An experimental device and method for exploring the friction characteristics between a metal projectile and target particles during the penetration process

Abstract

An experimental device and method for exploring the friction characteristics between metals and particles, belonging to the technical field of experimental equipment. The present invention solves the problem in the prior art of lacking the research on the friction coefficient and friction characteristics between the target and the projectile. The sample groove is fixedly installed on the support bracket, the fixed pulley assembly is installed on the frame, the counterweight and the support bracket are respectively hoisted on both sides of the fixed pulley assembly through the connecting rope, and the up and down movement of the support bracket along the frame is realized through the counterweight, the connecting rope and the fixed pulley assembly. A tension sensor is installed on the connecting rope between the support bracket and the fixed pulley assembly. The motor is fixedly installed on the upper part of the frame. The top end of the friction disc is coaxially fixedly installed with an input shaft. The output shaft, the connecting shaft and the input shaft of the motor are coaxially fixedly connected in sequence from top to bottom, and a torque sensor is installed on the connecting shaft. The friction disc is circumferentially rotatably installed on the frame and is arranged directly above the sample groove, and a temperature sensor is installed at the lower part of the friction disc.

Description

Technical Field

[0001] The present invention relates to a test device and a test method for exploring the friction characteristics between a metal projectile and a target particle during the penetration process, belonging to the technical field of test equipment. Background Technique

[0002] Exploring the heat generation during penetration is of great significance for obtaining the thermal physical properties of the target. The heat generated during the penetration process mainly comes from the frictional resistance and deformation between the projectile and the target. Therefore, it is very important to explore the frictional resistance between the projectile and the target during the penetration process.

[0003] At present, domestic and foreign scholars' exploration of the frictional resistance during the penetration process mainly focuses on the influence of the frictional resistance on the penetration process. For example, Luk found that introducing the theoretical value of the friction coefficient would be closer to the actual value when deriving the penetration resistance model of concrete; Shan Yu et al. obtained that the influence of the frictional resistance on the penetration depth is significant at high speeds by deriving the penetration depth prediction model. The above studies only illustrate the influence of the frictional resistance on the penetration, and do not explore the friction coefficient and friction characteristics between the target and the projectile. Summary of the Invention

[0004] The present invention is to solve the problem that there is a lack of research on the friction coefficient and friction characteristics between the target and the projectile in the prior art, and further provides a test device and a test method for exploring the friction characteristics between a metal projectile and a target particle during the penetration process.

[0005] The technical solution adopted by the present invention to solve the above technical problems is:

[0006] A test device for exploring the friction characteristics between a metal projectile and a target particle during the penetration process includes a frame, a motor, a connecting shaft, a friction disc, a sample tank, a support bracket, a counterweight, and a fixed pulley assembly. The sample tank is fixedly installed on the support bracket, the fixed pulley assembly is installed on the frame, the counterweight and the support bracket are respectively hoisted on both sides of the fixed pulley assembly through a connecting rope, and the up and down movement of the support bracket along the frame is realized through the counterweight, the connecting rope, and the fixed pulley assembly. A tension sensor is installed on the connecting rope between the support bracket and the fixed pulley assembly. The motor is fixedly installed on the upper part of the frame. An input shaft is coaxially fixedly installed at the top of the friction disc. The output shaft of the motor, the connecting shaft, and the input shaft are coaxially fixedly connected in sequence from top to bottom. A torque sensor is installed on the connecting shaft. The friction disc is circumferentially rotatably installed on the frame and is arranged directly above the sample tank. A temperature sensor is installed at the lower part of the friction disc.

[0007] Further, the friction disc includes a disc, a friction ring, and a plurality of Z-shaped connecting pieces. The disc and the friction ring are coaxially arranged up and down and are fixedly connected by a plurality of circumferentially evenly distributed Z-shaped connecting pieces. The input shaft is coaxially fixedly installed on the disc.

[0008] Further, a gasket is fixedly provided between each Z-shaped connecting piece and the friction ring.

[0009] Further, a slip ring is rotatably installed on the upper part of the input shaft of the friction disc.

[0010] Further, the sample groove is an annular groove.

[0011] Further, a plurality of slide rails are installed on the inner side wall of the frame, and a plurality of sliders that are slidably connected to the plurality of slide rails are installed on the outer side wall of the support bracket. The support bracket is slidably connected up and down with the frame through the slide rails and the sliders.

[0012] Further, the frame includes a main frame body and a limiting plate. The limiting plate is vertically arranged in the middle of the main frame body, and the top end of the limiting plate is fixedly connected to the top end of the main frame body. The torque sensor is fixedly connected to the limiting plate.

[0013] Further, at least one limiting block is fixedly installed on the side surface of the limiting plate, and the input shaft of the friction disc is rotatably inserted into the limiting block.

[0014] Further, the frame further includes a limiting cross beam fixedly installed inside the main frame body. The lower part of the input shaft of the friction disc is circumferentially and rotatably installed on the limiting cross beam through a bearing seat assembly.

[0015] A test method using the above test device includes the following steps:

[0016] Step 1: Prepare a test sample in the sample groove, and install the sample groove with the prepared sample on the support bracket;

[0017] Step 2: Start the motor before the test, first idle the friction disc, and record the idle torque M0 at this time;

[0018] Step 3: Release the counterweight, and drive the support bracket and the sample groove on it to move upward through the fixed pulley assembly and the connecting rope;

[0019] Step 4: When the friction disc is in stable contact with the sample particles in the sample groove: First, record the torque M1 at this time. The frictional torque in this state is M1 - M0, and the frictional force Ff between the friction disc and the sample particles is calculated through the frictional torque; Second, record the reading F of the tension sensor and the gravity G of the counterweight. Through force analysis, the pressure of the friction disc on the sample particles at this time is G - F. Under the condition that the pressure and the frictional force are known, calculate the friction coefficient μ of the contact interface between the friction disc and the sample particles; Third, record the reading T of the temperature sensor to obtain the interface temperature of the metal and particle friction; Fourth, record the motor speed v and the average radius r, and calculate the relative speed v between the friction disc and the sample particles at this speed;

[0020] Step 5: Change the motor speed and the mass of the counterweight to conduct multiple groups of experiments, and compare the experimental results to obtain the friction characteristics between the metal and the particles.

[0021] The present invention has the following effects compared with the prior art:

[0022] The torque sensor, the tension sensor and the temperature sensor form a detection module. Among them, the torque sensor is used to measure the torque acting between the friction disc and the particles; the tension sensor is used to measure the tension received by the sample tank; the temperature sensor is used to measure the interface temperature of the frictional interaction between the friction disc and the particles. The number of temperature sensors is three and they are evenly distributed on the friction disc.

[0023] For the frictional interaction between the friction disc and the particles in the sample tank, experiments are carried out under different pressures and relative speeds by changing the pressure between the particles and the metal and the relative speed between the particles and the metal, so as to explore the influence of pressure and relative speed on the friction coefficient and obtain the friction characteristics between the metal and the particles.

[0024] Through this application, the pressure and friction force between the metal and the particles can be accurately obtained. Thus, the friction coefficient between the metal and the particles can be calculated under the known conditions of pressure and friction force. And by changing the mass of the weight and the motor speed, multiple groups of experimental results can be obtained to explore the influence of the pressure and relative speed between the metal and the particles on the friction characteristics. Brief Description of the Drawings

[0025] Figure 1 is the first three-dimensional schematic diagram of this application;

[0026] Figure 2 is the second three-dimensional schematic diagram of this application;

[0027] Figure 3 is the three-dimensional schematic diagram of this application with the frame removed (for showing the connection structure of the power module, the first limit plate is not removed for illustration).

[0028] Figure 4 is the schematic diagram of the installation position of the sample tank (the frame is not shown);

[0029] Figure 5 is the three-dimensional structure schematic diagram of the friction disc. Detailed Description of the Invention

[0030] Detailed Description of the Invention One: Combine Figures 1 to 5This embodiment describes a test device for exploring the friction characteristics between a metal projectile and target particles during the penetration process. The device includes a frame 1, a motor 2, a connecting shaft 3, a friction disc 4, a sample groove 5, a support bracket 6, a counterweight 7, and a fixed pulley assembly 8. The sample groove 5 is fixedly installed on the support bracket 6, the fixed pulley assembly 8 is installed on the frame 1, and the counterweight 7 and the support bracket 6 are respectively hoisted on both sides of the fixed pulley assembly 8 through a connecting rope 9. The up and down movement of the support bracket 6 along the frame 1 is realized by the counterweight 7, the connecting rope 9, and the fixed pulley assembly 8. A tension sensor 11 is installed on the connecting rope 9 between the support bracket 6 and the fixed pulley assembly 8. The motor 2 is fixedly installed on the upper part of the frame 1. The top end of the friction disc 4 is coaxially and fixedly installed with an input shaft 10. The output shaft of the motor 2, the connecting shaft 3, and the input shaft 10 are coaxially and fixedly connected in sequence from top to bottom. A torque sensor 12 is installed on the connecting shaft 3. The friction disc 4 is circumferentially rotatably installed on the frame 1 and is arranged directly above the sample groove 5. A temperature sensor 13 is installed at the lower part of the friction disc 4.

[0031] The torque sensor 12 is fixedly connected to the frame 1.

[0032] The motor 2 and the connecting shaft 3 form a power module to provide power for the rotation of the friction disc 4.

[0033] The output shaft of the motor 2 and the connecting shaft 3 are fixedly connected through a first coupling 14, and the connecting shaft 3 and the input shaft 10 of the friction disc 4 are fixedly connected through a second coupling 15.

[0034] The torque sensor 12, the tension sensor 11, and the temperature sensor 13 form a detection module. The torque sensor 12 is used to measure the torque acting between the friction disc 4 and the particles; the tension sensor 11 is used to measure the tension received by the sample groove 5; the temperature sensor 13 is used to measure the interface temperature of the frictional interaction between the friction disc 4 and the particles. The number of temperature sensors 13 is three and they are evenly distributed on the friction disc 4.

[0035] The frictional interaction between the friction disc 4 and the particles in the sample groove 5 is tested under different pressures and relative speeds by changing the pressure between the particles and the metal and the relative speed between the particles and the metal, so as to explore the influence of pressure and relative speed on the friction coefficient and obtain the friction characteristics between the metal and the particles.

[0036] The fixed pulley assembly 8, the connecting rope 9, the counterweight 7, and the sample groove 5 form a movable particle sample groove 5 unit. The fixed pulley assembly 8 includes several fixed pulleys, and each fixed pulley is installed at the top of the frame 1 through bolt assembly; the counterweight 7 is connected to the support bracket through the connecting rope 9. The connecting rope 9 is a steel wire rope.

[0037] Preferably, an installation plate 16 is fixedly installed at the top of the counterweight 7. The number of connecting ropes 9 is two. The number of fixed pulleys in the fixed pulley assembly 8 is four and they are arranged symmetrically in pairs. One end of each connecting rope 9 is fixedly connected to the installation plate 16. Each connecting rope 9 sequentially winds around two fixed pulleys on one side and is fixedly connected to the supporting bracket 6.

[0038] Through this application, the pressure and friction force between the metal and the particles can be accurately obtained. Under the known conditions of pressure and friction force, the friction coefficient between the metal and the particles can be obtained. And by changing the mass of the weight and the rotation speed of the motor 2, multiple groups of test results can be obtained to explore the influence of the pressure and relative speed between the metal and the particles on the friction characteristics.

[0039] The friction disc 4 includes a disc 4-1, a friction ring 4-2 and a plurality of Z-shaped connectors 4-3. The disc 4-1 and the friction ring 4-2 are arranged coaxially up and down and are fixedly connected by a plurality of circumferentially evenly distributed Z-shaped connectors 4-3. The input shaft 10 is coaxially and fixedly installed on the disc 4-1. Designed in this way, in order to reduce the overall weight of the friction disc 4, a plurality of lightweight holes can be opened on the disc 4-1. The disc 4-1 and the input shaft 10 are assembled and connected by threads. The number of Z-shaped connectors 4-3 is preferably six. Blind holes are opened on the upper surface of the friction ring 4-2 for connecting the Z-shaped connectors 4-3 so that the mechanical friction surfaces on the lower surface of the friction ring 4-2 are consistent. The relative speed between the friction ring 4-2 and the particles can be calculated by the rotation speed of the motor 2 and the diameter of the friction ring 4-2. The relative speed is set as the penetration speed to simulate the friction between the metal projectile and the target particles during the penetration process.

[0040] A gasket 4-4 is fixedly installed between each Z-shaped connector 4-3 and the friction ring 4-2. Designed in this way, the disc 4-1 and the Z-shaped connector 4-3, the Z-shaped connector 4-3 and the gasket 4-4, and the gasket 4-4 and the friction ring 4-2 are all connected by screw devices. Since the Z-shaped connector 4-3 and the friction ring 4-2 are both thin, directly connecting with screws is very likely to cause insecure connection, while connecting with bolts will cause the bottom surface of the friction ring 4-2 to be uneven, affecting the accuracy of the friction test results. By adding the gasket 4-4, the number of screws can be increased, and at the same time the thread length is a little longer, making the connection between the Z-shaped connector 4-3 and the friction ring 4-2 more stable.

[0041] A slip ring 17 is rotatably installed on the upper part of the input shaft 10 of the friction disc 4. Designed in this way, the slip ring 17 is preferably a six-way slip ring 17. It is convenient for the wiring arrangement of the temperature sensor 13. The wire of the temperature sensor 13 needs to be connected to the monitoring instrument. When the friction disc 4 rotates, the wire is connected to the monitoring instrument through the six-way slip ring 17, so that the wire of the temperature sensor 13 rotates together with the friction disc 4, and then the monitoring instrument is also connected to the six-way slip ring 17 to avoid the rotation of the part of the wire connecting the monitoring instrument.

[0042] The sample slot 5 is an annular slot.

[0043] A plurality of slide rails 18 are installed on the inner side wall of the frame 1, and a plurality of sliders 19 which are slidably connected with the plurality of slide rails 18 are installed on the outer side wall of the support bracket 6. The support bracket 6 is slidably connected with the frame 1 up and down through the slide rails 18 and the sliders 19. The number of the slide rails 18 can be determined according to the specific structures of the frame 1 and the support bracket 6. When both the frame 1 and the support bracket 6 are in a rectangular structure, the number of the slide rails 18 is preferably four and is evenly distributed around the support bracket 6, so that the sliding connection between the support bracket 6 and the frame 1 is more stable.

[0044] The frame 1 includes a main frame body 1-1 and a first limiting plate 1-2. The first limiting plate 1-2 is vertically arranged in the middle of the main frame body 1-1, and the top end of the first limiting plate 1-2 is fixedly connected with the top end of the main frame body 1-1. The torque sensor 12 is fixedly connected with the first limiting plate 1-2. With such a design, it is convenient to fix the position of the torque sensor 12 by arranging the first limiting plate 1-2.

[0045] At least one limiting block 1-3 is fixedly installed on the side surface of the first limiting plate 1-2. The input shaft 10 of the friction disc 4 is rotatably installed in the limiting block 1-3. With such a design, the radial limitation of the input shaft 10 is realized by arranging the limiting block 1-3, and the rotation action of the input shaft 10 is ensured to be stable during the high-speed rotation of the friction disc 4 driven by the motor 2.

[0046] The frame 1 further includes a limiting cross beam 1-4 fixedly installed inside the main frame body 1-1. The lower part of the input shaft 10 of the friction disc 4 is circumferentially and rotatably installed on the limiting cross beam 1-4 through a bearing seat assembly 20. With such a design, the rotational connection between the input shaft 10 and the limiting cross beam 1-4 and the vertical position fixation of the friction disc 4 are realized through the bearing seat assembly 20. In order to facilitate the connection between the bearing seat assembly 20 and the limiting cross beam 1-4, a second limiting plate 1-5 can be fixedly installed on the limiting cross beam 1-4, and the bearing seat assembly 20 is fixedly connected with the second limiting plate 1-5, making the connection more convenient and stable.

[0047] A test method using the above test device includes the following steps:

[0048] Step 1: Prepare a test sample in the sample slot 5, and install the sample slot 5 with the prepared sample on the support bracket 6;

[0049] Step 2: Start the motor 2 before the test, first idling the friction disc 4, and record the idling torque M0 at this time;

[0050] Step 3: Release the counterweight 7, and drive the support bracket 6 and the sample slot 5 thereon to move upward through the fixed pulley assembly 8 and the connecting rope 9;

[0051] Step 4: When the friction disc 4 is in stable contact with the sample particles in the sample groove 5:

[0052] First, record the torque M1 at this time. The frictional torque in this state is ΔM = M1 - M0. Calculate the frictional force F between the friction disc 4 and the sample particles through the frictional torque. f ;

[0053]

[0054] where: r is the average radius, 2r = r1 + r2;

[0055] Second, record the reading F of the tension sensor 11 and the gravity G of the counterweight 7. Through force analysis, the pressure of the friction disc 4 on the sample particles at this time is G - F. Under the condition that the pressure and frictional force are known, calculate the friction coefficient μ of the contact interface between the friction disc 4 and the sample particles.

[0056] The normal pressure on the contact interface is:

[0057] F N = 9.8G / A

[0058]

[0059] where: A is the effective contact area during the action of the friction ring;

[0060] Third, record the reading T of the temperature sensor 13 to obtain the interface temperature of the metal - particle friction.

[0061] Fourth, record the rotational speed n of the motor 2 and the average radius r, and calculate the relative velocity v between the friction disc 4 and the sample particles at this rotational speed.

[0062] v = 2πnr

[0063] Step 5: Change the rotational speed of the motor 2 and the mass of the counterweight 7 to conduct multiple groups of experiments, and compare the experimental results to obtain the friction characteristics between the metal and the particles. Designed in this way, since the friction characteristics are related to the pressure and relative velocity between the metal and the particles, the control variable method is used for multiple groups of experiments. First, keep the relative velocity, that is, the rotational speed of the motor 2 unchanged, change the pressure, that is, change the mass of the counterweight 7, and compare the experimental results to obtain the influence of pressure on friction; Second, keep the pressure unchanged, change the relative velocity, and compare the experimental results to obtain the influence of relative velocity on friction. Through the above experiments, the purpose of exploring the friction characteristics between the metal and the particles is finally achieved.

Claims

1. An experimental device for exploring the friction characteristics between a metal projectile and target particles during the penetration process, characterized in that: It includes a frame (1), a motor (2), a connecting shaft (3), a friction disc (4), a sample slot (5), a support bracket (6), a counterweight (7) and a fixed pulley assembly (8). The sample slot (5) is fixedly installed on the support bracket (6), the fixed pulley assembly (8) is installed on the frame (1), the counterweight (7) and the support bracket (6) are respectively hoisted on both sides of the fixed pulley assembly (8) through a connecting rope (9), and the up and down movement of the support bracket (6) along the frame (1) is realized through the counterweight (7), the connecting rope (9) and the fixed pulley assembly (8). A tension sensor (11) is installed on the connecting rope (9) between the support bracket (6) and the fixed pulley assembly (8). The motor (2) is fixedly installed on the upper part of the frame (1). The top end of the friction disc (4) is coaxially and fixedly installed with an input shaft (10). The output shaft of the motor (2), the connecting shaft (3) and the input shaft (10) are coaxially and fixedly connected in sequence from top to bottom. A torque sensor (12) is installed on the connecting shaft (3). The friction disc (4) is circumferentially rotatably installed on the frame (1) and is arranged directly above the sample slot (5). A temperature sensor (13) is installed at the lower part of the friction disc (4). The friction disc (4) includes a disc (4-1), a friction ring (4-2) and a plurality of Z-shaped connectors (4-3). The disc (4-1) and the friction ring (4-2) are coaxially arranged up and down and are fixedly connected through a plurality of circumferentially evenly distributed Z-shaped connectors (4-3). The input shaft (10) is coaxially and fixedly installed on the disc (4-1). Blind holes are formed on the upper surface of the friction ring (4-2) for connecting the Z-shaped connectors (4-3).

2. The test device for exploring the friction characteristics between a metal projectile and a target particle during the penetration process according to claim 1, characterized in that: A gasket (4-4) is fixedly installed between each Z-shaped connector (4-3) and the friction ring (4-2).

3. The test device for exploring the friction characteristics between a metal projectile and a target particle during the penetration process according to claim 1 or 2, characterized in that: A slip ring (17) is rotatably installed on the upper part of the input shaft (10) of the friction disc (4).

4. An experimental device for exploring the friction characteristics between a metal projectile and target particles during the penetration process according to claim 1, characterized in that: The sample slot (5) is an annular slot.

5. An experimental device for exploring the friction characteristics between a metal projectile and a target particle during the penetration process according to claim 1, 2 or 4, characterized in that: A plurality of slide rails (18) are installed on the inner side wall of the frame (1), and a plurality of sliders (19) that are slidably connected with the plurality of slide rails (18) are installed on the outer side wall of the support bracket (6). The support bracket (6) and the frame (1) are slidably connected up and down through the slide rails (18) and the sliders (19).

6. The experimental device for exploring the friction characteristics between a metal projectile and a target particle during the penetration process according to claim 1, wherein: The frame (1) includes a main frame body (1-1) and a first limiting plate (1-2). The first limiting plate (1-2) is vertically arranged in the middle of the main frame body (1-1), and the top end of the first limiting plate (1-2) is fixedly connected with the top end of the main frame body (1-1). The torque sensor (12) is fixedly connected with the first limiting plate (1-2).

7. The test device for exploring the friction characteristics between a metal projectile and target particles during the penetration process according to claim 6, characterized in that: At least one limiting block (1-3) is fixedly installed on the side surface of the first limiting plate (1-2). The input shaft (10) of the friction disc (4) rotatably passes through the limiting block (1-3).

8. The test device for exploring the friction characteristics between a metal projectile and a target particle during the penetration process according to claim 1, wherein: The frame (1) further includes a limiting cross beam (1-4) fixedly installed inside the main frame body (1-1). The lower part of the input shaft (10) of the friction disc (4) is circumferentially rotatably installed on the limiting cross beam (1-4) through a bearing seat assembly (20).

9. A test method using the test device described in any one of the above claims 1 to 8, characterized in that: It includes the following steps: Step 1: Prepare a test sample in the sample slot (5), and install the sample slot (5) with the prepared sample on the support bracket (6). Step 2: Before the test, start the motor (2), first let the friction disc (4) rotate idly, and record the idling torque M0 at this time; Step 3: Release the counterweight (7), and drive the bearing bracket (6) and the sample groove (5) thereon to move upward through the fixed pulley assembly (8) and the connecting rope (9); Step 4. When the friction disc (4) is in stable contact with the sample particles in the sample groove (5): First, record the torque M1 at this time. The frictional torque in this state is M1 - M0, and the frictional force F between the friction disc (4) and the sample particles is calculated through the frictional torque. f Second, record the reading F of the tension sensor (11) and the gravity G of the counterweight (7). Through force analysis, the pressure of the friction disc (4) on the sample particles at this time is G - F. Under the condition that the pressure and frictional force are known, the friction coefficient μ of the contact interface between the friction disc (4) and the sample particles is calculated. Third, record the reading T of the temperature sensor (13) to obtain the interface temperature of the metal and particle friction. Fourth, record the rotational speed n and the average radius r of the motor (2), and calculate the relative velocity v between the friction disc (4) and the sample particles at this rotational speed. Step 5: Change the rotational speed of the motor (2) and the mass of the counterweight (7) to conduct multiple groups of tests, and compare the test results to obtain the friction characteristics between the metal and the particles.

Images