Explosive tablet elasticity modulus testing device and method based on pulse excitation method

Abstract

The invention discloses an explosive tablet elasticity modulus testing device and method based on a pulse excitation method, the explosive tablet elasticity modulus testing device comprises a man-machine isolation testing cabin, and further comprises an excitation module and a signal acquisition module, the man-machine isolation testing cabin comprises a testing box body and an explosive sample laying assembly; the excitation module comprises a knocking head, the knocking head is arranged in the test box body through a knocking head support, and the knocking head is located above the explosive sample laying assembly and can make contact with a standard sample laid on the explosive sample laying assembly; the signal acquisition module comprises a sonic sensor, the sonic sensor is arranged in the test box body through a sensor bracket, and the sonic sensor is positioned above the explosive sample laying assembly and is a certain distance away from a standard sample laid on the explosive sample laying assembly. According to the invention, through the man-machine isolation test cabin and the excitation module, non-contact operation in the test process is realized, and the risk that an operator is exposed to a dangerous environment is fundamentally avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of material mechanical property testing and safety engineering technology, and in particular to a device and method for testing the elastic modulus of explosive tablets based on the impulse excitation method. BACKGROUND

[0002] Elastic modulus (including Young's modulus, shear modulus and Poisson's ratio) is a key parameter for characterizing the mechanical properties of materials. For energetic materials such as explosives, their elastic modulus directly affects the structural integrity, safety and initiation reliability during manufacturing, storage, transportation and use. Therefore, it is of great practical significance to accurately measure the elastic modulus of explosive tablets. Currently, traditional methods for testing the elastic modulus of materials (such as static tensile method, compression method, etc.) require direct contact loading on the sample, which can easily cause damage inside the sample or even trigger an unexpected reaction. For high-sensitivity materials such as explosives, the risk is extremely high and it is difficult to implement safely. In addition, these methods have specific requirements for the shape and size of the sample, and are destructive testing methods, so the tested sample cannot be used for other performance analysis. The impulse excitation method is a mature non-destructive testing technology that measures the natural frequency of the sample after excitation to calculate the elastic modulus, and has been widely used in the detection of ceramics, metals, glasses and other materials (such as IET-01 detector). However, when this method is applied to dangerous materials such as explosives, there are two major technical bottlenecks: 1. Safety issues: The standard operation requires manual placement of the sample and knocking excitation at close range, exposing personnel to dangerous environments.

[0003] 2. Sample adaptability issues: Conventional impulse excitation methods are designed for strip or rod samples, while explosive materials are more likely to be pressed into round tablets, requiring the development of corresponding testing models and parameter setting methods.

[0004] Therefore, there is an urgent need in the art for a safe and accurate elastic modulus testing scheme that can achieve human-machine isolation and adapt to the characteristics of explosive tablets. SUMMARY

[0005] In view of the deficiencies in the prior art, the purpose of the present application is to provide a device and method for testing the elastic modulus of explosive tablets based on the impulse excitation method, which solves the problem of poor safety of the device and method in the prior art.

[0006] To solve the above technical problems, the present application adopts the following technical scheme: a device for testing the elastic modulus of explosive tablets based on the impulse excitation method, comprising a human-machine isolation test cabin, and further comprising an excitation module installed in the human-machine isolation test cabin and a signal acquisition module installed in the human-machine isolation test cabin.

[0007] The man-machine isolation test cabin is a box structure that can be opened and closed, comprising a test box and an explosive sample laying assembly installed in the test box.

[0008] The excitation module comprises a knocking head arranged in the test box through a knocking head support, and the knocking head is located above the explosive sample laying assembly and can contact the standard sample laid on the explosive sample laying assembly.

[0009] The signal acquisition module comprises an acoustic wave sensor arranged in the test box through a sensor support, and the acoustic wave sensor is located above the explosive sample laying assembly and at a distance from the standard sample laid on the explosive sample laying assembly.

[0010] The present application also has the following technical features: The test box cabin wall is provided with sound insulation materials.

[0011] The acoustic wave sensor can be replaced by a laser vibration meter.

[0012] The explosive sample laying assembly is two parallel support wires, and the distance between the support wires is 0.552D, and D is the diameter of the standard sample.

[0013] The knocking head support and the sensor support can be adjusted in position.

[0014] The signal acquisition module further comprises a data acquisition card and a computer, and the acoustic wave sensor or the laser vibration meter is connected to the data acquisition card, and the data acquisition card is connected to the computer.

[0015] The explosive tablet elastic modulus testing device based on the pulse excitation method further comprises a data processing and analysis module, and the data processing and analysis module is connected to the signal acquisition module.

[0016] The data processing and analysis module is built-in with an elastic modulus calculation model suitable for a round tablet-shaped sample.

[0017] The present application also provides an explosive tablet elastic modulus testing method, characterized in that the above device is used to realize the method, comprising the following steps: Step one: making a standard sample: pressing explosive powder into a round thin sample standard sample.

[0018] Step two: installing the standard sample: installing the standard sample in the man-machine isolation test cabin, and the standard sample is located on the explosive sample laying assembly.

[0019] Step three: remote excitation: exciting the standard sample through the excitation module.

[0020] Step four: data acquisition: acquiring the vibration signal of the standard sample through the signal acquisition module.

[0021] Step five: calculation: analyzing the signal obtained in step four by the data processing and analysis module, and calculating the elastic modulus.

[0022] The standard sample is a circular thin sheet, and the ratio of the diameter of the standard sample to the thickness is not less than 5.

[0023] The elastic modulus includes Young's modulus, shear modulus and Poisson's ratio.

[0024] Compared with the prior art, the present application has the following technical effects: (I) The explosive tablet elastic modulus testing device based on the pulse excitation method provided by the present application realizes non-contact operation of the testing process through the man-machine isolation testing cabin and the excitation module, and fundamentally avoids the risk of exposing the operator to a dangerous environment.

[0025] (II) The explosive tablet elastic modulus testing device based on the pulse excitation method provided by the present application adopts the pulse excitation method, which does not cause damage to the sample, and the tested explosive tablet can still be used for characterization of other key properties (such as detonation performance), saving precious samples.

[0026] (III) The explosive tablet elastic modulus testing method based on the pulse excitation method provided by the present application adopts the testing device for performing the test in the man-machine isolation testing cabin through the excitation module and collecting experimental data by the signal acquisition module, realizing man-machine isolation in the whole testing process and fundamentally ensuring operation safety.

[0027] (IV) The explosive tablet elastic modulus testing method based on the pulse excitation method provided by the present application is convenient to operate and has good repeatability: high degree of automation, reduced human operation error, good repeatability of test results, strong popularization: the design concept and method of the system can be popularized to the mechanical property testing of other flammable, explosive, toxic or environmentally sensitive materials. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is a schematic diagram of the overall structure of the explosive tablet elastic modulus testing device based on the pulse excitation method of the present application.

[0029] Figure 2 It is a schematic diagram of the overall structure of the explosive tablet elastic modulus testing device based on the pulse excitation method of the present application. Figure I .

[0030] Figure 3 It is a schematic diagram of the overall structure of the explosive tablet elastic modulus testing device based on the pulse excitation method of the present application. Figure II .

[0031] Figure 4 It is a schematic diagram of the frequency spectrum of the present application.

[0032] The meanings of the labels in the attached diagram are as follows: 1-Human-machine isolation test chamber, 2-Excitation module, 3-Signal acquisition module, 4-Standard sample.

[0033] 1-1-Test chamber, 1-2-Explosive sample placement assembly.

[0034] 2-1-Strike head, 2-2-Strike head support.

[0035] 3-1-Acoustic wave sensor, 3-2-Sensor bracket.

[0036] The specific content of the present invention will be further explained in detail below with reference to the embodiments. Detailed Implementation

[0037] Unless otherwise specified, all components in this invention are components known in the prior art.

[0038] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0039] Example 1: This embodiment provides a device for testing the elastic modulus of explosive fragments based on the pulse excitation method, such as... Figures 1-3 As shown, it includes a human-machine isolation test chamber 1, an excitation module 2 installed in the human-machine isolation test chamber 1, and a signal acquisition module 3 installed in the human-machine isolation test chamber 1.

[0040] The human-machine isolation test chamber 1 is an openable box structure, including a test box 1-1 and an explosive sample placement assembly 1-2 installed inside the test box 1-1; the human-machine isolation test chamber 1 is a sealed box with sound insulation function, used to place standard samples and conduct experiments.

[0041] The excitation module 2 includes a striking head 2-1, which is arranged inside the test chamber 1-1 via a striking head bracket 2-2. The striking head 2-1 is located above the explosive sample placement assembly 1-2 and can contact the standard sample 4 placed on the explosive sample placement assembly 1-2.

[0042] The excitation module 2 is installed inside the test chamber 1-1 and includes a striking head 2-1 driven by a stepper motor or servo motor, and a striking head support 2-2, which can be precisely positioned. The excitation module 2 is controlled by an external computer control system, which controls the striking head to strike specific positions of the standard sample 4 at a set speed and stroke, such as striking the edge to excite torsional modes. It can achieve remote and precise adjustment of the striking force, position, and number of strikes, completely replacing manual striking.

[0043] The signal acquisition module 3 includes an acoustic sensor 3-1, which is arranged in the test chamber 1-1 via a sensor bracket 3-2. The acoustic sensor 3-1 is located above the explosive sample placement assembly 1-2 and at a certain distance from the standard sample 4 placed on the explosive sample placement assembly 1-2.

[0044] The signal acquisition module 3 is used to acquire the vibration signal generated by the standard sample after it is excited. The acoustic sensor 3-1 is aligned about 5-10 mm above the center of the standard sample.

[0045] As a preferred embodiment: The test chamber 1-1 is equipped with sound insulation material on its walls, and the acoustic sensor 3-1 can be replaced with a laser vibration meter.

[0046] The explosive sample placement assembly 1-2 consists of two parallel support wires with a spacing of 0.552D, where D is the diameter of the standard sample.

[0047] Both the striking head bracket 2-2 and the sensor bracket 3-2 are adjustable in position.

[0048] As a preferred embodiment: The signal acquisition module 3 further includes a data acquisition card and a computer. The acoustic sensor 3-1 or the laser vibrometer is connected to the data acquisition card, and the data acquisition card is connected to the computer.

[0049] As a preferred embodiment: The explosive pellet elastic modulus testing device based on pulse excitation method further includes a data processing and analysis module, which is connected to the signal acquisition module 3.

[0050] The data processing and analysis module has a built-in model for calculating the elastic modulus of disc-shaped specimens.

[0051] The elastic modulus calculation model is based on the principle of pulse excitation and includes a built-in elastic modulus calculation model suitable for disc-shaped specimens (such as the "disc E / G" mode). The elastic modulus calculation model receives the acquired vibration signal, performs a fast Fourier transform to obtain a spectrum, identifies the natural frequencies of the specimen (bending frequency and torsional frequency), and automatically calculates and displays Young's modulus E, shear modulus G, and Poisson's ratio μ.

[0052] The elastic modulus calculation model is based on data conversion according to ASTM E1876-22 standard "Standard Test Method for Determining Dynamic Young's Modulus, Shear Modulus and Poisson's Ratio by Vibrational Pulse Excitation".

[0053] Example 2: This embodiment provides a method for testing the elastic modulus of explosive fragments, characterized by employing the apparatus described in Embodiment 1, and comprising the following steps: Step 1: Prepare standard samples: Press the explosive powder into round, thin sheet-shaped standard samples 4.

[0054] Using specialized molds, explosive molding powder is pressed into a predetermined size, such as a circular thin sheet sample of Φ50mm×5mm, and its mass, diameter and thickness are accurately measured.

[0055] Step 2: Install standard specimens: Install standard specimen 4 in the human-machine isolation test chamber. The standard specimen 4 is located on the explosive sample placement assembly 1-2.

[0056] The specimen is placed on a support line that conforms to standards such as ASTM E1876 using a robotic arm or a specific fixture (the support point is located at a distance of 0.552 times the diameter from the center of the specimen).

[0057] Step 3: Remote excitation: Excite the standard sample 4 through the excitation module.

[0058] Step 4: Data Acquisition: Acquire the vibration signal of standard sample 4 through the signal acquisition module.

[0059] Start the testing software on the control computer, select the sample shape as "circular piece E / G", and input the basic parameters of the sample (mass, diameter, thickness) measured in step S1.

[0060] The computer-controlled excitation module gently and accurately taps the sample. Simultaneously, the signal acquisition module starts working, recording the vibration response signal of the sample.

[0061] The amplitude threshold is set to 0.05V, and the initial bending frequency range is set to 1-10kHz, and the torsion frequency range is set to 10-20kHz.

[0062] Step 5: Calculation: Analyze the signal obtained in Step 4 through the data processing and analysis module, and calculate the elastic modulus.

[0063] The system analyzes the acquired signals and displays a spectrum. Operators can observe the spectrum and set appropriate frequency ranges (bending and twisting frequencies) to eliminate noise interference. It automatically calculates and displays Young's modulus E, shear modulus G, and Poisson's ratio μ in real time.

[0064] like Figure 4 As shown, observing the spectrum reveals a distinct fundamental frequency peak at approximately 5.1 kHz and another peak at approximately 9.1 kHz. Adjusting the bending frequency range to 4-7 kHz and the twisting frequency range to 7-12 kHz...

[0065] The software's dynamic display shows that E = 10.5 GPa, G = 3.8 GPa, and μ = 0.38. This Poisson's ratio is within a reasonable range (0~0.5), and the result is valid.

[0066] In practical applications, multiple excitation tests can be performed to verify the repeatability of the results. After confirming the reliability of the results, the data for a single sample are saved. Repeating the excitation three times, with a deviation of less than 1%, indicates good repeatability.

[0067] Multiple samples can be tested consecutively, and a unified test report can be generated and exported. After the test, the standard sample can be safely removed using a robotic arm or a specific fixture.

[0068] As a preferred embodiment: The standard sample is in the shape of a thin circular sheet, and the ratio of the diameter to the thickness of the standard sample is not less than 5.

[0069] The elastic modulus mentioned includes Young's modulus, shear modulus, and Poisson's ratio.

[0070] The above technical solutions are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions conceived by those skilled in the art within the scope of the technology disclosed in the present invention without creative effort are covered within the scope of protection of the present invention.

Claims

1. A device for testing the elastic modulus of explosive fragments based on pulse excitation method, comprising a human-machine isolated testing chamber (1), characterized in that, It also includes an excitation module (2) installed in the human-machine isolation test chamber (1) and a signal acquisition module (3) installed in the human-machine isolation test chamber (1). The human-machine isolation test chamber (1) is an openable box structure, including a test box (1-1) and an explosive sample placement assembly (1-2) installed in the test box (1-1). The excitation module (2) includes a striking head (2-1), which is arranged in the test box (1-1) via a striking head bracket (2-2). The striking head (2-1) is located above the explosive sample placement assembly (1-2) and can contact the standard sample placed on the explosive sample placement assembly (1-2). The signal acquisition module (3) includes an acoustic sensor (3-1), which is arranged in the test box (1-1) through a sensor bracket (3-2). The acoustic sensor (3-1) is located above the explosive sample placement assembly (1-2) and at a certain distance from the standard sample placed on the explosive sample placement assembly (1-2).

2. The elastic modulus test of explosive fragments based on pulse excitation method as described in claim 1, characterized in that, Sound insulation material is arranged on the walls of the test chamber (1-1); The acoustic sensor (3-1) can be replaced by a laser vibration meter; The explosive sample placement assembly (1-2) consists of two parallel support wires with a spacing of 0.552D, where D is the diameter of the standard sample. Both the striking head bracket (2-2) and the sensor bracket (3-2) are adjustable in position.

3. The elastic modulus test of explosive fragments based on pulse excitation method as described in claim 2, characterized in that, The signal acquisition module (3) further includes a data acquisition card and a computer. The acoustic sensor (3-1) or laser vibrometer is connected to the data acquisition card, and the data acquisition card is connected to the computer.

4. The elastic modulus test of explosive fragments based on pulse excitation method as described in claim 3, characterized in that, The explosive pellet elastic modulus testing device based on pulse excitation method also includes a data processing and analysis module, which is connected to the signal acquisition module (3). The data processing and analysis module has a built-in model for calculating the elastic modulus of disc-shaped specimens.

5. A method for testing the elastic modulus of an explosive pellet, characterized in that, Implemented using the apparatus described in any one of claims 1-4, comprising the following steps: Step 1: Prepare standard test specimens: Press the explosive powder into thin, round standard test specimens; Step 2: Install standard specimens: Install standard specimens inside the human-machine isolation test chamber. The standard specimens are located on the explosive sample placement assembly (1-2). Step 3: Remote excitation: Excite the standard sample through the excitation module; Step 4: Data Acquisition: Acquire vibration signals from the standard sample using the signal acquisition module; Step 5: Calculation: Analyze the signal obtained in Step 4 through the data processing and analysis module, and calculate the elastic modulus.

6. The method for testing the elastic modulus of explosive fragments as described in claim 1, characterized in that, The standard sample is in the shape of a thin circular sheet, and the ratio of the diameter to the thickness of the standard sample is not less than 5. The elastic modulus mentioned includes Young's modulus, shear modulus, and Poisson's ratio.

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