Concrete filled steel tube quality detection method based on ultrasonic guided waves

Abstract

The invention relates to the technical field of nondestructive testing, and provides a concrete filled steel tube quality detection method based on ultrasonic guided waves, which comprises the following steps: collecting guided wave amplitudes of a quality detection position of a concrete filled steel tube member under different primary selection frequencies, and determining a guided wave sequence and a frequency spectrum sequence of the primary selection frequencies; defining a target primary selection frequency, determining the loss degree of the target primary selection frequency, determining the dominant frequency of the target primary selection frequency and the adjacent spectrum amplitude of the dominant frequency according to the guided wave sequence and the spectrum sequence, and further determining the frequency response matching degree of the target primary selection frequency; determining a matching degree threshold according to the numerical distribution of the frequency response matching degrees of all the primary frequencies, and screening out all the final detection frequencies according to the values of the frequency response matching degrees and the matching degree threshold; and obtaining a quality detection result of the quality detection position according to all the final detection frequencies screened out from the quality detection position and the frequency response matching degree of the final detection frequencies. The invention aims to improve the precision of concrete filled steel tube quality detection.

Description

Technical Field

[0001] The invention relates to the technical field of nondestructive testing, and in particular to a quality testing method for steel tube concrete based on ultrasonic guided waves. Background Art

[0002] Steel tube concrete components are widely used in industrial plants, equipment structure columns, high-rise buildings and other buildings. However, steel tube concrete components will inevitably produce stress accumulation under long-term pressure. When the stress accumulation is too large, the bearing capacity and quality of the steel tube concrete components will be affected, which may cause cracks or other damage to the steel tube concrete components. Therefore, it is necessary to regularly inspect steel tube concrete components and repair and reinforce the damaged locations. Ultrasonic guided wave technology can be used to judge the damage condition inside the steel tube concrete component based on the response characteristics of ultrasonic guided waves.

[0003] The garbage incineration plant is a single-story or multi-story industrial plant with a high main structure and a large span. The interior is composed of steel tube concrete components of various sizes, and the connection structure between the steel tube concrete components is relatively complex, which makes the stress changes in different positions of the steel tube concrete more complicated. The detection accuracy of ultrasonic guided waves of different frequencies is affected to different degrees by the stress state of the steel tube concrete. The ultrasonic guided wave technology generally uses ultrasonic guided waves of fixed frequency, ignoring the complex stress changes of steel tube concrete components in garbage incineration plants, and the accuracy of steel tube concrete quality detection is often insufficient. Summary of the invention

[0004] The present invention provides a steel tube concrete quality detection method based on ultrasonic guided waves to solve the problem that the stress difference at different positions of the steel tube concrete structure has different frequency responses to ultrasonic guided waves, resulting in insufficient accuracy of steel tube concrete quality detection. The technical scheme adopted is as follows: An embodiment of the present invention provides a method for detecting quality of steel tube concrete based on ultrasonic guided waves, the method comprising the following steps: Collect the guided wave amplitudes at a preset number of different primary selected frequencies at any quality inspection position of the steel tube concrete component, and determine the guided wave sequence and spectrum sequence of the primary selected frequency according to the guided wave amplitudes at the same primary selected frequency; Record any one of the preliminary selected frequencies as the target preliminary selected frequency, determine the loss degree of the target preliminary selected frequency according to the difference between the waveguide amplitudes contained in different subsequences divided from the spectrum sequence of the target preliminary selected frequency, determine the main frequency of the target preliminary selected frequency and the adjacent spectrum amplitude of the main frequency according to the waveguide sequence and the spectrum sequence, determine the frequency response matching degree of the target preliminary selected frequency according to the difference between the main frequency of the target preliminary selected frequency and all adjacent spectrum amplitudes of the main frequency, the difference between all values ​​in the spectrum sequence of the target preliminary selected frequency that are not adjacent spectrum amplitudes, and the loss degree of the target preliminary selected frequency; According to the numerical distribution of the frequency response matching degrees of all the preliminarily selected frequencies, a matching degree threshold is determined, and according to the values ​​of the frequency response matching degrees and the matching degree threshold, all the final detection frequencies are screened out; The quality detection result of the quality detection position is obtained according to the frequency response matching degree of all final detection frequencies screened out at the quality detection position and the final detection frequency.

[0005] Further, the loss degree of the target primary selected frequency is determined based on the difference between the waveguide amplitudes contained in different subsequences divided from the spectrum sequence of the target primary selected frequency, including the specific method of: The spectrum sequence of the target preliminary frequency is equally divided into a first preset threshold number of spectrum subsequences, and the root mean square of all guided wave amplitudes contained in any spectrum subsequence divided from the spectrum sequence of the target preliminary frequency is recorded as the discreteness of any spectrum subsequence; The loss degree of the target primary frequency is determined according to the difference and value distribution between the discrete degrees of all spectrum subsequences divided from the spectrum sequence of the target primary frequency.

[0006] Furthermore, the loss degree of the target primary selected frequency is determined based on the difference and value distribution between the discreteness of all spectrum subsequences divided from the spectrum sequence of the target primary selected frequency, including the specific method of: The maximum value of the discreteness of all the spectrum subsequences divided from the spectrum sequence of the target primary frequency is recorded as the maximum discreteness, and the mean value of the discreteness of all the spectrum subsequences divided from the spectrum sequence of the target primary frequency is recorded as the average discreteness of the target primary frequency; The difference between the maximum discreteness and the discreteness of the spectrum subsequence is recorded as the discreteness difference of the spectrum subsequence, and the cumulative sum of the discreteness differences of all spectrum subsequences divided from the spectrum sequence of the target primary frequency is recorded as the cumulative discreteness difference of the target primary frequency; The ratio of the cumulative difference in the dispersion of the target primary frequency to the average dispersion is recorded as the loss degree of the target primary frequency.

[0007] Furthermore, the method for determining the amplitude of the main frequency and the adjacent spectrum of the main frequency of the target primary frequency is as follows: The largest value in the frequency spectrum sequence of the target primary selected frequency is recorded as the main frequency of the target primary selected frequency; A window with a length of the second preset threshold value is established with the main frequency of the target preliminary frequency as the center, and all values ​​in the spectrum sequence of the target preliminary frequency within the window are recorded as the adjacent spectrum amplitudes of the main frequency of the target preliminary frequency.

[0008] Further, the frequency response matching degree of the target preliminary selected frequency is determined according to the difference between the main frequency of the target preliminary selected frequency and all adjacent spectrum amplitudes of the main frequency, the difference between all values ​​in the spectrum sequence of the target preliminary selected frequency that are not adjacent spectrum amplitudes, and the loss degree of the target preliminary selected frequency, including the specific method of: The sum of the differences between the main frequency of the target primary frequency and all the adjacent spectrum amplitudes of the main frequency is recorded as the main frequency difference of the target primary frequency; The standard deviation of all values ​​of the adjacent spectrum amplitudes except the main frequency in the spectrum sequence of the target primary frequency is recorded as the non-main frequency difference of the target primary frequency; The frequency response matching degree of the target primary selected frequency is determined according to the main frequency difference, non-main frequency difference and loss degree of the target primary selected frequency.

[0009] Further, the frequency response matching degree of the target primary selected frequency is determined according to the main frequency difference, non-main frequency difference and loss degree of the target primary selected frequency, and the specific method includes: The product of the main frequency difference and the non-main frequency difference of the target primary frequency is recorded as the first product of the target primary frequency; The ratio of the first product of the target preliminary frequency and the loss degree is recorded as the frequency response matching degree of the target preliminary frequency.

[0010] Furthermore, the calculation formula of the matching degree threshold is: in, represents the matching threshold; It represents the minimum value of the frequency response matching of all the primary selected frequencies; Indicates the extreme difference in frequency response matching of all the primary selected frequencies; represents the variance of the frequency response matching of all the primary frequencies; represents the mean of the frequency response matching of all the primary selected frequencies; represents the first tuning parameter coefficient; Represents the normalization function.

[0011] Further, the screening method of the final detection frequency is: All the preliminarily selected frequencies whose frequency response matching degree is greater than or equal to the matching degree threshold are recorded as the final detection frequencies.

[0012] Further, the quality detection result of the quality detection position is obtained according to the frequency response matching degree of all the final detection frequencies screened out at the quality detection position and the final detection frequency, and the specific method includes: The guided wave velocity, the first wave amplitude, the main frequency amplitude, the weighted spectrum area and the nonlinear coefficient are used as the guided wave detection parameters corresponding to the final detection frequency; All final detection frequencies corresponding to the quality detection positions of 1000 steel tube concrete components with known quality detection results, waveguide detection parameters of the final detection frequencies, frequency response matching of the final detection frequencies, and quality detection results of the quality detection positions are used as training sets, and the frequency response matching of the final detection frequencies is used as the waveguide feature value of the decision tree of the random forest algorithm. The random forest is trained to obtain a quality detection model, wherein all final detection frequencies corresponding to the quality detection positions and the waveguide detection parameters of the final detection frequencies are input into the quality detection model to obtain a decision value of the quality detection result, and the decision value of the quality detection result is -1 or 1; Input all final detection frequencies of the quality detection position and the waveguide detection parameters of the final detection frequencies into the quality detection model, obtain the decision values ​​corresponding to all the final detection frequencies of the quality detection position, and obtain 5 waveguide eigenvalues ​​extracted by the decision tree of the random forest algorithm corresponding to each final detection frequency, and record the product of the cumulative sum of all the waveguide eigenvalues ​​corresponding to the final detection frequency and the decision value of the final detection frequency as the frequency characteristic decision value of the final detection frequency; The cumulative sum of the frequency characteristic decision values ​​of all final detection frequencies screened out at the quality detection position of the steel tube concrete component is recorded as the quality judgment value of the quality detection position; According to the quality judgment value of the quality detection position, the quality detection result of the quality detection position is obtained.

[0013] Further, the method of obtaining the quality detection result of the quality detection position according to the quality judgment value of the quality detection position includes the following specific methods: When the quality judgment value of the quality detection position is greater than or equal to 0, there is no quality problem at the quality detection position; When the quality judgment value of the quality detection position is less than 0, there is a quality problem at the quality detection position.

[0014] The beneficial effects of the present invention are: The present application takes into account the energy information of the waveguide expressed by the waveguide amplitude contained in the waveguide sequence, directly determines the accuracy of the steel pipe quality inspection of the primary selected frequency corresponding to the waveguide sequence, evaluates the strength of the waveguide energy information expressed by the waveguide amplitude contained in the waveguide sequence, and determines the loss degree of the target primary selected frequency. The greater the energy of the waveguide collected at the primary selected frequency, the less the loss caused by the quality inspection position of the steel tube concrete component, and the smaller the loss degree of the primary selected frequency. The frequency spectrum sequence of the primary selected frequency reflects the sensitivity characteristics of the frequency response of the steel tube concrete component to the waveguide of the primary selected frequency, and determines the frequency response matching degree of the target primary selected frequency. When the target primary selected frequency is selected to have a smaller loss of the main frequency energy of the waveguide, the more damage information contained in the spectrum sequence obtained by the target primary selected frequency is selected. The richer the quality inspection results of steel tube concrete, the more accurate they are, and the more sensitive they are to the internal damage in the quality inspection position. At this time, the greater the frequency response matching degree of the preliminary selected frequency is. According to the numerical distribution of the frequency response matching degrees of all the preliminary selected frequencies, all the final inspection frequencies are screened out from both the time domain and the frequency domain to improve the accuracy and reliability of the frequency values ​​for quality inspection at the current quality inspection position of the steel tube concrete component. According to the frequency response matching degrees of all the final inspection frequencies screened out at the quality inspection position and the final inspection frequency, the quality inspection results of the quality inspection position are obtained, so as to solve the problem that the stress difference at different positions of the steel tube concrete structure has different frequency responses to ultrasonic guided waves, resulting in insufficient accuracy of steel tube concrete quality inspection, and improve the accuracy of steel tube concrete quality inspection. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0016] Figure 1 A schematic flow chart of a method for quality detection of concrete-filled steel tubes based on ultrasonic guided waves provided by one embodiment of the present invention; Figure 2 A flow chart of loss degree acquisition provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] See also Figure 1 , which shows a flow chart of a method for quality detection of steel tube concrete based on ultrasonic guided waves provided by an embodiment of the present invention, the method comprising the following steps: Step S001, collecting the guided wave amplitudes of any quality inspection position of the steel tube concrete component at a preset number of different primary selected frequencies, and determining the guided wave sequence and spectrum sequence of the primary selected frequency according to the guided wave amplitudes at the same primary selected frequency.

[0019] The connection structure between steel tube concrete components is relatively complex, which makes the stress changes in different positions of steel tube concrete relatively complex. Therefore, steel tube concrete components contain multiple positions that require quality inspection. The positions and specific number of steel tube concrete components that require quality inspection are determined by the engineers performing quality inspection.

[0020] For any quality inspection position of the steel tube concrete component, two planar transducer probes of the ultrasonic detector are respectively arranged on two opposite sides of the quality inspection position of the steel tube concrete component, so that the propagation path of the ultrasonic guided wave of the ultrasonic detector is along the direction of the axis of the steel tube concrete component, and the width of the steel tube concrete component between the two planar transducer probes is measured, and the width is input into the ultrasonic detector, which can automatically output the guided wave velocity according to the emitted ultrasonic guided wave.

[0021] The frequency variation range of the ultrasonic detector transmitting guided waves is , in the frequency change range, starting from 50kHz, the instrument collects a primary frequency every 10kHz, and a total of 21 primary frequencies are collected.

[0022] Use the planar transducer probe of the ultrasonic detector to transmit ultrasonic guided waves of each primary selected frequency in sequence, and use the planar transducer probe at the receiving end of the ultrasonic detector to collect the guided wave amplitude corresponding to each primary selected frequency, arrange all the guided wave amplitudes corresponding to the same primary selected frequency in the order of collection, and obtain the guided wave sequence of the same primary selected frequency.

[0023] In this embodiment, the frequency of the ultrasonic guided waves collected by the planar transducer probe at the pre-selected frequency is set to 1 MHz, and the number of guided wave amplitudes included in the guided wave sequence at the pre-selected frequency is set to 2048.

[0024] The waveguide sequence of the primary selected frequency is processed by using fast Fourier transform to obtain the spectrum sequence of the primary selected frequency.

[0025] It can be understood that the values ​​included in the spectrum sequence of the primary selected frequency are the guided wave amplitudes.

[0026] At this point, the guided wave sequence and spectrum sequence of the quality inspection position of the steel tube concrete component at the primary selected frequency are obtained.

[0027] Step S002, record any one of the preliminary frequencies as the target preliminary frequency, determine the loss degree of the target preliminary frequency according to the difference between the waveguide amplitudes contained in different subsequences divided from the spectrum sequence of the target preliminary frequency, determine the main frequency of the target preliminary frequency and the adjacent spectrum amplitude of the main frequency according to the waveguide sequence and the spectrum sequence, determine the frequency response matching degree of the target preliminary frequency according to the difference between the main frequency of the target preliminary frequency and all adjacent spectrum amplitudes of the main frequency, the difference between all values ​​in the spectrum sequence of the target preliminary frequency that are not adjacent spectrum amplitudes, and the loss degree of the target preliminary frequency.

[0028] The energy information of the waveguide expressed by the waveguide amplitude contained in the waveguide sequence directly determines the accuracy of the primary frequency corresponding to the waveguide sequence for steel pipe quality detection. When the energy information of the waveguide is weak, the more serious the energy loss of the waveguide inside the steel tube concrete, the more vague the energy information of the waveguide expressed by the waveguide amplitude contained in the waveguide sequence, and the less reliable the obtained steel pipe quality detection result.

[0029] Any primary selected frequency is recorded as the target primary selected frequency, and the spectrum sequence of the target primary selected frequency is divided into R spectrum subsequences. Different spectrum subsequences correspond to energy distribution information of ultrasonic guided waves in different time periods.

[0030] Among them, R represents the first preset threshold value. In this embodiment, the value of the first preset threshold value is 16, that is, the 1st to 128th guided wave amplitudes in the spectrum sequence of the target preliminary frequency are arranged in the order of collection to obtain the first spectrum sub-sequence, the 129th to 256th guided wave amplitudes in the spectrum sequence of the target preliminary frequency are arranged in the order of collection to obtain the second spectrum sub-sequence, the 257th to 384th guided wave amplitudes in the spectrum sequence of the target preliminary frequency are arranged in the order of collection to obtain the third spectrum sub-sequence, and so on, a total of 16 spectrum sub-sequences are obtained.

[0031] The loss degree of the target primary selected frequency is determined according to the difference between the root mean squares of the guided wave amplitudes contained in different spectrum subsequences divided from the spectrum sequence of the target primary selected frequency.

[0032] Preferably, as an embodiment of the present application, the root mean square of all waveguide amplitudes contained in any spectrum subsequence divided from the spectrum sequence of the target primary frequency is recorded as the discreteness of the any spectrum subsequence, the maximum value of the discreteness of all spectrum subsequences divided from the spectrum sequence of the target primary frequency is recorded as the maximum discreteness, and the mean value of the discreteness of all spectrum subsequences divided from the spectrum sequence of the target primary frequency is recorded as the average discreteness of the target primary frequency; the difference between the maximum discreteness and the discreteness of the spectrum subsequence is recorded as the discreteness difference of the spectrum subsequence, the cumulative sum of the discreteness differences of all spectrum subsequences divided from the spectrum sequence of the target primary frequency is recorded as the cumulative discreteness difference of the target primary frequency; the ratio of the cumulative discreteness difference of the target primary frequency to the average discreteness is recorded as the loss degree of the target primary frequency.

[0033] The loss degree of any primary selected frequency can be obtained in the same way.

[0034] The loss calculation formula for any primary frequency is: in, Indicates the frequency of primary elections The loss degree; Indicates the frequency of primary elections The average dispersion of Indicates the frequency of primary elections The number of spectrum subsequences divided from the spectrum sequence is The value of is 16; Indicates the frequency of primary elections The maximum discreteness of Indicates the frequency of primary elections The spectrum sequence is divided into The discreteness of a spectral subsequence.

[0035] When the ultrasonic detector emits guided waves at different primary frequencies, the guided wave amplitudes are the same. After passing through the same quality inspection position of the steel tube concrete component, the steel tube concrete component has different degrees of energy dissipation of the guided waves of different primary frequencies. Therefore, the guided wave sequences collected at different primary frequencies are different. The spectrum subsequences divided from the spectrum sequence of the primary frequency correspond to the energy distribution information of the ultrasonic guided waves in different time periods. When the average discreteness of the primary frequency is larger, the energy of the guided waves collected at the primary frequency is larger, and the loss caused by passing through the quality inspection position of the steel tube concrete component is smaller. At this time, the loss degree of the primary frequency is smaller. At the same time, when the difference in the discreteness of the spectrum subsequences divided from the spectrum sequence of the primary frequency is smaller, the loss caused by passing through the quality inspection position of the steel tube concrete component is also smaller. At this time, the loss degree of the primary frequency is smaller.

[0036] The loss degree acquisition flow chart is as follows Figure 2 shown.

[0037] The garbage incineration plant is a single-story or multi-story industrial plant with a high main structure and a large span. The interior is composed of steel tube concrete components of various sizes, and the connection structure between the steel tube concrete components is relatively complex, which makes the stress changes in different positions of the steel tube concrete relatively complex. The guided waves emitted by the ultrasonic detector at different primary frequencies will also be affected by the stress state of the steel tube concrete. When the primary frequencies are different, the dispersion degree of the steel tube concrete components to the guided waves of different primary frequencies is different, and the sensitivity response degree of different primary frequencies to different damages is different. The spectrum sequence of the primary frequency reflects the frequency response of the steel tube concrete components to the guided waves of the primary frequency.

[0038] The largest value in the spectrum sequence of the target primary frequency is recorded as the main frequency of the target primary frequency. With the main frequency of the target primary frequency as the center, a length of The window is used to record all the values ​​in the frequency spectrum sequence of the target preliminary frequency within the window as the adjacent frequency spectrum amplitude of the main frequency of the target preliminary frequency. represents the second preset threshold. In this embodiment, the value of the second preset threshold is 21.

[0039] When the value contained in the window established with the main frequency of the target primary frequency as the center is less than the second preset threshold, only the value contained in the window established with the main frequency of the target primary frequency as the center is calculated as follows, and the number of values ​​contained in the window established with the main frequency of the target primary frequency as the center is recorded as ,but The value of is less than or equal to the second preset threshold.

[0040] The frequency response matching degree of the target primary frequency is determined based on the difference between the main frequency of the target primary frequency and all adjacent spectrum amplitudes of the main frequency, the difference between all values ​​in the spectrum sequence of the target primary frequency that are not adjacent spectrum amplitudes, and the loss degree of the target primary frequency.

[0041] Preferably, as an embodiment of the present application, the cumulative sum of the differences between the main frequency of the target primary frequency and all adjacent spectrum amplitudes of the main frequency is recorded as the main frequency difference of the target primary frequency; the standard deviation of all numerical values ​​of the adjacent spectrum amplitudes of the main frequency in the spectrum sequence of the target primary frequency excluding the main frequency is recorded as the non-main frequency difference of the target primary frequency; the product of the main frequency difference and the non-main frequency difference of the target primary frequency is recorded as the first product of the target primary frequency, and the ratio of the first product of the target primary frequency to the loss degree is recorded as the frequency response matching degree of the target primary frequency.

[0042] The frequency response matching degree of any primary selected frequency can be obtained in the same way.

[0043] The calculation formula for the frequency response matching degree of any primary selected frequency is: in, Indicates the frequency of primary elections Frequency response matching; Indicates the frequency of primary elections Non-main frequency differences; Indicates the frequency of primary elections The loss degree; Indicates the frequency of primary elections The number of values ​​contained in the window established with the main frequency as the center; Indicates the frequency of primary elections The main frequency; Indicates the frequency of primary elections The main frequency of adjacent spectrum amplitudes.

[0044] When the natural frequency of the damaged structure appearing in the quality inspection position of the steel tube concrete component or the natural frequency of the quality inspection position itself is closer to the frequency of the guided wave, the main frequency energy loss of the guided wave emitted by the ultrasonic detector is smaller, and at the same time, the energy loss difference of the other frequency clutter is larger, the damage information contained in the spectrum sequence obtained by the guided wave is richer, and the result obtained by selecting the primary frequency corresponding to the guided wave for the steel tube concrete quality inspection is more accurate. Therefore, when the difference between the main frequency of the target primary frequency and all the adjacent spectrum amplitudes of the main frequency is larger, the difference between all the values ​​that are not adjacent spectrum amplitudes in the spectrum sequence of the target primary frequency is larger, and the loss of the primary frequency is smaller, the main frequency energy loss of the selected target primary frequency to the guided wave is smaller, the damage information contained in the spectrum sequence obtained by selecting the target primary frequency is richer, the result obtained by the steel tube concrete quality inspection is more accurate, and the internal damage in the quality inspection position is more sensitive. At this time, the frequency response matching degree of the primary frequency is greater.

[0045] At this point, the frequency response matching of all the preliminarily selected frequencies is obtained.

[0046] Step S003: determine a matching degree threshold value according to the numerical distribution of the frequency response matching degrees of all the preliminarily selected frequencies, and screen out all the final detection frequencies according to the values ​​of the frequency response matching degrees and the matching degree threshold value.

[0047] According to the numerical distribution of the frequency response matching degree of all the primary selected frequencies, the matching degree threshold is determined. The calculation formula of the matching degree threshold is: in, represents the matching threshold; It represents the minimum value of the frequency response matching of all the primary selected frequencies; Indicates the extreme difference in frequency response matching of all the primary selected frequencies; represents the variance of the frequency response matching of all the primary frequencies; represents the mean of the frequency response matching of all the primary selected frequencies; represents the first parameter adjustment coefficient, which is used to prevent the denominator from being 0. In this embodiment, the value of the first parameter adjustment coefficient is 0.01; Represents a normalization function, which is used to obtain the normalized value of the value in brackets.

[0048] It should be noted that this embodiment uses the Z-Score standard normalization method to calculate the normalized value. In actual application, the implementer may use other methods in the prior art such as the maximum and minimum value normalization method, the sigmoid function, etc. to calculate the normalized value, which is not limited here.

[0049] When the range and variance of the frequency response matching of all the primary frequencies are larger, the difference in sensitivity of different primary frequency values ​​to steel tube concrete damage detection is greater. A larger matching threshold should be set to screen out the primary frequencies with poor detection performance and improve the accuracy of steel tube concrete quality detection. When the mean of the frequency response matching of all the primary frequencies is larger, the overall sensitivity of different primary frequencies to steel tube concrete damage detection is greater. A smaller matching threshold is set to select more frequency waveguides to monitor the quality of steel tube concrete and enhance the reliability of quality detection.

[0050] All the preliminarily selected frequencies whose frequency response matching degree is greater than or equal to the matching degree threshold are recorded as the final detection frequency. The final detection frequency can be used as the frequency value for quality detection of the current quality detection position of the steel tube concrete component.

[0051] In summary, all final detection frequencies are determined.

[0052] Step S004: Acquire the quality detection result of the quality detection position according to all final detection frequencies screened out at the quality detection position and the frequency response matching degree of the final detection frequency.

[0053] The guided wave velocity, first wave amplitude, main frequency amplitude, weighted spectral area and nonlinear coefficient are five commonly used guided wave detection parameters. These guided wave detection parameters are all known parameters. Specifically, the ultrasonic detector can automatically output the guided wave velocity according to the emitted ultrasonic guided wave. The first wave amplitude is the maximum value of the guided wave amplitude in the first spectrum subsequence divided by the guided wave sequence, the main frequency amplitude is the spectrum amplitude of the main frequency of the spectrum sequence, the weighted spectral area is the cumulative sum of all spectrum amplitudes in the spectrum sequence, and the nonlinear coefficient is the ratio of the spectrum amplitude of twice the main frequency to the square of the spectrum amplitude of the main frequency.

[0054] Each final detection frequency corresponds to five guided wave detection parameters, and each quality detection position of a concrete-filled steel tube component may correspond to multiple final detection frequencies or one final detection frequency.

[0055] All final inspection frequencies corresponding to the quality inspection positions of 1000 steel tube concrete components with known quality inspection results, waveguide inspection parameters of the final inspection frequencies, frequency response matching of the final inspection frequencies, and quality inspection results of the quality inspection positions are used as training sets, and the frequency response matching of the final inspection frequencies is used as the waveguide feature value of the decision tree of the random forest algorithm. The random forest is trained to obtain a quality inspection model. All final inspection frequencies corresponding to the quality inspection positions and the waveguide inspection parameters of the final inspection frequencies are input into the quality inspection model to obtain the decision value of the quality inspection result. The decision value of the quality inspection result is -1 or 1, where the decision value of the quality inspection result is -1, indicating that there is a quality problem at the quality inspection position, and the decision value of the quality inspection result is 1, indicating that there is no quality problem at the quality inspection position.

[0056] Among them, the number of decision trees of the random forest algorithm is 100, the number of waveguide features randomly selected by each decision tree is 5, and it is a well-known technology to train the random forest using the training set to obtain the quality detection model, which will not be repeated here.

[0057] All final detection frequencies of the quality detection position and the waveguide detection parameters of the final detection frequencies are input into the quality detection model to obtain the decision values ​​corresponding to all the final detection frequencies of the quality detection position. At the same time, 5 waveguide eigenvalues ​​extracted by the decision tree of the random forest algorithm corresponding to each final detection frequency are obtained, and the cumulative sum of all waveguide eigenvalues ​​corresponding to the final detection frequency and the product of the decision value of the final detection frequency are recorded as the frequency characteristic decision value of the final detection frequency.

[0058] The cumulative sum of the frequency characteristic decision values ​​of all final detection frequencies screened out at the quality detection position of the steel tube concrete component is recorded as the quality judgment value of the quality detection position.

[0059] When the quality judgment value of the quality detection position is greater than or equal to 0, there is no quality problem at the quality detection position; when the quality judgment value of the quality detection position is less than 0, there is a quality problem at the quality detection position, and an alarm signal is sent to the buzzer for alarm.

[0060] At this point, the quality inspection results of steel tube concrete based on ultrasonic guided waves are obtained.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A quality detection method for steel tube concrete based on ultrasonic guided waves, characterized in that: The method comprises the following steps: Collect the guided wave amplitudes at a preset number of different primary selected frequencies at any quality inspection position of the steel tube concrete component, and determine the guided wave sequence and spectrum sequence of the primary selected frequency according to the guided wave amplitudes at the same primary selected frequency; Record any one of the preliminary selected frequencies as the target preliminary selected frequency, determine the loss degree of the target preliminary selected frequency according to the difference between the waveguide amplitudes contained in different subsequences divided from the spectrum sequence of the target preliminary selected frequency, determine the main frequency of the target preliminary selected frequency and the adjacent spectrum amplitude of the main frequency according to the waveguide sequence and the spectrum sequence, determine the frequency response matching degree of the target preliminary selected frequency according to the difference between the main frequency of the target preliminary selected frequency and all adjacent spectrum amplitudes of the main frequency, the difference between all values ​​in the spectrum sequence of the target preliminary selected frequency that are not adjacent spectrum amplitudes, and the loss degree of the target preliminary selected frequency; According to the numerical distribution of the frequency response matching degrees of all the preliminarily selected frequencies, a matching degree threshold is determined, and according to the values ​​of the frequency response matching degrees and the matching degree threshold, all the final detection frequencies are screened out; The quality detection result of the quality detection position is obtained according to the frequency response matching degree of all final detection frequencies screened out at the quality detection position and the final detection frequency.

2. The method for quality detection of steel tube concrete based on ultrasonic guided waves according to claim 1 is characterized in that: The loss degree of the target primary selected frequency is determined based on the difference between the guided wave amplitudes contained in different subsequences divided from the spectrum sequence of the target primary selected frequency, and the specific method includes: The spectrum sequence of the target preliminary frequency is equally divided into a first preset threshold number of spectrum subsequences, and the root mean square of all guided wave amplitudes contained in any spectrum subsequence divided from the spectrum sequence of the target preliminary frequency is recorded as the discreteness of any spectrum subsequence; The loss degree of the target primary frequency is determined according to the difference and value distribution between the discrete degrees of all spectrum subsequences divided from the spectrum sequence of the target primary frequency.

3. The method for quality detection of steel tube concrete based on ultrasonic guided waves according to claim 2 is characterized in that: The method of determining the loss degree of the target primary frequency based on the difference and value distribution between the discrete degrees of all spectrum subsequences divided from the spectrum sequence of the target primary frequency includes the following specific methods: The maximum value of the discreteness of all the spectrum subsequences divided from the spectrum sequence of the target primary frequency is recorded as the maximum discreteness, and the mean value of the discreteness of all the spectrum subsequences divided from the spectrum sequence of the target primary frequency is recorded as the average discreteness of the target primary frequency; The difference between the maximum discreteness and the discreteness of the spectrum subsequence is recorded as the discreteness difference of the spectrum subsequence, and the cumulative sum of the discreteness differences of all spectrum subsequences divided from the spectrum sequence of the target primary frequency is recorded as the cumulative discreteness difference of the target primary frequency; The ratio of the cumulative difference in the dispersion of the target primary frequency to the average dispersion is recorded as the loss degree of the target primary frequency.

4. The method for quality detection of steel tube concrete based on ultrasonic guided waves according to claim 1 is characterized in that: The method for determining the amplitude of the main frequency and the adjacent spectrum of the main frequency of the target primary frequency is as follows: The largest value in the frequency spectrum sequence of the target primary selected frequency is recorded as the main frequency of the target primary selected frequency; A window with a length of the second preset threshold value is established with the main frequency of the target preliminary frequency as the center, and all values ​​in the spectrum sequence of the target preliminary frequency within the window are recorded as the adjacent spectrum amplitudes of the main frequency of the target preliminary frequency.

5. The method for quality inspection of concrete-filled steel tubes based on ultrasonic guided waves according to claim 1, characterized in that: The method of determining the frequency response matching degree of the target primary selected frequency according to the difference between the main frequency of the target primary selected frequency and all adjacent spectrum amplitudes of the main frequency, the difference between all values ​​in the spectrum sequence of the target primary selected frequency that are not adjacent spectrum amplitudes, and the loss degree of the target primary selected frequency includes the following specific methods: The sum of the differences between the main frequency of the target primary frequency and all the adjacent spectrum amplitudes of the main frequency is recorded as the main frequency difference of the target primary frequency; The standard deviation of all values ​​of the adjacent spectrum amplitudes except the main frequency in the spectrum sequence of the target primary frequency is recorded as the non-main frequency difference of the target primary frequency; The frequency response matching degree of the target primary selected frequency is determined according to the main frequency difference, non-main frequency difference and loss degree of the target primary selected frequency.

6. The method for quality inspection of concrete-filled steel tubes based on ultrasonic guided waves according to claim 5, characterized in that: The method of determining the frequency response matching degree of the target primary selected frequency according to the main frequency difference, non-main frequency difference and loss degree of the target primary selected frequency includes: The product of the main frequency difference and the non-main frequency difference of the target primary frequency is recorded as the first product of the target primary frequency; The ratio of the first product of the target preliminary frequency and the loss degree is recorded as the frequency response matching degree of the target preliminary frequency.

7. The method for quality inspection of steel tube concrete based on ultrasonic guided waves according to claim 1, characterized in that: The calculation formula of the matching degree threshold is: in, represents the matching threshold; It represents the minimum value of the frequency response matching of all the primary selected frequencies; Indicates the extreme difference in frequency response matching of all the primary frequencies; represents the variance of the frequency response matching of all the primary frequencies; represents the mean of the frequency response matching of all the primary selected frequencies; represents the first tuning parameter coefficient; Represents the normalization function.

8. The method for quality inspection of concrete-filled steel tubes based on ultrasonic guided waves according to claim 1, characterized in that: The screening method of the final detection frequency is: All the preliminarily selected frequencies whose frequency response matching degree is greater than or equal to the matching degree threshold are recorded as the final detection frequencies.

9. The method for quality inspection of concrete-filled steel tubes based on ultrasonic guided waves according to claim 1, characterized in that: The method of obtaining the quality detection result of the quality detection position according to the frequency response matching degree of all the final detection frequencies screened out at the quality detection position and the final detection frequency includes the following specific methods: The guided wave velocity, the first wave amplitude, the main frequency amplitude, the weighted spectrum area and the nonlinear coefficient are used as the guided wave detection parameters corresponding to the final detection frequency; All final detection frequencies corresponding to the quality detection positions of 1000 steel tube concrete components with known quality detection results, waveguide detection parameters of the final detection frequencies, frequency response matching of the final detection frequencies, and quality detection results of the quality detection positions are used as training sets, and the frequency response matching of the final detection frequencies is used as the waveguide feature value of the decision tree of the random forest algorithm. The random forest is trained to obtain a quality detection model, wherein all final detection frequencies corresponding to the quality detection positions and the waveguide detection parameters of the final detection frequencies are input into the quality detection model to obtain a decision value of the quality detection result, and the decision value of the quality detection result is -1 or 1; Input all final detection frequencies of the quality detection position and the waveguide detection parameters of the final detection frequencies into the quality detection model, obtain the decision values ​​corresponding to all the final detection frequencies of the quality detection position, and obtain 5 waveguide eigenvalues ​​extracted by the decision tree of the random forest algorithm corresponding to each final detection frequency, and record the product of the cumulative sum of all the waveguide eigenvalues ​​corresponding to the final detection frequency and the decision value of the final detection frequency as the frequency characteristic decision value of the final detection frequency; The cumulative sum of the frequency characteristic decision values ​​of all final detection frequencies screened out at the quality detection position of the steel tube concrete component is recorded as the quality judgment value of the quality detection position; According to the quality judgment value of the quality detection position, the quality detection result of the quality detection position is obtained.

10. The method for quality inspection of concrete-filled steel tubes based on ultrasonic guided waves according to claim 9, characterized in that: The specific method of obtaining the quality detection result of the quality detection position according to the quality judgment value of the quality detection position includes: When the quality judgment value of the quality detection position is greater than or equal to 0, there is no quality problem at the quality detection position; When the quality judgment value of the quality detection position is less than 0, there is a quality problem at the quality detection position.

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