RU2190203C1 - Method and bed to study electromagnetic radiation of solid body in the form of ring deformed to break-down - Google Patents

Abstract

FIELD: mining industry, flaw detection in articles of mining industry, study of electromagnetic fields emitted by rocks in process of their break-down. SUBSTANCE: technical result of proposal lies in provision of possibility of study of electromagnetic radiation signals emitted by deformation of solid bodies, rocks included, in the form of rings by tensile stress by recording parameters of electromagnetic radiation emerging with deformation of body with the use of variable-capacitance and strain-gauge transducers. Solid body to be deformed in the form of ring is put on bed between plates of variable- capacitance transducer of electromagnetic radiation, it is deformed by tensile stress by application of outside force with the aid of loading unit that includes frame and immobile and mobile tie-rods installed in opposition in which deformed body is placed. Mobile tie-rod is given translational motion. Signal of electromagnetic radiation emerging in process of cracking of deformed solid body is converted by means of above-mentioned variable-capacitance transducer and is recorded by recording system. Outside force from loading unit is transmitted to deformed ring with the help of semi-cylindrical protrusions with which mobile and immobile tie-rods are fitted and on which deformed ring is put. Translational motion is given to mobile tie- rod by means of mobile screw with handwheel put on frame of loading unit. Effort emerging in immobile tie-rod at moment of break-down of ring is recorded with the aid of strain-gauge transducer mounted on it. Signals of variable-capacitance and strain-gauge transducers are recorded in step over first and second channels of recording system correspondingly. Recording results are used to make judgment on time interval between emergence of electromagnetic radiation signal and moment of break-down of deformed solid body. EFFECT: provision for study of electromagnetic radiation signals emerging with deformation of solid bodies. 2 cl, 3 dwg

Description

 The invention relates to the field of mining and can be used in flaw detection of engineering products, as well as in studies of electromagnetic fields emitted by rocks in the process of their destruction, in particular in order to predict the dynamic manifestations of rock pressure.

 A known method for predicting the destruction of rocks by auth. 1740665, class E 21 C 39/00, publ. in BI 22, 1992, including the registration in time of pulses of electromagnetic radiation (EMP), measuring their amplitude and determining the rate of change of the amplitude of the maximum spectral component of the pulses in time, while additionally registering the minimum value of the rate of change of the amplitude of the maximum spectral component of the pulses and the moment the occurrence of this minimum value determines the approximation of the destruction process.

 The disadvantage of this method is that it is intended for recording EMR signals from a rock mass, and therefore is ineffective in experiments in laboratory conditions with samples of small solid bodies made, in particular, in the form of rings, since the ring cannot play the role of an array.

 Closest to the claimed solution in terms of technical nature and the achieved result is a method for studying EMR when tensile samples of solids in the form of cylindrical metal rods (Electromagnetic effect at metallic fracture. Ashok Misra // Nature, vol. 254, March 13, 1975, p. 133-134), according to which a deformable metal rod is placed along the axis of a metal plate made in the form of a half-cylinder, which is used as a lining of the capacitor and from the side surface of which a tap is made to connect to the first input of the register torus, which is used as a storage oscilloscope, a deformable metal core is used as a second electrode of the capacitor, connected to the second input of the registrar and grounded.

 The disadvantage of this method is the impossibility of using samples of solid dielectrics, for example rocks, as a deformable solid body, since by their physical properties they cannot serve as a capacitor plate and cannot be grounded.

 Another disadvantage of this method is the inability to use samples of solids in the form of rings.

 A device for testing ring samples according to auth. USSR 1610378, class G 01 N 3/10, publ. in BI 44, 1990. It is intended for testing samples in the form of coaxial annular plates. The device contains two annular chambers installed concentrically, while the inner wall of the outer chamber and the outer wall of the inner chamber are made elastic, the covers mounted on the ends of the chambers so that they form an interchamber cavity with the elastic walls of the chambers to accommodate a stepped sample in the form of coaxial annular plates, overlapped, each of the covers being made with an annular protrusion on its inner surface, located opposite the cavity of the other cap, the outer diameter of one of the protrusions is equal to the larger diameter interchamber cavity, the inner diameter of the other is a smaller diameter interchamber cavity, and the height of the projections is chosen so that the distance therebetween along axis is not more than half the thickness of the elastic walls.

 The disadvantage of this device is that the loading force in it is created using a liquid supplied under pressure or compressed air, which dramatically complicates the design as a whole, in addition, it is designed to test ring samples of a complex step shape in the form of coaxial ring plates connected overlap, which also complicates the design of the device. In addition, it does not have devices for detecting EMR arising from ring deformation.

 A device is also known for testing the long-term strength of ring samples (V. G. Cherepanov. Long-term strength tests using ring samples // Factory Laboratory, 7, 1960, pp. 852-854), including a device in which the sample is installed - the ring and using four semi-cylindrical protrusions expose it to pure tension. The device for testing ring samples made of heat-resistant steel is placed with the sample in an electric furnace of a testing machine, where it is kept at a given temperature and voltage until it breaks. The device includes two rods that are mounted on a testing machine. Grips with semi-cylindrical protrusions, on which the sample ring is mounted, are attached to the rods.

 The disadvantage of this device is its design for testing rings of relatively high strength, which requires the use of a special press that provides a force of several tons. As a result, it is ineffective in studies of rings whose wall is 1-5 mm. In addition, it does not allow to register the EMP arising from the destruction of the ring.

 A device for testing the long-term strength of ring samples (V. N. Gulyaev, V. I. Strokopytov. To testing ring samples from steam heating pipes for long-term strength // Factory Laboratory, 5, 1973, S. 611-613). A fixture of two rods is used, near the ends of which annular grooves are formed, forming semi-cylindrical protrusions. A ring is placed in the grooves, external forces are applied to the rods.

 The disadvantage of this device is its purpose for testing rings with tensile forces of up to 900 kgf, which makes it cumbersome and metal-intensive when testing small-sized rings. In addition, it does not have devices for recording EMR.

 A device is also known for testing the long-term strength of ring samples (MB Asviyan and I. A. Azizov. On the question of the method of testing pipes for long-term strength // Factory Laboratory, 9, 1966, p. 1122-1123). To test the rings for long-term strength on an IP-4 type testing machine, a fixture made of heat-resistant austenitic steel is used, consisting of rods screwed into the machine grips and cheeks having semicircular grooves that form semi-cylindrical protrusions where the ring sample is mounted. Cheeks are tightened with nuts and bolts. A force from the testing machine is applied to the rods, due to which the ring is stretched by the forces transmitted to it from the semi-cylindrical protrusions.

 The disadvantage of this device is the use of a testing machine as a loading device, generating a force of more than 1 tc, as a result of which the described device is designed for tensile testing of rings with tensile strength up to 100 MPa. It is ineffective when testing rings with a strength of 1-5 MPa due to metal consumption and bulkyness. In addition, it does not have devices for recording the EMR of deformable rings.

 The closest to the claimed solution in terms of technical nature, the achieved result and the set of essential features is a test bench for the study of electromagnetic radiation when tensile samples of solids in the form of metal rods (Electromagnetic effect at metallic fracture. Ashok Misra // Nature, vol. 254, March 13, 1975 , p. 133-134), including a base enclosed in an electromagnetic screen, a capacitive sensor, and a load device comprising a frame consisting of columns fixed to the base of a fixed plate, columns mounted on it, and a movable plate moved along them, chrome moreover, a fixed sleeve is installed on the base, in which one end of a stretched solid in the form of a rod is fixed, the second end of which is fixed in a movable sleeve placed under the movable plate, while the movable sleeve is connected by a movable rod to the drive of the device, in addition, around the stretched a solid body in the form of a rod there is a metal plate made in the form of a half-cylinder, equipped with a tap for connecting to the first input of the storage oscilloscope and serving as one of the capacitive plates sensor, while its second lining is a stretchable rod connected to the second input of the storage oscilloscope.

 The technical task of the proposed solution is to provide the possibility of studying the EMP signals during the deformation of solids, including rocks, in the form of rings by tensile force due to registration of the parameters of EMP arising during its deformation using capacitive and tensometric sensors.

 The problem is solved in that in a method for studying an EMP deformable to fracture of a solid in the form of a ring, including installing it on a bench between the plates of a capacitive EMP sensor, deforming it with a tensile load by applying external force using a load device that includes a frame and oppositely mounted on it motionless and movable thrusts in which a deformable solid is placed, while the movable thrust reports translational motion, transformation using the specified capacitive sensor arising in the process of crack formation of a deformable solid body of the EMP signal and its registration by the registration system, according to the technical solution, the external force is transmitted from the load device to the deformable ring using semi-cylindrical protrusions, which are equipped with movable and fixed rods and on which a deformable ring is worn, while translational the movement of the movable rod is reported using a movable screw with a steering wheel mounted on the frame of the loading device, and the register comfort, the force arising in the fixed rod at the time of rupture of the ring, using the strain gauge installed on it, and the signals of the capacitive and strain gauge sensors are recorded synchronously on the first and second channels of the registration system, respectively, and according to the registration results, an additional time is judged on the time interval between the occurrence of the signal EMP and the moment of destruction of a deformable solid.

 Deformation of the sample in the form of a ring by tensile load is carried out using a loading device due to the installation of the deformable ring on the semi-cylindrical protrusions of the fixed and movable rods and giving the movable screw, to which the movable rod with the semi-cylindrical protrusion is connected, translational movement at the moment of applying the load to the ring due to the steering wheel turning, mounted on the free end of the movable screw, which provides tensile ring cracking and destruction of the ring. At the same time, charges arise on the banks of the formed cracks, the oscillations of which are accompanied by EMR, which makes it possible to register the emerging EMR and to study its features with rupture of the rings.

 In the test bench for research of EMR of a ring-shaped rigid body deformable to destruction, including a base enclosed in an electromagnetic screen, a capacitive sensor and a loading device including a frame mounted on the base, oppositely mounted fixed and movable rods, the stationary rod being fixed to the frame wall with an internal side, and the registration system, according to the technical solution, the movable rod is connected to the movable screw, at the opposite end equipped with a steering wheel, while the fixed and The individual rods are equipped with semi-cylindrical protrusions on which a deformable ring is mounted and placed between the capacitance sensor plates fixed to the grounded base of the stand, one of the capacitive sensor plates installed through an insulating gasket and connected to the first channel of the registration system, and the second connected to the grounded base, at the same time, a strain gauge sensor connected to the second channel of the registration system is installed on a fixed rod.

 The study of EMP arising in the process of deformation of a ring by tension is carried out by placing it on the semi-cylindrical protrusions of the fixed and movable rods between the plates of the capacitive EMR sensor, the plates of which are fixed on the grounded base of the stand from different sides relative to the rods with a deformable ring. In this case, one of the plates of the capacitive EMR sensor, mounted on a grounded base, is connected by a shielded wire to the first channel of the registration system, and the second to the base.

 By turning the steering wheel on the movable rotor due to external force, translational motion is reported to the movable rotor and the movable rod connected to it with a half-cylindrical protrusion, the latter informs the ring of the tensile force arising from the simultaneous action of the movable and stationary half-cylindrical protrusions on the ring of the movable and fixed rods. In this case, electric charges are formed on the banks of microcracks and cracks. Oscillations and movement of the crack faces are accompanied by oscillations of electric charges, which leads to the appearance of electromagnetic radiation. The latter is converted by a capacitive sensor and recorded by a registration system.

 Thus, the stand under consideration provides the study of EMP signals during the deformation of solids in the form of rings by tensile force.

 The essence of the proposed technical solution is illustrated by an example of a specific implementation and drawings, in which Fig. 1 shows a general view of a bench for studying the EMP of deformable samples of solids in the form of rings, in Fig. 2 - view A in Fig. 1, in Fig. 3 - section B -B in figure 1.

 A method for studying the EMP of a ring-shaped solid deformable to fracture is implemented using a bench designed for this purpose.

 The stand consists of a grounded base 1 (Fig. 1), on which, using a bolt 2, an annular frame 3 of a load device is fixed, in the upper part of which a movable screw 4 with a steering wheel 5. is mounted. Bolts 2 and a movable screw 4 are fixed with curly nuts 6 traction - fixed 7 and movable 8 load device. The rod heads 7 and 8 are fixed in the nests of the figured nuts 6 through bearings 9 made of insulating material. The fixed rod 7 and the movable rod 8 are equipped with the same shape and size of the semicylindrical protrusions 10 and 11, respectively (FIG. 2), on which a solid body sample is formed, which is deformed to ring 12 and deformable to fracture. On both sides relative to the rods 7 and 8 with the ring 12 are placed plates 13 and 14 of the capacitive EMR sensor 15. The plates 13 and 14 of the capacitive EMR sensor 15 are fixed on the grounded base 1, and the lining 14 is through the insulating gasket 16. The lining 13 is connected to the grounded base 1. The lining 14 (made, for example, in a semi-cylindrical shape - figure 3) is connected by a shielded wire 17 with The first channel of the registration system. A fixed rod 7 is equipped with a strain gauge 18 connected by a shielded wire 19 to the second channel of the registration system. The latter consists of an amplifier 20 of EMP signals removed from the cover 14 of the capacitive sensor 15, an amplifier 21 of the signals of the strain gauge sensor 18 and a computer 22 connected to their outputs.

 The inventive method is carried out using the inventive stand as follows.

 A deformable solid body, whose EMP is supposed to be investigated, made of, for example, rock in the form of a ring 12, is placed on the semi-cylindrical protrusions 10 and 11 of the fixed rod 7 and the movable rod 8. Then, the steering wheel 5 of the movable screw 4 is manually rotated, due to which the latter is moved upward (figure 1), pulling up the rod 8. The latter through the semicylindrical protrusion 11 begins to move up the upper part of the deformable ring 12. In this case, the lower part of the ring 12 is kept from moving by the semicylindrical protrusion 10 traction 7. The forces transmitted by the semi-cylindrical protrusions 10 and 11 to the ring 12 are directed in opposite directions, and the latter begins to stretch, acquiring the shape of an oval. At the next stage, when the steering wheel 5 is further rotated, the movable rod 8 continues to move upward, stretching the walls of the ring 12, which has turned into an oval. A neck begins to form on the weakest section of the oval walls, and microcracks and cracks begin to form in the material of the latter, along which electric charges are formed, movement the latter together with the walls of microcracks and sprouting cracks leads to the emergence of EMR. The waves of EMP, reaching the plates 13 and 14 of the capacitive sensor 15, form electric charges in it, which is accompanied by the appearance of an electric current in the external circuit of the capacitive sensor 15 (plate 14 - wire 17, amplifier 20 - ground - grounded base 1 - plate 13). Between the plates 13 and 14 of the capacitive sensor 15, the electrical circuit is closed by means of an electromagnetic field. The current arising in this circuit is supplied to the amplifier 20 of the EMP signals and then to the first input of the computer 22, where the received signals are processed and analyzed. The result is, for example, in the form of oscillograms on a computer monitor 22.

 The strain gauge 18, glued to the fixed rod 7 and connected in a bridge circuit with the amplifier 21 through the wire 19, allows you to control the amount of force in the fixed rod 7, and therefore the magnitude of the force applied to the ring 12. The signal from the strain gauge sensor 18 via a shielded wire 19 enters the amplifier 21 and then to the second input of the computer 22. The registration system generates synchronous EMP waveforms and loads, which are used to judge the time interval between the occurrence of the EMP signal and the moment the ring breaks.

 Thus, the inventive method for studying the EMP of a ring-shaped solid deformable to fracture together with the inventive stand of a similar purpose provides the study of the EMP of ring-shaped solids deformable by a tensile load and, therefore, solve the technical problem.

Claims (2)

 1. A method for studying electromagnetic radiation of a ring-shaped solid deformable to destruction, including installing it on a bench between the plates of a capacitive electromagnetic radiation sensor, deforming it with a tensile load by applying external force using a load device including a frame and fixed and movable oppositely mounted on it thrusts in which the deformable solid is placed, while the movable thrust reports translational motion, transformation with the help of the specified capacitive sensor that occurs during crack formation of a deformable solid body of the electromagnetic radiation signal and its registration by a registration system, characterized in that the external force from the load device to the deformable ring is transmitted using semi-cylindrical protrusions, which are equipped with movable and fixed rods and on which the deformable ring, while the translational motion of the movable rod is reported using a movable screw with a steering wheel mounted on a load frame device, and record the force that occurs in the stationary thrust at the time of rupture of the ring using a strain gauge mounted on it, and the signals of the capacitive and strain gauge sensors are recorded synchronously on the first and second channels of the registration system, respectively, and the registration results additionally judge the time interval between the occurrence of a signal of electromagnetic radiation and the moment of destruction of a deformable solid.  2. A bench for studying electromagnetic radiation of a ring-shaped solid deformable to destruction, including a base enclosed in an electromagnetic screen, a capacitive sensor and a loading device including a frame mounted on the base, oppositely mounted fixed and movable rods, the fixed rod fixed to the frame wall on the inside, and a registration system, characterized in that the movable rod is connected to the movable screw, equipped with a steering wheel at the opposite end, while the movable and movable rods are equipped with semi-cylindrical protrusions on which a deformable ring is mounted and placed between the capacitive sensor plates fixed to the grounded base of the stand, one of the capacitive sensor plates installed through an insulating gasket and connected to the first channel of the registration system, and the second connected to the grounded the base, while on a fixed rod installed strain gauge connected to the second channel of the registration system.

Images