A target body resistance characteristic testing device

Abstract

The application discloses a kind of target body resistance characteristic testing devices, including elastic body head, bullet body, test rod, top plate, energy-absorbing component, bottom plate, bullet-borne test storage device.The application utilizes the test mode of Hopkinson bar, and the response test problem of the impact end of the projectile is converted into the test problem of stress wave in the rod.The area of the test rod in the bullet body can be used as the test area, and the interface state of the test sensor can be controlled to ensure the validity of the test signal data.The test signal in the test rod is directly related to the response of the impact end of the projectile, and the test signal can directly reflect the resistance characteristics of the target body at the impact end.The application can reflect the resistance characteristics of the target body under different impact velocities and other dynamic conditions, and the test environment is closer to the real impact scene.The energy characteristics of the target resistance can also be quantitatively evaluated by monitoring the deformation of the energy-absorbing component during the target impact process.

Description

Technical Field

[0001] This invention relates to the field of impact testing technology, and in particular to a target resistance characteristic testing device. Background Technology

[0002] In studying scenarios where projectiles impact targets in different media, experiments are often conducted by projectiles impacting targets in various media. Common target media include concrete, water, and sand. Determining the equivalence of targets in different media is the first question that needs to be answered in these studies. A common method for demonstrating target equivalence is to compare the mechanical properties of the target specimen and the target medium specimen. Typically, only the quasi-static compressive mechanical properties of the specimens are compared; dynamic and complex stress state mechanical properties are generally not compared. Furthermore, obtaining representative target medium specimens is very difficult, especially for sand. While water media has good consistency, constructing water targets often requires the addition of auxiliary structures, and the impact of these structures is difficult to assess. Therefore, identifying the drag characteristics of the target is crucial for demonstrating its equivalence.

[0003] In experiments, the acceleration and strain responses of the projectile during its impact with the target can often be measured through measuring points. However, the data from these measuring points generally only reflects the response of the components of interest in the projectile structure and cannot directly reflect the drag characteristics of the target. In some experiments, attempts have been made to place measuring points in the impact area of ​​the projectile's head. However, due to the complexity of the projectile-target impact interface, it is difficult to determine whether the test requirements of the sensor can be met, which increases the difficulty in identifying the validity of the experimental data.

[0004] Therefore, it is necessary to develop a target resistance characteristic testing device to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to design a target resistance characteristic testing device to solve the above-mentioned problems.

[0006] The present invention achieves the above objectives through the following technical solutions:

[0007] A target drag characteristic testing device, comprising:

[0008] Projectile head; A central opening is provided axially inside the projectile head;

[0009] The projectile body has stepped openings axially arranged inside the projectile body, which include interconnected small holes and large holes; the first end of the projectile head is connected to the first end of the projectile body.

[0010] Test rod; the first end of the test rod is installed to match the shape and position of the second end of the projectile head; the test rod can be slidably placed in the central opening and the small hole;

[0011] Top plate; the first end of the top plate contacts the stepped surface of the stepped opening; the second end of the test rod passes through the central opening, the small hole and the large hole and connects to the center of the first end of the top plate;

[0012] Energy-absorbing component; the second end of the top plate contacts the first end of the energy-absorbing component; the top plate and the energy-absorbing component are slidably placed inside the large hole;

[0013] Base plate; the second end of the energy-absorbing component contacts the first end of the base plate; the outer wall of the base plate is connected to the inner wall of the large hole;

[0014] The missile-borne test storage device is used to record the stress / strain signals measured at the test rod and the compression deformation signals measured at the energy-absorbing component in real time. The missile-borne test storage device is connected to the second end of the base plate.

[0015] Preferably, both the projectile head and the projectile body are gyroscopic structures.

[0016] Preferably, the test rod is a one-dimensional stress rod.

[0017] Preferably, the test rod is made of high-strength steel.

[0018] The beneficial effects of this invention are as follows:

[0019] 1. This invention utilizes the Hopkinson bar testing method to transform the response testing problem of the projectile's direct impact end into the stress wave testing problem in the bar. The area inside the projectile body can be used as the testing area, and the test sensor interface state is controllable, which can ensure the validity of the test signal data.

[0020] 2. The test signal in the test rod is directly related to the response of the projectile impact end, and the test signal can directly reflect the drag characteristics of the target at the impact end;

[0021] 3. The drag characteristics of the target are related to the structure of the projectile's head. This invention can adjust the diameter of the test rod to preserve the projectile's head structure as realistically as possible, making the tested target drag characteristics more meaningful.

[0022] 4. This invention can reflect the drag characteristics of a target under dynamic conditions such as different impact velocities, and the test environment can be closer to the real impact scenario.

[0023] 5. By monitoring the deformation of the energy-absorbing components during the impact process, the energy characteristics of the target's drag can also be quantitatively assessed;

[0024] 6. The impact load testing technology is the same as that of the Hopkinson bar, the testing technology is mature, the overall structure of the device is similar to that of test pieces such as artillery and air cannons, the technologies for launching, testing and data storage are universal, and the implementation cost is low. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the target resistance characteristic testing device of the present invention;

[0026] Figure 2 A simulation model of the ball-head target resistance characteristic testing device and a schematic diagram of the measuring point positions on the test rod;

[0027] Figure 3 To compare the stress response in the impact direction at measuring points A and B after the test device collides head-on with a C20 concrete target at a speed of 350 m / s in the simulation calculation;

[0028] Figure 4 To compare the stress response in the impact direction at measuring points C and D after the test device collides head-on with a C20 concrete target at a speed of 350 m / s in the simulation calculation;

[0029] Figure 5 To compare the stress response in the impact direction at measuring points E and F after the test device collides head-on with a C20 concrete target at a speed of 350 m / s in the simulation calculation;

[0030] Figure 6 To compare the stress response in the impact direction at measuring points A, C, and E after the test device collides head-on with a C20 concrete target at a speed of 350 m / s in the simulation calculation;

[0031] Figure 7 To compare the stress response in the impact direction at measuring points A, C, and E after the test device collides head-on with the water target at a speed of 350 m / s in the simulation calculation;

[0032] Figure 8 To compare the stress response in the impact direction at measuring points A, C, and E after the test device collides head-on with the soil target at a speed of 350 m / s in the simulation calculation.

[0033] Figure 9 This study compares the changes in the thickness of the energy-absorbing components after the test device collides head-on with a C20 concrete target, a water target, and a soil target at a speed of 350 m / s in the simulation calculation.

[0034] Legend: 1-Projectile head; 2-Projectile body; 3-Test rod; 4-Top plate; 5-Energy-absorbing component; 6-Base plate; 7-Projectile test storage device. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0037] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0038] In the description of this invention, it should be understood that the terms "upper," "lower," "inner," "outer," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0039] Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0040] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, terms such as "set" and "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0042] like Figure 1 As shown, a target drag characteristic testing device includes:

[0043] Projectile head 1; A central opening is provided axially inside the projectile head 1. The shape of the projectile head 1 is generally determined according to the projectile head shape under test.

[0044] Projectile body 2; The projectile body 2 is provided with stepped openings axially, the stepped openings include small holes and large holes that are interconnected; The first end of the projectile head 1 is connected to the first end of the projectile body 2.

[0045] Test rod 3; The first end of test rod 3 is installed to match the shape and position of the second end of the projectile head 1. Test rod 3 is a cylindrical rod. Test rod 3 is slidably placed in the central opening and the small hole.

[0046] Top plate 4; the first end of top plate 4 contacts the stepped surface of the stepped opening; the second end of test rod 3 passes through the central opening, the small hole and the large hole and connects to the center of the first end of top plate 4;

[0047] Energy-absorbing component 5; the second end of the top plate 4 contacts the first end of the energy-absorbing component 5; the top plate 4 and the energy-absorbing component 5 are slidably placed inside the large hole;

[0048] Base plate 6; the second end of the energy-absorbing component 5 contacts the first end of the base plate 6; the outer wall of the base plate 6 is connected to the inner wall of the large hole;

[0049] The missile-borne test storage device 7 is used to record the stress / strain signals measured at the test rod 3 and the compression deformation signals measured at the energy-absorbing component 5 in real time. The missile-borne test storage device 7 is connected to the second end of the base plate 6. The projectile body 2, the projectile head 1, and the missile-borne test storage device 7 together form a projectile that can be launched by a cannon or air cannon. The operation of the missile-borne test storage device 7 is based on mature missile-borne test technologies such as cannons or air cannons.

[0050] In some embodiments, both the projectile head 1 and the projectile body 2 are gyroscopic structures.

[0051] In some embodiments, the test rod 3 is a one-dimensional stress rod.

[0052] In some embodiments, the energy-absorbing component 5 is made of aluminum foam, and the test rod 3 is made of high-strength steel.

[0053] In some embodiments, without regard to the energy characteristics of the target resistance, the top plate 4 and the energy-absorbing component 5 may be omitted, allowing the second end of the test rod 3 to be directly connected to the bottom plate 6.

[0054] In this invention, the test rod 3 is placed at the central opening of the projectile head 1 and can move freely. Initially, it is connected to the top plate 4. The installation and positioning are achieved through the tight contact between the top plate 4 and the stepped opening inside the projectile body 2, and the tight contact between the energy-absorbing component 5 and the top plate 4. The outer and inner surfaces of the projectile body 2 can be conical or other shapes, and are not limited to cylindrical shapes. After impacting the target, the projectile head 1 and the test rod 3 form a deformation area related to the shape of the projectile head 1 at the impact site. The impact load response generated by the impact between the target and the test rod 3 in the central region of the impact end is transmitted to the test rod 3. The stress / strain signal characteristics that reflect the drag characteristics of the target are obtained from the test rod 3. Subsequently, under the action of the impact load transmitted to the test rod 3, the test rod 3 and the top plate 4 move as a whole to squeeze the energy-absorbing component 5. In the subsequent impact process, they repeatedly squeeze and collide with the energy-absorbing component 5. The stress / strain signal measured at the test rod 3 and the compression deformation signal measured at the energy-absorbing component 5 are recorded in real time in the onboard test storage device 7. After the impact is completed, the onboard test storage device 7 is retrieved and the target drag characteristic test information is read.

[0055] This invention utilizes the Hopkinson bar testing concept to transform the complex problem of measuring the interface response of a projectile impact into the problem of measuring stress wave signals in a one-dimensional stress bar. The stress / strain signal propagating in the test bar 3 is used as a characterization of the target's drag characteristics. By arranging energy-absorbing components 5, the deformation of the energy-absorbing components 5 caused by the target's drag during the impact is used as an energy characteristic characterization of the target's drag characteristics, thereby realizing the testing of the target's drag characteristics during the impact.

[0056] The technical features of this invention are as follows: 1. The shape and structure of the projectile head 1 should be designed according to the head characteristics of the actual projectile being tested. It can be a single piece or multi-layered. During the impact process, the projectile head 1 can form a stress state response area in the target impact zone that is similar to that of the actual projectile impacting the target, so that the measured target drag characteristics are closer to the situation of the actual projectile impact. 2. The dimensions of the test rod 3 should meet the requirements of a one-dimensional stress rod. During the impact process, the deformation in the test rod 3 should meet the "plane section" assumption. At the same time, in order to avoid the influence of the strain rate effect in the rod, the test rod 3 should be in an elastic state or only generate a small plastic strain state during the impact process. 3. The top plate 4 should not undergo significant structural deformation when compressing the energy-absorbing component 5, and should not cause significant deformation in the test rod 3. 4. The energy-absorbing component 5 can be an energy-absorbing material such as aluminum foam, or a structural component that is easy to judge the deformation.

[0057] In this embodiment, a ball-head target resistance characteristic testing device is used for illustration. The simulation model of the ball-head target resistance testing device and a schematic diagram of the measuring point positions on the test rod 3 are shown below. Figure 2As shown, the positions of the measuring points on test rod 3 are arbitrarily selected. To ensure the effective data length of the measuring points, no measuring points are selected in the tail region of test rod 3. Specifically, measuring points A and B are equidistant from the tail end of test rod 3 at 225.8 mm, measuring points C and D are equidistant from the tail end of test rod 3 at 159.4 mm, and measuring points E and F are equidistant from the tail end of test rod 3 at 116.2 mm. Based on the distances of measuring points E and F from the tail end of test rod 3, the time required for the stress wave from test rod 3 and top plate 4 to reflect to measuring points E and F is 0.077 ms. Therefore, within 0.077 ms, the stress response from measuring points A to F is only related to the impact process on the target, and the test signal during this period is a valid signal. The ball-head target drag testing device has a diameter of 100mm and a length of 353mm. The projectile head 1 is a hemispherical structure; the test rod 3 has a diameter of 20mm and a length of 282mm; the top plate 4 has a diameter of 70mm and a thickness of 8mm; and the bottom plate 6 has a diameter of 70mm and a thickness of 8mm. For ease of comparison, in the simulation calculation, except for the energy-absorbing component 5 which uses aluminum foam, all other structural materials are G50 steel. In this case, the total weight of the ball-head target drag testing device is approximately 16kg. Since the onboard test storage device 7 has no significant impact in the numerical simulation calculation, it is not included in the simulation model. The simulation calculation shows the stress response at measuring points A and B in the impact direction after the ball-head target drag characteristic testing device impacts a C20 concrete target at a speed of 350m / s. Figure 3 As shown, the stress response in the impact direction at measuring point C and measuring point D is compared as follows: Figure 4 As shown, the stress response in the impact direction at measuring point E and measuring point F is compared as follows: Figure 5 As shown, the stress responses at the comparison test points are basically the same, especially within 0.077 ms, which indicates that test rod 3 conforms to the assumption of "plane section" deformation during the impact. Similar results were obtained when the ball-head target drag characteristic testing device collided head-on with a water target and a soil target at a speed of 350 m / s, and will not be shown here. Within 0.077 ms, the stress responses obtained at each test point exhibit the following characteristics: in the first stage, the stress increases rapidly; in the second stage, the stress gradually decreases to a certain stress level and begins to oscillate downwards. The first stage stress response characteristics represent the initial impact response of the target to the projectile, while the second stage stress response represents the drag of the target to the projectile during the stable penetration process. From the test point responses, it can be seen that after the ball-head target drag characteristic testing device collided head-on with a C20 concrete target at a speed of 350 m / s, the peak impact response of the C20 concrete target to the device was 1.27 GPa, and the stress subsequently decreased to around 500 MPa, reflecting the drag characteristics during the stable penetration stage. The stress response in the impact direction at measuring points A, C, and E after the ball-head target drag characteristic testing device impacts a C20 concrete target at a speed of 350 m / s is compared in the simulation calculation. Figure 6As shown, within 0.077 ms, the stress responses measured at the three measuring points are basically the same, and can all be used as a characterization of the target's drag characteristics at this time. The simulation calculation compares the stress responses in the impact direction at measuring points A, C, and E after the ball-head target drag characteristic testing device impacts the water target at a velocity of 350 m / s. Figure 7 As shown, within 0.077 ms, the dual-wave response characteristics were measured at three measuring points, which is significantly different from the impact on the C20 concrete target. The first stress response peak at the three measuring points is relatively consistent and can be used to characterize the drag characteristics of the water-impact target. At this point, the peak impact response of the water target to the device is 700 MPa, followed by a stress drop to around 72 MPa, reflecting the response characteristics of the water-impact target. The simulation calculation shows the stress response in the impact direction at measuring points A, C, and E after the ball-head target drag characteristic testing device impacts the soil target at a speed of 350 m / s. Figure 8 As shown, within 0.077 ms, relatively complex waveform responses were measured at the three measuring points. The first stress response at each measuring point still showed good consistency, with even better consistency at measuring points C and E, which are closer to the center of test rod 3. This can be used as the drag characteristic of the impact on the soil target. At this point, the peak impact response of the soil target to the device was 563 MPa, followed by a stress drop to around 260 MPa, reflecting the response characteristics of the impact on the soil target. The simulation calculation of the ball-head target drag characteristic test device impacting a C20 concrete target, a water target, and a soil target at a speed of 350 m / s is compared to the thickness change of the energy-absorbing component 5. Figure 9 As shown, the curve changes can intuitively display the energy characteristics of the target drag of different targets.

[0058] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A target drag characteristic testing device, characterized in that, include: Projectile head; A central opening is provided axially inside the projectile head. bullet body; The projectile body has stepped openings arranged axially inside, including interconnected small holes and large holes; the first end of the projectile head is connected to the first end of the projectile body. Test rod; the first end of the test rod is installed to match the shape and position of the second end of the projectile head; the test rod can be slidably placed in the central opening and the small hole; Top plate; the first end of the top plate contacts the stepped surface of the stepped opening; the second end of the test rod passes through the central opening, the small hole and the large hole and connects to the center of the first end of the top plate; Energy-absorbing component; the second end of the top plate contacts the first end of the energy-absorbing component; the top plate and the energy-absorbing component are slidably placed inside the large hole; Base plate; the second end of the energy-absorbing component contacts the first end of the base plate; the outer wall of the base plate is connected to the inner wall of the large hole; The missile-borne test storage device is used to record the stress / strain signals measured at the test rod and the compression deformation signals measured at the energy-absorbing component in real time. The missile-borne test storage device is connected to the second end of the base plate.

2. The target resistance characteristic testing device according to claim 1, characterized in that, Both the projectile's head and body are gyroscopic structures.

3. The target resistance characteristic testing device according to claim 1, characterized in that, The test rod is a one-dimensional stress rod.

4. The target resistance characteristic testing device according to claim 1, characterized in that, The test rod is made of high-strength steel.

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