Crack detection system for solid propellant grain
By using ultrasonic longitudinal wave signals to detect cracks in solid propellant grains inside the engine, the problems of time-consuming, labor-intensive, and highly destructive traditional detection methods have been solved, achieving non-destructive testing and real-time evaluation of the internal structure of the propellant grain.
Patent Information
- Application Number
- CN202423318907.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2026-01-23
- Estimated Expiration
- 2034-12-31
AI Technical Summary
In the existing technology, traditional methods for detecting cracks in solid propellant grains require destroying the integrity of the grain and are difficult to fully assess the internal structure, which is time-consuming and labor-intensive.
The solid propellant grain inside the engine is excited by ultrasonic longitudinal wave signals. The echo signals are acquired by a transceiver isolation duplexer, an ultrasonic transducer, and an oscilloscope. The characteristics of the echo signals are analyzed by a processing module to determine whether there are cracks in the propellant grain.
It enables non-destructive testing of cracks in solid propellant grains, allowing for real-time assessment of internal structural integrity, improving testing efficiency and reducing destructive human intervention.
Smart Images
Figure CN223827624U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to solid propellant grain technical field, in particular to a kind of crack detection system of solid propellant grain. BACKGROUND
[0002] Solid propellant is a kind of energetic composite material with specific performance, and the commonly used solid propellant is a mixture of high polymer as matrix, mixed with oxidant and metal fuel.
[0003] Solid propellant grain is obtained after the solid propellant raw material is shaped and prepared by using a forming device, and the structural integrity thereof is destroyed, which is one of the core reasons leading to engine failure. Crack is a common factor to destroy the structural integrity of solid propellant grain, and it may occur during the process of filling solid propellant grain into the engine. Therefore, it is very important to detect the crack of solid propellant grain filled into the engine.
[0004] The conventional crack detection method of solid propellant grain is often to sample the solid propellant grain filled into the engine, and then to perform experimental detection in the laboratory. This process destroys the integrity of the solid propellant grain, which not only consumes time and effort, but also is difficult to comprehensively evaluate the internal structure of the entire solid propellant grain. SUMMARY
[0005] Therefore, it is necessary to provide a crack detection system of solid propellant grain to detect the crack of the entire solid propellant grain including the internal structure thereof without destroying the integrity of the solid propellant grain.
[0006] The utility model provides a kind of crack detection system of solid propellant grain, comprising:
[0007] Signal generator is used to generate ultrasonic longitudinal wave signal;
[0008] Power amplifier is connected with signal generator, for receiving and amplifying ultrasonic longitudinal wave signal sent by signal generator;
[0009] Transmit-receive isolation duplexer is connected with power amplifier, for forwarding amplified ultrasonic longitudinal wave signal;
[0010] Ultrasonic transducer is fixedly arranged on the outer wall of engine shell, and ultrasonic transducer is connected with transmit-receive isolation duplexer, for receiving ultrasonic longitudinal wave signal sent by transmit-receive isolation duplexer and exciting ultrasonic longitudinal wave signal to engine, and receiving echo signal returned by engine;
[0011] An oscilloscope is connected to a transmit / receive isolation duplexer. The transmit / receive isolation duplexer is also used to forward the echo signal to the oscilloscope, which is used to convert the echo signal into a visual waveform.
[0012] The processing module, connected to the oscilloscope, is used to receive the echo signal forwarded by the oscilloscope and process the echo signal to obtain the distance of the ultrasonic longitudinal wave to the wave packet, and to compare the distance of the ultrasonic longitudinal wave to the wave packet with the thickness of the solid propellant grain to determine whether there are cracks in the solid propellant.
[0013] In one embodiment, the processing module includes a signal reconstruction unit, a filtering unit, an envelope calculation unit, a peak detection unit, a distance calculation unit, and a comparison unit connected in sequence, with the signal reconstruction unit connected to an oscilloscope;
[0014] The signal reconstruction unit is used to denoise the echo signal using wavelet transform to obtain the reconstructed signal.
[0015] The filtering unit is used to filter drift and background noise of the reconstructed signal through low-pass filtering and / or high-pass filtering;
[0016] The envelope calculation unit is used to perform Hilbert transform on the filtered reconstructed signal to calculate the envelope of the signal;
[0017] The peak detection unit is used to identify wave packets in the envelope using a peak detection algorithm and determine the arrival time of the wave packets.
[0018] The distance calculation unit is used to calculate the distance of the ultrasonic longitudinal wave to the wave packet based on the ultrasonic longitudinal wave velocity and the arrival time of the wave packet;
[0019] The comparison unit is used to compare the distance of the ultrasonic longitudinal wave to the wave packet with the thickness of the solid propellant grain to determine whether there are cracks in the solid propellant.
[0020] In one embodiment, the power amplifier has a gain of 200 or greater.
[0021] The beneficial effects of this utility model are as follows: In this utility model, an ultrasonic longitudinal wave signal is excited to the engine filled with solid propellant by an ultrasonic transducer, and the echo signal of the engine is received. Finally, the echo signal is processed in the processing module to determine the distance of the ultrasonic longitudinal wave to the wave packet. The processing module can determine whether there are cracks in the solid propellant. Attached Figure Description
[0022] Figure 1 A schematic diagram of the connection between the solid propellant grain crack detection system and the engine provided in this embodiment of the utility model;
[0023] Figure 2This is a structural block diagram of the processing module provided in an embodiment of the present utility model. Detailed Implementation
[0024] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.
[0025] In one embodiment, such as Figure 1 As shown, the solid propellant grain crack detection system of this embodiment includes:
[0026] A signal generator used to generate ultrasonic longitudinal wave signals.
[0027] A power amplifier, connected to a signal generator, is used to receive and amplify the ultrasonic longitudinal wave signal sent by the signal generator. Specifically, in this embodiment, the power amplifier has a gain greater than or equal to 200. The power amplifier ensures that the signal has sufficient energy to excite the propagation of ultrasonic waves in the propellant.
[0028] A transceiver isolation duplexer, connected to a power amplifier, is used to forward the amplified ultrasonic longitudinal wave signal.
[0029] An ultrasonic transducer is fixedly installed on the outer wall of the engine housing. The ultrasonic transducer is connected to a transceiver isolation duplexer and is used to receive ultrasonic longitudinal wave signals sent by the transceiver isolation duplexer and to excite ultrasonic longitudinal wave signals to the engine, as well as to receive echo signals returned by the engine.
[0030] The propellant charge section of the engine, from the outside in, includes the engine casing, the heat insulation layer, and the solid propellant charge.
[0031] Ultrasonic longitudinal waves propagate within solid propellant grains. During transmission, they are affected by the internal structure and physical properties of the propellant grain. Cracks or damage can cause reflection, scattering, or attenuation of the ultrasonic signal, resulting in characteristic changes in the echo signal, forming wave packets. The characteristics of the echo signal reflect the internal structure and existing defects of the solid propellant grain.
[0032] An oscilloscope is connected to a transmit / receive isolation duplexer. The transmit / receive isolation duplexer is also used to forward the echo signal to the oscilloscope, which is used to convert the echo signal into a visual waveform.
[0033] An oscilloscope converts signals into visual waveforms, providing data support for subsequent analysis.
[0034] The processing module, connected to the oscilloscope, is used to receive the echo signal forwarded by the oscilloscope and process the echo signal to obtain the distance of the ultrasonic longitudinal wave to the wave packet, and to compare the distance of the ultrasonic longitudinal wave to the wave packet with the thickness of the solid propellant grain to determine whether there are cracks in the solid propellant.
[0035] It should be noted that the connection method of each component in this embodiment can be either wire connection or signal connection.
[0036] The solid propellant grain crack detection system of this embodiment uses ultrasonic waves to detect cracks, and can detect cracks in the entire solid propellant grain, including its internal structure, without damaging the integrity of the solid propellant grain.
[0037] Furthermore, the echo signal obtained by the system in this embodiment can also be used to measure the real-time elastic modulus of solid propellant grains placed in the engine.
[0038] The specific measurement process is as follows: First, the elastic modulus and ultrasonic longitudinal wave velocity of the solid propellant material are obtained through mechanical testing. Based on the elastic modulus and ultrasonic longitudinal wave velocity of the solid propellant material, the calibrated Poisson's ratio is calculated according to the elastic modulus calculation formula. Then, longitudinal wave signals are sent to the solid propellant grain inside the engine from outside the engine and the echo signals are received. The ultrasonic longitudinal wave velocity in the solid propellant grain is determined according to the echo signals. Finally, the elastic modulus of the solid propellant grain is calculated according to the elastic modulus calculation formula based on the calibrated Poisson's ratio and the ultrasonic longitudinal wave velocity in the solid propellant grain.
[0039] The formula for calculating the elastic modulus is:
[0040]
[0041] In the formula, E represents the elastic modulus, and C L ρ represents the longitudinal wave intensity of ultrasound, σ represents the density, and σ represents the calibrated Poisson's ratio.
[0042] Solid propellant feedstock is prepared by molding to obtain solid propellant grains. The solid propellant feedstock can be a portion of a solid propellant grain or a parallel storage component of a solid propellant grain, with the parallel storage component being the most preferred.
[0043] In one embodiment, such as Figure 2 As shown, the processing module includes a signal reconstruction unit, a filtering unit, an envelope calculation unit, a peak detection unit, a distance calculation unit, and a comparison unit connected in sequence. The signal reconstruction unit is connected to the oscilloscope.
[0044] The signal reconstruction unit is used to denoise the echo signal using wavelet transform to obtain the reconstructed signal; the filtering unit is used to filter the drift and background noise of the reconstructed signal using low-pass and / or high-pass filtering; the envelope calculation unit is used to calculate the envelope of the filtered reconstructed signal using Hilbert transform; the peak detection unit is used to identify wave packets in the envelope using a peak detection algorithm and determine the arrival time of the wave packets; the distance calculation unit is used to calculate the distance of the ultrasonic P-wave to the wave packet based on the ultrasonic P-wave velocity and the arrival time of the wave packet; and the comparison unit is used to compare the distance of the ultrasonic P-wave to the wave packet with the thickness of the solid propellant grain to determine whether there are cracks in the solid propellant.
[0045] Due to the characteristics of ultrasonic wave propagation, it will produce a relatively strong echo when it encounters a crack or damage; this echo signal is called a wave packet. The distance the ultrasonic longitudinal wave travels to the wave packet is the same as the distance the ultrasonic wave travels to the crack.
[0046] It should be noted that when the ultrasonic wave reaches the other side of the solid propellant grain, the side wall is also considered a crack and will also generate wave packets.
[0047] In this embodiment, the comparison unit compares the distance of the ultrasonic longitudinal wave to the wave packet with the thickness of the solid propellant grain to determine whether there is a crack in the solid propellant. Specifically, if the distance of the ultrasonic longitudinal wave to the wave packet is less than the thickness of the solid propellant grain, then there is a crack in the solid propellant grain; if the distance of the ultrasonic longitudinal wave to the wave packet is greater than or equal to the thickness of the solid propellant grain, then there is no crack in the solid propellant grain.
[0048] In this embodiment, the filtering unit includes a low-pass Butterworth filter with a cutoff frequency of 0.1Hz and a high-pass Butterworth filter with a cutoff frequency of 10Hz. The peak detection unit uses the findpeaks algorithm for peak detection.
[0049] The solid propellant grain crack detection system of this embodiment can assist in the calculation of the real-time elastic modulus of solid propellant and can analyze and confirm whether there are cracks in the solid propellant placed inside the engine.
[0050] The above-described embodiments are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the appended claims.
Claims
1. A crack detection system for solid propellant grains, characterized in that, include: A signal generator is used to generate ultrasonic longitudinal wave signals; A power amplifier, connected to the signal generator, is used to receive and amplify the ultrasonic longitudinal wave signal sent by the signal generator; A transceiver isolation duplexer, connected to a power amplifier, is used to forward the amplified ultrasonic longitudinal wave signal; An ultrasonic transducer is fixedly mounted on the outer wall of the engine housing. The ultrasonic transducer is connected to the transceiver isolation duplexer and is used to receive the ultrasonic longitudinal wave signal sent by the transceiver isolation duplexer and to excite the engine with the ultrasonic longitudinal wave signal, as well as to receive the echo signal returned by the engine. An oscilloscope is connected to the transceiver isolation duplexer, the transceiver isolation duplexer is also used to forward the echo signal to the oscilloscope, and the oscilloscope is used to convert the echo signal into a visual waveform. The processing module, connected to the oscilloscope, is used to receive the echo signal forwarded by the oscilloscope and process the echo signal to obtain the distance of the ultrasonic longitudinal wave to the wave packet, and to compare the distance of the ultrasonic longitudinal wave to the wave packet with the thickness of the solid propellant grain to determine whether there are cracks in the solid propellant.
2. The crack detection system for solid propellant grains according to claim 1, characterized in that, The processing module includes a signal reconstruction unit, a filtering unit, an envelope calculation unit, a peak detection unit, a distance calculation unit, and a comparison unit connected in sequence. The signal reconstruction unit is connected to the oscilloscope. The signal reconstruction unit is used to obtain a reconstructed signal by denoising the echo signal through wavelet transform. The filtering unit is used to filter the drift and background noise of the reconstructed signal through low-pass filtering and / or high-pass filtering; The envelope calculation unit is used to perform Hilbert transform on the filtered reconstructed signal to calculate the envelope of the signal; The peak detection unit is used to identify wave packets in the envelope using a peak detection algorithm and determine the arrival time of the wave packets. The distance calculation unit is used to calculate the distance of the ultrasonic longitudinal wave to the wave packet based on the ultrasonic longitudinal wave velocity and the arrival time of the wave packet. The comparison unit is used to compare the distance of the ultrasonic longitudinal wave to the wave packet with the thickness of the solid propellant grain to determine whether there are cracks in the solid propellant.
3. The crack detection system for solid propellant grains according to claim 2, characterized in that, The power amplifier has a gain of 200 or greater.