Ignition controllable test device for impact shear of energetic materials

Abstract

The present application relates to a kind of impact shear ignition controllable test device of energetic material.It includes protective shell, protective shell cover and guide rail;Loading system includes high-pressure cylinder, acceleration track and loading component, loading component and sample support system are arranged in the interior of protective shell, acceleration track is connected with guide rail by slider, high-pressure cylinder is arranged at the end of acceleration track away from protective shell, and loading component is arranged at the other end of acceleration track;Sample support system includes bottom plate, stand, sample seat, sample cup, force sensor and cover plate, bottom plate, stand are connected with the flange of track of loading system and cover plate by stud and form cage structure, force sensor, sample seat and sample cup are arranged from bottom to top in the interior of cage structure.The device is low in cost, can not be influenced by human factors, loading component can be replaced according to experimental purpose, meet different working condition test demand, and mechanism analysis is carried out to the flow condition of internal substance of sample.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of impact test device design for energetic materials, and particularly to an impact shear ignition controllable test device for energetic materials. BACKGROUND

[0002] During the process of battlefield environment and daily service, ammunition often faces mechanical stimulation such as collision, falling, and jolting. Mechanical collision is the most common type of stimulation leading to accidental ignition of ammunition and causing safety accidents, so it is necessary to study the response and ignition process of energetic materials under impact load.

[0003] The response types that may occur in energetic materials under the action of impact, shear and other mechanical loads are sorted in time sequence as follows: deformation, damage, ignition, combustion, deflagration, and detonation. Different measurement and characterization techniques are used for different response processes. The deformation and damage processes are mainly characterized by optical microscopy, electron microscopy and other techniques to characterize the internal morphology of the material. X-ray tomography technology is used to analyze the internal material flow and density changes during the deformation process of the sample. The ignition and combustion processes mainly rely on infrared thermal imaging technology to measure the surface temperature distribution of the sample, and high-speed photography technology is used to record the sample ignition position, time and reaction propagation. The deflagration and detonation processes are mainly recorded by various pressure monitoring techniques to record the air shock wave pressure and reflect the reaction intensity. The test and characterization methods are as follows:

[0004] (1) Optical microscopy. The morphological scale that can be observed by visible light penetration or reflection from the free surface of the material is 0.2 pm. However, due to the difficulty in obtaining the final image at this extreme resolution, optical techniques are usually not used when the spatial resolution is less than 1 pm.

[0005] (2) Electron microscopy. Compared with optical microscopy, scanning electron microscopy (SEM) is more useful, with the ability to resolve details several orders of magnitude smaller, although it mainly provides qualitative information, and its minimum resolution can reach 6 nm. The measurement results are easier to interpret the two-dimensional projection of the actual three-dimensional surface topography.

[0006] (3) X-ray tomography. X-rays are emitted from a light source to penetrate the sample with almost no refraction, and another detection device receives them at the other end. The energy attenuation of X-rays is related to the density of the sample being tested, so the X-rays received by the detection device can be converted into a two-dimensional density image of the sample slice. To establish a three-dimensional image, the sample needs to be gradually rotated by a known angle to take a series of two-dimensional images. Computer reconstruction of two-dimensional images can construct a three-dimensional relative density image (tomogram). The advantage of X-ray tomography is that the measurement process is non-destructive, and it can reveal the internal microstructure of the material.

[0007] (4) Infrared thermal imaging technology. If the surface temperature of an object exceeds absolute zero, it will radiate electromagnetic waves. As the temperature changes, the intensity and wavelength distribution characteristics of electromagnetic waves also change. By detecting the infrared difference between the target and the background, different infrared images can be obtained, and the temperature value can be further calculated. The advantage of infrared thermal imaging technology is that it can reflect the temperature field changes during the response process of energetic materials, and further understand the formation mechanism of hot spots.

[0008] Currently, the main safety test methods of explosives under accidental impact are impact sensitivity test, drop test and low-speed impact test, which simulate the response characteristics of explosives under the impact of objects with certain mass and speed, and are of great significance for the safety evaluation of explosives.

[0009] Impact sensitivity test is a commonly used material-level impact sensitivity test method. The energetic material sample is placed between the upper and lower steel impact columns of the drop hammer impact sensitivity instrument. Different mass drop hammers are released from different heights to apply impact load to the explosive sample, and the sample response is observed and recorded. There are two methods to characterize the impact sensitivity of explosives: (1) Explosion probability method: a certain mass drop hammer is dropped from a certain height to impact a certain mass of explosive, repeated 25 times, record the number of explosive sample ignition, calculate the ignition percentage (P). (2) Characteristic drop height method: a certain mass drop hammer impacts a certain mass of explosive, and the drop height is adjusted to determine the drop height that makes the explosive sample ignition probability 50%, which is recorded as the characteristic drop height (H50).

[0010] Impact sensitivity test uses a small amount of sample (30-50 mg), and the sample is in the form of granular powder, which is significantly different from the actual charge state of ammunition. It cannot simulate the density, constraint, pressure and other effects of real charge under accidental impact, and can only be used as a means of screening the sensitivity of energetic compounds in the early stage of material synthesis, and has limited guiding significance for ammunition safety evaluation.

[0011] In terms of product-level testing, many national military standards and related industry standards specify ammunition drop test methods. The test object is a full ammunition or warhead, which is dropped from a height of 3 meters or 12 meters at a certain attitude (horizontal, vertical or a certain angle) to impact a steel target plate installed on the ground concrete. The test determines the damage and reaction intensity of the ammunition according to the damage state of the ammunition and the air shock wave overpressure value recorded by the air shock wave overpressure sensor within a certain distance.

[0012] The research on the impact response of energetic materials also has Steven test. The Steven test uses a sample with a diameter of 11 cm and a thickness of 1.285 cm, and the total mass of the sample is about 400 g. The sample is assembled into a target by a cover plate with a thickness of 0.375 cm and a sample cup made of steel with a bottom thickness of 1.905 cm. A gas gun is used to launch a tantalum projectile with a diameter of 6.01 cm to impact the target at a speed of 20-150 m / s. The pressure during the impact and the subsequent reaction process is measured by an overpressure gauge at a distance of 10 feet and an embedded pressure gauge.

[0013] Gruau, C et al. visualizes the classic Steven test by using a circular projectile and a stepped projectile to achieve the observation of point ignition and ring ignition.

[0014] Dorough, Green et al. developed a low-speed impact test Susan test. The Susan test test projectile is composed of a sample, an aluminum cap, a weight, etc. The test projectile is launched by a light gas gun to impact a vertical target at a speed of 20-600 m / s. An air shock wave pressure sensor is installed at a certain distance from the vertical target to monitor the reaction pressure and determine the severity of the impact response.

[0015] The existing impact safety test method has a rough measurement means. For example, the impact sensitivity test method relies on sensory indicators such as sound, light, smoke and color to qualitatively determine the experimental results, which is greatly affected by human factors. The ammunition drop test consumes a lot of resources and investment, and can only observe whether the sample explodes or not, and the test data is extremely limited. The low-speed impact test such as the Steven test and the Susan test increases the test data, and the pressure change of the sample during loading can be measured, but the internal material flow of the sample cannot be obtained, and mechanism analysis cannot be performed. SUMMARY

[0016] The purpose of the present application is to provide an impact shear ignition controllable test device for energetic materials, which has low cost, is not affected by human factors, can replace the loading components according to the experimental purpose, meets the testing requirements of different working conditions, and performs mechanism analysis on the internal material flow of the sample.

[0017] To achieve the above purpose, the present application provides the following scheme:

[0018] An impact shear ignition controllable test device for energetic materials comprises a protection system, a loading system and a sample support system.

[0019] The protection system comprises a protection shell, a protection shell cover and a guide rail. The protection shell cover is used to be pulled out during experimental preparation to perform sample installation and instrument debugging operations. The protection shell cover is closed during the experiment to ensure that the impact shear test is performed in a closed shell. One end of the guide rail is located inside the protection shell, and the other end is located outside the protection shell.

[0020] The loading system comprises a high-pressure cylinder, an acceleration track and a loading component, the loading component and the sample support system are arranged inside the protective shell, the acceleration track is connected with the guide rail through a sliding block, one end of the acceleration track is located inside the protective shell and the other end is located outside the protective shell, the high-pressure cylinder is arranged at the end of the acceleration track away from the protective shell, and the other end of the acceleration track is provided with the loading component.

[0021] The sample support system comprises a base plate, a column, a sample seat, a sample cup, a force sensor and a cover plate, the base plate and the column form a cage structure with the track flange of the loading system and the cover plate through studs, the cage structure is internally provided with the force sensor, the sample seat and the sample cup from bottom to top, the force sensor records the pressure change of the sample during the experiment, and the sample cup is used for receiving the sample.

[0022] Optionally, the protective shell is made of a strong constraint spherical steel with a set thickness, the shell of the protective shell is provided with an observation window for observing the experiment process, and the shell of the protective shell is also provided with an explosion venting window for releasing pressure when the sample reacts violently.

[0023] Optionally, the high-pressure cylinder uses compressed nitrogen as a power source to drive the loading component to move along the acceleration track and act on the sample.

[0024] Optionally, the high-pressure cylinder is made of 17-4PH stainless steel and has a maximum pressure resistance of 5MPa, and is used to change the loading speed of the loading component by adjusting the gas pressure in the cylinder.

[0025] Optionally, the acceleration track is made of 17-4PH stainless steel pipe, the inner surface of the acceleration track is polished for the accelerated movement of the loading component, and a remote control switch is arranged at the starting end of the loading track.

[0026] Optionally, the loading component comprises a needle bolt, a needle handle and a needle tip, the needle bolt is tightly matched with the acceleration track and is pushed to move the entire loading component by compressed gas energy, the needle handle is used for connecting the needle tip and the needle bolt, and the needle tip is in contact with the sample and directly invades the inside of the sample.

[0027] Optionally, the needle tip comprises a flat needle tip, a 20° needle tip, a 40° needle tip and a spherical needle tip.

[0028] Optionally, the sample cup comprises a thick-walled full-restraint sample cup, a half-width transparent sample cup and a bottom transparent sample cup.

[0029] Optionally, the bottom transparent sample cup comprises an upper cavity and a lower cavity, the sample is placed on sapphire glass, wrapped with a rubber gasket, and installed in the upper cavity, a 45° reflector is installed in the lower cavity, and the reflector is used to change the light path to facilitate observation by external test instruments.

[0030] According to the specific embodiments provided by the present application, the following technical effects are disclosed:

[0031] The present application provides a kind of impact shear ignition controllable test device of energetic material.It is divided into protection system, loading system and sample support system, protection system includes protective shell, protective shell cover and guide rail;Loading system includes high-pressure cylinder, acceleration track and loading component, loading component and sample support system are arranged in the inside of protective shell, acceleration track is connected with guide rail by sliding block, high-pressure cylinder is arranged at the end of acceleration track away from protective shell, and loading component is arranged at the other end of acceleration track;Sample support system includes bottom plate, stand, sample seat, sample cup, force sensor and cover plate, bottom plate, stand are connected with the flange of track of loading system and cover plate by stud and form cage structure, force sensor, sample seat and sample cup are arranged from bottom to top in the inside of cage structure.The above-mentioned device has low cost, can not be affected by human factors, can replace loading component according to experimental purpose, meets different working condition test demand, and mechanism analysis is carried out to the flow condition of internal substance of sample. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0033] Figure 1 The present application provides an impact shear ignition controllable test device for energetic materials.

[0034] Figure 2 The present application provides an impact shear ignition controllable test device for energetic materials.

[0035] Figure 3 The present application provides an impact shear ignition controllable test device for energetic materials.

[0036] Figure 4 The present application provides an impact shear ignition controllable test device for energetic materials.

[0037] Figure 5 The present application provides an impact shear ignition controllable test device for energetic materials.

[0038] Figure 6 The present application provides an impact shear ignition controllable test device for energetic materials.

[0039] Figure 7 Figure is a schematic diagram of a half-transparent sample cup according to the present application;

[0040] Figure 8 Figure is a schematic diagram of a bottom-transparent sample cup according to the present application. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0042] The purpose of the present application is to provide an impact shear ignition controllable test device for energetic materials, which is low in cost, can be free from human factors, can replace loading components according to experimental purposes, meets different working condition test requirements, and can analyze the mechanism of the flow of substances in the sample.

[0043] In order to make the above-mentioned purposes, characteristics and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0044] Impact shear refers to dynamic action of a loading component with a certain shape and sharpness on a loaded object, causing a certain impact compression and shear action.

[0045] Energetic materials are a kind of compounds or mixtures containing explosive groups or containing oxidants and combustibles, which can independently perform chemical reactions and output energy, and the impact shear test of the energetic materials has certain risk, and when ignition occurs in the impact shear test of the energetic materials, explosion may be caused, so a large number of related tests are performed outdoors. In order to realize laboratory research on the impact shear ignition of the energetic materials, the present application designs an impact shear ignition controllable test device for energetic materials. Figure 1 As shown in Figure 1, the impact shear ignition controllable test device for energetic materials according to the present application comprises a protection system, a loading system and a sample support system. Figure 1 As shown in Figure 1, the impact shear ignition controllable test device for energetic materials according to the present application comprises a protection system, a loading system and a sample support system.

[0046] The protection system comprises a protection shell 1, a protection shell cover 2 and a guide rail 3. The protection shell cover 2 is used to be pulled out when the experiment is prepared, and is used to perform sample installation and instrument debugging and other operations. The protection shell cover 2 is closed when the experiment is performed, so as to ensure that the impact shear test is performed in a closed shell, and the safety of the experimental personnel and external instrument equipment is effectively protected. One end of the guide rail 3 is located inside the protection shell 1, and the other end is located outside the protection shell 1. The protection shell cover 2, the loading system and the sample support system are assembled into an integral whole, and are realized by two sliding blocks 4 cooperating with the guide rail 3 to realize entering and exiting the protection shell 1. Figure 2It is a schematic diagram of the test protection system of the application.

[0047] The loading system comprises a high-pressure cylinder 5, an acceleration track 6 and a loading component, the loading component and the sample support system are arranged inside the protective shell 1, the acceleration track 6 is connected with the guide rail 3 through the sliding block 4, one end of the acceleration track 6 is located inside the protective shell 1 and the other end is located outside the protective shell 1, the high-pressure cylinder 5 is arranged at the end of the acceleration track 6 away from the protective shell 1, and the other end of the acceleration track 6 is provided with the loading component. Figure 3 It is a schematic diagram of the loading system of the application.

[0048] The sample support system comprises a bottom plate 10, a column 11, a sample seat 12, a sample cup 13, a force sensor 14 and a cover plate 15, the bottom plate 10 and the column 11 form a cage structure with the track flange 26 of the loading system and the cover plate 15 through the stud 16, the cage structure is used for installing the sample 20 and implementing the impact shear test, the force sensor 14, the sample seat 12 and the sample cup 13 are arranged in the cage structure from bottom to top, the force sensor 14 records the pressure change of the sample in the experiment process, the sample cup 13 is used for receiving the sample 20, and the sample seat 12 is connected with the force sensor 14 and used for fixing the sample cup 13. Figure 5 It is a structural diagram of the sample support system of the application.

[0049] The protective shell 1 adopts a strong constraint spherical steel with a set thickness, and can prevent the fragments generated by explosion of the sample 20 from flying.

[0050] The high-pressure cylinder 5 uses compressed nitrogen as a power source, drives the loading component to move at a high speed along the acceleration track 6, and finally acts on the sample 20. The high-pressure cylinder 5 adopts 17-4PH stainless steel and has a maximum pressure resistance of 5MPa, and is used for changing the loading speed of the loading component by adjusting the gas pressure in the cylinder. The acceleration track 6 adopts 17-4PH stainless steel pipe, the inner surface of the acceleration track 6 is polished, the acceleration track 6 is used for accelerating the movement of the loading component, and a remote control switch is arranged at the starting end of the loading track. During the inflation stage of the high-pressure cylinder 5, the switch locks the loading component; during the experiment, the switch is opened to release the loading component, and remote operation of the experiment is realized. The tail part of the loading track is connected with the sample support system and is provided with a stop washer 25, so that the loading component can be reliably stopped at the end of the track. Figure 4Load component detail diagram of the application. To realize different quality, different shape load demand, the load component is composed of three parts, respectively, the needle tip 7, the needle handle 8 and the needle bolt 9, the needle bolt is closely matched with the acceleration track 6, accepts the compressed gas energy to promote the movement of the whole load component, the needle handle 8 is used to connect the needle tip 7 and the needle bolt 9, in the experiment, the needle tip 7 contacts with the sample 20, directly invades into the inside of the sample 20. The needle tip 7 includes four different specifications, the plane needle tip 73, the 20° needle tip 72, the 40° needle tip and the spherical needle tip 71. Simulate the load action in different actual scenes; the needle bolt 9 is located at the rear end of the load component, closely matched with the acceleration track 6, accepts the compressed gas energy to promote the movement of the whole load component, in addition, the needle bolt 9 is made of different materials, the weight of itself is variable, 2-20 kg; the needle handle 8 is the intermediate component connecting the needle tip 7 and the needle bolt 9. In the experiment, the needle tip 7 and the needle bolt 9 can be flexibly replaced, meeting the different load shape, different load quality, different load speed demand.

[0051] To realize the impact shear visualization, the sample cup 13 includes three different specifications, the thick wall full constraint sample cup, the half-width transparent sample cup and the bottom transparent sample cup. Figure 6 The thick wall full constraint sample cup schematic diagram of the application, symbol 17 is a screw, 18 is a nut, 19 is a fastening ring. The thick wall full constraint sample cup has an inner diameter of 30 mm, an outer diameter of 40 mm, a bottom and wall thickness of 5 mm, a charge height of 30 mm, and can be selected to cover a 2 mm metal cover plate according to needs, respectively simulating the impact shear scene of the shell charge and the bare charge. The half-width transparent sample cup is cut in half on the basis of the full constraint sample cup, installs the semicylindrical sample, and uses the sapphire glass 25 to cover, to increase the light transmission, to facilitate the observation of the sample impact shear cross section material flow condition. Figure 7 The half-width transparent sample cup schematic diagram of the application, symbol 17 is a screw, 19 is a fastening ring.

[0052] To realize the bottom observation of the sample impact shear ignition, the bottom transparent sample cup structure is designed. Figure 8 The bottom transparent sample cup sectional view of the application. The bottom transparent sample cup is designed with a boss with a light transmission hole 23 in the middle to hold the sample, which divides the bottom transparent sample cup into two cavities. The light transmission hole is installed with a sapphire material light transmission glass 21 above, to increase the light transmission. The sample is placed on the sapphire material light transmission glass 21, wrapped with a rubber gasket 22, and installed in the upper cavity. The lower cavity is installed with a 45° reflector 24, which changes the light path, facilitating the observation of the external test instrument. Figure 8 Symbol 15 is a cover plate, symbol 19 is a fastening ring. The cover plate is a metal cover plate.

[0053] In order to solve the wide load spectrum impact shear safety analysis of ammunition in actual use process, the application designs a visual test device of impact shear ignition of energetic material which can be operated in laboratory and disassembled and assembled. The test device is small in size and light in weight, and is convenient to carry and move as a whole. The test device integrates functions of loading, temperature measurement, pressure measurement and optical observation. The device can replace loading components according to experimental purposes, and meets different working condition test requirements. The device can observe sample changes on the side and bottom through a half-width sample cup and a bottom transparent sample cup. The device is equipped with high-speed photography, infrared thermal imaging and X-ray observation technology, can accurately judge sample ignition results, record sample response process under impact shear load, and provide evidence for analyzing ignition mechanism.

[0054] The various embodiments are described in a progressive manner in the specification, and each embodiment focuses on the difference from other embodiments, and the same or similar parts between various embodiments can be referred to each other.

[0055] The principles and implementation modes of the application are described by applying specific examples in the specification, and the above description of the examples is only used to help understand the method of the application and its core idea; meanwhile, according to the idea of the application, the specific implementation mode and application range can be changed by the person skilled in the art. In conclusion, the content of the specification should not be understood as the limitation of the application.

Claims

1. A controllable experimental device for impact shear ignition of energetic materials, characterized in that, include: Protective systems, loading systems, and sample support systems; The protective system includes a protective shell, a protective shell cover, and a guide rail. The protective shell cover is pulled out during experimental preparation for sample installation and instrument debugging; it is closed during the experiment to ensure that the impact shear test is conducted within the sealed shell. One end of the guide rail is located inside the protective shell, and the other end is located outside the protective shell. The loading system includes a high-pressure cylinder, an acceleration track, and a loading component. The loading component and the sample support system are disposed inside the protective shell. The acceleration track is connected to the guide rail via a slider. One end of the acceleration track is located inside the protective shell, and the other end is located outside the protective shell. The high-pressure cylinder is disposed at the end of the acceleration track away from the protective shell, and the loading component is disposed at the other end of the acceleration track. The sample support system includes a base plate, a column, a sample holder, a sample cup, a force sensor, and a cover plate. The base plate and column form a cage-like structure with the track flange and cover plate of the loading system through studs. The force sensor, sample holder, and sample cup are respectively installed inside the cage-like structure from bottom to top. The force sensor records the pressure change of the sample during the experiment, and the sample cup is used to hold the sample. The protective shell is made of strongly constrained spherical steel with a set thickness. The shell of the protective shell is provided with an observation window for observing the experimental process. The shell of the protective shell is also provided with an explosion relief window for releasing pressure when the sample reacts violently. The loading component includes a needle plug, a needle handle, and a needle tip. The needle plug is made of different materials and its weight can vary from 2 to 20 kg. The needle handle is the intermediate component connecting the needle tip and the needle plug. The needle tip and needle plug can be flexibly replaced.

2. The controllable test device for impact shear ignition of energetic materials according to claim 1, characterized in that, The high-pressure cylinder uses compressed nitrogen as a power source to drive the loading component to accelerate along the acceleration track and act on the sample.

3. The controllable test apparatus for impact shear ignition of energetic materials according to claim 1, characterized in that, The high-pressure cylinder is made of 17-4PH stainless steel and has a maximum pressure resistance of 5MPa. It is used to change the loading speed of the loading component by adjusting the gas pressure inside the cylinder.

4. The controllable test apparatus for impact shear ignition of energetic materials according to claim 1, characterized in that, The acceleration track is made of 17-4PH stainless steel tubing, and the inner surface of the acceleration track is polished to allow the loading component to accelerate. A remote control switch is installed at the starting end of the acceleration track.

5. The controllable test apparatus for impact shear ignition of energetic materials according to claim 1, characterized in that, The needle plug is closely fitted with the acceleration track and receives compressed gas energy to drive the entire loading component to move. The needle handle is used to connect the needle tip and the needle plug. The needle tip contacts the sample and directly penetrates the sample.

6. The controllable test apparatus for impact shear ignition of energetic materials according to claim 1, characterized in that, The needle tip includes four different specifications: flat needle tip, 20° needle tip, 40° needle tip and spherical needle tip.

7. The controllable test apparatus for impact shear ignition of energetic materials according to claim 1, characterized in that, The sample cups include three different specifications: thick-walled fully constrained sample cups, half-width transparent sample cups, and bottom-transparent sample cups.

8. The controllable test apparatus for impact shear ignition of energetic materials according to claim 7, characterized in that, The bottom transparent sample cup includes an upper cavity and a lower cavity. The sample is placed on sapphire glass, wrapped with a rubber gasket, and then installed in the upper cavity. A 45° reflector is installed in the lower cavity. The reflector is used to change the optical path to facilitate observation by external experimental instruments.

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