As is the cross-sectional area of the sample, m 2;Ls is the length of the sample, m; c e and E e are respectively the longitudinal wave velocity and the elastic modulus, m/s and GPa of the elastic rod.
Embodiment 1: the SHPB testing device is loaded by coupling the freeze thawing cycle and the power disturbance.
Fig. 1, fig. 2A, fig. 2B, and fig. 2C are respectively a three-dimensional diagram and a three-dimensional diagram of a freezing and thawing cycle-three-dimensional static load-power disturbance coupling hopkinson pressure bar testing device.
As shown in fig. 1 and 3A, the whole testing device is centered on a sample 107, wherein a one-dimensional hopkinson pressure bar system 1 propelled based on oil pressure on two sides is arranged on the left side and the right side of the sample 107, a controllable high-frequency pendulum striking system 3 based on a pressure sensor is arranged on one side of the tail end of a transmission rod 106, and the tail end is one end far away from the sample 107.
Fig. 3A is a three-dimensional diagram of a one-dimensional hopkinson pressure bar system based on two-side oil pressure propulsion, which mainly comprises a supporting platform 100, a guide rail 101, a high-pressure air chamber 102, a gun barrel 103, a bullet 104, an incident bar 105, a transmission bar 106, a sample 107, two-side propulsion oil pressure cylinders 108, a plurality of supports and strain gauges. Wherein: high pressure range of high pressure air chamber: 0.05MPa to 1.0MPa.
The high-pressure air chamber 102 is connected with the gun barrel 103, and the bullet 104 is arranged in the gun barrel 103; the incidence rod 105 is provided with an incidence rod thick diameter 1051, the transmission rod 106 is provided with a transmission rod thick diameter 1061, a thick diameter portion of the incidence rod thick diameter 1051 is abutted against a first support 111 of the supports, and a thick diameter portion of the transmission rod thick diameter 1061 is abutted against a sixth support 116 of the supports.
Referring to fig. 4, the freeze-thawing cycle confining pressure loading system 2 includes a confining pressure loading cylinder base 200, a confining pressure loading cylinder upper end fixing frame 201, a confining pressure cylinder body 202, a pressure gauge 203, an oil inlet 204, an oil outlet 205, a cold air inlet 206, a cold air outlet 207, a thermocouple power cord 208, a thermocouple 209, a cold air circulation pipe 210, a confining pressure loading rubber sleeve 211 and a freeze-thawing cycle control device 212. The confining pressure loading device is composed of a confining pressure loading cylinder base 200, a confining pressure loading cylinder upper end fixing frame 201, a confining pressure cylinder body 202, a pressure gauge 203, an oil inlet 204, an oil outlet 205 and a confining pressure loading rubber sleeve 211, wherein the confining pressure loading cylinder base 200 is arranged on a guide rail 101, the confining pressure cylinder body 202 is placed on the confining pressure loading cylinder base 200, the confining pressure loading cylinder upper end fixing frame 201 is buckled on the confining pressure loading cylinder base 200, a fixing screw is screwed, the oil outlet 205 is closed when confining pressure is applied to a sample 107, hydraulic oil is pumped into the confining pressure cylinder body 202 from the oil inlet 204, after the number of the pressure gauge 203 reaches a preset confining pressure, the oil pumping is stopped, and finally the oil inlet 204 is closed, so that the confining pressure loading step is completed.
The freeze-thawing cycle device mainly comprises a cold air inlet 206, a cold air outlet 207, a thermocouple power line 208, a thermocouple 209, a cold air circulation pipeline 210 and a freeze-thawing cycle control device 212; a cold air inlet 206 and a cold air outlet 207 are connected to the freeze/thaw cycle control device 212 from above, and a thermocouple power cord 208 is also connected to the freeze/thaw cycle control device 212 above. The cold air is fed into the cold air circulation duct 210 from the cold air inlet 206 and is discharged from the cold air outlet 207. The freeze-thaw cycle control device 212 is internally provided with a cold air compressor and a second main control system, and the thermocouple 209 is heated by the second main control system.
Fig. 8, 9A, 9B, and 9C are three-dimensional and three-dimensional views of a controllable high-frequency pendulum striking system based on a pressure sensor, respectively, from bottom to top, a column base 300, a screw column 301, a hammer body 302, a hammer head 303, a pendulum rod 304, a fixed cross rod 305, a dual-gear embedded center cross shaft 306, a left servo motor 307, a right servo motor 308, a dual-gear transmission shaft 309, a pressure data processing device 311, a first main control system 310, and an angle sensor 312.
The screw rod support 301 is connected to the support base 300 through welding, the fixed cross rod 305 is connected to the screw rod support 301 through a screw, the double-gear embedded central cross shaft 306 is connected to the fixed cross shaft 305 through a bearing rotor, so that the effect of random rotation is achieved, the angle sensor 312 is installed on the front side of the fixed cross shaft 305 and keeps the height consistent with the central plane of the double-gear embedded central cross shaft 306, the pendulum rod 304 is connected to the double-gear embedded central cross shaft 306 through a screw, the hammer head 303 is also connected with the pendulum rod 304 through a screw, meanwhile, the pressure sensor is embedded at the front end of the hammer head 303, the left servo motor 307, the right servo motor 308, the first main control system 310 and the pressure data processing device 311 are welded above the fixed cross shaft 305, and the double-gear transmission shaft 309 is welded and penetrates through the rotors of the left servo motor 307 and the right servo motor 308, so that the purpose of timely rotation is achieved.
Four screw rods 301 on two sides are used for lifting and fixing a pendulum striking device, and the length of the pendulum striking device can be adjusted, so that the hammer 303 can be aligned to the center of the tail end of the transmission rod 106 quickly and conveniently; the lower ends of the screw rods support columns 301 are connected with four support column bases 300, and one surface of each base, which is clung to the ground, is covered with a coating with a higher friction coefficient, so that the whole controllable high-frequency pendulum striking system 3 based on the pressure sensor is stabilized on the ground by using higher friction force, and the sliding of the controllable high-frequency pendulum striking system is avoided.
Embodiment 2: the method for testing the SHPB by coupling freeze thawing cycle and power disturbance.
(1) How to apply axial pressure to the sample and building a basic test platform: as shown in fig. 3A, since the hydraulic cylinder position and the shaft pressure transmission mode are changed, the installation sequence of the one-dimensional hopkinson compression bar system 1 based on the hydraulic propulsion at two sides during the test is as follows: the guide rail 101 is first fixed to the support platform 100 by screws.
As shown in fig. 1, a fourth support 114, a fifth support 115 and a confining pressure loading cylinder base 200 are sequentially installed and fixed, one end of the transmission rod 106 without a thick diameter passes through the fifth support 115 and the fourth support 114, and then one end of the transmission rod 106 with a thick diameter sequentially passes through a sixth support 116 and a seventh support 117, wherein the seventh support 117 is fixedly connected with two side pushing hydraulic cylinders 108, and the two side pushing hydraulic cylinders 108 are used for applying shaft pressure.
Then, the second support 112 and the third support 113 are sequentially installed along the guide rail 101, one end of the incident rod 105 without a thick diameter penetrates through the second support 112 and the third support 113, one end with a thick diameter penetrates through the first support 111 along the incident rod 105, then the bullet 104 is pushed into the gun barrel 103, then the ninth support 109 and the tenth support 110 are installed along the guide rail 101, then the high-pressure air chamber 102 and the gun barrel 103 penetrate through the ninth support 109 and the tenth support 110 from the front end of the device, and finally screws for fixing the supports are screwed, so that the installation work of the improved Hopkinson pressure bar system can be completed.
(2) Performing freeze thawing cycle on the rock sample and applying confining pressure: as shown in fig. 1,4, 5A and 5B, a confining pressure loading cylinder base 200 is pre-installed on a guide rail 101, then a confining pressure cylinder body 202 is placed on the confining pressure loading cylinder base 200, a confining pressure loading cylinder upper end fixing frame 201 is buckled, and a screw is screwed to fixedly connect the confining pressure loading cylinder upper end fixing frame 201 with the confining pressure loading cylinder base 200, so that the confining pressure cylinder body 202 is fixed.
As shown in fig. 6 and 7, the freeze/thaw cycle confining pressure loading system 2 seals the sample 107 inside to perform freeze/thaw cycle and confining pressure loading. The method comprises the steps of conveying a sample 107 from one side of a freeze thawing cycle confining pressure loading system 2 to the central position inside a confining pressure loading rubber sleeve 211, inserting an incident rod 105 and a transmission rod 106 into the confining pressure loading rubber sleeve 211 from two sides respectively, clamping the sample 107 between the incident rod 105 and the transmission rod 106 by utilizing a two-side pushing hydraulic cylinder 108, providing shaft pressure, pressing the two-side pushing hydraulic cylinder 108 to apply the shaft pressure to the sample 107, and closing an oil inlet channel of the two-side pushing hydraulic cylinder 108 after the shaft pressure reaches a preset value so as to maintain the shaft pressure of the two-side pushing hydraulic cylinder 108 at the preset value; then hydraulic oil is pumped into the confining pressure cylinder 202 by using the oil inlet 204 in the freezing and thawing cycle confining pressure loading system 2, so as to apply confining pressure to the sample 107, and after the confining pressure reaches a preset value, the oil inlet 204 of the confining pressure loading device is closed, so that the confining pressure of the confining pressure loading device is maintained at the preset value;
The freeze-thaw cycle is then started to freeze and thaw the sample 107 for a predetermined time until a predetermined freeze-thaw cycle is reached.
The freeze-thawing cycle control device 212 is internally provided with a cold air compressor and a second main control system, wherein the second main control system can set the freeze-thawing cycle time and period, the thermocouple 209 is also heated by the second main control system, cold air manufactured by the air compressor is sent into the cold air circulation pipeline 210 from the cold air inlet 206 after confining pressure is stable, and then is discharged from the cold air outlet 207, so that the sample 107 is subjected to freezing cycle until reaching the preset freezing temperature, the cold air delivery is stopped after reaching the preset freezing time, the thermocouple 209 is started at the same time to gradually melt the frozen sample 107, and the sample is stopped after reaching the preset melting temperature and maintaining the preset melting time, and then freezing and thawing are restarted, so that the cycle is completed until the preset freeze-thawing period. Freezing and thawing of sample 107 during the freeze-thaw cycle is accomplished by transferring the temperature of the hydraulic oil within the confining pressure cylinder 202.
(3) High-frequency, high-cycle and low-amplitude dynamic disturbance is carried out on the rock sample: the controllable high-frequency pendulum beating system 3 based on a pressure sensor is used for periodically performing power disturbance on the sample 107, the pendulum beating height, the transfer time (namely, the time for separating from a transmission rod and transferring to the preset beating height after the pendulum beating is completed and being monitored and controlled by an angle sensor 312) and the power disturbance period (namely, the number of pendulum repeated beating times corresponding to specific working conditions can be more than tens of thousands) are preset through the first main control system 310, so that the left servo motor 307 and the right servo motor 308 are controlled to rotate to improve the pendulum height, after the pendulum rises to the preset height, the first main control system 310 immediately sends a power-off instruction to the left servo motor 307 and the right servo motor 308, which causes the double-gear embedded central transverse shaft 306 to lose the limitation of the left servo motor 307 and the right servo motor 308, thereby realizing the free swinging of the pendulum in the same plane, the pressure monitored by the pressure sensor arranged in the hammer head 303 is always 0N in the period from the beginning of the pendulum to the beginning of the pendulum when the hammer head 303 just contacts the center of the tail end of the transmission rod 106, the pressure monitored by the pressure sensor is rapidly increased when the hammer head 303 reaches the maximum contact position with the tail end of the transmission rod 106, the pressure reaches the maximum value, then the pressure gradually decreases along with the beginning of the rebound of the hammer head 303 until the hammer head 303 just separates from the tail end of the transmission rod 106, at the moment, the pressure returns to 0N again, the pressure monitored by the pressure sensor changes in a sine function along with time in the whole striking process, the pressure data processing device 311 sends the processed pressure signal to the first main control system 310, and when the first main control system 310 monitors that the pressure decreases from the peak value to 0N, the servo motor 307 on the left side immediately, the right servo motor 308 sends out an energizing instruction so that the pendulum is transferred again to a preset height by the left servo motor 307 and the right servo motor 308 within a preset transfer time. The working principle of the pressure sensor-based controllable high-frequency pendulum striking system 3 in one striking period is as above, and then the period is repeated continuously through the first main control system 310 until the striking is stopped after the preset power disturbance period is completed.
(4) How to perform dynamic impact test on the rock sample subjected to dynamic disturbance: after the sample 107 completes a preset power disturbance period, the striking is stopped, the bullet 104 is driven by high-pressure gas in the high-pressure air chamber 102 at the front end of the Hopkinson pressure bar system to strike the front end of the incident bar 105, so that the dynamic impact test of the sample 107 is completed, and the stress wave time course is recorded by the strain gauge on the bar, so that the corresponding dynamic mechanical characteristics such as peak stress, peak strain, elastic modulus and the like are calculated.
Embodiment 3: under different freeze thawing cycle periods, the dynamic disturbance of different periods affects the dynamic mechanical characteristics and the destruction rules of granite.
Taking mining areas in northwest regions of China as references, the common temperature difference range is-20 ℃ to 20 ℃, and the influence of dynamic disturbance on the dynamic mechanical properties and the destruction rules of granite under the freeze thawing circulation action of different periods is explored. Taking 9 granite samples, and carrying out dynamic impact tests after the freeze thawing cycle period is 10 times, 20 times and 40 times respectively on 3 groups of granite samples, and comparing and analyzing the influences of the freeze thawing cycles and dynamic disturbance in different cycles on the dynamic peak strength, peak strain, elastic modulus and other mechanical characteristics of the samples and macro-micro destruction rules. Through calculation, the power disturbance periods corresponding to 10 times, 20 times and 40 times of freeze thawing cycles are 57600, 115200 and 230400 times respectively.
The related equipment of the one-dimensional Hopkinson pressure bar system 1 based on the hydraulic propulsion of two sides is arranged on a supporting platform 100 with the length, the width and the height of 5m, 0.6 m and 0.4m respectively according to the connection mode shown in fig. 3A, and the connection relation and the related functions of the equipment are specifically described as follows: the guide rail 101 is fixed on the supporting platform 100 through screws, then the fourth support 114, the fifth support 115 and the confining pressure loading cylinder base 200 are sequentially installed and fixed, one end of the transmission rod 106 with the diameter of 50mm and the length of 2m and without the thick diameter passes through the fifth support 115 and the fourth support 114 from the left side of the freeze thawing cycle confining pressure loading system 2, Then sequentially penetrating into a sixth support 116 and a seventh support 117 along the transmission rod with one end with a thick diameter, wherein the seventh support 117 is integrated with two side pushing hydraulic cylinders 108 for applying axial pressure, sequentially installing a second support 112 and a third support 113 along the guide rail 101, penetrating one end with a diameter of 50mm and a length of 2m of the incident rod 105 without the thick diameter through the second support 112 and the third support 113 along the right end of the freeze thawing cycle confining pressure loading system 2, penetrating one end with a thick diameter into the first support 111 along the incident rod 105, pushing a bullet 104 with a diameter of 50mm and a length of 200mm into the gun barrel 103, Then, a ninth support 109 and a tenth support 110 are installed along the guide rail 101, then the high-pressure air chamber 102 and the gun barrel 103 pass through the ninth support 109 and the tenth support 110 from the front end of the device, and finally screws for fixing the supports are screwed, so that the installation work of the improved one-dimensional Hopkinson pressure bar system can be completed. When in use, the distance between the tail end of the incident rod 105 and the front end of the transmission rod 106 is regulated by the two-side pushing hydraulic cylinders 108, so that the incident rod can be placed into the freeze-thawing cycle confining pressure loading system 2, the confining pressure cylinder 202 is placed on the confining pressure loading cylinder base 200 from the upper side of the one-dimensional Hopkinson pressure bar system 1 based on the hydraulic pushing of the two sides, the confining pressure loading cylinder upper end fixing frame 201 is buckled, the confining pressure loading cylinder upper end fixing frame 201 and the confining pressure loading cylinder base 200 are fixedly connected by screwing, the confining pressure cylinder can be fixed, then a sample 107 (granite, the diameter and the height are 50mm and the porosity is about 6%) is sent to the central position inside the confining pressure loading rubber sleeve 211 from the left side of the freeze-thawing cycle confining pressure loading system 2, Then the incident rod 105 and the transmission rod 106 are respectively inserted into the confining pressure loading rubber sleeve 211 from the right side and the left side, the two-side pushing oil hydraulic cylinders 108 are pressed to apply shaft pressure (10 MPa) to the sample 107, after the shaft pressure reaches 10MPa, the oil inlet channels of the two-side pushing oil hydraulic cylinders 108 are closed to maintain the shaft pressure in the two-side pushing oil hydraulic cylinders 108 at 10MPa, then the confining pressure (10 MPa) is applied to the sample 107 by pressing the confining pressure oil hydraulic cylinders, after the confining pressure reaches 10MPa, the oil inlet 204 of the confining pressure loading device is closed to maintain the confining pressure in the confining pressure cylinders at 10MPa, after the confining pressure is stable, the second main control system is operated, Cold air produced by an air compressor is sent into a cold air circulation pipeline 210 from a cold air inlet 206 and is discharged from a cold air outlet 207, so that the sample 107 is subjected to a freezing cycle (the cooling rate is 0.5 ℃/min) until reaching a preset freezing temperature (-20 ℃), the freezing is stopped after reaching a preset freezing time (2 h), a thermocouple 209 is started at the same time to gradually melt the frozen sample 107 (the heating rate is also 0.5 ℃/min), the sample is stopped after reaching a preset melting temperature (20 ℃) and maintaining the preset melting time (2 h), the freezing cycle time is 8h, and then the freezing is performed again, the thawing process is cycled until a preset freeze-thawing period (10 times). The high-frequency power disturbance is performed while the freezing and thawing cycle action is performed on the sample 107, a controllable high-frequency pendulum striking system 3 based on a pressure sensor is erected, the pendulum striking height (10 cm), the transfer time (5 s) and the power disturbance period (57600 times) are preset through the first main control system 310, so that the left servo motor 307 and the right servo motor 308 are controlled to rotate to improve the pendulum height, and after the pendulum is lifted to the preset height (10 mm), the first main control system 310 immediately sends out a power-off instruction to the left servo motor 307 and the right servo motor 308, which causes the double-gear embedded central transverse shaft 306 to lose the left servo motor 307, the right servo motor 308 limits, thus realizing free pendulum of the pendulum in the same plane, the pressure monitored by the pressure sensor arranged in the hammer head 303 is always 0N in the period from the moment that the pendulum starts to swing down to the moment that the hammer head 303 just contacts the center of the tail end of the transmission rod 106, the pressure monitored by the pressure sensor rapidly rises when the hammer head just starts to strike the tail end of the transmission rod 106, the pressure reaches the maximum value when the hammer head 303 reaches the maximum contact position with the tail end of the transmission rod 106, then the pressure gradually drops along with the beginning of rebound of the hammer head 303 until the hammer head 303 just separates from the tail end of the transmission rod 106, at the moment, the pressure returns to 0N again, in the whole striking process, the pressure value monitored by the pressure sensor changes in a sine function along with time, the pressure data processing device 311 sends a processed pressure signal to the first main control system 310, and when the first main control system 310 monitors that the pressure is reduced to 0N from a peak value, an energizing instruction is immediately sent to the left servo motor 307 and the right servo motor 308, so that the pendulum bob is transferred to a preset height by the left servo motor 307 and the right servo motor 308 within a preset transfer time again. The working principle of the pressure sensor-based controllable high-frequency pendulum striking system 3 in one striking period (a power disturbance period can be controlled by the first main control system to be completed within 5 s) is as above, and then the period is repeated continuously by the first main control system 310 until the preset freeze thawing cycle period is completed, so that the power disturbance times can be calculated: n=8h×10×60×60/5=57600 times. Then, the same test procedure is carried out on the two remaining samples 107 of 10 freeze thawing cycles, and after the test is finished on the same group of 3 samples, the dynamic mechanical properties of the samples are averaged、、The following are all the following. Similarly, the same test steps and data processing are carried out on 3 samples respectively subjected to 20 freeze thawing cycles and 40 freeze thawing cycles, so that dynamic mechanical properties can be obtained、、·····，、、The following are all the following. The influence of different dynamic disturbance periods on granite dynamic mechanical response and damage rules, damage degradation mechanism and the like are analyzed through the dynamic mechanical characteristics obtained by 10 times, 20 times and 40 times of freeze thawing cycles, and the calculation formula is as follows:
Wherein A e is the cross-sectional area of the compression bar (0.196 m 2);As is the cross-sectional area of the sample (0.196 m 2);Ls is the sample length (50 mm); C e and E e are the longitudinal wave velocity (5934 m/s) and the elastic modulus (271 GPa) of the elastic bar, respectively; an incident strain signal is measured for a strain gauge on the incident beam, A reflected strain signal is measured for a strain gauge on the incident beam,The transmitted strain signal is measured for a strain gauge on the transmission rod.
The foregoing is a further detailed description of the invention in connection with the preferred embodiments, and it is not intended that the invention be limited to the specific embodiments described. It will be apparent to those skilled in the art that several simple deductions or substitutions may be made without departing from the spirit of the invention, and these should be considered to be within the scope of the invention.
Claims (10)
1. The freeze thawing cycle and power disturbance coupling loading SHPB testing device is characterized in that: the device comprises a one-dimensional Hopkinson pressure bar system (1) based on oil pressure propulsion on two sides, a freeze thawing cycle confining pressure loading system (2), a controllable high-frequency pendulum striking system (3) based on a pressure sensor and a data acquisition and analysis system; the freeze-thawing cycle confining pressure loading system (2) comprises a confining pressure loading device, a freeze-thawing cycle device and a second main control system, and the freeze-thawing cycle confining pressure loading system (2) simulates the working condition that rocks in cold areas bear freeze-thawing cycle-confining pressure loading; the controllable high-frequency pendulum striking system (3) based on the pressure sensor comprises a supporting structure, a control system and a striking structure; the striking structure is a pendulum; the one-dimensional Hopkinson pressure bar system (1) based on hydraulic propulsion at two sides comprises a plurality of supports arranged on a supporting platform, wherein an incident bar (105) and a transmission bar (106) are arranged on the supports; the hydraulic device also comprises two side pushing hydraulic cylinders (108); a seventh support (117) in the supports is fixedly connected with two side pushing oil pressure cylinders (108), the tail end of the transmission rod (106) extends out from the center position of the seventh support (117), and a controllable high-frequency pendulum striking system (3) based on a pressure sensor is arranged on one side of the tail end of the transmission rod (106); the pendulum in the controllable high-frequency pendulum striking system (3) based on the pressure sensor directly strikes the tail end of the transmission rod (106), wherein the tail end is the end far away from the sample.
2. The freeze-thaw cycle and power disturbance coupled loading SHPB test device of claim 1, wherein: the incidence rod (105) is provided with an incidence rod thick diameter (1051), and a thick diameter portion of the incidence rod thick diameter (1051) is abutted against a first support (111) among the supports.
3. The freeze-thaw cycle and power disturbance coupled loading SHPB test device of claim 1, wherein: the transmission rod (106) is provided with a transmission rod thick diameter (1061), and a thick diameter portion of the transmission rod thick diameter (1061) abuts against a sixth one (116) of the holders.
4. The freeze-thaw cycle and power disturbance coupled loading SHPB test device of claim 1, wherein: the one-dimensional Hopkinson pressure bar system (1) based on oil pressure propulsion on two sides further comprises a high-pressure air chamber (102), a gun barrel (103) and a bullet (104), wherein the gun barrel (103) is connected with the high-pressure air chamber (102), and the bullet (104) is arranged in the gun barrel (103).
5. The freeze-thaw cycle and power disturbance coupled loading SHPB test device of claim 1, wherein: the controllable high-frequency pendulum striking system (3) based on the pressure sensor sequentially comprises a support base (300), a screw rod support (301), a hammer body (302), a hammer head (303), a pendulum rod (304), a fixed cross rod (305), a double-gear embedded central cross shaft (306), a left servo motor (307), a right servo motor (308), a double-gear transmission shaft (309), a first main control system (310), a pressure data processing device (311) and an angle sensor (312) from bottom to top; the screw rod support (301) is connected to the support base (300), the fixed cross rod (305) is connected to the screw rod support (301), the double-gear embedded type center cross shaft (306) is connected with the fixed cross shaft (305) through a bearing rotor, the angle sensor (312) is installed on the front side of the fixed cross shaft (305) and keeps the same height with the center plane of the double-gear embedded type center cross shaft (306), the pendulum rod (304) is connected with the double-gear embedded type center cross shaft (306), the hammer head (303) is arranged on the pendulum rod (304), meanwhile, the pressure sensor is embedded at the front end of the hammer head (303), the left servo motor (307), the right servo motor (308), the first main control system (310) and the pressure data processing device (311) are arranged above the fixed cross shaft (305), and the double-gear transmission shaft (309) is welded and penetrates through rotors of the left servo motor (307) and the right servo motor (308).
6. The freeze-thaw cycle and power disturbance coupled loading SHPB test device of claim 5, wherein: the four screw rod struts (301) on the two sides can adjust the length; the support base (300) is tightly attached to one side of the ground is covered with a coating.
7. The freeze-thaw cycle and power disturbance coupled loading SHPB test device of claim 1, wherein: the freeze-thawing cycle device comprises a cold air inlet (206), a cold air outlet (207), a thermocouple power line (208), a thermocouple (209), a cold air circulation pipeline (210) and a freeze-thawing cycle control device (212); the cold air inlet (206) and the cold air outlet (207) are connected with the cold thawing cycle control device (212) from the upper part, the thermocouple power line (208) is also connected with the cold thawing cycle control device (212), cold air is sent into the cold air circulation pipeline (210) from the cold air inlet (206), and then is discharged from the cold air outlet (207), the cold air compressor and the second main control system are arranged in the cold thawing cycle control device (212), and the thermocouple (209) is heated through the second main control system.
8. The method for testing the SHPB by coupling freeze thawing cycle and power disturbance is characterized by comprising the following steps of: testing with the SHPB testing device of coupled freeze-thaw cycle and power disturbance of any of claims 1 to 7; before a test, a sample (107) is placed in the middle of an incident rod (105) and a transmission rod (106) in parallel along the height direction, a freeze-thawing cycle confining pressure loading system (2) seals the sample (107) in the sample to carry out freeze-thawing cycle and confining pressure loading, a two-side propulsion oil pressure cylinder (108) is used for providing shaft pressure with preset size for the sample (107), during the test, a striking structure of a controllable high-frequency pendulum striking system (3) based on a pressure sensor strikes the transmission rod (106) under the action of power driving, and when the controllable high-frequency pendulum striking system (3) based on the pressure sensor strikes a one-dimensional Hopkinson pressure bar system (1) based on two-side oil pressure propulsion, the time of primary power disturbance is less than 10s; the number of times of impact required by the sample to be destroyed is more than 10000 times; the incident stress intensity of the striking is less than 50Mpa.
9. The method for testing the freeze-thaw cycle and power disturbance coupled loading SHPB of claim 8, wherein the method comprises the steps of: after the dynamic disturbance is finished, the impact rock breaking is carried out, the final dynamic mechanical property of the sample is calculated, an incident stress wave is generated at the incident rod (105) end and the wave speed is increasedPropagating forward, E e is the elastic modulus of the rod body,The density of the rod body is the density of the rod body, and reflected stress wave and transmitted stress wave are respectively generated in the incident rod (105) and the transmission rod (106) after the rod body is contacted with the sample; measurement of incident Strain Signal Using Strain gauge attached to incident rodAnd a reflected strain signalThe strain gauge stuck on the transmission rod measures the transmission strain signal; The stress, strain and strain rate time course curve of the sample is calculated by the following formula:
Wherein: a e is the cross-sectional area of the compression bar, m 2;As is the cross-sectional area of the sample, m 2;Ls is the length of the sample, m; c e and E e are respectively the longitudinal wave velocity and the elastic modulus, m/s and GPa of the elastic rod.
10. The method for testing the freeze-thaw cycle and power disturbance coupled loading SHPB of claim 8, wherein the method comprises the steps of: after the power disturbance of a preset period is finished, high-pressure air stored in a high-pressure air chamber (102) in a one-dimensional Hopkinson pressure bar system (1) based on oil pressure propulsion at two sides is used for driving a bullet to strike an incident bar, high-amplitude incident stress can be used for realizing rock breaking by striking, and power disturbance and dynamic impact test data are recorded to an oscilloscope and a high-performance computer through a strain gauge (118) and are used for researching dynamic mechanical response of surrounding rock of a submarine tunnel after seawater corrosion and high-frequency power disturbance coupling damage.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103234844A (en) * | 2013-03-29 | 2013-08-07 | 东北大学 | Pendulum load intermediate strain rate split Hopkinson pressure bar test device and method |
| CN213779758U (en) * | 2020-11-09 | 2021-07-23 | 中南大学 | Test device for realizing freeze thawing and dynamic disturbance coupling effect |
| CN115060599A (en) * | 2022-05-24 | 2022-09-16 | 辽宁科技大学 | Hopkinson pressure bar experiment system and method based on CT scanning and freeze-thaw damage |
| CN116642775A (en) * | 2023-07-26 | 2023-08-25 | 深圳市深勘工程咨询有限公司 | Testing device for underground space spalling strength |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103234844A (en) * | 2013-03-29 | 2013-08-07 | 东北大学 | Pendulum load intermediate strain rate split Hopkinson pressure bar test device and method |
| CN213779758U (en) * | 2020-11-09 | 2021-07-23 | 中南大学 | Test device for realizing freeze thawing and dynamic disturbance coupling effect |
| CN115060599A (en) * | 2022-05-24 | 2022-09-16 | 辽宁科技大学 | Hopkinson pressure bar experiment system and method based on CT scanning and freeze-thaw damage |
| CN116642775A (en) * | 2023-07-26 | 2023-08-25 | 深圳市深勘工程咨询有限公司 | Testing device for underground space spalling strength |
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