A solid propellant structural deformation monitoring device and method based on displacement sensing

Abstract

A solid propellant structure deformation monitoring and detection device based on displacement sensing is provided, comprising a heating furnace (2), a displacement sensor (3), a time cycle relay (4), a data acquisition instrument (5) and a clamping tool (6); the heating furnace (2) is used to heat a solid propellant sample to be tested; the displacement sensor (3) is arranged above the solid propellant sample to be tested and is used to measure the distance between the surface of the solid propellant block and the displacement sensor; the time cycle relay (4) is connected to the displacement sensor (3) and is used to control the opening and closing of the displacement sensor; the data acquisition instrument (5) is connected to the displacement sensor (3); and the clamping tool (6) is used to fix the displacement sensor to ensure that the absolute distance between the solid propellant sample to be tested and the displacement sensor (3) remains unchanged. The device of the present invention has a simple structure, low price, and is easy to operate. It does not require embedding or pasting sensors and can meet the multi-task test requirements of solid propellant structure monitoring and detection.

Description

Technical Field

[0001] The present invention relates to a solid propellant and solid motor health status monitoring and detection technology, and in particular to a solid propellant structural deformation monitoring and detection device and method based on displacement sensing. Background Art

[0002] Solid propellants are the power source for missile flight. High-energy solid propellants are thermosetting cross-linked propellants, using a polyether plasticized with a mixed nitrate ester as a binder and filled with a large amount of high-energy oxidizers such as octogen (HMX), AP, and aluminum powder (Al). With increasing energy requirements, a wide range of hydrogen-containing metal compounds, metal alloys, high-energy oxidizers, and high-energy binders have been introduced into solid propellants, such as aluminum hydride (AlH3), aluminum-lithium alloys, ammonium dinitramide (ADN), and glycidyl polyazide (GAP). Active components in solid propellants, such as nitrate esters, explosives, or AlH3 hydrogen metal fuel, can decompose or vaporize during accelerated aging or storage, leading to gas accumulation. This can cause cavitation, bulging, or even cracking in the propellant grain. Ultimately, the grain undergoes structural deformation (expansion, cracking, and holes), compromising the motor's structural integrity and combustion stability, potentially leading to ignition failure or even explosion, seriously threatening missile safety. Therefore, evaluating structural deformation in solid propellants is an essential component of solid propellant research.

[0003] Monitoring the deformation of solid propellants and engine structures falls under the umbrella of engine health monitoring, with a key focus on monitoring the structural integrity of the propellant and engine. With the rapid development of micro-electromechanical technologies, sensor technologies for measuring the structural integrity of engine charges have emerged. Typical examples include stress sensors, strain sensors, and fiber Bragg grating (FBG) sensors. Stress-strain sensors utilize strain gauges mounted on a diaphragm to convert pressure or stress signals into electrical signals. Fiber Bragg grating sensors are a key type of sensor for strain measurement. If a fiber Bragg grating (FBG) is stretched or compressed, the grating's period and effective refractive index change accordingly, shifting the grating's central wavelength accordingly. The corresponding relationship between the central wavelength and stress and strain allows for the measurement of the strain and stress condition of the object being measured. Stress-strain sensors and fiber optic sensors, with their advantages of small size, light weight, and remote sensing capabilities, have attracted widespread attention for solid propellant engine structural health monitoring. However, stress-strain sensors and fiber optic sensors are embedded in applications, which not only require high accuracy and long-term stability of the sensors, but also require compatibility with the materials of propellants and engine grains, low corrosion sensitivity, and good adhesion and embeddability in long-term or high-temperature accelerated environments. Embedded sensors may also cause propellant stress and strain distortion points, resulting in errors in test results. Summary of the Invention

[0004] The problem solved by the technology of the present invention is to overcome the deficiencies of the prior art and propose a monitoring device and method for monitoring the deformation and damage of the structure of solid propellant and engine propellant grain by using displacement sensing and ranging technology.

[0005] The theoretical basis of the present invention is that during long-term storage and high-temperature accelerated aging of solid propellants, especially high-energy solid propellants, components such as nitrates, oxidants, or AlH3 metal hydrides slowly decompose to produce gases. These gases do not have time to diffuse and accumulate within the propellant, leading to internal pores and cracks, and external expansion and deformation of the propellant. Displacement ranging sensors often use a laser transmitter as a ranging light source. The laser transmitter emits a laser beam directed at the surface of the object being measured. The emitted laser beam is scattered and reflected on the object's surface, and the reflected light path is received by a laser receiving point. The laser emission point, target point, and receiving point form a triangle. The position of the target point is calculated by knowing the angle and position information of the emission point and receiving point. When the absolute distance between the propellant and the displacement sensor is fixed, when the propellant decomposes due to heat, expands, and deforms, the relative distance between the propellant surface and the displacement sensor changes. The displacement sensor detects the slight deformation of the propellant and transmits it to a data acquisition device, thus achieving non-contact, non-destructive monitoring of deformation and damage to the solid propellant and engine structure.

[0006] The technical solution of the present invention is: a solid propellant structural deformation monitoring and detection device based on displacement sensing, comprising a heating furnace, a displacement sensor, a time cycle relay, a data acquisition instrument, and a clamping tool; the heating furnace is used to heat a solid propellant sample to be tested, accelerate the propellant aging reaction, and cause the solid propellant sample to be tested to decompose and release gas; the displacement sensor is arranged above the solid propellant sample to be tested, and is used to measure the distance between the surface of the solid propellant block and the displacement sensor; the time cycle relay is connected to the displacement sensor, and is used to control the opening and closing of the displacement sensor; the data acquisition instrument is connected to the displacement sensor, and is used to collect and record the output signal of the displacement sensor; and the clamping tool is used to fix the displacement sensor to ensure that the absolute distance between the solid propellant sample to be tested and the displacement sensor remains unchanged.

[0007] Furthermore, the number of the above-mentioned displacement sensors is one or more, and a single displacement sensor measures the deformation of a measurement point on the surface of the solid propellant; multiple displacement sensors form a displacement sensor array to measure the two-dimensional surface deformation of the solid propellant surface.

[0008] Furthermore, the above-mentioned displacement sensor is a laser displacement sensor, an acoustic wave sensor or other displacement sensors that meet the test requirements.

[0009] Furthermore, the solid propellant sample to be tested is a solid propellant pellet or an engine grain.

[0010] The present invention also provides a method for monitoring and detecting deformation of a solid propellant structure based on displacement sensing, which uses the above-mentioned solid propellant structure deformation monitoring and detecting device based on displacement sensing using a single displacement sensor, and includes the following steps:

[0011] S1. Connect the components of the solid propellant structural deformation monitoring and detection device based on displacement sensing, and place the solid propellant sample to be tested in a heating furnace;

[0012] S2. Turn on the displacement sensor and the data acquisition instrument to measure and record the distance Z1 from the ranging point A1 on the surface of the solid propellant sample to be tested to the displacement sensor;

[0013] S3. Synchronously start the time cycle relay and the heating furnace, measure and record the distance Z from the displacement sensor to the measuring point A1 on the surface of the solid propellant sample to be tested at different time points. t2 ~Z tn .

[0014] Furthermore, in the above step S2, the distance measurement point A1 is converted into a two-dimensional coordinate X1Y1; the distance Z in step S3 is converted into tn Convert to three-dimensional coordinates X1Y1~Z tn .

[0015] The present invention also provides a method for monitoring and detecting deformation of a solid propellant structure based on displacement sensing, which uses the above-mentioned solid propellant structure deformation monitoring and detecting device based on displacement sensing using multiple displacement sensors, and includes the following steps:

[0016] The first step is to connect the components of the solid propellant structural deformation monitoring and detection device based on displacement sensing, and place the solid propellant sample to be tested in a heating furnace;

[0017] The second step is to set up multiple point displacement sensors or line displacement sensors to form a displacement sensor array, and take multiple distance measurement points A1-A at different positions on the surface of the solid propellant sample to be tested. n , turn on the displacement sensor and data acquisition instrument, measure and record the distance measurement point A1-A on the surface of the solid propellant sample to be tested n Distance to the displacement sensor;

[0018] The third step is to synchronously start the time cycle relay and the heating furnace to measure and record the distance change from the displacement sensor array to the ranging point on the surface of the solid propellant sample to be measured at each ranging point at different heating time points.

[0019] Furthermore, the distance measurement point A1-A in the above step S2 n Use the two-dimensional coordinates x1y1-x n y n Indicates: Convert the distance coordinate in step S3 into the three-dimensional coordinate Xn Y n ~Z tn .

[0020] The present invention provides a monitoring device and method for monitoring the accelerated aging of solid propellants and solid engines and the structural deformation during storage based on displacement sensing technology.

[0021] The advantages of the present invention compared with the prior art are:

[0022] 1) The present invention is designed based on the principles of ranging and propellant deformation, with a simple device and low-cost components: the displacement sensor, data acquisition instrument and time cycle relay are all mature commercial products with low prices.

[0023] 2) The method of the present invention is a non-contact, non-destructive monitoring and testing method for solid propellants and engines. It does not require embedding or pasting sensors in samples, thus solving problems such as sensor packaging, material compatibility, corrosion, and safety, and is easy to operate.

[0024] Therefore, the present invention proposes a non-contact non-destructive monitoring method for deformation and damage of solid propellants and engine structures based on displacement sensing technology, which does not require embedding or pasting sensors, filling the relevant gaps in the non-destructive monitoring of solid propellants and engines at home and abroad. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] These and / or other aspects and advantages of the present invention will become more apparent and more readily understood from the following detailed description of embodiments of the present invention in conjunction with the accompanying drawings, in which:

[0026] Figure 1 1 is a schematic structural diagram of a solid propellant structural deformation monitoring and detection device based on displacement sensing in an embodiment of the present invention;

[0027] Figure 2 Schematic diagram of the principle of the device of the present invention for monitoring and detecting the structural deformation of solid propellant;

[0028] Figure 3 It is a schematic diagram of the principle of using a laser displacement sensor array to monitor the two-dimensional surface scanning of solid propellant structural deformation.

[0029] Figure 4 Laser displacement sensors are used to monitor the structural deformation and damage of a high-energy propellant during accelerated aging at 90°C. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Example 1

[0032] A solid propellant structural deformation monitoring device based on displacement sensing, its structure and connection relationship are as follows Figure 1 As shown, its main components include: a sample to be tested 1, a heating furnace 2, a displacement sensor 3, a time cycle relay 4, a data acquisition instrument 5 and a clamping tool 6;

[0033] The sample to be tested is a solid propellant block or column, and the heating furnace 2 is used to heat the sample to be tested so that the components decompose and degas, resulting in structural deformation. The displacement sensor 3 is used to measure the distance between the ranging point on the surface of the sample to be tested and the displacement ranging sensor. It is generally a laser displacement sensor, and a displacement sensor based on acoustic waves or other ranging principles can also be used. The sensor only needs to meet the ranging range and accuracy requirements. The time cycle relay 4 is mainly used to control the opening and closing of the displacement sensor. The power supply can be set to an "open-closed" cycle to prevent long-term laser irradiation of the solid propellant surface from causing heat accumulation and leading to safety problems such as spontaneous combustion, and to improve the long-term working stability of the sensor. The data acquisition instrument 5 collects and records the output signal of the displacement sensor 3 to realize online automatic recording and monitoring of experimental data. The clamping fixture 6 is used to fix the displacement sensor 3 to ensure that the absolute distance between the sample to be tested and the displacement sensor remains unchanged.

[0034] The principle of monitoring and detecting the deformation of the solid propellant structure of the device in this embodiment is as follows: Figure 2 As shown: solid propellants, especially high-energy solid propellants, during long-term storage and high-temperature accelerated aging, components such as nitrates, oxidants or AlH3 metal hydrides slowly decompose to produce gases. The gases do not have time to diffuse and accumulate inside the propellant, which will cause internal pores and cracks, and external expansion and deformation of the propellant. The displacement sensor 3 often uses a laser transmitter as a ranging light source. The laser transmitter emits a laser at the surface of the object to be measured. The emitted laser beam is scattered and reflected on the surface of the object. The reflected light path is received by the laser receiving point. The laser emission point, the target point and the receiving point form a triangle. The position of the target point is calculated by knowing the angle and position information of the emission point and the receiving point. When the absolute distance between the propellant and the displacement sensor 3 is fixed, when the propellant is decomposed by heat and expands and deforms, the relative distance between the propellant surface and the displacement sensor 3 changes (Z t1 is the distance between the solid propellant and the displacement sensor 3 in the initial state, Z t2 Z is the distance between the solid propellant and the displacement sensor 3 when heated to the first time point; t3 The distance between the solid propellant and the displacement sensor 3 when heated to the second time point is detected by the displacement sensor 3 and transmitted to the data acquisition instrument, thereby realizing non-contact non-destructive monitoring of the deformation and damage of the solid propellant and the engine structure.

[0035] The preferred displacement sensor 3 of the device of this embodiment is a plurality of displacement sensors forming a displacement sensor array, such as Figure 3 As shown, when a displacement sensor array is formed for multiple displacement sensors, the change in the distance of each distance measuring point from the sensor caused by the change in heating time can be measured and monitored simultaneously. The relative position of the distance measuring point can be converted into two-dimensional coordinates X and Y. The two-dimensional coordinates of different distance measuring points are: x1y1, x2y2...x n y n (like Figure 3 The distances Z between the displacement sensor and different distance measurement points on the surface of the solid propellant sample are measured at different times, and the distances Z between the multiple distance measurement points on the sample surface and the displacement sensor 3 are obtained at different times. t1 ~Z tn , and combined with the two-dimensional coordinate x, y values, the three-dimensional surface monitoring of the sample structure deformation can be achieved through three-dimensional coordinate mapping (such as Figure 3 (as shown in the middle right picture).

[0036] Example 2:

[0037] A method for monitoring the structural deformation of high-energy propellant pellets is proposed. Utilizing the apparatus of Example 1, an oil bath heating furnace, a time cycle relay, a laser displacement sensor, a data acquisition instrument, and a clamping fixture, a device for structural deformation destruction during high-energy solid propellant high-temperature accelerated aging is constructed. The high-energy solid propellant sample is cut into pellets with a size of 10mm*30mm*30mm, placed in an oil bath heating furnace, and the ranging light spot is positioned at the center of the sample as much as possible. The sample to be tested is heated and the start time of the test is recorded. The time cycle relay is set to power on for 3 minutes and off for 5 minutes in a cycle, and the time cycle relay controls the operation of the displacement sensor. The displacement sensor used in the test is a laser displacement sensor with a center ranging displacement of 200mm, a range of -80mm to +80mm, and an accuracy of 0.1mm. The displacement sensor transmits the relative distance signal between the sensor and the propellant surface during the test to the data acquisition instrument. After the test, the data is exported from the data acquisition instrument and processed. The relative distance measured during the test is subtracted from the initial absolute distance to obtain the time-deformation height curve of the solid propellant surface ranging point at the accelerated temperature. Combined with the propellant structural deformation failure criterion, non-contact non-destructive monitoring and detection of structural deformation and damage of solid propellants or engine grains during storage can be achieved.

[0038] Figure 4 The data are experimentally measured for the structural deformation and damage monitoring of a high-energy propellant pellet with a size of 10mm*30mm*30mm under 90℃ high-temperature accelerated aging.

[0039] While various embodiments of the present invention have been described above, the foregoing description is intended to be illustrative, non-exhaustive, and not limiting of the disclosed embodiments. Numerous modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. Therefore, the scope of the present invention shall be determined by the scope of the claims.

Claims

1. A solid propellant structural deformation monitoring and detection device based on displacement sensing, characterized in that: It includes a heating furnace (2), a displacement sensor (3), a time cycle relay (4), a data acquisition device (5) and a clamping tool (6); The heating furnace (2) is used to heat the solid propellant sample to be tested, accelerate the propellant aging reaction, and decompose the solid propellant sample to be tested to release gas; The displacement sensor (3) is used to measure the distance between the surface of the solid propellant sample block and the displacement sensor; The time cycle relay (4) is connected to the displacement sensor (3) and is used to control the opening and closing of the displacement sensor; The data acquisition device (5) is connected to the displacement sensor (3) and is used to collect and record the output signal of the displacement sensor; The clamping fixture (6) is used to fix the displacement sensor to ensure that the absolute distance between the solid propellant sample to be tested and the displacement sensor (3) remains unchanged; The number of the displacement sensors (3) is one or more, and the plurality of displacement sensors (3) are point displacement sensors or line displacement sensors; the plurality of displacement sensors form a displacement sensor array to measure the two-dimensional surface deformation of the solid propellant; The solid propellant sample to be tested is a solid propellant pellet or an engine pellet.

2. A method for monitoring the deformation of a solid propellant structure based on displacement sensing, characterized in that: The solid propellant structure deformation monitoring and detection device based on displacement sensing as claimed in claim 1 includes the following steps: S1. Connect the components of the solid propellant structural deformation monitoring and detection device based on displacement sensing, and place the solid propellant sample to be tested in a heating furnace (2); S2, turning on the displacement sensor (3) and the data acquisition instrument (5), measuring and recording the distance Z1 from the ranging point A1 on the surface of the solid propellant sample to be tested to the displacement sensor (3); S3, synchronously start the time cycle relay (4) and the heating furnace (2), measure and record the distance Z from the displacement sensor (3) to the distance measurement point A1 on the surface of the solid propellant sample to be tested at different time points t2 ~Z tn .

3. The solid propellant structural deformation monitoring and detection method based on displacement sensing according to claim 2, characterized in that: In step S2, the distance measurement point A1 is converted into a two-dimensional coordinate X1Y1; The distance Z in step S3 tn Convert to three-dimensional coordinates X1Y1~Z tn .

4. A method for monitoring deformation of solid propellant structure based on displacement sensing, characterized in that: It uses the solid propellant structure deformation monitoring and detection device based on displacement sensing as claimed in claim 1, including the following steps: The first step is to connect the components of the solid propellant structural deformation monitoring and detection device based on displacement sensing, and place the solid propellant sample to be tested in a heating furnace (2); The second step is to set up multiple point displacement sensors or line displacement sensors to form a displacement sensor array, and take multiple distance measurement points A1-A at different positions on the surface of the solid propellant sample to be tested. n , turn on the displacement sensor and data acquisition instrument (5), measure and record the distance measurement point A1-A on the surface of the solid propellant sample to be tested n Distance to displacement sensor (3); The third step is to synchronously start the time cycle relay (4) and the heating furnace (2), and respectively measure and record the distance change from the displacement sensor array to the ranging point on the surface of the solid propellant sample to be measured at each ranging point at different heating time points.

5. The solid propellant structural deformation monitoring and detection method based on displacement sensing according to claim 4 is characterized in that: The distance measurement point A1-A in the second step n Use the two-dimensional coordinates x1y1-x n y n express; Convert the distance coordinates from the displacement sensor array to the surface of the solid propellant sample to be measured in the third step into three-dimensional coordinates X n Y n ~Z tn .

Images