Device and method for measuring micro-scale transient detonation pressure

Abstract

The invention belongs to the field of research of explosives and powders, and particularly relates to a device and a method for measuring micro-scale transient detonation pressure. Comprising a loading tool, a test piece, a quartz glass sheet, a central through hole bolt, an energy source and a PDV system, one end of the loading tool is provided with a small hole for assembling the test piece, the other end of the loading tool is provided with an explosive loading opening, an explosive to be tested and a detonating explosive are pressed in the loading tool through a central through hole bolt and a quartz glass sheet, and the test piece is assembled in the small hole of the loading tool in an unconstrained manner; a PDV probe of the PDV system is arranged at the rear end of the loading tool through a PDV clamp, the PDV probe, the loading tool and the center of the to-be-tested piece are coaxially arranged, and laser emitted by the PDV system is perpendicular to the end face of the test piece; the energy source is arranged at the front end of the loading tool and used for detonating the to-be-tested explosive. The measurement method provided by the invention is easy to implement, has high feasibility, and can complete measurement of the detonation pressure under the microscale.

Description

Technical Field

[0001] The invention belongs to the research field of explosives and firearms, and in particular relates to a device and method for measuring microscale transient detonation pressure. Background Art

[0002] After a certain form of energy stimulation, explosives will detonate, and a detonation shock wave will be generated during the detonation process. As one of the important parameters of the detonation shock wave, the detonation pressure has great research significance. At present, the main measurement methods for detonation pressure include manganese copper piezoresistance method, free surface velocity method, water tank method and other measurement methods.

[0003] The manganese copper piezoresistance method and the water tank method only have good results at larger sizes and are not applicable to micro-scale charges. The free surface velocity method is a non-contact test method that measures the free surface velocity of a metal plate under the action of explosives and then infers the explosion pressure of the explosive. Currently, there are optical probe and electrical probe test methods for measuring free surface velocity, but the test accuracy cannot be applied to millimeter-level free-flying sheets. Summary of the invention

[0004] The purpose of the present invention is to provide a simple and efficient device and method for measuring the detonation pressure of explosives in order to solve the current situation that there is a relative shortage of methods for measuring micro-region detonation pressure.

[0005] The technical solution for achieving the purpose of the present invention is: a device for measuring microscale transient detonation pressure, comprising a loading fixture, a test piece, a quartz glass piece, a central through-hole bolt, an energy source and a PDV system;

[0006] The loading tool has a small hole for assembling the test piece at one end and a charge port at the other end. The explosive to be tested and the detonator are pressed into the loading tool through a central through-hole bolt and a quartz glass sheet, and the test piece is assembled in the small hole of the loading tool without restraint;

[0007] The PDV probe of the PDV system is arranged at the rear end of the loading tool through the PDV fixture, and is arranged coaxially with the center of the loading tool and the test piece, and the laser emitted by the PDV system is perpendicular to the end face of the test piece;

[0008] The energy source is arranged at the front end of the loading device and is used to detonate the explosive to be tested.

[0009] Further, the PDV system also includes a laser source for generating laser light, a photon Doppler velocimeter, an optical fiber, a PDV probe, and an oscilloscope;

[0010] The laser generated by the laser source is amplified by the amplifier, and the emitted laser is irradiated to the surface of the piece to be tested. The reflected laser is received by the PDV probe, and after mixing processing by the photon Doppler velocimeter, the signal is transmitted to the oscilloscope.

[0011] Furthermore, the diameter of the small hole for assembling the test piece on the loading device is between 1 and 10 mm, the diameter of the piece to be tested is 2%-10% smaller than the diameter of the small hole, and the material of the piece to be tested is titanium with a thickness of between 1 and 100 μm.

[0012] Furthermore, a plexiglass plate is provided in front of the PDV fixture, and the distance between the PDV probe and the piece to be tested is 1-20 cm.

[0013] Furthermore, the energy source is light stimulation, thermal stimulation or electrical stimulation.

[0014] Furthermore, the energy source is a continuous laser with a central wavelength of 976nm and an output power of 120W.

[0015] Further, the explosive to be tested is RDX, and the detonator is BPN;

[0016] The charge amount of RDX is 50±5mg, the pressing pressure is 110±10kgf, and the charge density is 1.78±0.2g / cm 3 ; The BPN charge is 10±2mg, and the pressing pressure is 50±5kgf.

[0017] Furthermore, the diameter of the quartz glass sheet is 4±0.4 mm and the thickness is 1±0.2 mm; the thickness of the organic glass plate is 8-12 mm.

[0018] A method for measuring transient detonation pressure using the above device, comprising the steps of: (1) loading a reagent into a loading device, loading a piece to be tested from the other side and fitting it to the end face of the reagent;

[0019] Step (2): Setting up the PDV system to ensure that the outgoing laser of the PDV system is perpendicular to the end face of the wafer to be tested;

[0020] Step (3): detonating the explosive by means of an energy source, and the PDV system collecting the velocity signal of the piece to be tested;

[0021] Step (4): input the signal obtained in step (3) into the programmed program for Fourier transform to obtain the velocity curve of the flying piece;

[0022] Step (5): Read the effective velocity of the flying piece and calculate using the corresponding formula to obtain the detonation pressure.

[0023] Furthermore, step (5) is specifically as follows: calculating the detonation pressure of the explosive to be tested according to the corresponding formula (1) of the free surface velocity method, the Hugoniot relation (2) of the relevant metal, and the criterion that the free surface velocity of the metal is twice the particle velocity (3);

[0024] p=0.25u f (ρ0D0+ρ0m D m ) (1)

[0025] Where p is the detonation pressure, u is f is the effective velocity of the metal sheet, ρ0 is the compressed density of the explosive, ρ 0m is the density of the metal, D0 is the detonation velocity of the explosive, D m is the shock wave velocity in the metal plate;

[0026] D m =A+Bμ m (2)

[0027] Where D m is the shock wave velocity in the metal plate, μ m is the metal particle velocity;

[0028] u f =2μ m (3).

[0029] Compared with the prior art, the present invention has the following significant advantages:

[0030] Photon Doppler velocimetry (PDV) technology uses the Doppler effect of photons, that is, the frequency of light reflected from a moving object changes, to measure the velocity of the moving object to be measured. By Fourier transforming the image of the oscilloscope, the velocity history of the moving object can be obtained, which has the measurement conditions of a micro-scale free surface. Combining PDV technology with free surface velocimetry can simply, efficiently and conveniently measure the detonation pressure of the explosive to be tested. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the measuring device of the present invention.

[0032] Figure 2 It is a schematic diagram of the measurement principle of the present invention.

[0033] Description of reference numerals:

[0034] 1-PDV probe, 2-PDV fixture, 3-plexiglass plate, 4-loading fixture, 5-test piece, 6-quartz glass piece, 7-center through-hole bolt. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0036] The invention provides a simple and efficient device and method for measuring the explosion pressure of explosives.

[0037] The device includes a PDV system, an optical fiber, a loading device, an energy source, etc. The PDV system includes components such as a laser light source, a laser amplifier, a PDV host, a high-bandwidth oscilloscope, and an optical fiber.

[0038] The PDV system is mainly divided into five parts: (1) Laser source, used to generate laser. (2) Laser amplifier, amplifies the laser generated by the laser source and increases the laser energy. (3) Photon Doppler velocimeter, in which the test signal undergoes difference frequency interference and outputs the signal. (4) Optical fiber and probe, transmits laser and receives the reflected signal light, and then transmits the signal light to the photon Doppler velocimeter. (5) High-bandwidth oscilloscope, the output signal is collected by the oscilloscope, and the initial signal can be processed by the program to obtain its speed. The laser is generated by the laser source, transmitted to the laser amplifier through the optical fiber, and then transmitted to the PDV host after the laser energy is increased by the laser amplifier. The output laser of the PDV is irradiated to the surface of the titanium sheet, and the reflected laser is received by the PDV probe. After the PDV host mixes the signal, the signal is transmitted to the oscilloscope.

[0039] A method for measuring microscale transient detonation pressure comprises the following steps:

[0040] S1. Process a series of loaders according to actual requirements or actual working conditions

[0041] S2. Process the small hole to be tested for explosion pressure on the loading tool

[0042] S3. According to the size of the small hole, process the metal sheet slightly smaller than the hole diameter

[0043] S4. Load the drug to be tested into the loading device described in S2, and fill the small hole with the metal sheet described in S3.

[0044] S5. Fix the loading device described in S4, and align the PDV test probe with the small hole metal sheet and keep it at the same level.

[0045] S6. Use the energy source to detonate the explosive to be tested, and the oscilloscope of the PDV system records the signal.

[0046] S7. Input the PDV signal obtained in S6 into the prepared software or use Matlab to perform Fourier transform to obtain the velocity curve of the thin film.

[0047] S8. Read the effective velocity of the flying piece, calculate using the corresponding formula, and obtain the corresponding detonation pressure.

[0048] The specific requirements in S1 above are as follows:

[0049] The processed loading tool must meet the actual working conditions. The size and tolerance of the loading tool must be tested. It is believed that the error between the key size and the actual size is less than 3%.

[0050] The specific requirements in S2 above are as follows:

[0051] The small hole processed in the part to be tested of the loading fixture should not be too large. To facilitate the alignment of light, the aperture should be controlled between 1 and 10 mm according to the actual working conditions.

[0052] The specific requirements in the above S3 are as follows:

[0053] According to the size of the hole in S3, the diameter of the metal sheet should be slightly smaller than the diameter of the hole; to ensure that the mass of the metal sheet is small enough, the thickness of the processed metal sheet should be controlled between 1 and 100 μm.

[0054] The specific requirements in S4 above are as follows:

[0055] The medicine to be tested is loaded into the loading device described in S2 by pressing. During the pressing process, a mold consistent with the small hole should be used to block the opening to prevent the medicine from spilling during the pressing process. The metal sheet is loaded from the other side, and it should be ensured that the metal sheet is tightly combined with the end surface of the charge.

[0056] The specific requirements in S5 above are as follows:

[0057] The laser emitted by the PDV should be aligned and as perpendicular to the end face of the metal sheet as possible, and the distance between the PDV and the metal sheet should be between 1 and 20 cm. The degree of perpendicularity between the PDV and the metal sheet will greatly affect the measurement accuracy of the PDV system.

[0058] The specific requirements in S6 above are as follows:

[0059] The energy source is stimulated by light stimulation, heat stimulation, electrical stimulation and the like to detonate the explosive, and the velocity signal of the metal sheet is collected and stored by an oscilloscope.

[0060] The specific requirements in the above S7 are as follows:

[0061] The effective data obtained in S6 are input into the prepared program or Fourier transformed in Matlab to obtain the effective speed of the flying piece. The data with obvious inaccurate measurement are eliminated, and the remaining data are averaged to obtain the effective average speed.

[0062] The specific requirements in the above S8 are as follows:

[0063] The detonation pressure of the explosive to be tested is calculated based on the corresponding formula of the free surface velocity method (1), the Hugoniot relationship of the relevant metal (2), and the criterion that the free surface velocity of the metal is twice the particle velocity (3).

[0064] p=0.25u f (ρ0D0+ρ 0m Dm ) (1)

[0065] Where p is the detonation pressure, u is f is the effective velocity of the metal sheet, ρ0 is the compressed density of the explosive, ρ 0m is the density of the metal, D0 is the detonation velocity of the explosive, D m is the shock wave velocity in the metal plate.

[0066] D m =A+Bμ m (2)

[0067] Where D m is the shock wave velocity in the metal plate, μ m is the metal particle velocity.

[0068] u f =2μ m (3).

[0069] Example

[0070] The charge used in this embodiment is a two-stage charge, with BPN on the side close to the window and RDX on the side close to the metal sheet. RDX is the main charge, and BPN only plays an ignition role. The RDX charge is 50 mg, and the pressure is 110 kgf. After testing, the charge density is 1.78 g / cm 3 ; The BPN charge is 10mg, and the pressing pressure is 50kgf. After the pressing is completed, a quartz glass slide with a diameter of 4mm and a thickness of 1mm is loaded on one side of the BPN and clamped with a loading fixture to seal the charge and allow the laser to pass through the quartz window, ignite the BPN and then detonate the RDX. A titanium sheet with a diameter of about 1mm and a thickness of 0.03mm is attached to the end face of the RDX. The front end of the titanium sheet is the PDV probe and probe fixture, which is used to capture the speed of the titanium sheet, measure and calculate the detonation pressure. In order to prevent the titanium sheet from damaging the probe, a 10mm thick organic glass plate is fixed in front of the PDV probe.

[0071] The energy source used in this embodiment is a continuous laser. The laser generated by the continuous laser is transmitted through an optical fiber, focused by a laser collimator, and irradiated to the window of the loading device, thereby detonating the charge. The semiconductor continuous laser used in the experiment has a central wavelength of 976nm and an output power of 120W. However, since the output spot size is approximately equal to 4 times the window size, the actual laser power irradiated to the charge is approximately 30W.

Claims

1. A device for measuring microscale transient detonation pressure, characterized in that: It includes a loading device (4), a test piece (5), a quartz glass piece (6), a central through-hole bolt, an energy source and a PDV system; The loading tool (4) has a small hole at one end for assembling the test piece (5), and a charge port at the other end. The explosive to be tested and the detonator are press-fitted into the loading tool through a central through-hole bolt and a quartz glass sheet, and the test piece (5) is assembled in the small hole of the loading tool without restraint; The PDV probe (1) of the PDV system is arranged at the rear end of the loading device through a PDV fixture (2), and is arranged coaxially with the loading device and the center of the piece to be tested, and the laser emitted by the PDV system is perpendicular to the end face of the test piece (5); The energy source is arranged at the front end of the loading device and is used to detonate the explosive to be tested.

2. The measuring device according to claim 1, characterized in that The PDV system also includes a laser source for generating laser light, a photon Doppler velocimeter, an optical fiber, a PDV probe, and an oscilloscope; The laser generated by the laser source is amplified by the amplifier, and the emitted laser is irradiated to the surface of the piece to be tested. The reflected laser is received by the PDV probe, and after mixing processing by the photon Doppler velocimeter, the signal is transmitted to the oscilloscope.

3. The measuring device according to claim 2, characterized in that The diameter of the small hole on the loading device for assembling the test piece is between 1 and 10 mm, the diameter of the piece to be tested is 2%-10% smaller than the diameter of the small hole, the material of the piece to be tested is titanium, and the thickness is between 1 and 100 μm.

4. The measuring device according to claim 3, characterized in that A plexiglass plate (3) is arranged in front of the PDV fixture, and the distance between the PDV probe and the piece to be tested is 1-20 cm.

5. The measuring device according to claim 4, characterized in that The energy source is light stimulation, thermal stimulation or electrical stimulation.

6. The measuring device according to claim 5, characterized in that The energy source is a continuous laser with a central wavelength of 976 nm and an output power of 120 W.

7. The measuring device according to claim 6, characterized in that The explosive to be tested is RDX, and the detonator is BPN; The RDX charge is 50±5mg, the pressing pressure is 110±10kgf, and the charge density is 1.78±0.2g / cm 3 ; The BPN charge is 10±2mg, and the pressing pressure is 50±5kgf.

8. The measuring device according to claim 7, characterized in that The diameter of the quartz glass sheet is 4±0.4mm and the thickness is 1±0.2mm; the thickness of the organic glass plate is 8-12mm.

9. A method for measuring transient detonation pressure using the device according to any one of claims 1 to 8, characterized in that: The steps include: Step (1): loading the reagent into the loading device, and loading the test piece from the other side and fitting it with the loading end surface; Step (2): Setting up the PDV system to ensure that the outgoing laser of the PDV system is perpendicular to the end face of the wafer to be tested; Step (3): detonating the explosive by means of an energy source, and the PDV system collecting the velocity signal of the piece to be tested; Step (4): input the signal obtained in step (3) into the programmed program for Fourier transform to obtain the velocity curve of the flying piece; Step (5): Read the effective velocity of the flying piece and calculate using the corresponding formula to obtain the detonation pressure.

10. The method according to claim 9, characterized in that Step (5) specifically comprises: calculating the detonation pressure of the explosive to be tested according to the corresponding formula (1) of the free surface velocity method, the Hugoniot relation (2) of the relevant metal, and the criterion that the free surface velocity of the metal is twice the particle velocity (3); p=0.25u f (ρ0D0+ρ 0m D m ) (1) Where p is the detonation pressure, u is f is the effective velocity of the metal sheet, ρ0 is the compressed density of the explosive, ρ 0m is the density of the metal, D0 is the detonation velocity of the explosive, D m is the shock wave velocity in the metal plate; D m =A+Bμ m (2) Where D m is the shock wave velocity in the metal plate, μ m is the metal particle velocity; you f =2μ m (3).

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