CN111006940A - Frequency conversion slow-speed disturbance rod mechanism capable of simulating blasting stress wave - Google Patents
Frequency conversion slow-speed disturbance rod mechanism capable of simulating blasting stress wave Download PDFInfo
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- CN111006940A CN111006940A CN201911257769.0A CN201911257769A CN111006940A CN 111006940 A CN111006940 A CN 111006940A CN 201911257769 A CN201911257769 A CN 201911257769A CN 111006940 A CN111006940 A CN 111006940A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/02—Details
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0001—Type of application of the stress
- G01N2203/001—Impulsive
Abstract
A frequency conversion slow-speed disturbing rod mechanism meeting the simulation of blasting stress waves has two matching modes of bullets and an incident rod; in the first matching mode, a bullet and an incident rod are separately arranged, a PVDF piezoelectric film sensor is installed on the front end face of the incident rod, a shaping sheet is installed on the rear end face of a rod body, and the incident rod abuts against and contacts a rock sample; under a second matching mode, the front end face of the bullet is butted with the rear end face of the incident rod to form an elongated bullet, a splicing sleeve is sleeved at the butted position, the incident rod and the rock sample are arranged in a separated mode, the front end face of the incident rod is provided with a shaping sheet, and the outer surface of the shaping sheet is provided with a PVDF piezoelectric film sensor; bullet shooting is realized through a special air path structure; the outer suit of incident pole can linear displacement's single pulse quality piece, and the downthehole pore wall of single pulse quality piece incident pole is worn to adorn has seted up annular groove, is equipped with annular boss on the incident pole, and annular boss is located annular groove, and annular boss axial thickness is less than annular groove axial width, forms incident pole axial fine motion clearance between boss and the recess.
Description
Technical Field
The invention belongs to the technical field of rock indoor mechanical tests, and particularly relates to a variable-frequency slow-speed disturbance rod mechanism meeting blasting stress wave simulation.
Background
In the deep rock engineering construction process, blasting excavation has the characteristics of high excavation efficiency and good economy, and is always used as one of the most main excavation modes at present. The blasting can be mainly divided into three areas according to different stress characteristics generated by the blasting, including a blasting shock wave area, a blasting stress wave area and a blasting elastic wave area.
The stress amplitude of the blasting shock wave exceeds the strength of the rock mass, and the rock mass can be directly crushed. The stress amplitude of the blasting stress wave is lower than the strength of the rock mass, but the blasting stress wave repeatedly acts on the rock mass, the rock mass can be continuously cracked, and finally the rock mass is unstable. The stress amplitude of the explosive elastic wave is the lowest, and the influence on the rock mass is the smallest.
According to the existing research results, when deep rock is subjected to blasting excavation, the main frequency range of the blasting stress wave is about 100 Hz-500 Hz, and the stress amplitude range of the blasting stress wave is about 0.1 MPa-30 MPa. From a strain rate perspective, the strain rate of the blast stress wave is in a range intermediate between the low strain rate of the static stress and the medium to high strain rate of the dynamic impact stress.
At present, in the indoor mechanical test of rock, blasting shock wave can realize the simulation through traditional hopkinson pole test equipment, and blasting elastic wave can realize the simulation through current low frequency dynamic device. However, the simulation of the blasting stress wave has problems, and the low stress amplitude characteristic is difficult to reach the requirement when the traditional Hopkinson bar test equipment is adopted, and the frequency characteristic cannot be reached when the traditional hydraulic equipment is adopted. In addition, the length of the test equipment cannot be too long when the blasting stress wave is to be simulated, and if the test equipment is too long, the selection of a test site is difficult, and inconvenience is brought to the installation and maintenance of the equipment.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides the frequency conversion slow-speed disturbance rod mechanism meeting the simulation of the blasting stress wave, the simulation of the low stress amplitude characteristic is realized through the low-speed emission of the bullet, the simulation of the specific frequency characteristic is realized through the rod splicing mode, the rod splicing mode also effectively shortens the length of equipment, the occupied space of the equipment is effectively saved, the difficulty in selecting a test site is reduced, and the installation and maintenance of the equipment are easier.
In order to achieve the purpose, the invention adopts the following technical scheme: a frequency conversion slow-speed disturbing rod mechanism meeting blasting stress wave simulation comprises a launching platform, a cylinder, a gun barrel, a bullet and an incident rod; the gun barrel is horizontally erected on the rear side of the launching platform, the air cylinder is installed on the rear portion of the gun barrel, the bullet is located in the gun barrel, and the polyethylene antifriction sleeve is sleeved on the bullet in the gun barrel; the incident rod is horizontally erected on the front side of the launching platform through an incident rod supporting seat; two matching modes are provided between the bullet and the incident rod; under a first matching mode, the bullet and the incident rod are arranged in a separated mode, a PVDF piezoelectric film sensor is installed on the front end face of the rod body of the incident rod, the front end face of the rod body of the incident rod is abutted and contacted on a rock sample through the PVDF piezoelectric film sensor, and a shaping sheet is installed on the rear end face of the rod body of the incident rod; under a second matching mode, the front end face of the bullet and the rear end face of the incident rod are abutted and butted together, the butted bullet and the incident rod jointly form an elongated bullet, a splicing sleeve is sleeved outside the butt joint of the bullet and the incident rod, the splicing sleeve has axial sliding freedom relative to the bullet and the incident rod, the front end face of the incident rod and the rock sample are arranged in a separated mode, a shaping sheet is arranged on the front end face of the incident rod, and a PVDF piezoelectric film sensor is arranged on the outer surface of the shaping sheet; the rod body of the incident rod is sleeved with a single pulse mass block, the single pulse mass block adopts a split combined structure, the hole wall of an incident rod penetrating hole of the single pulse mass block is provided with an annular groove, the rod body of the incident rod is provided with an annular boss, the annular boss is positioned in the annular groove, the axial thickness of the annular boss is smaller than the axial width of the annular groove, and an incident rod axial micro-motion gap is formed between the annular boss and the annular groove; the device comprises a single pulse mass block, and is characterized in that a sliding rail is installed on an emission platform below the single pulse mass block, the sliding rail is of a parallel double-rail structure, the sliding rail is parallel to an incident rod, a sliding block is arranged on the sliding rail, the sliding block is horizontally and fixedly connected to a sliding table, the single pulse mass block is fixedly connected to the upper surface of the sliding table, and the single pulse mass block has linear movement freedom degree relative to the sliding rail.
An air compressor and a control console are arranged on the ground at the side of the launching platform, a first button switch and a second button switch are arranged on the control console, and an air bottle, a first air control valve and a second air control valve are arranged in the launching platform below the gun barrel; the gun barrel is characterized in that the air cylinder is horizontally arranged, a front chamber and a rear chamber are arranged in the air cylinder, a piston rod penetrates through a partition plate of the front chamber and the rear chamber in a sealing manner, a gun barrel sealing plug is arranged at the end part of the piston rod positioned in the front chamber, a transmitting air outlet is formed in the axial cylinder wall of the front chamber, an air inlet end pipe orifice at the rear part of the gun barrel is communicated with the transmitting air outlet in a sealing manner, a transmitting air inlet is formed in the radial cylinder wall of the front chamber, and the transmitting air inlet is communicated with the air outlet; a piston disc is arranged at the end part of a piston rod of the rear cavity, the rear cavity is divided into a rod cavity and a rodless cavity by the piston disc, and the diameter of the piston disc is larger than that of the gun tube sealing plug; the first button switch and the second button switch are identical in structure and respectively comprise an air inlet, a normally open air outlet, a normally closed air outlet and a pressure relief opening, and the pressure relief opening is directly communicated with the atmosphere; the air supply port of the air compressor is output in three paths, the first path is communicated with the air inlet of the first button switch, the second path is communicated with the air inlet of the first pneumatic control valve, and the third path is communicated with the air inlet of the air bottle; the normally open air outlet of the first button switch is communicated with a rodless cavity of the rear cavity of the cylinder, the normally closed air outlet of the first button switch is communicated with an air inlet of the second button switch, the normally open air outlet of the second button switch is output in two ways, the first way is communicated with a valve closing air control port of the first air control valve, and the second way is communicated with a valve opening air control port of the second air control valve; the normally closed air outlet of the second button switch is output in two paths, the first path is communicated with the valve opening air control port of the first air control valve, and the second path is communicated with the valve closing air control port of the second air control valve; the air outlet of the first pneumatic control valve is output in two ways, the first way is communicated with the air inlet of the second pneumatic control valve, and the second way is communicated with the rod cavity of the rear cavity of the cylinder; and the air outlet of the second air control valve is communicated with the atmosphere.
The launching platform is characterized in that a vacuum pump is arranged on the ground on the side of the launching platform, air exhaust ports are formed in the pipe body at the rear end of the gun barrel and the pipe body in the middle of the splicing sleeve, the air exhaust ports at two positions are connected with the vacuum pump, the pipe cavities of the gun barrel and the splicing sleeve are vacuumized through the vacuum pump, bullets in the gun barrel automatically retreat to a launching position under the action of negative pressure through vacuumizing, and the bullets in the splicing sleeve are automatically abutted and butted together with an incident rod through vacuumizing.
A bullet velocimeter is arranged on the launching platform adjacent to the outlet of the gun barrel, and an incident rod velocimeter is arranged on the launching platform at the front side of the single pulse mass block; and a charge amplifier is arranged on the ground at the side of the transmitting platform, the signal output end of the PVDF piezoelectric film sensor is connected with the charge amplifier, and a voltage signal of the charge amplifier is connected into an oscilloscope or a computer.
An incident rod bearing platform is installed on the side of the transmitting platform, and a temporarily unused incident rod is placed through the incident rod bearing platform; and a gantry crane is arranged above the launching platform, and the incident rod is installed and disassembled through the gantry crane.
The invention has the beneficial effects that:
the variable-frequency slow-speed disturbing rod mechanism meeting the simulation of the blasting stress wave realizes the simulation of the low stress amplitude characteristic by the low-speed launching of the bullet, realizes the simulation of the specific frequency characteristic by the rod splicing mode, effectively shortens the length of equipment by the rod splicing mode, effectively saves the occupied space of the equipment, reduces the difficulty in selecting a test site, and makes the installation and maintenance of the equipment easier.
Drawings
FIG. 1 is a schematic structural diagram of a frequency-conversion slow-speed disturbing rod mechanism (a bullet and an incident rod are separately arranged) satisfying a simulation of a blasting stress wave according to the present invention;
FIG. 2 is a schematic structural diagram of a frequency-conversion slow-speed disturbing lever mechanism (a bullet and an incident lever jointly form an elongated bullet by a mutual butt joint matching mode) meeting the simulation of a blasting stress wave of the invention;
FIG. 3 is a schematic diagram of the assembly of the single pulse mass block, the incident rod, the slide rail, the slide block and the slide table of the present invention;
FIG. 4 is a schematic diagram of the gas circuit connection of the cylinder, the first button switch, the second button switch, the gas cylinder, the first pneumatic control valve and the second pneumatic control valve of the present invention;
in the figure, 1-launching platform, 2-cylinder, 3-gun barrel, 4-bullet, 5-launching rod, 6-launching rod support base, 7-splicing sleeve, 8-single pulse mass block, 9-slide rail, 10-slide block, 11-sliding table, 12-air compressor, 13-control platform, 14-first button switch, 15-second button switch, 16-air bottle, 17-first air control valve, 18-second air control valve, 19-front chamber, 20-rear chamber, 21-gun barrel sealing plug, 22-launching air port, 23-launching air inlet pipe, 24-piston disc, 25-vacuum pump, 26-bullet velocimeter, 27-launching rod velocimeter, 28-charge amplifier, 29-gantry crane, 30-annular groove, 31-annular boss, 32-piston rod, 33-launching rod support platform.
Detailed Description
The invention is described in further detail below with reference to the figures and the specific embodiments.
As shown in fig. 1 to 4, a frequency conversion slow-speed disturbance rod mechanism satisfying the simulation of blasting stress wave comprises a launching platform 1, a cylinder 2, a gun barrel 3, a bullet 4 and an incident rod 5; the gun barrel 3 is horizontally erected on the rear side of the launching platform 1, the air cylinder 2 is installed on the rear portion of the gun barrel 3, the bullet 4 is located in the gun barrel 3, the polyethylene antifriction sleeve is sleeved on the bullet 4 in the gun barrel 3, the friction force between the gun barrel 3 and the bullet 4 is reduced through the polyethylene antifriction sleeve, the inner surface of the gun barrel 3 is processed in a honing mode and used for reducing the friction force between the polyethylene antifriction sleeve and the inner surface of the gun barrel 3; the incident rod 5 is horizontally erected on the front side of the launching platform 1 through an incident rod supporting seat 6; two matching modes are provided between the bullet 4 and the incident rod 5; under a first matching mode, the bullet 4 and the incident rod 5 are arranged in a separated mode, a PVDF piezoelectric film sensor is installed on the front end face of the incident rod 5, the front end face of the incident rod 5 abuts against and contacts a rock sample through the PVDF piezoelectric film sensor, and a shaping sheet is installed on the rear end face of the incident rod 5; under a second matching mode, the front end face of the bullet 4 abuts against and is butted with the rear end face of the incident rod 5, the bullet 4 and the incident rod 5 which are butted together form an elongated bullet, a splicing sleeve 7 is sleeved outside the butt joint of the bullet 4 and the incident rod 5, the splicing sleeve 7 has axial sliding freedom relative to the bullet 4 and the incident rod 5, the front end face of the incident rod 5 and a rock sample are arranged in a separated mode, a shaping sheet is arranged on the front end face of the incident rod 5, and a PVDF piezoelectric film sensor is arranged on the outer surface of the shaping sheet; the single pulse mass block 8 is sleeved outside the rod body of the incident rod 5, the single pulse mass block 8 adopts a split combined structure, an annular groove 30 is formed in the inner hole wall of the incident rod penetrating hole of the single pulse mass block 8, an annular boss 31 is arranged on the rod body of the incident rod 5, the annular boss 31 is positioned in the annular groove 30, the axial thickness of the annular boss 31 is smaller than the axial width of the annular groove 30, and an incident rod axial micro-motion gap is formed between the annular boss 31 and the annular groove 30; install slide rail 9 on the launching pad 1 of single pulse quality piece 8 below, slide rail 9 adopts parallel double track structure, and slide rail 9 parallels with incident pole 5, is provided with slider 10 on slide rail 9, and the level links firmly at slip table 11 on slider 10, single pulse quality piece 8 links firmly at slip table 11 upper surface, and single pulse quality piece 8 has the rectilinear movement degree of freedom for slide rail 9.
An air compressor 12 and a control console 13 are arranged on the ground at the side of the launching platform 1, a first button switch 14 and a second button switch 15 are arranged on the control console 13, and an air bottle 16, a first air control valve 17 and a second air control valve 18 are arranged in the launching platform 1 below the gun barrel 3; the gun barrel is characterized in that the cylinder 2 is horizontally arranged, a front cavity 19 and a rear cavity 20 are arranged in the cylinder 2, a piston rod 32 penetrates through a partition plate of the front cavity 19 and the rear cavity 20 in a sealing manner, a gun barrel sealing plug 21 is arranged at the end part of the piston rod positioned in the front cavity 19, an emission air port 22 is formed in the axial cylinder wall of the front cavity 19, an air inlet end pipe orifice at the rear part of the gun barrel 3 is communicated with the emission air port 22 in a sealing manner, an emission air inlet 15 is formed in the radial cylinder wall of the front cavity 19, and the emission air inlet 15 is communicated with an air outlet of an air bottle 16 in; a piston disc 24 is arranged at the end part of the piston rod of the rear chamber 20, the rear chamber 20 is divided into a rod chamber and a rodless chamber by the piston disc 24, and the diameter of the piston disc 24 is larger than that of the gun tube sealing plug 21; the first button switch 14 and the second button switch 15 are identical in structure and respectively comprise an air inlet, a normally open air outlet, a normally closed air outlet and a pressure relief opening, and the pressure relief opening is directly communicated with the atmosphere; the air supply port of the air compressor 12 is output in three ways, wherein the first way is communicated with the air inlet of the first button switch 14, the second way is communicated with the air inlet of the first pneumatic control valve 17, and the third way is communicated with the air inlet of the air bottle 16; the normally open air outlet of the first button switch 14 is communicated with a rodless cavity of the rear cavity 20 of the cylinder 2, the normally closed air outlet of the first button switch 14 is communicated with an air inlet of the second button switch 15, the normally open air outlet of the second button switch 15 is output in two ways, the first way is communicated with a valve closing air control port of the first air control valve 17, and the second way is communicated with a valve opening air control port of the second air control valve 18; the normally closed air outlet of the second button switch 15 is output in two paths, the first path is communicated with the valve opening air control port of the first air control valve 17, and the second path is communicated with the valve closing air control port of the second air control valve 18; the air outlet of the first pneumatic control valve 17 is output in two paths, the first path is communicated with the air inlet of the second pneumatic control valve 18, and the second path is communicated with the rod cavity of the rear cavity 20 of the cylinder 2; the air outlet of the second air control valve 18 is communicated with the atmosphere. In the embodiment, the model of the first pneumatic control valve 17 and the model of the second pneumatic control valve 18 are RAT052DA F02/F05-N11, and the working pressure range is 0.3 MPa-0.8 MPa; the model of the first button switch 14 is M5PL210-08, and the working pressure range is 0-1.0 MPa; the model of the second button switch 15 is 4H210-08, and the working pressure range is 0.15 MPa-0.8 MPa.
The subaerial vacuum pump 25 that is provided with in launch pad 1 side all seted up the extraction opening on 3 rear end bodys of barrel and splice sleeve 7 middle part bodys, two extraction openings all link to each other with vacuum pump 25, carry out the evacuation through vacuum pump 25 to the lumen of barrel 3 and splice sleeve 7, make bullet 4 in the barrel 3 retreat to the launch position automatically under the negative pressure effect through the evacuation, make bullet 4 in the splice sleeve 7 automatic top by the contact butt joint together with the pole 5 of inciting light through the evacuation.
A bullet velocimeter 26 is arranged on the launching platform 1 adjacent to the outlet of the gun barrel 3, and an incident rod velocimeter 27 is arranged on the launching platform 1 at the front side of the single pulse mass block 8; a charge amplifier 28 is arranged on the ground at the side of the transmitting platform 1, the signal output end of the PVDF piezoelectric film sensor is connected with the charge amplifier 28, and the voltage signal of the charge amplifier 28 is connected to an oscilloscope or a computer.
An incident rod bearing platform is arranged on the side of the launching platform 1, and a temporarily unused incident rod 5 is placed on the incident rod bearing platform; a gantry crane 29 is arranged above the launching platform 1, and the incident rod 5 is installed and disassembled through the gantry crane 29.
The application process of the invention is described below with reference to the accompanying drawings:
example one
In this example, the frequency of the simulated explosion stress wave set in the test was 300Hz, the bullet 4 and the incident rod 5 were fitted separately from each other, the length of the barrel 3 was 6m, the length of the incident rod 5 was 9m, the material of the incident rod 5 was 42CrMo, since the elastic modulus E of the 42CrMo material was 212GPa, and the density ρ of the 42CrMo material was 7850kg/m3The calculation formula of the wave velocity C is shown as
Therefore, the wave speed C can be calculated to be 5197 m/s; for a sine wave with a frequency of 300Hz, the waveform period T is 1/300-3.33 ms, so the pulse duration T of the half sine wave is T/2-1.67 ms, and the length L of the bullet 4 is calculated by the formula T-2L/C to be 4.34 m.
Before a test, an incident rod 5 is hoisted on an incident rod supporting seat 6, a PVDF piezoelectric film sensor is installed on the front end face of a rod body of the incident rod 5, the front end face of the rod body of the incident rod 5 is abutted against and contacted on a rock sample through the PVDF piezoelectric film sensor, meanwhile, a shaping sheet is installed on the rear end face of the rod body of the incident rod 5, and original rectangular waves are shaped into required half sine waves by means of the shaping sheet; then starting a vacuum pump 25 to enable the bullet 4 in the gun barrel 3 to automatically retreat to a launching position under the action of negative pressure; finally, the axial position of the single pulse mass block 8 is adjusted, so that a proper incident rod axial micro-motion gap is formed between the annular boss 31 on the incident rod 5 and the annular groove 30 in the single pulse mass block 8.
Next, the debugging of the cylinder 2 is started; in an initial state, the first pneumatic control valve 17 is in a closed state, the second pneumatic control valve 18 is in an open state, when the air compressor 12 is started, one path of compressed air directly enters the air bottle 16, the other path of compressed air directly enters a rodless cavity of the rear cavity 20 of the air cylinder 2, the piston disc 24, the piston rod 32 and the gun barrel sealing plug 21 are pushed to move towards the gun barrel 3 along with the increase of the pressure in the rodless cavity, meanwhile, the rod cavity of the rear cavity 20 of the air cylinder 2 is compressed, air in the rod cavity is discharged into the atmosphere through the open second pneumatic control valve 18 until the gun barrel sealing plug 21 completely abuts against the launching air outlet 22 and blocks the launching air outlet 22, and at the moment, the gun barrel 3 is sealed and isolated from the front cavity 19 of the air cylinder 2.
After the gun barrel 3 and the front chamber 19 of the air cylinder 2 are sealed and isolated, the control buttons of the first button switch 14 and the second button switch 15 are pressed simultaneously, at the moment, normally open air outlets of the first button switch 14 and the second button switch 15 are changed into a closed state, normally closed air outlets of the first button switch 14 and the second button switch 15 are changed into an open state, compressed air output by the air compressor 12 sequentially flows through the first button switch 14 and the second button switch 15 and then flows out from the normally closed air outlet of the open state of the second button switch 15, the flowing compressed air is divided into two paths and simultaneously enters an open air control port of the first air control valve 17 and a closed air control port of the second air control valve 18, the closed state of the first air control valve 17 is controlled to be changed into an open state, and the open state of the second air control valve 18 is controlled to be changed into a closed state.
When the open-close states of the first air control valve 17 and the second air control valve 18 are switched, compressed air output by the air compressor 12 enters a rod cavity of a rear cavity 20 of the air cylinder 2 through the opened first air control valve 17, because the diameter of the piston disc 24 is larger than that of the barrel sealing plug 21, under the condition of the same pressure intensity, the axial thrust applied to the piston disc 24 is larger, the piston disc 24 moves towards the reverse direction of the barrel 3 under the action of the axial thrust, air in a rodless cavity of the rear cavity 20 of the air cylinder 2 is exhausted into the atmosphere through a pressure relief port of the first button switch 14, and simultaneously along with the movement of the piston disc 24, the piston rod 32 and the barrel sealing plug are driven to synchronously move towards the reverse direction of the barrel 3 until the barrel sealing plug 21 breaks away from the blocking of the air outlet 22, and the barrel 3 is communicated with a front cavity 19 of the air cylinder 2, at the moment, air in the air cylinder 16 quickly enters the barrel 3 through the front cavity of the air cylinder 2, and pushes the cartridge 4 in the barrel 3 to fire.
After the bullet 4 is launched out of the gun barrel 3, the bullet directly impacts the rear end face of the rod body of the incident rod 5 provided with the shaping sheet, under the action of the single pulse mass block 8, the simulated blasting stress wave with the frequency of 300Hz directly acts on the rock sample through the incident rod 5 in the form of single pulse, at the moment, the piezoelectric signal obtained through the PVDF piezoelectric film sensor is accessed into an oscilloscope through the charge amplifier 28, the waveform of the stress wave acting on the rock sample in the test can be visually determined through the oscilloscope, and the simulated blasting stress wave in the test is ensured to be accurate; meanwhile, the shooting speed of the bullet 4 measured by the bullet velocimeter 26 is recorded, so that the shooting speed of the bullet 4 meets the simulation of the low stress amplitude characteristic.
In addition, as can be known from the debugging process of the air cylinder 2, the firing of the bullet 4 can be completed only by pressing the control buttons of the first button switch 14 and the second button switch 15 at the same time, and if the control button of the first button switch 14 is pressed alone due to a misoperation, since the initial state is that the first pneumatic control valve 17 is in the closed state and the second pneumatic control valve 18 is in the open state, even if the first button switch 14 is triggered alone to conduct, the second button switch 15 is still in the non-conducting state, and therefore the switching of the open-closed state of the first pneumatic control valve 17 and the second pneumatic control valve 18 is not triggered. Similarly, if the control button of the second button switch 15 is pressed alone due to a faulty operation, since the initial state is that the first pneumatic control valve 17 is in the closed state and the second pneumatic control valve 18 is in the open state, even if the second button switch 15 is triggered alone to be conducted, the first button switch 14 is still in the non-conducting state, and therefore, the switching of the open/close states of the first pneumatic control valve 17 and the second pneumatic control valve 18 is not triggered. Therefore, even if the control button of the first push switch 14 or the second push switch 15 is pressed by itself due to an erroneous operation, the bullet is not erroneously shot, and the safety of the test can be improved finally.
Example two
In the embodiment, the frequency of the simulated blasting stress wave set in the test is 100Hz, and the bullet 4 and the incident rod 5 form the lengthened bullet together in a mutual butt joint matching mode; the length of the gun barrel 3 is 6m, the length of the incident rod 5 is 9m, the material of the incident rod 5 is 42CrMo, the elastic modulus E of the 42CrMo material is 212GPa, and the density rho of the 42CrMo material is 7850kg/m3The calculation formula of the wave velocity C is shown as
Therefore, the wave speed C can be calculated to be 5197 m/s; for a sine wave with a frequency of 100Hz, the waveform period T of the sine wave is 1/100-10 ms, so the pulse duration T of the half sine wave is T/2-5 ms, and the length L of the bullet 4 is calculated by the formula T-2L/C to obtain 13 m. However, if 13m bullets 4 are to be tested in the manner of example one, a 26m entrance rod 5 is separately provided, and the total length of the bullets 4 and the entrance rod 5 reaches 39m, which makes it difficult to have a suitable field for the installation of the test equipment. Therefore, in the embodiment, the butt-joint matching mode of the bullet 4 and the incident rod 5 is adopted, the length of the bullet 4 is 4.34m, namely the existing bullet 4 in the embodiment I is directly adopted without being manufactured, the total length of the lengthened bullet formed after the butt-joint of the bullet 4 and the incident rod is only 13.34m, and the test is effectively savedThe floor space of the device can meet the test requirements.
Before a test, an incident rod 5 is hoisted on an incident rod supporting seat 6, a shaping sheet is firstly installed on the front end face of a rod body of the incident rod 5, and then a PVDF piezoelectric film sensor is installed on the shaping sheet and is not contacted with a rock sample; at this time, a splicing sleeve 7 is needed, the splicing sleeve 7 is firstly sleeved with the bullet 4, the rear end of the incident rod 5 is inserted into the splicing sleeve 7, then the vacuum pump 25 is started to vacuumize the inner cavity of the splicing sleeve 7, and the bullet 4 and the incident rod 5 automatically move to the middle of the splicing sleeve 7 under the action of negative pressure until the bullet 4 and the incident rod 5 automatically complete abutting contact butt joint in the splicing sleeve 7; and finally, mounting the single-pulse mass block 8 and adjusting the axial position of the single-pulse mass block to form a proper incident rod axial micro-motion gap between the annular boss 31 on the incident rod 5 and the annular groove 30 in the single-pulse mass block 8.
Next, referring to the first embodiment, the debugging of the cylinder 2 is completed until the whole lengthened bullet is launched through the gun barrel 3, the front end of the lengthened bullet directly impacts the rock sample and rebounds rapidly, so that the test that the simulated explosion stress wave with the frequency of 100Hz directly acts on the rock sample is realized, at this time, the piezoelectric signal obtained through the PVDF piezoelectric film sensor is connected to an oscilloscope through the charge amplifier 28, the waveform of the stress wave acting on the rock sample in the test can be visually determined through the oscilloscope, and the simulated explosion stress wave in the test is ensured to be accurate; meanwhile, the firing rate of the lengthened bullet measured by the incident rod velocimeter 27 is recorded, so that the firing rate of the lengthened bullet is ensured to meet the simulation of the low stress amplitude characteristic.
The embodiments are not intended to limit the scope of the present invention, and all equivalent implementations or modifications without departing from the scope of the present invention are intended to be included in the scope of the present invention.
Claims (5)
1. The utility model provides a satisfy blasting stress wave simulation's frequency conversion disturbance lever mechanism at a slow speed which characterized in that: comprises a launching platform, a cylinder, a gun barrel, a bullet and an incident rod; the gun barrel is horizontally erected on the rear side of the launching platform, the air cylinder is installed on the rear portion of the gun barrel, the bullet is located in the gun barrel, and the polyethylene antifriction sleeve is sleeved on the bullet in the gun barrel; the incident rod is horizontally erected on the front side of the launching platform through an incident rod supporting seat; two matching modes are provided between the bullet and the incident rod; under a first matching mode, the bullet and the incident rod are arranged in a separated mode, a PVDF piezoelectric film sensor is installed on the front end face of the rod body of the incident rod, the front end face of the rod body of the incident rod is abutted and contacted on a rock sample through the PVDF piezoelectric film sensor, and a shaping sheet is installed on the rear end face of the rod body of the incident rod; under a second matching mode, the front end face of the bullet and the rear end face of the incident rod are abutted and butted together, the butted bullet and the incident rod jointly form an elongated bullet, a splicing sleeve is sleeved outside the butt joint of the bullet and the incident rod, the splicing sleeve has axial sliding freedom relative to the bullet and the incident rod, the front end face of the incident rod and the rock sample are arranged in a separated mode, a shaping sheet is arranged on the front end face of the incident rod, and a PVDF piezoelectric film sensor is arranged on the outer surface of the shaping sheet; the rod body of the incident rod is sleeved with a single pulse mass block, the single pulse mass block adopts a split combined structure, the hole wall of an incident rod penetrating hole of the single pulse mass block is provided with an annular groove, the rod body of the incident rod is provided with an annular boss, the annular boss is positioned in the annular groove, the axial thickness of the annular boss is smaller than the axial width of the annular groove, and an incident rod axial micro-motion gap is formed between the annular boss and the annular groove; the device comprises a single pulse mass block, and is characterized in that a sliding rail is installed on an emission platform below the single pulse mass block, the sliding rail is of a parallel double-rail structure, the sliding rail is parallel to an incident rod, a sliding block is arranged on the sliding rail, the sliding block is horizontally and fixedly connected to a sliding table, the single pulse mass block is fixedly connected to the upper surface of the sliding table, and the single pulse mass block has linear movement freedom degree relative to the sliding rail.
2. The frequency conversion slow-speed disturbance rod mechanism meeting the simulation of the blasting stress wave of claim 1, which is characterized in that: an air compressor and a control console are arranged on the ground at the side of the launching platform, a first button switch and a second button switch are arranged on the control console, and an air bottle, a first air control valve and a second air control valve are arranged in the launching platform below the gun barrel; the gun barrel is characterized in that the air cylinder is horizontally arranged, a front chamber and a rear chamber are arranged in the air cylinder, a piston rod penetrates through a partition plate of the front chamber and the rear chamber in a sealing manner, a gun barrel sealing plug is arranged at the end part of the piston rod positioned in the front chamber, a transmitting air outlet is formed in the axial cylinder wall of the front chamber, an air inlet end pipe orifice at the rear part of the gun barrel is communicated with the transmitting air outlet in a sealing manner, a transmitting air inlet is formed in the radial cylinder wall of the front chamber, and the transmitting air inlet is communicated with the air outlet; a piston disc is arranged at the end part of a piston rod of the rear cavity, the rear cavity is divided into a rod cavity and a rodless cavity by the piston disc, and the diameter of the piston disc is larger than that of the gun tube sealing plug; the first button switch and the second button switch are identical in structure and respectively comprise an air inlet, a normally open air outlet, a normally closed air outlet and a pressure relief opening, and the pressure relief opening is directly communicated with the atmosphere; the air supply port of the air compressor is output in three paths, the first path is communicated with the air inlet of the first button switch, the second path is communicated with the air inlet of the first pneumatic control valve, and the third path is communicated with the air inlet of the air bottle; the normally open air outlet of the first button switch is communicated with a rodless cavity of the rear cavity of the cylinder, the normally closed air outlet of the first button switch is communicated with an air inlet of the second button switch, the normally open air outlet of the second button switch is output in two ways, the first way is communicated with a valve closing air control port of the first air control valve, and the second way is communicated with a valve opening air control port of the second air control valve; the normally closed air outlet of the second button switch is output in two paths, the first path is communicated with the valve opening air control port of the first air control valve, and the second path is communicated with the valve closing air control port of the second air control valve; the air outlet of the first pneumatic control valve is output in two ways, the first way is communicated with the air inlet of the second pneumatic control valve, and the second way is communicated with the rod cavity of the rear cavity of the cylinder; and the air outlet of the second air control valve is communicated with the atmosphere.
3. The frequency conversion slow-speed disturbance rod mechanism meeting the simulation of the blasting stress wave of claim 1, which is characterized in that: the launching platform is characterized in that a vacuum pump is arranged on the ground on the side of the launching platform, air exhaust ports are formed in the pipe body at the rear end of the gun barrel and the pipe body in the middle of the splicing sleeve, the air exhaust ports at two positions are connected with the vacuum pump, the pipe cavities of the gun barrel and the splicing sleeve are vacuumized through the vacuum pump, bullets in the gun barrel automatically retreat to a launching position under the action of negative pressure through vacuumizing, and the bullets in the splicing sleeve are automatically abutted and butted together with an incident rod through vacuumizing.
4. The frequency conversion slow-speed disturbance rod mechanism meeting the simulation of the blasting stress wave of claim 1, which is characterized in that: a bullet velocimeter is arranged on the launching platform adjacent to the outlet of the gun barrel, and an incident rod velocimeter is arranged on the launching platform at the front side of the single pulse mass block; and a charge amplifier is arranged on the ground at the side of the transmitting platform, the signal output end of the PVDF piezoelectric film sensor is connected with the charge amplifier, and a voltage signal of the charge amplifier is connected into an oscilloscope or a computer.
5. The frequency conversion slow-speed disturbance rod mechanism meeting the simulation of the blasting stress wave of claim 1, which is characterized in that: an incident rod bearing platform is installed on the side of the transmitting platform, and a temporarily unused incident rod is placed through the incident rod bearing platform; and a gantry crane is arranged above the launching platform, and the incident rod is installed and disassembled through the gantry crane.
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| CN201911257769.0A CN111006940B (en) | 2019-12-10 | 2019-12-10 | Frequency conversion slow-speed disturbance rod mechanism capable of simulating blasting stress wave |
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| CN112461639A (en) * | 2020-11-25 | 2021-03-09 | 煤炭科学研究总院 | Impact test equipment |
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| CN111006940B (en) | 2021-04-23 |
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