A loading control device and method for Hopkinson bar impact test

Abstract

The present invention discloses a loading control device and method for a Hopkinson bar impact test, belonging to the technical field of impact calibration of high-g acceleration sensors. The present invention comprises a linear motor, a limit rod, an end cap, a bullet launch tube, a test bullet, an air compressor, an air storage tank, a vacuum pump, a control console, a buffer gasket, and a gasket clamping plate. A movable limit rod is installed in the bullet launch tube. By controlling the length of the limit rod extending into the bullet launch tube, the launch position of the test bullet is adjusted and determined. The device and method of the present invention are used in conjunction with a Hopkinson bar. The limit mechanism precisely controls and adjusts the launch position and acceleration distance of the test bullet, accurately controls the peak acceleration value, and obtains a corresponding relationship between the driving air pressure, acceleration distance, and peak acceleration value. Pneumatic reset allows the test bullet to quickly return to its initial or specified position after launch, significantly improving the automation level, experimental efficiency, and control accuracy of the Hopkinson bar impact loading test.

Description

Technical Field

[0001] The invention belongs to the technical field of impact calibration of high-g value acceleration sensors, and in particular relates to a loading control device and method for a Hopkinson bar impact test. Background Art

[0002] Hopkinson bar impact test technology is widely used in civilian collision tests and national defense scientific research, production and testing. It is an important technology for the structure, functional reliability and test calibration of missile-borne electronic devices, acceleration sensors, etc., especially in the field of national defense. It is also widely used in aspects such as material mechanical properties testing.

[0003] Existing Hopkinson bar devices include conventional Hopkinson compression bars, Hopkinson tension bars, and Hopkinson torsion bars. Currently, there are generally two ways to drive a Hopkinson bar device. One is the most common pneumatic loading method, in which the compressed gas in a high-pressure container drives a bullet or collision rod to directly impact the incident rod. The collision at the front end of the incident rod generates a compressive stress wave, which propagates to electronic instruments or material samples such as the sensor to be tested that is connected to the rear end of the incident rod. The other driving method is electromagnetic loading, such as application numbers CN202210044762.6, CN201510956545.4, and CN201910038475, which use capacitors and copper coils to generate a strong magnetic field, which in turn generates an eddy current magnetic field and a repulsive force. This repulsive force pulse is transmitted through an amplifier, directly generating an incident pulse in the incident rod.

[0004] However, both methods have their own shortcomings. For pneumatic loading, the position of the bullet or impact rod in the airgun varies with each shot, making it difficult to determine the relationship between impact velocity and air pressure. Consequently, the amplitude of the incident wave cannot be accurately controlled, requiring multiple experiments to obtain the desired strain rate, resulting in poor experimental repeatability. Electromagnetic loading is technically complex and expensive, and the magnitude of the electromagnetic repulsion is affected by circuit structure parameters. Electromagnetic riveting technology generates stress waves primarily by accelerating the collision rod and the incident rod through electromagnetic repulsion, requiring cumbersome reinstallation for subsequent experiments. These issues result in very low test efficiency. Summary of the Invention

[0005] In response to the above-mentioned problems, the main purpose of the present invention is to provide a loading control device and method for a Hopkinson bar impact test. The device and method are used in conjunction with a Hopkinson bar to precisely control and adjust the launch position and acceleration distance of a test bullet through a limiting mechanism, accurately control the acceleration peak value, and obtain a corresponding relationship between the driving air pressure, acceleration distance, and acceleration peak value. Through pneumatic reset, the test bullet can quickly return to its initial position or a specified position after launch, significantly improving the degree of automation, experimental efficiency, and control accuracy of the Hopkinson bar impact loading test.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] The invention discloses a loading control device for a Hopkinson bar impact test, which comprises a linear motor, a limit rod, an end cover, a bullet launching tube, a test bullet, an air compressor, an air storage tank, a vacuum pump, a control console, a buffer gasket, and a gasket clamping plate.

[0008] The air compressor is connected to the air tank via an inlet valve. The air outlet of the air tank is connected to a gas pipeline via an outlet valve. The end of the gas pipeline is connected to the vent hole on the end cap of the bullet launcher. The number of gas pipelines is equal to the number of vent holes in the end cap. The control console is connected to the inlet valve and outlet valve to control the inflation and deflation of the air tank. Preferably, the bullet launcher is connected to multiple air tanks in parallel, and the multiple air tanks work in alternating order to reduce the time between the next firing.

[0009] The vacuum pump is connected to a gas pipeline via a valve, the end of which is connected to a vent on the end cap of the bullet launch tube. The vacuum pump extracts gas from the bullet launch tube through the vent, creating a negative pressure within the tube. This negative pressure acts on the bottom of the test bullet, returning the test bullet to its initial launch position. This avoids the inefficient and cumbersome process of using a magnetic device to retract the test bullet or manually pushing it back, significantly improving the automation level of the Hopkinson bar impact loading experiment.

[0010] The end cap is located at the end of the bullet launch tube and is connected to the bullet launch tube. A limiting hole is machined in the center of the end cap for the limiting rod to pass through and move back and forth. The limiting hole is a through hole. Ventilation holes are machined on both sides of the limiting hole. The vents are through holes. One end of the vents is connected to the gas pipeline, and the other end is connected to the inner cavity of the bullet launch tube. The negative pressure generated by the vacuum pump can reset the experimental bullet. Preferably, the vents are symmetrically distributed on both sides of the limiting hole. The symmetrically distributed vents have the following advantages: First, when the experimental bullet is launched, the driving compressed air can act evenly on the bottom of the experimental bullet, driving the experimental bullet to move linearly along the axis of the launch tube, avoiding eccentric movement. Second, when resetting the experimental bullet, the negative pressure generated by the vacuum pump can act evenly on the bottom of the experimental bullet, causing the experimental bullet to move linearly back to its original position, that is, reset, avoiding eccentric movement.

[0011] One end of the limit rod is inserted into the bullet launch tube through a limit hole, and the other end is connected to a linear motor. The linear motor is mounted at the rear end of the limit rod's axis, directly pushing and pulling the limit rod back and forth to adjust the launch position. Alternatively, the linear motor is located on one side of the limit rod, parallel to the limit rod, and drives the limit rod back and forth via a connecting rod, controlling the length of the limit rod's extension into the bullet launch tube, thereby determining and controlling the launch position of the experimental bullet. This eliminates the need to use transparent materials in the bullet launch tube to observe the position of the experimental bullet, as transparent materials have low pressure resistance and cannot withstand high pressure impacts. The limit rod is primarily used to determine and control the launch position of the experimental bullet. This is achieved by the following process: first, the limit rod is driven by the linear motor to move to the designated launch position. Then, a vacuum pump is used to extract the air in the bullet launch tube to create a negative pressure. Under the action of the negative pressure, the experimental bullet moves backward until it hits the limit rod and stops. At this point, the experimental bullet stops at the end of the limit rod, thereby controlling the launch position of the experimental bullet. Furthermore, the acceleration distance of the experimental bullet can be precisely controlled based on the distance the linear motor controls the limit rod's movement, improving the experimental accuracy of the Hopkinson bar impact test.

[0012] The bullet launcher, located on the device's support, is a cylindrical structure with a cylindrical through-hole machined inside. One end is capped, and the other end is open, facing the end face of the Hopkinson bar. The experimental bullet and the launcher are coaxially located. The experimental bullet is loaded into the launcher, and upon firing, it collides head-on with the end face of the Hopkinson bar.

[0013] The experimental bullet is cylindrical in shape, with a frustum machined into the front end. The diameter of the frustum is the same as the Hopkinson bar. Gas-sealing ring grooves are machined into each end of the bullet, and sealing rings are installed in these grooves. The sealing rings have two functions: first, they seal the gap between the experimental bullet and the inner cavity of the bullet tube, and second, they minimize friction between the experimental bullet and the bullet tube, allowing for faster acceleration of the experimental bullet. The presence of two gas-sealing ring grooves in the experimental bullet provides a better seal than traditional cylindrical bullets without grooves. They also reduce wear on the inner cavity of the bullet tube, facilitating repeatability and consistency in impact metrology testing.

[0014] The buffer gasket is a rectangular thin strip, clamped at both ends by a gasket clamping plate fixed to the device bracket. The plane of the buffer gasket is perpendicular to the axis of the Hopkinson bar and closely contacts the impact end face of the Hopkinson bar. When the experimental bullet collides with the Hopkinson bar, the buffer gasket performs pulse width modulation. The rectangular buffer gasket is made of a flexible thin strip material. Such flexible thin strip materials include nylon, rubber, and wool felt.

[0015] The present invention also discloses a loading control method for a Hopkinson bar impact test, which is implemented based on the loading control device for the Hopkinson bar impact test and includes the following steps:

[0016] Step 1: Fix the bullet launch tube and the Hopkinson bar of corresponding diameter on the device bracket, connect, install and debug the data measurement device of the Hopkinson bar.

[0017] Step 2: Install the test bullet's sealing ring and place the bullet in the launch tube. The sealing ring seals the gap between the test bullet and the launch tube, creating a closed cavity and minimizing friction between the test bullet and the launch tube, allowing the test bullet to accelerate more quickly. Install the end cap of the launch tube.

[0018] Step 3: Insert the limit rod connected to the linear motor into the limit hole in the end cap. The linear motor drives the limit rod back and forth, controlling the length of the limit rod's extension into the bullet barrel, thereby determining and controlling the launch acceleration distance of the experimental bullet. Seal the gas line interface to the vent hole in the end cap. The vent holes are symmetrically distributed around the limit hole. This symmetrical distribution of the vent holes ensures that air pressure is evenly applied to the base of the experimental bullet during launch and reset, ensuring linear motion and avoiding eccentric movement.

[0019] Step 4: Connect and inspect the air compressor, air tank, vacuum pump, and gas lines in sequence. The vacuum pump creates negative pressure within the launch tube. This negative pressure acts on the bottom of the test bullet, drawing it back to its initial launch position and significantly improving the automation of the impact loading experiment. Connect the cables between the control console and each valve, and verify that all components are functioning properly. The experimental system is now ready. Turn on the air compressor, adjust the pressure control knob, and the pressure indicator will display the pressure. Inflate the air tank to the specified pressure, and the test bullet is ready to fire.

[0020] Step 5: The present invention can realize three loading control methods for impact experiments. Control method one: manually adjust the position of the limit rod, control the acceleration distance of the experimental bullet, change the loading pressure of the gas tank, and realize a single impact loading experiment; control method two: set the number of impacts and the interval time to realize automatic multiple impact loading experiments with the same peak value; control method three: set the automatic adjustment of the moving limit rod distance, set the number of impacts and the interval time to realize automatic multiple impact loading experiments with different peak values. According to the working conditions of the Hopkinson bar impact test, select and execute the corresponding control method, and select one of the three control methods to execute step 6, step 7 or step 8 respectively, and perform the Hopkinson bar impact test under the corresponding working conditions. The control method one corresponds to step 6, the control method two corresponds to step 7, and the control method three corresponds to step 8. The working condition parameters of the Hopkinson bar impact test include the number of impact loading, acceleration distance, loading pressure, and interval time.

[0021] Step 6: Use the control method 1 in Step 5 to conduct a single impact loading test at any acceleration distance and pressure. Rotate the position adjustment knob clockwise or counterclockwise to manually adjust the target position of the limit rod. As the position adjustment knob is rotated, the linear motor automatically moves back and forth, moving the limit rod to the set target position. The position display shows the distance between the front end of the limit rod and the origin in real time. Press the reset button to automatically activate the vacuum pump, creating negative pressure within the bullet launcher chamber. This automatically draws the test bullet back to the end of the limit rod, completing the launch reset function and automatically shutting off the vacuum pump. Use the pressure loading and unloading knobs to adjust the pressure in the air tank to the target pressure. The pressure display shows the pressure in the air tank in real time. Click the acquisition button on the data acquisition software on the computer to enter the acquisition preparation state. When a trigger signal is received, the data acquisition device and software will automatically store and record the test data. When the acquisition software is in the acquisition preparation state, quickly press the launch button to initiate the firing of the experimental bullet, causing it to collide with the Hopkinson bar. Specifically, when the launch button is pressed, the compressed air in the gas tank is rapidly released through the outlet valve. This compressed air is then suddenly loaded into the bullet launch tube via the gas pipeline, driving the reset experimental bullet rapidly forward along its axis, causing it to collide with the end face of the Hopkinson bar. The end face of the Hopkinson bar is equipped with a buffering pad that allows for pulse width adjustment. The moment the experimental bullet collides with the Hopkinson bar, a trigger signal is generated, initiating the data acquisition device's acquisition function. The data acquisition software automatically stores and records the test data. The data processing software then automatically processes the data, displaying the experimental results and curves on the computer screen.

[0022] Step 7: Use the control method 2 in Step 5 to perform an automated multiple-peak impact loading experiment, setting the position of the limit rod and controlling the acceleration distance of the test bullet. First, set the number of impacts and the interval time. Use the increase and decrease buttons to adjust the number of impacts to the desired value. Then, press the confirm button to complete the number of impacts. Use the increase and decrease buttons to adjust the interval time to the desired value. Then, press the confirm button to complete the interval time setting. Use the increase and decrease buttons to adjust the initial loading pressure to the desired value. Set the step-by-step pressure increment to zero, ensuring a constant pressure increase. Then, press the confirm button to complete the setting of the loading pressure in the air tank. Finally, set the acceleration distance for the bullet. Use the increase and decrease buttons to adjust the initial acceleration distance to the desired value. Set the step-by-step acceleration distance increment to zero, ensuring a constant acceleration distance. Finally, press the confirm button to complete the limit rod position adjustment. After setting these four initial parameters, enter the experiment preparation state. Clicking the "collect" button on the computer's data acquisition software will cause the data acquisition device and software to enter a collection ready state. Upon receiving a trigger signal, the test data will be automatically stored and recorded. While the acquisition software is in the collection ready state, quickly pressing the "fire" button initiates the firing of the experimental bullet, causing it to collide with the Hopkinson bar. The Hopkinson bar has a buffer pad in front of its end, enabling pulse width adjustment. The moment the experimental bullet first collides with the Hopkinson bar, a trigger signal is generated, initiating the data acquisition device's acquisition function. After a single firing, the vacuum pump automatically activates, and the negative pressure applied to the experimental bullet returns it to its initial firing position. The next firing experiment automatically proceeds according to the set parameters for the number of impacts, interval time, loading pressure, and acceleration distance, until the set number of impacts is reached. Preferably, the bullet launcher is connected to multiple gas tanks in parallel, allowing them to operate alternately to reduce the time between the next firing. Clicking the "manually stop data acquisition" button causes the data acquisition software to automatically store and record the test data from multiple experiments to the computer's hard drive. Clicking the "manually process data" button in the data processing software displays the experimental results and experimental curves on the computer screen.

[0023] Step 8: Using control method three from step 5, set the automatic adjustment of the movable limiter position, the initial loading pressure value and the step pressure increment, and the number of impacts and interval time to conduct multiple automated impact loading experiments with varying peak values. First, use the Impact Count Increase and Decrease buttons to set the number of impacts, and use the Interval Time Increase and Decrease buttons to set the interval time. Use the Loading Pressure Increase and Decrease buttons to adjust the initial loading pressure to the desired value, set the step pressure increment value to the desired value, and finally, press the Confirm button to complete the setting of the loading pressure in the air tank. Finally, set the acceleration distance for the bullet launch. Use the Acceleration Distance Increase and Decrease buttons to adjust the initial acceleration distance to the desired value, set the step acceleration distance increment value to the desired value, and finally, press the Confirm button to complete the limiter position adjustment. After completing the above four initial parameters, enter the experiment preparation state. Click the acquisition button on the data acquisition software on the computer. When the acquisition software is in the acquisition preparation state, quickly press the launch button to start the experimental bullet firing. The moment the experimental bullet collides with the Hopkinson bar for the first time, a trigger signal is generated, and the data acquisition device starts the acquisition function. There is a buffer pad in front of the end of the Hopkinson bar, which can be used for pulse width adjustment. After completing a firing, the vacuum pump automatically starts and the experimental bullet resets. Based on the set parameters such as the number of impacts, interval time, loading pressure increase value, acceleration distance increase value, etc., the next firing experiment is automatically carried out until the set number of impacts is completed. Preferably, the bullet launch tube is connected to multiple gas tanks side by side, and the multiple gas tanks work alternately to reduce the interval time between the next firing. Click the manual stop data acquisition button, and the data acquisition software will automatically store and record the test data of multiple experiments to the computer hard disk. Click the manual data processing button in the data processing software to display the experimental results and experimental curves on the computer screen.

[0024] Beneficial effects:

[0025] 1. The present invention discloses a loading control device and method for a Hopkinson bar impact test. A movable limit rod is installed in a bullet launch tube. By controlling the length of the limit rod extending into the bullet launch tube, the launch position of the test bullet can be adjusted and determined, thereby precisely controlling the acceleration distance of the test bullet and significantly improving the accuracy of the Hopkinson bar impact test. This solves the problems in the prior art of the inability to precisely adjust the impact velocity of the test bullet, the difficulty in controlling the peak acceleration, and the difficulty in determining the corresponding relationship between the driving air pressure and the peak acceleration. This significantly improves the experimental accuracy and repeatability of the impact test results.

[0026] 2. The present invention discloses a loading control device and method for a Hopkinson bar impact test. By designing a test bullet reset system, negative pressure can be applied to the bottom of the test bullet, automatically sucking the test bullet back to the initial launch position. The device is simple to operate, automates the impact loading test, and significantly improves the experimental efficiency of the Hopkinson bar impact test. Because the pneumatic reset method overcomes the disadvantage of the current method of using an additional magnetic device to suck back the test bullet, the cost of resetting the magnetic device and the learning cost of the control software required to implement the magnetic reset are reduced. Furthermore, the air vents on the end cap are symmetrically distributed on both sides of the limit hole, allowing air pressure to act evenly on the bottom of the test bullet, causing the test bullet to move in a straight line, avoiding eccentric motion, and improving the accuracy of the Hopkinson bar impact test.

[0027] 3. The present invention discloses a loading control device and method for a Hopkinson bar impact test. By designing a buffer gasket clamped by both ends of a gasket clamping plate and placing it tightly against the impact end face of the Hopkinson bar, pulse width regulation is achieved when the experimental bullet collides with the Hopkinson bar.

[0028] 4. The present invention discloses a loading control device and method for a Hopkinson bar impact test. By manually adjusting the position of a limit rod, the acceleration distance of the test bullet is controlled and determined. By varying the launch pressure, a single impact test can be performed at any acceleration distance and pressure. Through multiple experiments, the corresponding relationship between the acceleration distance, launch pressure, and peak acceleration can be determined, significantly improving the accuracy of the impact test.

[0029] 5. The present invention discloses a loading control method for a Hopkinson bar impact test. By automatically opening and closing a gas tank and vacuum pump, the launch and resetting of the test bullet can be automated. By inputting the number of impacts, interval time, and acceleration distance of the test bullet into a console, multiple impact loading experiments with the same peak value can be performed, with controllable number of impacts and interval time. This automates the impact loading test and significantly improves the efficiency of continuous Hopkinson bar impact testing.

[0030] 6. The present invention discloses a loading control method for a Hopkinson bar impact test. By presetting the travel distance of a limit rod, the initial launch position of the test bullet can be automatically adjusted during each impact. In conjunction with a device that allows the test bullet to automatically launch and reset according to preset functions, the number of impacts, interval time, initial acceleration distance value and acceleration distance increment, initial loading pressure value and pressure increment are input into the console to automatically perform multiple impact loading tests with different peak values, significantly improving the efficiency and accuracy of impact tests.

[0031] 7. The present invention discloses a loading control device and method for a Hopkinson bar impact test. A limit rod is used to determine and control the acceleration distance of a test bullet. The bullet launch tube can be made of steel or other materials, eliminating the need to use transparent materials to make the bullet launch tube in order to observe the acceleration of the test bullet. Transparent materials have low pressure bearing capacity and cannot withstand high-pressure impacts, making them prone to rupture. Combined with the automated loading control of the Hopkinson bar impact test, the safety of the impact test is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the loading control device for the Hopkinson bar impact test proposed in the present invention.

[0033] Figure 2 This is a schematic diagram of the assembly relationship between the loading control device and the Hopkinson bar proposed in the present invention.

[0034] Figure 3 Schematic diagram of the end cover of the launch tube.

[0035] Figure 4 Schematic diagram of the experimental bullet.

[0036] Figure 5 This is a general flow chart of the loading control method for the Hopkinson bar impact test proposed in the present invention.

[0037] Figure 6 This is a flow chart of the second loading control method for the Hopkinson bar impact test proposed in the present invention.

[0038] Figure 7 This is a manual operation panel on the console of the loading control device proposed by the present invention.

[0039] Figure 8 This is a flow chart of the third loading control method for the Hopkinson bar impact test proposed in the present invention.

[0040] Figure 9 This is the automatic operation panel on the console of the loading control device proposed by the present invention.

[0041] In the figure: 1—linear motor, 2—limit rod, 3—end cover, 4—bullet launching tube, 5—experimental bullet, 6—air compressor, 7—inlet valve, 8—gas storage tank, 9—exhaust valve, 10—gas pipeline, 11—valve, 12—vacuum pump, 13—control console, 14—Hopkinson rod, 15—device bracket, 16—vent, 17—limit hole, 18—closed gas ring groove, 19—gasket clamping plate, 20—buffer gasket. DETAILED DESCRIPTION

[0042] In order to better illustrate the purpose and advantages of the present invention, the invention is further described below with reference to the accompanying drawings and examples.

[0043] Example 1:

[0044] Reference Figure 1 and Figure 2 The present invention discloses a loading control device for a Hopkinson bar impact test, comprising a linear motor 1, a limiting rod 2, an end cover 3, a bullet launching tube 4, a test bullet 5, an air compressor 6, an air storage tank 8, a vacuum pump 12, a control console 13, a gasket clamping plate 19, and a buffer gasket 20.

[0045] Reference Figure 1 The air compressor 6 is connected to the air inlet of the gas tank 8 through the air inlet valve 7, and the air outlet of the gas tank 8 is connected to the gas pipe 10 with an outer diameter of 8 mm via the air outlet valve 9. The end of the gas pipe 10 is connected to the air vent 16 on the end cover 3 of the bullet launch tube 4. The compressed air from the gas tank 8 enters the air vent to provide driving force for the experimental bullet. Connecting two gas tanks 8 side by side to work alternately can reduce the waiting time for the next firing. There are two gas pipes 10, the same number as the air vents 16 on the end cover 3. The console 13 is connected to the air inlet valve and the air outlet valve to realize the inflation and deflation control of the gas tank 8, and drives the experimental bullet 5 to be launched when the air is deflated.

[0046] Reference Figure 1 The vacuum pump 12 is connected to the gas pipeline 10 via the valve 11. The end of the gas pipeline 10 is connected to the vent 16 on the end cap 3 of the bullet launch tube 4. The vacuum pump 12 can extract gas from the bullet launch tube 4 through the valve 11, the gas pipeline 10, and the vent 16 on the end cap 3, creating a negative pressure in the inner cavity of the bullet launch tube 4. The negative pressure acts on the bottom of the test bullet 5, which can reset the test bullet 5 to the initial launch position, significantly improving the automation level of the impact loading experiment. This avoids the inefficiency and tediousness of using a magnetic device to suck back the test bullet 5 or manually pushing the test bullet 5 back.

[0047] Reference Figure 3The end cap 3 is located at the end of the bullet launching tube 4 and is connected to the bullet launching tube 4 by a thread with a thread depth of 10 mm. The outer diameter of the end cap 3 is 54 mm, and a limit hole 17 is processed at the center position for the limit rod 2 to pass through and move back and forth. The limit hole 17 is a through hole with a diameter of 2 mm. Two symmetrical air vents 16 are processed on both sides of the limit hole 17. The air vents 16 are through holes with a diameter of 8 mm. One end of the air vents 16 is connected to the gas pipeline 10, and the other end is connected to the inner cavity of the bullet launching tube 4. The negative pressure generated by the vacuum pump 12 can reset the experimental bullet 5. Preferably, the air vents 16 are symmetrically distributed on both sides of the limit hole 17. The symmetrical distribution of the air vents 16 has the following advantages: First, when the experimental bullet 5 is launched, the driving compressed air can act evenly on the bottom of the experimental bullet 5, driving the experimental bullet 5 to move linearly along the axis of the launching tube 4, avoiding eccentric movement. Secondly, when the experimental bullet 5 is reset, the negative pressure generated by the vacuum pump 12 can act evenly on the bottom of the experimental bullet 5, so that the experimental bullet 5 can move linearly back to its original position, that is, reset, to avoid eccentric movement.

[0048] Reference Figure 1 The limit rod 2 is 200 mm long and 2 mm in diameter. One end is inserted into the bullet launching tube 4 through the limit hole 17, and the other end is connected to the linear motor 1. The linear motor 1 can drive the limit rod 2 to move telescopically forward and backward, control the length of the limit rod 2 extending into the bullet launching tube 4, and thus determine and control the launching position of the experimental bullet 5. The linear motor 1 is installed at the rear end of the axis of the limit rod 2, and directly pushes and pulls the limit rod 2 to move back and forth to adjust the launching position. Alternatively, the linear motor 1 is located on one side of the limit rod 2, parallel to the limit rod 2, and drives the limit rod 2 to move back and forth through a connecting rod. There is no need to use transparent materials to make the bullet launching tube 4 in order to observe the position of the experimental bullet 5. Transparent materials have low pressure bearing capacity and cannot withstand the impact of high pressure. Limit rod 2 is primarily used to determine and control the launch position of experimental bullet 5. This is achieved through the following process: first, linear motor 1 drives limit rod 2 to a specified position. Then, vacuum pump 12 extracts gas from bullet launch tube 4 to create negative pressure. Under the action of this negative pressure, experimental bullet 5 moves backward until it hits limit rod 2 and stops. At this point, experimental bullet 5 stops at the end of limit rod 2, thereby controlling the launch position of experimental bullet 5. Furthermore, by controlling the distance limit rod 2 moves according to linear motor 1, the acceleration distance of experimental bullet 5 can be precisely controlled, improving experimental accuracy.

[0049] Reference Figure 2The bullet launch tube 4, located on the device support 15, is a cylindrical structure with a 22mm diameter cylindrical hole machined into it. It has an outer diameter of 50mm and a length of 220mm. One end is fitted with an end cap 3, while the other end is open, facing the end face of the Hopkinson bar 14. The experimental bullet 5 and the launch tube 4 are coaxial. The experimental bullet 5 is loaded into the launch tube 4, and upon discharge, the experimental bullet 5 will collide head-on with the end face of the Hopkinson bar 14.

[0050] Reference Figure 4 The experimental bullet 5 is cylindrical in shape as a whole, with a length and outer diameter of 20 mm. A truncated cone is processed at the front end of the cylinder, and the diameter of the cone is 16 mm, which is the same as the diameter of the Hopkinson bar. Both ends of the experimental bullet 5 are processed with closed air ring grooves 18, with a depth and width of 1 mm. A sealing ring is installed in the closed air ring groove 18, and the sealing ring is made of nylon. The sealing ring has two functions: one is to seal the gap between the experimental bullet 5 and the inner cavity of the bullet launching tube 4, and the other is to fully reduce the friction between the experimental bullet 5 and the bullet launching tube so that the experimental bullet 5 can accelerate faster. The experimental bullet 5 designed by the present invention has two closed air ring grooves 18, which has better sealing performance than the traditional cylindrical bullet without grooves, and reduces the wear of the experimental bullet 5 on the inner cavity of the bullet launching tube 4, which is beneficial to the repeatability and consistency requirements of the impact measurement test.

[0051] Reference Figure 2 The buffer pad 20 is a rectangular thin strip. The pad clamping plates 19 fixed to the device bracket 15 clamp the ends of the buffer pad 20. The plane of the buffer pad 20 is perpendicular to the axis of the Hopkinson bar 14 and closely contacts the impact end face of the Hopkinson bar 14. When the experimental bullet 5 collides with the Hopkinson bar 14, the buffer pad 20 performs pulse width modulation. The rectangular buffer pad 20 can be made of flexible, thin, long strips of material with varying thickness, density, and texture, such as nylon, rubber, and wool felt.

[0052] The present embodiment discloses a method for controlling the loading of a Hopkinson bar impact test, which is implemented based on the aforementioned device for controlling the loading of a Hopkinson bar impact test. The specific implementation steps are as follows:

[0053] Step 1: Reference Figure 5 , fix the bullet launching tube 4 and the Hopkinson bar 14 of corresponding diameter on the device bracket 15, and connect, install and debug the data measuring device of the Hopkinson bar 14.

[0054] Step 2: Install the sealing ring of the experimental bullet 5 and place it in the bullet launch tube 4. The sealing ring seals the gap between the experimental bullet 5 and the bullet launch tube 4, forming a closed cavity. This effectively reduces friction between the experimental bullet 5 and the bullet launch tube, allowing the experimental bullet 5 to accelerate more quickly. Install the end cap 3 of the bullet launch tube 4.

[0055] Step 3: Insert the limiting rod 2 connected to the linear motor 1 into the limiting hole 17 of the end cover 3; the linear motor 1 can drive the limiting rod 2 to move back and forth, controlling the length of the limiting rod 2 inserted into the bullet launch tube 4, thereby determining and controlling the launch acceleration distance of the experimental bullet. Seal the interface of the gas pipeline 10 to the vent hole 16 of the end cover 3. The vent holes 16 are symmetrically distributed around the limiting hole 17. The symmetrical distribution of the vent holes 16 ensures that the air pressure acts evenly on the bottom of the experimental bullet 5 when launching and resetting the experimental bullet 5, allowing the experimental bullet 5 to move in a straight line and avoid eccentric movement.

[0056] Step 4: Connect and inspect the air compressor 6, air tank 8, vacuum pump 12, and gas pipeline 10. Connect the cables from the control console 13 to each valve and verify that everything is functioning properly. The experimental system is now ready. Turn on the air compressor 6 and adjust the pressure control knob. The pressure indicator will display the pressure level. Inflate the air tank 8 to the specified pressure, and the experimental bullet 5 is ready to fire.

[0057] Step 5: The present invention can realize three loading control methods for impact experiments. Control method one: manually adjust the position of the limit rod 2, control the acceleration distance of the fired experimental bullet 5, change the loading pressure of the gas tank 8, and realize a single impact loading experiment; control method two: set the number of impacts and the interval time to realize automatic multiple impact loading experiments with the same peak value; control method three: set the automatic adjustment of the moving limit rod distance, set the number of impacts and the interval time to realize automatic multiple impact loading experiments with different peak values. According to the working conditions of the Hopkinson bar impact test, select and execute the corresponding control method, and select one of the three control methods to execute step 6, step 7 or step 8 respectively, and perform the Hopkinson bar impact test under the corresponding working conditions. The control method one corresponds to step 6, the control method two corresponds to step 7, and the control method three corresponds to step 8. The working condition parameters of the Hopkinson bar impact test include the number of impact loading, acceleration distance, loading pressure, and interval time.

[0058] Step 6: Use the control method 1 in step 5 to conduct a single impact loading test with any acceleration distance and any air pressure. Figure 7, rotate the position adjustment knob to manually adjust the target position of the limit rod 2, that is: as the position adjustment knob is rotated, the linear motor 1 automatically moves back and forth, moving the limit rod 2 to the set target position, and the position display screen displays the distance between the front end of the limit rod and the origin starting position in real time. Press the reset button, the vacuum pump 12 automatically starts, and a negative pressure is formed in the cavity of the bullet launching tube 4, which automatically sucks the experimental bullet 5 back to the end of the limit rod 2, completing the launch reset function of the experimental bullet 5, and the vacuum pump 12 automatically shuts down. Rotate the pressure loading knob clockwise to control the one-way valve, slowly inflate the gas tank 8 to the target pressure, and the pressure display screen displays the pressure in the gas tank 8 in real time. If the pressure exceeds the expected loaded target pressure, rotate the pressure unloading knob counterclockwise to slowly release the gas through the vent valve. Click the acquisition button of the data acquisition software on the computer, and the data acquisition device and data acquisition software enter the acquisition preparation state. When the trigger signal arrives, the test data will be automatically stored and recorded. When the acquisition software is in the acquisition preparation state, a quick press of the launch button initiates the firing of the experimental bullet 5, causing it to collide with the Hopkinson bar 14. Specifically, when the launch button is pressed, the compressed air in the gas tank 8 is rapidly released through the outlet valve 9. The compressed air is then suddenly loaded into the bullet launch tube 4 via the gas pipe 10, driving the reset experimental bullet 5 rapidly forward along its axis, causing it to collide with the end face of the Hopkinson bar 14. The end face of the Hopkinson bar 14 is provided with a buffering pad 20, which enables pulse width modulation. The data acquisition device activates the acquisition function, the data acquisition software automatically stores and records the test data, and the data processing software automatically processes the data, displaying the experimental results and experimental curves on the computer screen.

[0059] Step 7: Use the control method 2 in step 5 to set the position of the limit rod 2 and control the acceleration distance of the test bullet 5 to automatically perform multiple same peak impact loading tests. Figure 6 、 Figure 9First, set the number of impacts and the interval time. Specifically, use the impact number increase and decrease buttons to adjust the number of experiments to the desired value, then press the confirmation button to complete the impact number setting. Use the interval time increase and decrease buttons to adjust the interval time to the desired value, then press the confirmation button to complete the interval time setting. Use the loading pressure increase and decrease buttons to adjust the initial loading pressure value to the desired value, set the step pressure increment value to zero, i.e., the pressure remains constant and does not increase, then press the confirmation button to complete the loading pressure setting in the air tank 8. Finally, set the acceleration distance of the experimental bullet 5. Specifically, use the acceleration distance increase and decrease buttons to adjust the initial acceleration distance value to the desired value, set the step acceleration distance increment value to zero, i.e., the acceleration distance remains constant and does not increase, then press the confirmation button to complete the position adjustment setting of the limit rod 2. After the above four initial parameters are set, the experiment enters the experimental preparation state. Click the acquisition button on the data acquisition software on the computer, and the data acquisition device and data acquisition software enter the acquisition preparation state. When the trigger signal arrives, the test data will be automatically stored and recorded. When the acquisition software is in the acquisition preparation state, quickly press the launch button to start the firing of the experimental bullet 5, so that the experimental bullet 5 collides with the Hopkinson bar 14. At the moment of the first collision between the experimental bullet 5 and the Hopkinson bar 14, a trigger signal is generated, and the data acquisition device starts the acquisition function. After completing one firing, the vacuum pump 12 automatically starts, and the experimental bullet 5 is reset to the initial firing position under the action of negative pressure. According to the set number of impacts, interval time, loading pressure, and acceleration distance parameters, the next firing experiment is automatically carried out until the set number of impacts is completed. The two gas tanks 8 work alternately, which can reduce the interval time for the next firing. Click the manual stop data acquisition button, and the data acquisition software will automatically store and record the test data of multiple experiments to the computer hard disk. Click the manual data processing button of the data processing software to display the experimental results and experimental curves on the computer screen.

[0060] Step 8: Use the control method 3 in step 5 to set the position of the automatic adjustment limit rod 2, set the initial value of the loading pressure and the step pressure increase value, set the number of impacts and the interval time, and perform multiple automatic impact loading experiments with different peak values. Figure 8 、 Figure 9First, set the number of impacts and the interval time. Use the Increase / Decrease buttons to adjust the number of impacts to the desired value, then press the Confirm button to complete the number of impacts. Use the Increase / Decrease buttons to adjust the interval time to the desired value, then press the Confirm button to complete the interval time setting. Use the Loading Pressure Increase / Decrease buttons to adjust the initial loading pressure value to the desired value, set the step pressure increment value to the desired value, and increase the pressure by one step at a time. Finally, press the Confirm button to complete the setting of the loading pressure within the air tank 8. Finally, set the acceleration distance of the experimental bullet 5. Use the Acceleration Distance Increase / Decrease buttons to adjust the initial acceleration distance value to the desired value, set the step acceleration distance increment value to the desired value, and increase the acceleration distance by one step at a time. Finally, press the Confirm button to complete the position adjustment of the limit rod 2. After setting these four initial parameters, enter the experimental preparation state. Click the Acquisition button on the data acquisition software on the computer, and the data acquisition device and data acquisition software will enter the acquisition preparation state. When the trigger signal arrives, they will automatically store and record the test data. When the acquisition software is in the acquisition preparation state, quickly press the launch button to start the experimental bullet 5 firing, causing the experimental bullet 5 to collide with the Hopkinson bar 14, generating a trigger signal, and the data acquisition device starts the acquisition function. After completing one firing, the vacuum pump 12 automatically starts, and the experimental bullet is reset to the initial firing position under the action of negative pressure. According to the set parameters such as the number of impacts, interval time, loading pressure increase value, acceleration distance increase value, etc., the next firing experiment is automatically carried out until the set number of impacts is completed. The two gas tanks 8 work alternately, which can reduce the interval time for the next firing. Click the manual stop data acquisition button, and the data acquisition software will automatically store and record the test data of multiple experiments to the computer hard disk. Click the manual data processing button of the data processing software to display the experimental results and experimental curves on the computer screen.

[0061] The above specific description further illustrates the purpose, technical solutions and beneficial effects of the invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A loading control device for a Hopkinson bar impact test, characterized in that: Including linear motor, limit rod, end cover, bullet launch tube, experimental bullet, air compressor, air storage tank, vacuum pump, control console, buffer gasket, gasket clamping plate; The air compressor is connected to the air tank via an air inlet valve, the air outlet of the air tank is connected to a gas pipeline via an air outlet valve, and the end of the gas pipeline is connected to the vent hole on the end cover of the bullet launcher; the number of the gas pipelines is the same as the number of the vent holes on the end cover; the control console is connected to the air inlet valve and the air outlet valve to realize the inflation and deflation control of the air tank; The vacuum pump is connected to a gas pipeline via a valve, and the end of the gas pipeline is connected to a vent hole on the end cover of the bullet launch tube. The vacuum pump can extract gas from the bullet launch tube through the vent hole on the end cover, so that a negative pressure is formed in the inner cavity of the bullet launch tube. The negative pressure acts on the bottom of the experimental bullet, causing the experimental bullet to return to the initial launch position. The end cap is located at the end of the bullet launching tube and is connected to the bullet launching tube; a limiting hole is machined at the center of the end cap for the limiting rod to pass through and move forward and backward; vent holes are machined on both sides of the limiting hole, and the vent holes are through holes. One end of the vent hole is connected to the gas pipeline, and the other end is connected to the inner cavity of the bullet launching tube; the negative pressure generated by the vacuum pump can reset the experimental bullet; One end of the limit rod is inserted into the bullet launch tube through the limit hole, and the other end is connected to the linear motor; the linear motor is installed at the rear end of the limit rod axis, directly pushing and pulling the limit rod to move forward and backward to adjust the launch position; or the linear motor is located on one side of the limit rod, parallel to the limit rod, and drives the limit rod to move forward and backward through the connecting rod to control the length of the limit rod extending into the bullet launch tube, thereby determining and controlling the launch position of the experimental bullet; The bullet launching tube is located on the device bracket and is a cylindrical structure with a cylindrical through hole machined inside. One end is equipped with an end cap and the other end is open, facing the end face of the Hopkinson bar. The experimental bullet and the launching tube are located on the same axis. The experimental bullet is loaded inside the bullet launching tube, and after being fired, the experimental bullet collides head-on with the end face of the Hopkinson bar. The experimental bullet is cylindrical in shape, with a frustum machined at the front end of the cylinder. The diameter of the frustum is the same as the diameter of the Hopkinson bar. Both ends of the experimental bullet are machined with air-sealing ring grooves, in which sealing rings are installed. The sealing rings have two functions: first, to seal the gap between the experimental bullet and the inner cavity of the bullet launch tube, and second, to fully reduce the friction between the experimental bullet and the bullet launch tube, so that the experimental bullet can accelerate faster. The experimental bullet has two air-sealing ring grooves, which reduce the wear of the experimental bullet on the inner cavity of the bullet launch tube, which is conducive to the repeatability and consistency requirements of the impact measurement test. The buffer gasket is a rectangular strip of thin film, and its two ends are clamped by a gasket clamping plate fixed to the device bracket. The plane of the buffer gasket is perpendicular to the axis of the Hopkinson bar and is in close contact with the impact end face of the Hopkinson bar. When the experimental bullet collides with the Hopkinson bar, the pulse width is adjusted through the buffer gasket.

2. A loading control device for a Hopkinson bar impact test according to claim 1, characterized in that: The bullet launching tube is connected to multiple gas tanks in parallel, and the multiple gas tanks work alternately, which can reduce the interval time for the next firing.

3. The loading control device for a Hopkinson bar impact test according to claim 1, wherein: The vent holes are symmetrically distributed on both sides of the limit hole; the symmetrically distributed vent holes have the following advantages: first, when firing the experimental bullet, the driving compressed air can act evenly on the bottom of the experimental bullet, driving the experimental bullet to move linearly along the axis of the launch tube, avoiding eccentric movement; second, when resetting the experimental bullet, the negative pressure generated by the vacuum pump can act evenly on the bottom of the experimental bullet, so that the experimental bullet can move linearly back to its original position, that is, reset, avoiding eccentric movement.

4. The loading control device for a Hopkinson bar impact test according to claim 1, wherein: The limit rod is used to determine and control the launch position of the experimental bullet. This purpose is achieved through the following process: first, a linear motor drives the limit rod to move to the specified launch position, and then a vacuum pump is used to extract the gas in the bullet launch tube to form a negative pressure. Under the action of the negative pressure, the experimental bullet moves backward until it hits the limit rod and stops moving. At this time, the experimental bullet stops at the end of the limit rod, thereby controlling the launch position of the experimental bullet. Then, according to the distance the linear motor controls the movement of the limit rod, the acceleration distance of the experimental bullet can be accurately controlled, thereby improving the experimental accuracy of the Hopkinson bar impact test.

5. The loading control device for a Hopkinson bar impact test according to claim 1, wherein: The rectangular strip-shaped buffer gasket material is made of flexible thin strip material.

6. A loading control device for a Hopkinson bar impact test according to claim 5, characterized in that: The flexible thin sheet-like long strip material includes nylon, rubber, and wool felt.

7. A method for controlling a loading of a Hopkinson bar impact test, implemented based on a device for controlling a loading of a Hopkinson bar impact test according to claim 1, 2, 3, 4, 5, or 6, characterized in that: The following steps are included: Step 1: Fix the bullet launch tube and the Hopkinson bar of corresponding diameter to the device bracket, connect and install the Hopkinson bar data measurement device; Step 2: Install the sealing ring of the experimental bullet and install the experimental bullet in the bullet launch tube; the sealing ring can seal the gap between the experimental bullet and the bullet launch tube, forming a closed cavity, fully reducing the friction between the experimental bullet and the bullet launch tube, so that the experimental bullet can accelerate faster; install the end cover of the bullet launch tube; Step 3: Insert the limit rod connected to the linear motor into the limit hole of the end cover; the linear motor can drive the limit rod to move back and forth, control the length of the limit rod extending into the bullet launch tube, and thus determine and control the launch acceleration distance of the experimental bullet; seal the interface of the gas pipeline with the vent hole of the end cover; the vent holes are symmetrically distributed around the limit hole; the symmetrically distributed vent holes can ensure that the air pressure acts evenly on the bottom of the experimental bullet when launching and resetting the experimental bullet, so that the bullet can move in a straight line and avoid eccentric movement; Step 4: Connect and check the air compressor, air tank, vacuum pump, and gas pipeline in sequence. The vacuum pump can create negative pressure in the inner cavity of the bullet launch tube. The negative pressure acts on the bottom of the test bullet to suck it back to the initial launch position, significantly improving the automation level of the impact loading test. Connect the cables between the console and each valve, check whether each part can work normally, and the experimental system is ready; Turn on the air compressor, adjust the pressure control knob, the pressure display instrument will show the pressure in real time, the air tank will be inflated to the specified pressure, and the experimental bullet will be ready to fire; Step 5: Implement three loading control methods for impact experiments according to experimental requirements. Control method one: manually adjust the position of the limit rod, control the acceleration distance of the experimental bullet, change the loading pressure of the gas tank, and realize a single impact loading experiment; control method two: set the number of impacts and the interval time to realize automatic multiple impact loading experiments with the same peak value; control method three: set the automatic adjustment of the moving limit rod distance, set the number of impacts and the interval time to realize automatic multiple impact loading experiments with different peak values; according to the working conditions of the Hopkinson bar impact test, select and execute the corresponding control method, and select one of the three control methods to execute step 6, step 7 or step 8 respectively, and perform the Hopkinson bar impact test under the corresponding working conditions; the control method one corresponds to step 6, the control method two corresponds to step 7, and the control method three corresponds to step 8; the working condition parameters of the Hopkinson bar impact test include the number of impact loading, acceleration distance, loading pressure, and interval time; Step 6: Perform a single impact loading test with any acceleration distance and any air pressure using the control method 1 in step 5; Rotate the position adjustment knob clockwise or counterclockwise to realize the manual adjustment control function of the target position of the limit rod, that is: as the position adjustment knob rotates, the linear motor automatically moves back and forth to move the limit rod to the set target position, and the position display screen shows the distance between the front end of the limit rod and the origin starting position in real time; press the reset button, the vacuum pump automatically starts, and negative pressure is formed in the bullet launching barrel cavity, which automatically sucks the experimental bullet back to the end of the limit rod, completing the launch reset function of the experimental bullet, and the vacuum pump automatically shuts down; through the pressure loading knob and the pressure unloading knob, the two are operated in conjunction to adjust the pressure in the gas tank to the target pressure; The pressure display screen displays the pressure in the gas storage tank in real time; clicking the acquisition button of the data acquisition software on the computer causes the data acquisition device and the data acquisition software to enter an acquisition preparation state. When a trigger signal arrives, the data acquisition device and the data acquisition software will automatically store and record the test data; when the acquisition software is in the acquisition preparation state, quickly pressing the launch button starts the firing of the experimental bullet, so that the experimental bullet collides with the Hopkinson bar. That is, when the launch button is pressed, the compressed air in the gas storage tank is quickly released through the air outlet valve, and the compressed air is suddenly loaded into the bullet launch tube through the gas pipeline, driving the experimental bullet in the reset state to move forward rapidly along the axis and collide with the end face of the Hopkinson bar. The end face of the Hopkinson bar is provided with a buffer gasket that can perform pulse width adjustment; at the moment the experimental bullet collides with the Hopkinson bar, a trigger signal is generated, the data acquisition device starts the acquisition function, the data acquisition software completes the function of automatically storing and recording the test data, the data processing software automatically processes the data, and displays the experimental results and experimental curves on the computer screen; Step 7: Use the control method 2 in step 5 to perform automatic multiple same peak impact loading experiments to set the limit rod position and control the acceleration distance of the experimental bullet; first set the number of impacts and the interval time, that is: adjust the number of experiments to the expected value through the impact number increase and decrease buttons, and then click the confirmation button to complete the impact number setting; adjust the interval time to the expected value through the interval time increase and decrease buttons, and then click the confirmation button to complete the interval time setting; adjust the initial value of the loading pressure to the expected value through the loading pressure increase and decrease buttons, set the step pressure increase value to zero, that is, the pressure is constant and does not increase, and then click the confirmation button to complete the loading pressure setting in the gas tank; finally, set the acceleration distance of the fired bullet, that is: adjust the initial value of the acceleration distance to the expected value through the acceleration distance increase and decrease buttons, set the step acceleration distance increase value to zero, that is, the acceleration distance is constant and does not increase. Add, and finally click the confirmation button to complete the limit rod position adjustment setting; after the above four initial parameters are set, enter the experimental preparation state; click the acquisition button of the data acquisition software on the computer, the data acquisition device and the data acquisition software enter the acquisition preparation state, and when the trigger signal arrives, the test data will be automatically stored and recorded; when the acquisition software is in the acquisition preparation state, quickly press the launch button to start the experimental bullet firing, so that the experimental bullet collides with the Hopkinson bar. There is a buffer gasket in front of the end of the Hopkinson bar, which can be used for pulse width adjustment; the moment the experimental bullet collides with the Hopkinson bar for the first time, a trigger signal is generated, and the data acquisition device starts the acquisition function; after completing one firing, the vacuum pump automatically starts, and the experimental bullet is reset to the initial firing position under the action of negative pressure; the next firing experiment is automatically carried out according to the set number of impacts, interval time, loading pressure, and acceleration distance parameters until the set number of impacts is completed; Step 8: Use the control method three in step 5 to set the automatic adjustment of the position of the moving limit rod, set the initial value of the loading pressure and the step pressure increase value, set the number of impacts and the interval time, and conduct multiple automatic impact loading experiments with different peak values; first, use the impact increase and decrease buttons to set the number of impacts, and use the interval increase and decrease buttons to complete the interval time setting; use the loading pressure increase and decrease buttons to adjust the initial value of the loading pressure to the expected value, and set the step pressure increase value to the expected value, that is, the pressure increases by one step pressure each time, and finally press the confirmation button to complete the loading pressure setting in the gas tank; finally, set the acceleration distance for firing the bullet, that is: use the acceleration distance increase and decrease buttons to adjust the initial value of the acceleration distance to the expected value, and set the step acceleration distance increase value to the expected value. Set the expected value, that is, the acceleration distance increases by one step distance each time, and finally click the confirmation button to complete the limit rod position adjustment setting; after the above four initial parameters are set, enter the experimental preparation state; click the acquisition button of the data acquisition software on the computer. When the acquisition software is in the acquisition preparation state, quickly press the launch button to start the experimental bullet firing. The moment the experimental bullet collides with the Hopkinson bar for the first time, a trigger signal is generated, and the data acquisition device starts the acquisition function. There is a buffer gasket in front of the end of the Hopkinson bar, which can be used for pulse width adjustment; after completing one firing, the vacuum pump starts automatically and the experimental bullet is reset; according to the set number of impacts, interval time, loading pressure increase value, and acceleration distance increase value parameters, the next firing experiment is automatically carried out until the set number of impacts is completed.

8. The method for controlling the loading of a Hopkinson bar impact test according to claim 7, wherein: The bullet launch tube is connected to multiple gas tanks in parallel, and the multiple gas tanks work alternately, which can reduce the interval time for the next firing; Click the manual stop data acquisition button, and the data acquisition software will automatically store and record the test data of multiple experiments to the computer hard disk. Click the manual data processing button of the data processing software to display the experimental results and experimental curves on the computer screen.

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