Ultrasonic guided wave detection method for bolt damage in complex environment
Through ultrasonic waveguide sensors and new waveguide bolt detection methods, the ultrasonic characteristics of complex environmental bolt damage are analyzed, and the damage information mapping relationship is established, and the problem of limited detection capabilities of complex environmental bolt damage is solved, achieving efficient and accurate detection results.
Patent Information
- Application Number
- CN202411611883.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-13
- Publication Date
- 2025-02-18
AI Technical Summary
The prior art is difficult to effectively detect bolt damage served in complex environments, especially in the multi-layer structure of the base, with large signal interference and errors, resulting in limited detection capabilities.
Ultrasonic waveguide sensors are used to generate and receive waveguide signals, and the action rules of damage of different lengths are analyzed through the new waveguide bolt detection method, ultrasonic characteristic parameters are extracted, the mapping relationship of bolt damage information is established, and quantitative evaluation is carried out.
It improves the detection ability of bolt damage served in complex environments, reduces the difficulty of signal analysis, reduces errors and uncertainties, and realizes the rapid and convenient detection of bolt damage caused by complex environments.
Smart Images
Figure CN119470631A_ABST
Abstract
Description
Technical Field
[0001] The present invention discloses an ultrasonic guided wave detection method for bolt damage in service in a complex environment, which belongs to the field of nondestructive testing and evaluation. An ultrasonic guided wave sensor generates an ultrasonic guided wave signal, analyzes the interaction between ultrasonic guided waves of the same frequency component and damage of different lengths, extracts ultrasonic characteristic parameters of ultrasonic guided waves at different times, uses a new guided wave bolt detection method, establishes a mapping relationship between service bolts and standard sample damage information, and performs quantitative evaluation on the damage of service complex bolts. Background Art
[0002] Guided wave technology is used to detect the length damage of implanted bolts. Bolts are a common connection device and are widely used in various engineering and mechanical equipment. The service environment of bolts is complex and diverse. Temperature, humidity, vibration and impact can cause damage to bolts. The implanted length of bolts directly affects the service life and structural safety of important components. Therefore, it is essential to use non-destructive testing methods to quantitatively evaluate the length of service bolts, which is of great significance for ensuring the safe operation of important components.
[0003] At present, the pull-out detection method is mostly used for bolt damage detection in complex environments. The pull-out detection method uses the interaction between the pull-out fixture and the bolt for measurement. The adapter on the pull-out fixture is connected to the fastener, and the force is applied to the fastener in a tensile manner, and the load is gradually increased until the predetermined test force is reached. The tensile force and displacement data during the test are monitored and recorded in real time. When the test end point is reached or the fastener failure is observed, the test is stopped and the maximum tensile force value is recorded. The length of the service bolt is quantitatively evaluated by comparing the standard bolt pull-out force. In the bolt damage detection in complex environments, the service environment of the bolt is relatively harsh, and the bolt detection faces challenges in the multi-layer structure of the base. When the steel plate, concrete or underground steel bar is in hard contact with the bolt, obvious signal interference will be generated, affecting the ultrasonic propagation and reception. This makes it difficult for conventional ultrasonic thickness measurement methods to receive clear signals, making signal analysis difficult. Hard contact causes signal attenuation, reflection and scattering, resulting in large errors and uncertainties in the detection process. In summary, the current methods for bolt damage detection in complex environments are very limited and cannot meet the requirements for bolt damage detection in complex environments. Therefore, there is an urgent need to develop a detection method for bolts serving in complex environments that can quickly, conveniently and preliminarily detect the bolts in service.
[0004] The present invention uses an ultrasonic guided wave sensor to excite and receive a guided wave signal at one end of the bolt, uses a new guided wave bolt detection method to analyze the received echo signal, and compares it with the standard bolt signal to quantitatively evaluate the damage of the service bolt, thus solving the problem of limited damage detection of bolts serving in complex environments. Quantitative evaluation of damage to bolts serving in complex environments has not been reported at home and abroad. Summary of the invention
[0005] The present invention aims to develop an ultrasonic guided wave detection method for bolt damage in complex service environments to solve the problem of limited detection capability of bolts in complex service environments. The proposed new guided wave bolt detection method can improve the ability to detect bolt damage in complex service environments.
[0006] In order to achieve the above object, the present invention adopts the following design scheme:
[0007] Use ultrasonic guided wave sensors to generate guided wave signals. Use ultrasonic guided wave sensors to receive guided wave signals after the effects of damage on the end faces of different lengths. Based on the new guided wave bolt detection method, the effects of damage on different bolt lengths are analyzed, and the correlation analysis is performed with the standard bolt detection signal. By analyzing the measured original signal and the half-wave signal correlation coefficient with the standard bolt specimen reference signal, the statistical principle is used to evaluate the damage of the complex bolts in service, thereby realizing the detection of the damage of the bolts in service.
[0008] The service bolts and standard bolt samples are subjected to correlation analysis to obtain a correlation coefficient distribution diagram, which is characterized by describing the correlation between the echo signals in different time domain segments and the reference signals.
[0009] The statistical results of the multiple signal analysis are characterized by describing that the correlation between the detected bolts and the standard bolts in different time domain segments at the same frequency is poor, and length damage is prone to occur.
[0010] The method of establishing the relationship between ultrasonic guided waves and damage information of in-service bolts is characterized in that the characteristic parameter is indirectly related to the bolt damage information.
[0011] The present invention can achieve the following effects:
[0012] 1. Use broadband sensor excitation to obtain broadband ultrasonic guided wave signals;
[0013] 2. Describes the correlation between the echo signal and the standard signal at the same frequency and different time periods;
[0014] 3. The detection of service bolts based on ultrasonic guided waves improves the ability to detect damage to bolts serving in complex environments. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 Schematic diagram of standard bolts and damaged bolts;
[0016] Figure 2 A damage detection experimental system for bolts serving in complex environments based on ultrasonic guided waves;
[0017] Figure 3 Ultrasonic guided wave signal of standard bolt
[0018] Figure 4 Distribution diagram of bolt correlation coefficient in different time periods
[0019] Figure 5 Schematic diagram of damage evaluation of in-service bolts
[0020] Figure 2 In: 1. Ultrasonic guided wave detector, 2. Digital oscilloscope, 3. Ultrasonic guided wave sensor, 4. Detection bolt. DETAILED DESCRIPTION
[0021] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.
[0022] Step 1: Bolt sample processing.
[0023] The bolt used in the experiment is 250mm long, with a thread end face diameter of 16mm. The upper end face is a regular hexagon with the longest diagonal of 10mm. There is an unprocessed threaded part of 8mm in the middle of the bolt. Since the end face of the bolt is relatively rough, in order to ensure that the ultrasonic guided wave sensor can be normally excited and received, the contact end face of the bolt sample should be polished to ensure that the sensor and the bolt are in full contact. Three bolts were randomly selected from the 20 service bolts for processing to simulate the damage of the bolts, such as Figure 1 shown.
[0024] Step 2: Ultrasonic guided wave testing experiment of complex bolts.
[0025] Build a broadband ultrasonic guided wave detection experimental system, such as Figure 2 The system includes an ultrasonic guided wave detector 1, a digital oscilloscope 2, an ultrasonic guided wave sensor 3 and a bolt specimen 4.
[0026] The experiment adopts the self-excitation and self-receiving mode, with the ultrasonic guided wave sensor as the excitation end and the receiving end. The ultrasonic guided wave sensor and the polished end face of the bolt sample are tightly linked by a coupling agent. The equipment is adjusted to a center frequency of 2MHz. The 2MHz ultrasonic guided wave sensor is used to measure two groups of standard bolt styles of different lengths to obtain the reflected echoes of the two groups of samples. According to the wave packets of different samples and the time difference of the wave packets, the sound velocity of the ultrasonic guided wave in the bolt sample is calculated. It is also measured that for the transit time of the guided wave in the bolt for the end face reflection echo, the transit time difference of every 1μs is equal to the bolt length difference of 5.464mm. The detection signal is observed using a digital oscilloscope, and the ultrasonic guided wave detector is used to save the received signal. The bolts that have been in service in a complex environment are tested and the corresponding ultrasonic echo signals are obtained. The guided wave detector is used to output the modulated signal and observe and save the received signal.
[0027] Ultrasonic guided wave measurement is performed on the undamaged bolt specimen to obtain the corresponding guided wave signal such as Figure 3 As shown. The service bolts that may be damaged are tested to obtain the corresponding 20 sets of original signal data. With the complexity of the service environment of the bolts and the uncertainty of damage, the information contained in the waveguide signal is changing. During the transmission process, the waveguide signal passes through objects that affect the signal propagation, such as bolt damage, the unthreaded plane in the middle of the bolt, the fixing nut, and the steel bars in the deep buried environment of the bolt, which will generate corresponding ultrasonic guided wave echo signals. In the measurement data of bolts of the same model, the interference waveguide signals generated by the fixing nut and the unthreaded plane in the middle of the bolt are almost the same. Therefore, it is only necessary to analyze the correlation between the original signals of the service bolts and the standard bolt specimens to obtain the correlation coefficient between the service bolts and the standard bolt specimens.
[0028] Step 3: Use the new bolt ultrasonic guided wave detection technology to analyze and process the collected data.
[0029] The signals received by the guided wave detector are processed to obtain the original signals and envelope signals of different bolts. Considering the complexity of the service environment, the entire time domain signal is segmented, and the correlation coefficient of multiple segments is used to improve the robustness of the subsequent correlation analysis. The data is separated from 30μs-90μs with a step size of 10μs, and 6 groups of data are intercepted. The data set is established with the above data, and the correlation scatter plot is drawn, as shown in the figure. Figure 4As shown. According to the correlation data of different time periods, damage judgment standards for different time periods are formulated. According to different time periods, a correlation lower than 0.15 in 30μs-90μs is considered to be a possible damage; a correlation lower than 0.15 in 40μs-90μs is considered to be a possible damage; a correlation lower than 0.15 in 50μs-90μs is considered to be a possible damage; a correlation lower than 0.15 in 60μs-90μs is considered to be a possible damage; a correlation lower than 0.15 in 70μs-90μs is considered to be a possible damage; a correlation lower than 0.15 in 80μs-90μs is considered to be a possible damage. Based on the number of problems that occur in the tested bolts in different data sets as the standard, a number of occurrences less than or equal to 2 is considered to be a low-probability problem, a number of occurrences between 3 and 5 is considered to be a medium-probability problem, and a number of occurrences greater than or equal to 5 is considered to be a high-probability problem. Applying statistical principles, a comprehensive damage assessment of the 20 service bolts tested was conducted with three evaluation levels of high, medium and low. The schematic diagram of service bolt damage evaluation is shown in the figure. Figure 5 It was found that bolts No. 14, No. 18, and No. 19 were the bolts with high probability of being damaged, which were consistent with the numbers of the damaged bolts processed by humans.
[0030] When ultrasonic guided waves are used to detect service bolts, the bolts are analyzed based on the correlation between frequency, different time periods and standard bolt specimens. When the correlation coefficient of the tested bolt is lower than the predetermined threshold, the damage of the tested bolt is evaluated.
[0031] The present invention designs an ultrasonic guided wave detection method for bolt damage serving in a complex environment, which solves the problem of limited detection capability of bolts in a complex service environment, and utilizes the characteristics of ultrasonic guided waves, such as rich signal frequency component information and obvious effect on damage. The damage of the bolt is detected by using an ultrasonic guided wave sensor to excite and receive guided wave signals. The ultrasonic signal of the end face of the bolt and the interference is judged according to the reflected echo signal of the standard sample. The serving bolts are detected, and the measured guided wave signals and the guided wave signals of the standard sample are calculated and analyzed to detect the damage of the serving bolts. The proposed method can solve the problem of limited detection capability of bolt damage in a complex service environment. Based on the action law of ultrasonic guided waves and bolt damage, the characteristic parameters of signals in different time periods are extracted, thereby improving the ability to detect bolt damage. It has great application value in the field of nondestructive testing and structural health monitoring.
Claims
1. An ultrasonic guided wave detection method for bolt damage in a complex environment, characterized by: The ultrasonic guided wave sensor generates and obtains ultrasonic guided wave signals; analyzes the effect of ultrasonic guided waves on damage of different lengths; extracts ultrasonic characteristic parameters of ultrasonic guided waves at different times; detects the correlation between the service bolts at different time domains and the standard specimens, and uses statistical principles to evaluate the damage status of bolts serving in complex environments.
2. The ultrasonic guided wave detection method for bolt damage serving in a complex environment according to claim 1 is characterized in that: The ultrasonic guided wave sensor generates and obtains ultrasonic guided wave signals.
3. The ultrasonic guided wave detection method for bolt damage serving in a complex environment according to claim 1 is characterized in that: Analyze the effects of ultrasonic guided waves on damage of different lengths.
4. The ultrasonic guided wave detection method for bolt damage serving in a complex environment according to claim 1 is characterized in that: The received ultrasonic guided wave signals in different time domain segments are intercepted to obtain multiple ultrasonic characteristic parameters.
5. The ultrasonic guided wave detection method for bolt damage serving in a complex environment according to claim 1 is characterized in that: Detect the correlation between ultrasonic characteristic parameters in different time periods in ultrasonic guided waves and the damage of bolts serving in complex environments.
6. The ultrasonic guided wave detection method for bolt damage in a complex environment according to claim 1, characterized in that: Based on the correlation coefficient of signals in different time domain segments, the correlation coefficient threshold is set and a damaged sample number library is established; statistical methods are used to screen samples with a high probability of damage.
7. The ultrasonic guided wave detection method for bolt damage in a complex environment according to claim 1, characterized in that: The method comprises the following steps, Step 1: Bolt sample processing; The bolt specimen used in the experiment is 250mm long, with a thread end face diameter of 16mm. The upper end face is a regular hexagon with the longest diagonal of 10mm. There is an unprocessed threaded part of 8mm in the middle of the bolt. Since the bolt end face is rough, in order to ensure the normal excitation and reception of the ultrasonic guided wave sensor, the contact end face of the bolt specimen should be polished to ensure full contact between the sensor and the bolt. Three bolts were randomly selected from the 20 service bolts for processing to simulate the damage of the bolts. Step 2: Ultrasonic guided wave testing experiment of complex bolts; A broadband ultrasonic guided wave detection experimental system is constructed, including an ultrasonic guided wave detector, a digital oscilloscope, an ultrasonic guided wave sensor and a bolt sample; the bolt sample is connected to the ultrasonic guided wave detector through the ultrasonic guided wave sensor, and the ultrasonic guided wave detector is connected to the digital oscilloscope; The experiment adopts the self-excitation and self-receiving mode, with the ultrasonic guided wave sensor as the excitation end and the receiving end. The ultrasonic guided wave sensor and the polished end face of the bolt sample are tightly connected using a coupling agent, and the center frequency is adjusted to 2MHz. The 2MHz ultrasonic guided wave sensor is used to measure two groups of standard bolt samples of different lengths to obtain the reflected echoes of the two groups of samples; the sound velocity of the ultrasonic guided wave in the bolt sample is calculated according to the wave packets of different samples and the time difference of the wave packets; and the transit time of the guided wave in the bolt for the end face reflected echo is measured. The transit time difference of 1μs is equal to the bolt length difference of 5.464mm; the detection signal is observed using a digital oscilloscope, and the ultrasonic guided wave detector is used to save the received signal; the bolts that have been in service in a complex environment are tested to obtain the corresponding ultrasonic echo signal; the guided wave detector is used to output the modulated signal and observe and save the received signal; Ultrasonic guided wave measurement is performed on the undamaged bolt specimen to obtain the corresponding guided wave signal; the service bolts that may have damage are tested to obtain the corresponding 20 sets of original signal data; with the complexity of the service environment of the bolt and the uncertainty of damage, the information contained in the guided wave signal is changing; during the transmission process, the guided wave signal passes through the objects that affect the signal propagation, such as the damaged bolt, the threadless plane in the middle of the bolt, the fixing nut, and the steel bars in the deep-buried environment of the bolt, which will generate corresponding ultrasonic guided wave echo signals; in the measurement data of the same type of bolts, the interference guided wave signals generated by the threadless plane in the middle of the fixing nut and the bolt are almost the same; therefore, it is only necessary to analyze the correlation between the original signals of the service bolt and the standard bolt specimen to obtain the correlation coefficient between the service bolt and the standard bolt specimen; Step 3: Use the new ultrasonic guided wave detection technology for bolts to analyze and process the collected data; The signals received by the guided wave detector are processed to obtain the original signals and envelope signals of different bolts. Considering the complexity of the service environment, the entire time domain signal is segmented, and the correlation coefficient of multiple signal segments is used to improve the robustness of the subsequent correlation analysis. The data is separated from 30μs to 90μs with a step size of 10μs, and 6 groups of data are intercepted. A data set is established to draw a correlation scatter plot. For the correlation data of different time periods, damage judgment criteria for different time periods are formulated. According to different time periods, the correlation is less than 0.15 in 30μs-90μs, which is considered to be a possible damage; the correlation is less than 0.15 in 40μs-90μs, which is considered to be a possible damage; the correlation is less than 0. 15 is considered to be possible damage; in 60μs-90μs, a correlation lower than 0.15 is considered to be possible damage; in 70μs-90μs, a correlation lower than 0.15 is considered to be possible damage; in 80μs-90μs, a correlation lower than 0.15 is considered to be possible damage; based on the number of times the tested bolts have problems in different data sets as the standard, a number of occurrences less than or equal to 2 is considered to be a low-probability problem, a number of occurrences between 3 and 5 is considered to be a medium-probability problem, and a number of occurrences greater than or equal to 5 is considered to be a high-probability problem; applying statistical principles, a comprehensive damage assessment was conducted on the 20 service bolts tested with three evaluation levels of high, medium and low, and it was measured that No. 14, No. 18, and No. 19 were bolts with high probability of damage, which are consistent with the numbers of artificially processed damaged bolts.