A target-like line burning rate testing device and method based on acoustic emission technology

Abstract

The present application belongs to the technical field of static burning rate test of energetic materials, and specifically provides a target line-like burning rate test device and method based on acoustic emission technology. A sample is prepared by cutting and coating the measured propellant strip using a sample preparation cutter and a coating device, the sample is loaded into an acoustic emission method burning rate instrument, ignition is initiated, the acoustic emission signal strength-time curve is detected, recorded and identified by the acoustic emission method burning rate instrument, the pulse signals emitted during the combustion of the high-energy propellant tablets at the beginning and end of the curve are obtained, the burning rate of the measured propellant strip is obtained from the length of the cut measured propellant strip and the interval time length of the first and last pulse signals, and the burning rate test of the measured propellant strip is completed. The present application solves the problems of the existing target line method burning rate test, such as the complicated process of threading the target line and binding the propellant, and the poor nitrogen acoustic emission method burning rate test signal, which cannot effectively capture the complete signal. The present application does not need to punch, thread and burn the support to bind the target line, simplifies the target line method burning rate test, and makes the burning rate test in a high-pressure gas environment more easily automated.

Description

Technical Field

[0001] This invention belongs to the field of static burning rate testing technology for energetic materials, specifically relating to a target-like burning rate testing device and method based on acoustic emission technology. Background Technology

[0002] Static burning rate testing of energetic materials follows the national military standards 770B-2005 706.1 and 706.2. Specifically, the 706.1 burning rate-target line method involves two steps in the preparation of the propellant strip: drilling and threading the wire, and binding the wire to the combustion support. Because the target line is thin, soft, and easily broken, and energetic materials have extremely high requirements for process reliability and safety, automated testing has progressed slowly.

[0003] Currently, some energetic material production units have attempted to improve the automation of target line testing, but many problems remain unsolved.

[0004] Another method uses nitrogen acoustic emission burning rate testing technology to replace the target line method, eliminating the need for threading and binding wires. The principle is to measure the duration of the acoustic emission signal emitted during the combustion of the burning propellant, and combine this with the length to obtain the burning rate. However, some propellant burning in nitrogen or argon emits very weak acoustic emission signals, or the signal-to-noise ratio of the ending signal at the tail end of the propellant is poor. This means that traditional acoustic emission burning rate meters cannot effectively capture the complete signal, hindering the widespread adoption of nitrogen (argon) acoustic emission testing technology.

[0005] Currently, there is no suitable burning rate testing device for factories and research institutes that can perform large-scale, high-intensity, and efficient automated testing using the target line method.

[0006] Chinese patent document CN104345118A discloses a multi-target line dynamic combustion performance testing system and method for solid propellants. This method uses a multi-target line burning rate testing system, which can perform both dynamic and static combustion performance tests, with convenient switching between the two measurement modes. It obtains the relationship between burning rate and pressure, and burning rate and temperature, and calculates the burning rate-pressure index and burning rate-temperature sensitivity coefficient. Small-scale testing can evaluate the combustion performance of the tested propellant within a corresponding pressure and temperature range, making it highly suitable for rapid performance testing and quality control of each batch of propellant during production. Compared with commonly used burning rate testing systems, this system shortens the propellant development and production cycle, reduces raw material consumption, minimizes manual operations, and saves costs. However, this document does not address the problems of cumbersome target threading and propellant binding processes in the target line burning rate testing method, complex sample preparation and testing processes, and the inability to automate these processes; nor does it address the poor signal quality and inability to effectively capture complete signals in the nitrogen acoustic emission burning rate testing method. Summary of the Invention

[0007] The present invention provides a target-line burning rate testing device and method based on acoustic emission technology. The purpose is to overcome the problems in the prior art where the process of threading the target line and binding the propellant in the burning rate test of energetic materials by the target line method is cumbersome, the sample preparation and testing process is complicated and cannot be automated; and the nitrogen acoustic emission method has poor burning rate test signal and cannot effectively capture the complete signal.

[0008] Therefore, the present invention provides a target-like burning rate testing device based on acoustic emission technology, including...

[0009] Sample preparation tools are used to cut test strips, high-energy propellant tablets at the nose end, and high-energy propellant tablets at the tail end.

[0010] The coating device is used to clamp the ignition wire and move the test strip with the high-energy propellant tablet and ignition wire attached to the head end and the high-energy propellant tablet attached to the tail end of the test strip of a fixed length to the coating agent for coating, so as to complete the sample preparation.

[0011] An acoustic emission probe is used to detect the sound signal during sample combustion and send the detected sound signal to a signal amplifier.

[0012] The signal amplifier is used to receive the sound signal sent by the acoustic emission probe, amplify the received sound signal, and send it to the data acquisition and processing module.

[0013] An acoustic emission combustion rate meter is used to receive sound signals sent by a signal amplifier and to process the received signals.

[0014] Preferably, the sample preparation tool includes a cylinder, a cutting fixture, a front cutting tool, and a rear cutting tool. The power output end of the cylinder is connected to the cutting fixture, and the clamping ends of the cutting fixture are connected to the front cutting tool and the rear cutting tool, respectively.

[0015] Preferably, the position between the first-end cutter and the last-end cutter is adjustable.

[0016] Preferably, the coating device includes a second cylinder, a fixture, a pneumatically driven gripper, and a container for holding the coating agent. The power output end of the second cylinder is connected to the pneumatically driven gripper through the fixture, and the pneumatically driven gripper is located above the opening of the container for holding the coating agent.

[0017] A test method using a target-line burning rate testing device based on acoustic emission technology includes the following steps:

[0018] 1) Use a sample preparation tool to cut the test strip to the target length, and attach high-energy propellant tablets to the first and last ends of the cut test strip in sequence;

[0019] 2) Connect an ignition wire between the high-energy propellant tablet at the front end and the test strip cut to a fixed length. The ignition wire is connected to a coating device. The coating device completely immerses the test strip cut to a fixed length, the high-energy propellant tablet at the front end, and the high-energy propellant tablet at the rear end into the coating agent for coating through the ignition wire until the sample preparation is completed.

[0020] 3) Load the sample into the acoustic emission combustion rate tester, ignite it, and burn it axially from the front end to the rear end in parallel. Both the high-energy propellant tablets at the front and rear ends emit acoustic emission signals stronger than the test strip of a fixed length during combustion. The intensity-time curve of the acoustic emission signal during combustion is detected by the acoustic emission combustion rate tester, and the intensity-time curve of the acoustic emission signal is recorded. The pulse signals emitted by the high-energy propellant tablets at the front and rear ends during combustion are identified in the intensity-time curve of the acoustic emission signal, and the interval between the front and rear pulse signals is obtained. The burning rate of the test strip is obtained from the length of the test strip of a fixed length and the interval between the front and rear pulse signals, thus completing the burning rate test of the test strip.

[0021] Preferably, the burning rates of the high-energy propellant tablets at the front and rear ends are both not less than 1.5 times the burning rate of the test strip, and the intensity of the acoustic emission signals emitted by the burning of the high-energy propellant tablets at the front and rear ends are both not less than 1.5 times the intensity of the test strip.

[0022] Preferably, both the high-energy propellant tablets at the front and rear ends are pre-made tablet-shaped high-energy propellants; or, a high-energy propellant in the form of a thick slurry is adhered to the front and rear ends of a test strip cut to a fixed length, and after the adhered thick slurry solidifies, the front end is a high-energy propellant tablet and the rear end is a high-energy propellant tablet.

[0023] Preferably, the cross-sectional dimensions of the high-energy propellant tablets at the front and rear ends are equal to the cross-section of the test strip cut to a fixed length.

[0024] Preferably, the pulse signals emitted during the combustion of the high-energy propellant tablets at the front and rear ends in the intensity-time curve of the acoustic emission signal are identified by analog circuit methods or digital signal processing methods.

[0025] Preferably, the coating device completely immerses the test strip of a fixed length, the high-energy propellant tablet at the front end, and the high-energy propellant tablet at the rear end into the coating agent for coating by means of an ignition wire. The specific method is as follows: the coating device clamps the ignition wire, moves it horizontally above the coating agent, moves it vertically downward to completely immerse the test strip of a fixed length, the high-energy propellant tablet at the front end, and the high-energy propellant tablet at the rear end into the coating agent, lifts it vertically upward to dry, and repeats the above steps according to the combustion energy of the sample to complete the sample preparation.

[0026] The beneficial effects of this invention are:

[0027] 1. The target-like burning rate testing device and method based on acoustic emission technology provided by this invention attaches high-energy propellant tablets at the head and tail ends of a test strip of a fixed length. The burning rates of the high-energy propellant tablets at the head and tail ends are much higher than those of the test strip of a fixed length, and the acoustic emission signals they emit are much stronger than those of the test strip of a fixed length. The tablets are small in size, and the acoustic emission signals they emit are narrow and sharp pulse-shaped. When the test strip of a fixed length burns at the head end, it simultaneously ignites the high-energy propellant tablets attached to the head end; when the test strip of a fixed length burns at the tail end, it simultaneously ignites the high-energy propellant tablets attached to the tail end. Therefore, the moment when the acoustic emission signal emitted by the high-energy propellant tablet at the head end is the moment when the test strip of a fixed length begins to burn, and the moment when the acoustic emission signal emitted by the high-energy propellant tablet at the tail end is the moment when the test strip of a fixed length ends to burn. The burning rate is equal to the length of the test strip cut to a fixed length divided by the interval between the first and last pulses. The combustion environment of the sample in this invention is exactly the same as that of the target line method, ensuring that the data results can completely coincide with those of the target line method. At the same time, it avoids the drilling, threading, and binding of the target line method. The only steps involved are cutting to a fixed length, attaching the first and last high-energy propellant tablets, and coating. Using the sample preparation tool, coating device, and acoustic emission burning rate meter described in this device, automated burning rate testing can be achieved at the current level of technology in the industry. It solves the signal problem of nitrogen acoustic emission burning rate testing and overcomes the cumbersome process of threading the target line and binding the propellant in the target line method. There is no need for drilling, threading, and binding the target line to the combustion support, which simplifies the target line method burning rate testing and makes it easier to automate and "lights-out" burning rate testing in high-pressure gas environments such as the target line method.

[0028] 2. The target-line burning rate testing device and method based on acoustic emission technology provided by this invention can identify the pulse signals emitted by the high-energy propellant tablets at the front and rear ends during combustion in the intensity-time curve of the acoustic emission signal. The identification method adopts either analog circuit method or digital signal processing method; the signal is easy to identify and the identification accuracy is high.

[0029] 3. The target-line burning rate testing device and method based on acoustic emission technology provided by this invention uses pre-formed high-energy propellant tablets at both the propellant tip and tail end; it is suitable for manual mode and pre-formed mode where high-energy propellant is not readily available. Alternatively, a thick slurry of high-energy propellant can be adhered to the propellant strip cut to a fixed length at both ends. After the adhered slurry solidifies, the propellant at the propellant tip becomes a high-energy propellant tablet, and the propellant at the tail end becomes a high-energy propellant tablet. This method has a wide range of applications, is easy to operate, and reduces costs.

[0030] 4. The target-like burning rate testing device and method based on acoustic emission technology provided by this invention has an adjustable position between the front and rear cutting tools, and is suitable for cutting test strips of multiple lengths. Attached Figure Description

[0031] The present invention will now be described in further detail with reference to the accompanying drawings.

[0032] Figure 1 This is a schematic diagram of the sample preparation tool.

[0033] Figure 2 This is a schematic diagram of a pre-prepared sheet of high-energy drug adhered to the first and last ends of a test strip cut to a fixed length.

[0034] Figure 3 This is a schematic diagram of a high-energy propellant in a thick slurry state adhering to the head and tail ends of a test strip cut to a fixed length;

[0035] Figure 4 This is a structural diagram of the coating device;

[0036] Figure 5 This is a structural diagram of the sample;

[0037] Figure 6 This is a graph showing the measured results of the target standard drug, bis-lead-2, using the testing method of this invention.

[0038] Figure 7 A graph showing the measured results of a conventional target line sample using the testing method of this invention;

[0039] Figure 8 yes Figure 4 Enlarged view of point A in the middle.

[0040] Explanation of reference numerals in the attached diagram: 1.1 Cylinder 1; 1.2 Cutting fixture; 1.3 Head cutter; 1.4 Tail cutter; 1.5 Test strip; 2.1 Head high-energy propellant tablet; 2.2 Test strip cut to a fixed length; 2.3 Tail high-energy propellant tablet; 2.4 Ignition wire; 2.5 High-energy slurry; 3.1 Cylinder 2; 3.2 Fixture tooling; 3.3 Pneumatically driven gripper; 3.4 Coating agent; 3.5 Coating layer. Detailed Implementation

[0041] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0042] Example 1:

[0043] like Figures 1-5 As shown, a target-like burning rate testing device based on acoustic emission technology includes...

[0044] Sample preparation tool, used to cut the test strip 1.5, the high-energy propellant tablet at the front end 2.1 and the high-energy propellant tablet at the rear end 2.3;

[0045] The coating device is used to clamp the ignition wire and move the test strip 2.2 with the high-energy propellant tablet 2.1 and the ignition wire 2.4 attached to the head end, and the test strip 2.2 with the high-energy propellant tablet 2.3 attached to the tail end, to the coating agent 3.4 for coating, thus completing the sample preparation.

[0046] An acoustic emission probe is used to detect the sound signal during sample combustion and send the detected sound signal to a signal amplifier.

[0047] The signal amplifier is used to receive the sound signal sent by the acoustic emission probe, amplify the received sound signal, and send it to the data acquisition and processing module.

[0048] An acoustic emission combustion rate meter is used to receive sound signals sent by a signal amplifier and to process the received signals.

[0049] Specifically, the acoustic emission combustion rate meter is an acoustic emission combustion rate measuring device that complies with the national military standard 770B-2005-706.2. The signal processing process includes: on the basis of the national military standard, adding the recording and reproduction function of the acoustic emission signal curve of the propellant strips and tablets during the combustion process to the combustion rate measuring device, and based on this, designing the time interval identification function of the strong acoustic emission signal pulses of the tablets at both ends (high-energy propellant tablet 2.1 at the front end and high-energy propellant tablet 2.3 at the rear end).

[0050] The sample preparation tool, coating device, acoustic emission probe, signal amplifier, and acoustic emission burn rate meter described in the target-line burning rate testing device based on acoustic emission technology of this invention can achieve automated burning rate testing at the current level of technology in the industry.

[0051] Preferred, such as Figure 1 As shown, the sample preparation tool includes a cylinder 1.1, a cutting fixture 1.2, a front cutting tool 1.3, and a rear cutting tool 1.4. The power output end of the cylinder 1.1 is connected to the cutting fixture 1.2, and the clamping ends of the cutting fixture 1.2 are connected to the front cutting tool 1.3 and the rear cutting tool 1.4, respectively.

[0052] Specifically, cylinder 1.1 provides power to the cutting fixture 1.2. The cutting fixture 1.2 controls the position movement (left and right movement, up and down movement) of the first-end cutter 1.3 and the last-end cutter 1.4. The distance between the first-end cutter 1.3 and the last-end cutter 1.4 is adjusted by moving left and right, and the drug strip under test is cut by moving up and down (the first end of the drug strip under test is cut by the first-end cutter 1.3, and the last end of the drug strip under test is cut by the last-end cutter 1.4). The cutting fixture 1.2 is an existing fixture used to hold and adjust the first-end cutter 1.3 and the last-end cutter 1.4. It has a simple structure, is convenient for cutting, and has a high degree of automation.

[0053] Preferably, the position between the first-end cutter 1.3 and the last-end cutter 1.4 is adjustable. This is suitable for cutting test strips of various lengths.

[0054] Preferred, such as Figure 4 and Figure 8 As shown, the coating device includes a second cylinder 3.1, a fixture 3.2, a pneumatically driven gripper 3.3, and a container for holding the coating agent 3.4. The power output end of the second cylinder 3.1 is connected to the pneumatically driven gripper 3.3 through the fixture 3.2. The pneumatically driven gripper 3.3 is located above the opening of the container for holding the coating agent 3.4.

[0055] Specifically, the pneumatically driven gripper 3.3 clamps the ignition wire 2.4, and the cylinder 3.1 provides power to the fixture 3.2. The fixture 3.2 controls the movement of the pneumatically driven gripper 3.3 to move the ignition wire 2.4, the high-energy propellant tablet at the front end 2.1, the high-energy propellant tablet at the rear end 2.3, and the test strip 2.2 cut to a fixed length to the coating agent 3.4 for coating, thus preparing the sample. The structure is simple and highly automated.

[0056] Example 2:

[0057] Based on Example 1, a testing method using a target-like burning rate testing device based on acoustic emission technology includes the following steps:

[0058] 1) Use a sample preparation tool to cut the test strip 1.5 to the target length, and attach the high-energy propellant tablet 2.1 at the head end and the high-energy propellant tablet 2.3 at the tail end of the cut test strip 2.2 in sequence;

[0059] Specifically, the test propellant strip 1.5 can be a screw-pressed cylindrical strip or a test propellant strip of other shapes; the screw-pressed cylindrical strip can be cut into equal lengths, with a typical size of 5mm in diameter and 100mm in length, or it can be cut to the required length as needed; when cutting the high-energy propellant tablets 2.1 at the front end and 2.3 at the rear end, the billet-shaped cast propellant block can be cut into equal-thickness sheets, the sheets can be cut into equal-width strips, and the equal-thickness and equal-width strips can be cut into equal-length cuboids, with a typical size of 100mm*5mm*5mm; the typical deviation of the above values ​​is ±0.5mm.

[0060] Specifically, the cutting process is as follows: Figure 1 The cylinder 1.1 moves up and down remotely, and the spacing of the cutting clamp position on the cutting clamp 1.2 is adjustable. The first cutting tool 1.3 and the last cutting tool 1.4 are driven by the cylinder 1.1 and the cutting clamp 1.2 to cut the drug strip 1.5 to be cut downwards.

[0061] Preferred, such as Figure 2 As shown, both the high-energy propellant tablet 2.1 at the front end and the high-energy propellant tablet 2.3 at the rear end are pre-formed high-energy propellants; suitable for manual mode and pre-formed mode where high-energy propellants are not readily available. Figure 3 As shown, or, a thick, slurry-like high-energy propellant can be adhered to the beginning and end of a test strip 2.2 cut to a fixed length. After the adhered thick slurry solidifies, the beginning end becomes the beginning high-energy propellant tablet 2.1, and the end end becomes the end high-energy propellant tablet 2.3. This method has a wide range of applications, is easy to operate, and reduces costs.

[0062] Specifically, the attachment of high-energy propellant pellets (high-energy propellant pellet 2.1 at the bow and high-energy propellant pellet 2.3 at the tail) and the insertion of the ignition wire 2.4 are carried out in the following two ways:

[0063] Method 1: Use a mixture of ignition powder and acetone to attach the high-energy propellant tablet 2.1 at the front end and the high-energy propellant tablet 2.3 at the rear end to the test strip 2.2 cut to a fixed length, forming prefabricated high-energy propellant tablet 2.1 at the front end and high-energy propellant tablet 2.3 at the rear end. This method is suitable for manual mode and prefabricated mode where high-energy propellants are not readily available.

[0064] Method 2: A robotic arm is used to grasp a pre-cut test strip 2.2. The head of the strip 2.2 is coated with high-energy propellant slurry 2.5, lifted, and allowed to solidify, forming a high-energy propellant tablet 2.1 at the head of the device. The strip is then rotated 180°, and the tail is coated with the same slurry 2.5, lifted, and allowed to solidify, forming a high-energy propellant tablet 2.3 at the tail of the device. For cost-constrained devices, Method 2 can be simplified to manually applying a thick, slurry-like high-energy propellant slurry 2.5 to both ends of the pre-cut test strip 2.2. The ignition wire 2.4 is located at the head of the pre-cut test strip 2.2.

[0065] Preferably, the cross-sectional dimensions of the high-energy propellant tablet 2.1 at the front end and the high-energy propellant tablet 2.3 at the rear end are equal to the cross-sectional dimensions of the test strip 2.2 cut to a fixed length. This ensures that the high-energy propellant tablets emit the required pulse signal during combustion.

[0066] Specifically, the typical thickness of the tablet is 2mm ± 1mm. The high-energy propellant tablet is small enough that the emitted acoustic emission signal is a narrow, sharp pulse.

[0067] Preferably, the burning rates of the high-energy propellant tablet 2.1 at the front end and the high-energy propellant tablet 2.3 at the rear end are both not less than 1.5 times the burning rate of the test strip, and the intensity of the acoustic emission signal emitted by the combustion of the high-energy propellant tablet 2.1 at the front end and the high-energy propellant tablet 2.3 at the rear end is both not less than 1.5 times the intensity of the test strip.

[0068] Specifically, it can ensure that the pulse signals emitted during the combustion of the high-energy propellant tablet 2.1 at the front end, the high-energy propellant tablet 2.3 at the rear end, and the test strip 2.2 cut to a fixed length are significantly different and easy to identify.

[0069] 2) Connect an ignition wire 2.4 between the high-energy propellant tablet 2.1 at the nose end and the test strip 2.2 cut to a fixed length. The ignition wire 2.4 is connected to a coating device. The coating device completely immerses the test strip 2.2 cut to a fixed length, the high-energy propellant tablet 2.1 at the nose end, and the high-energy propellant tablet 2.3 at the tail end into the coating agent 3.4 for coating until the sample preparation is completed (e.g., Figure 5 (as shown);

[0070] Specifically, the test strip 1.5 is cut to the target length, which is the test strip 2.2 of fixed length. The first end of the test strip 2.2 of fixed length is bonded with the high-energy propellant tablet 2.1. The ignition wire 2.4 is connected between the first end of the test strip 2.2 of fixed length and the high-energy propellant tablet 2.1 of the first end. The tail end of the test strip 2.2 of fixed length is bonded with the high-energy propellant tablet 2.3 of the tail end.

[0071] The ignition wire 2.4 is pre-embedded or inserted between the high-energy propellant tablet 2.1 at the nose end and the test strip 2.2 cut to a fixed length. Except for the part of the ignition wire that will contact the power supply electrode, the entire sample is immersed in the coating agent using a coating device for coating. The above-mentioned propellant strip, tablet, ignition wire, coating layer 3.5, etc., are collectively referred to as the sample.

[0072] Preferably, the coating device completely immerses the test strip 2.2 of a fixed length, the high-energy propellant tablet 2.1 at the front end, and the high-energy propellant tablet 2.3 at the rear end into the coating agent 3.4 through the ignition wire 2.4. The specific method is as follows: the coating device clamps the ignition wire 2.4, moves it horizontally above the coating agent 3.4, moves it vertically downward to completely immerse the test strip 2.2 of a fixed length, the high-energy propellant tablet 2.1 at the front end, and the high-energy propellant tablet 2.3 at the rear end into the coating agent 3.4, and lifts it vertically upward to dry. The above steps are repeated according to the combustion energy of the sample to complete the sample preparation.

[0073] Specifically, the fixture 3.2 is equipped with multiple pneumatically driven grippers 3.3. The ignition wire 2.4 is bent upwards at both ends and clamped onto the pneumatically driven grippers 3.3. The cylinder 3.1 and the fixture 3.2 are controlled to move the cut-to-length test strip 2.2 and the high-energy propellant tablet above the coating agent 3.4. The strip is then vertically immersed in the coating agent 3.4, lifted upwards, and dried. This process is repeated multiple times, referring to the National Military Standard 770B-2005 706.1. The number of repetitions varies depending on the energy of the propellant strip. Typically, 3 to 12 cycles are performed.

[0074] 3) Load the sample into the acoustic emission combustion rate tester, ignite the ignition wire 2.4 to start the combustion. The burning surface extends axially from the first end to the last end of the cut-to-length test strip 2.2, with the end faces burning parallel to each other. Both the high-energy propellant tablets 2.1 at the first end and 2.3 at the last end emit stronger acoustic emission signals than the cut-to-length test strip 2.2 during combustion. The intensity-time curve of the acoustic emission signal during combustion is detected using the acoustic emission combustion rate tester. The intensity-time curve is recorded, and the pulse signals emitted by the high-energy propellant tablets 2.1 and 2.3 at the first and last ends during combustion are identified. The interval between the first and last pulse signals is obtained. The combustion rate of the test strip is obtained from the length of the cut-to-length test strip 2.2 and the interval between the first and last pulse signals, thus completing the combustion rate test of the test strip (e.g., ...). Figure 6 and Figure 7 (As shown).

[0075] Specifically, ignition: bring the prepared sample into the combustion chamber, load the sample into the acoustic emission burn rate meter, and ignite the ignition wire 2.4 by turning on the power;

[0076] Record: An acoustic emission probe is installed on the side wall of the combustion chamber. The signal from the acoustic emission probe is amplified by a signal amplifier. The acoustic emission combustion rate meter collects the amplified signal and converts it into a digital signal. The existing software that is matched with the acoustic emission combustion rate meter processes the data and displays the waveform, resulting in the curve shown.

[0077] Analysis: To facilitate a direct comparison, the sample model was rotated and stretched by 90° so that the first end face of the cut-to-length test strip 2.2 was aligned with the first pulse of the signal curve, and the tail end face of the cut-to-length test strip 2.2 was aligned with the second pulse of the signal curve.

[0078] The specific combustion process is as follows: After the ignition wire 2.4 is energized, the high-energy propellant tablet 2.1 at the front end and the front end face of the test strip 2.2 cut to a fixed length are ignited. At the same time as the sample begins to burn, the test strip 2.2 cut to a fixed length emits a strong acoustic emission signal. The time t0 at this moment is identified by the matching software signal processing. The sample continues to burn. When the test strip 2.2 cut to a fixed length burns to the rear end face, the high-energy propellant tablet 2.3 at the rear end is ignited, and a strong acoustic emission signal is emitted again. The time t1 at this moment is identified by the software signal processing.

[0079] Therefore, the combustion time Δt of the test strip 2.2 of a fixed length is:

[0080] Δt=t1-t0

[0081] Let the length of the test strip 2.2 be L (mm), and the burning rate r (mm / s) of the test strip be:

[0082]

[0083] Taking advantage of the fact that the acoustic emission signal intensity emitted by high-energy propellant tablets during combustion is significantly greater than that of the propellant strip, the timing of the acoustic emission signals emitted by the tablets at both ends of the propellant strip is distinguished from the recorded acoustic emission signal intensity-time curve during combustion. The time interval obtained by subtracting the first and last times is equal to the duration of propellant strip combustion. Therefore, the burning rate is equal to the length of the fixed-length propellant strip divided by the time interval between the first and last pulses.

[0084] Preferably, the pulse signals emitted during the combustion of the high-energy propellant tablet 2.1 at the front end and the high-energy propellant tablet 2.3 at the rear end in the intensity-time curve of the acoustic emission signal are identified by an analog circuit method or a digital signal processing method.

[0085] Specifically:

[0086] Analog circuit method identification is as follows:

[0087] The acoustic emission combustion rate meter includes an amplifier circuit, a filter circuit, a comparator circuit, a trigger circuit, and a timer; the amplifier circuit, filter circuit, comparator circuit, trigger circuit, and timer are electrically connected in sequence.

[0088] The acoustic emission combustion rate meter of the present invention employs an amplifier circuit, a filter circuit, an operational amplifier to build a comparator circuit and a trigger circuit. The amplifier circuit, the filter circuit, the operational amplifier to build the comparator circuit and the trigger circuit are all implemented using existing technology, and their circuits will not be described in detail here.

[0089] The acoustic emission signal intensity-time curve is generated by the combustion of the test strip 2.2 (cut to a fixed length), the high-energy propellant tablet 2.1 at the front end, and the high-energy propellant tablet 2.3 at the rear end. The acoustic emission signals are converted into electrical signals by an acoustic emission probe. After passing through the amplification and filtering circuits on the acoustic emission burn rate meter, an operational amplifier is used to build a comparator and trigger circuit. Based on the threshold set by the comparator, the first and last pulses of the acoustic emission electrical signal are converted into trigger signals (trigger circuit). The first pulse trigger signal is connected to the start of the timer, and the last pulse trigger signal is connected to the stop of the timer. Thus, the start and stop triggering of the timer circuit is completed by an analog circuit. The time obtained by the timer is the combustion duration of the test strip 2.2 (cut to a fixed length), which is equal to the duration of combustion of the test strip 2.2 (cut to a fixed length). Therefore, the burning rate is equal to the length of the test strip 2.2 (cut to a fixed length) divided by the interval between the first and last pulses.

[0090] Digital signal processing methods are identified as follows:

[0091] The acoustic emission combustion rate meter of the present invention uses an analog-to-digital conversion circuit, which is implemented using existing technology. The circuit will not be described in detail here.

[0092] The acoustic emission signal with sharp pulses at the beginning and end is converted into an electrical signal using an acoustic emission probe. This electrical signal is then converted to a digital signal intensity-time curve using an analog-to-digital converter. Matching software is used to program the waveform digitally, filtering and differentiating the waveform to obtain the pulse tips of the high-energy propellant tablets 2.1 at the beginning and 2.3 at the end. Subtracting the beginning pulse tip from the end pulse tip yields the pulse interval, which is equal to the duration of combustion of the fixed-length test propellant strip 2.2. Therefore, the burning rate equals the length of the fixed-length test propellant strip 2.2 divided by the pulse interval.

[0093] The combustion environment of the sample in this invention is exactly the same as that of the target line method, ensuring that the data results can completely coincide with those of the target line method. At the same time, it avoids the drilling, threading, and binding of the target line method. The only steps involved are cutting to the desired length, attaching high-energy propellant tablets at the beginning and end, and coating. Using the sample preparation tool, coating device, and acoustic emission combustion rate meter described in this device, automated combustion rate testing can be achieved at the current level of technology in the industry. It solves the signal problem of nitrogen acoustic emission combustion rate testing and overcomes the cumbersome process of threading the target line and binding the propellant in the target line method. There is no need for drilling, threading, and binding the target line to the combustion support, which simplifies the target line method combustion rate testing and makes it easier to automate and "lights-out" combustion rate testing in high-pressure gas environments such as the target line method.

[0094] In the description of this invention, it should be understood that if terms such as "upper" or "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, it does not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are for illustrative purposes only and should not be construed as limiting the invention.

[0095] The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention are within the scope of protection of the present invention.

Claims

1. A target-like burning rate testing device based on acoustic emission technology, characterized in that: include Sample preparation tool, used to cut the test strip (1.5), the high-energy propellant tablet at the front end (2.1), and the high-energy propellant tablet at the rear end (2.3). The coating device is used to clamp the ignition wire to move the test strip (2.2) with the head end connected to the head end high-energy propellant tablet (2.1) and the tail end connected to the tail end high-energy propellant tablet (2.3) when the head end of the test strip (2.2) is connected to the tail end high-energy propellant tablet (2.1), the tail end high-energy propellant tablet (2.3) and the ignition wire (2.4) are connected to the coating agent (3.4) for coating, thus completing the sample preparation; the cross-sectional dimensions of the head end high-energy propellant tablet (2.1) and the tail end high-energy propellant tablet (2.3) are equal to the cross-sectional dimensions of the test strip (2.2) with the head end high-energy propellant tablet (2.1) and the tail end high-energy propellant tablet (2.3) are equal to the cross-sectional dimensions of the test strip (2.2) with the head end high-energy propellant tablet (2.1) and the test strip (2.2) with the head end high-energy propellant tablet (2.1) and the test strip (2.2) with the head end high-energy propellant tablet (2.3) and the tail end high-energy propellant tablet (2.4) are connected to the coating device; An acoustic emission probe is used to detect the sound signal during sample combustion and send the detected sound signal to a signal amplifier. The signal amplifier is used to receive the sound signal sent by the acoustic emission probe, amplify the received sound signal, and send it to the data acquisition and processing module. An acoustic emission combustion rate meter is used to receive sound signals sent by a signal amplifier and to process the received signals.

2. The target-line burning rate testing device based on acoustic emission technology as described in claim 1, characterized in that: The sample preparation tool includes a cylinder (1.1), a cutting fixture (1.2), a front cutting tool (1.3), and a rear cutting tool (1.4). The power output end of the cylinder (1.1) is connected to the cutting fixture (1.2), and the clamping end of the cutting fixture (1.2) is connected to the front cutting tool (1.3) and the rear cutting tool (1.4) respectively.

3. The target-line burning rate testing device based on acoustic emission technology as described in claim 2, characterized in that: The positions of the head cutter (1.3) and tail cutter (1.4) are adjustable.

4. The target-line burning rate testing device based on acoustic emission technology as described in claim 3, characterized in that: The coating device includes a second cylinder (3.1), a fixture (3.2), a pneumatically driven gripper (3.3), and a container for holding the coating agent (3.4). The power output end of the second cylinder (3.1) is connected to the pneumatically driven gripper (3.3) through the fixture (3.2). The pneumatically driven gripper (3.3) is located above the opening of the container for holding the coating agent (3.4).

5. A testing method using a target-like burning rate testing device based on acoustic emission technology as described in any one of claims 1-4, characterized in that: Includes the following steps: 1) Use a sample preparation tool to cut the test strip (1.5) to the target length, and attach a high-energy propellant tablet (2.1) to the head end and a high-energy propellant tablet (2.3) to the tail end of the cut test strip (2.2). 2) Connect an ignition wire (2.4) between the high-energy propellant tablet (2.1) at the front end and the test strip (2.2) cut to a fixed length. The ignition wire (2.4) is connected to a coating device. The coating device completely immerses the test strip (2.2), the high-energy propellant tablet (2.1) at the front end, and the high-energy propellant tablet (2.3) at the tail end into the coating agent (3.4) for coating until the sample preparation is completed. 3) Load the sample into the acoustic emission combustion rate tester, ignite it, and burn it in parallel from the front end to the rear end along the axial direction. The high-energy propellant tablets (2.1) at the front end and (2.3) at the rear end emit acoustic emission signals stronger than the test strip (2.2) of the fixed length during combustion. The intensity-time curve of the acoustic emission signal during combustion is detected by the acoustic emission combustion rate tester. The intensity-time curve of the acoustic emission signal is recorded. The pulse signals emitted by the high-energy propellant tablets (2.1) at the front end and (2.3) at the rear end during combustion are identified in the intensity-time curve of the acoustic emission signal. The interval between the front and rear pulse signals is obtained. The burning rate of the test strip is obtained from the length of the test strip (2.2) of the fixed length and the interval between the front and rear pulse signals. The burning rate test of the test strip is completed.

6. The test method as described in claim 5, characterized in that: The burning rates of the high-energy propellant tablets (2.1) at the front end and (2.3) at the rear end are both not less than 1.5 times the burning rate of the test strip, and the intensity of the acoustic emission signal emitted by the burning of the high-energy propellant tablets (2.1) at the front end and (2.3) at the rear end is not less than 1.5 times the intensity of the test strip.

7. The test method as described in claim 5, characterized in that: The high-energy propellant tablets (2.1) at the front end and (2.3) at the rear end are both pre-made tablet-shaped high-energy propellants; or, high-energy propellant in the form of a thick slurry is adhered to the front and rear ends of a test strip (2.2) cut to a fixed length. After the adhered thick slurry solidifies, the front end is the high-energy propellant tablet (2.1) at the front end and the rear end is the high-energy propellant tablet (2.3) at the rear end.

8. The test method as described in claim 5, characterized in that: The pulse signals emitted during the combustion of the high-energy propellant tablet (2.1) at the front end and the high-energy propellant tablet (2.3) at the rear end in the intensity-time curve of the acoustic emission signal are identified by either analog circuit method or digital signal processing method.

9. The test method as described in claim 5, characterized in that: The coating device uses an ignition wire (2.4) to completely immerse the test strip (2.2), the high-energy propellant tablet (2.1) at the front end, and the high-energy propellant tablet (2.3) at the rear end into the coating agent (3.4) for coating. The specific method is as follows: the coating device clamps the ignition wire (2.4), moves it horizontally above the coating agent (3.4), moves it vertically downward to completely immerse the test strip (2.2), the high-energy propellant tablet (2.1) at the front end, and the high-energy propellant tablet (2.3) at the rear end into the coating agent (3.4), and lifts it vertically upward to dry. The above steps are repeated according to the combustion energy of the sample to complete the sample preparation.

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