Ultrasonic testing method for debonding of tank curved sidewall lining

Abstract

The present application relates to the ultrasonic detection method suitable for the debonding of the curved side wall lining of the storage tank, comprising: obtaining the maximum amplitude of the interface wave and the maximum amplitude of the bottom wave in the ultrasonic detection signal corresponding to each step of the test block, using the fitting relationship to obtain the relationship satisfied by the maximum amplitude of the interface wave and the maximum amplitude of the bottom wave respectively; then, obtaining the maximum amplitude of the interface wave, the maximum amplitude of the bottom wave and the thickness value of each position in the detected area, and substituting all the thickness average values and the thickness values of each position in the detected area into the corresponding relationship; finally, calculating the bonding quality evaluation index according to the calculation result substituted into the relationship, comparing the bonding quality evaluation index with the preset bonding quality evaluation index threshold, and obtaining the debonding result of the detected area. According to the calibrated relationship, the method can correct the influence of surface curvature change and poor coupling on the detection structure, is easy to realize automatic detection, convenient to operate and high in automation degree.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic testing technology, and in particular to an ultrasonic testing method suitable for detecting the debonding of the inner lining of the curved sidewall of a storage tank. Background Technology

[0002] Hydrochloric acid, sodium hydroxide, sodium hypochlorite, and other acidic and alkaline hazardous chemicals are commonly used industrial consumables in energy and chemical industrial parks. Due to their strong corrosive and oxidizing properties, they are often stored in steel metal tanks lined with plastic (or rubber). With increasing service life, the performance of the lining gradually declines, leading to aging, loosening, perforation, and even detachment. The service life of the lining is significantly reduced under the influence of factors such as the usage environment, corrosiveness, temperature, and intensity of use. Therefore, achieving non-destructive testing of the lining quality of acidic and alkaline hazardous chemical storage tanks is of significant practical importance for the production safety of the operating plants.

[0003] Currently, there are various diagnostic techniques for the wall quality of double-layered storage tanks, such as infrared thermography, X-ray inspection, nonlinear ultrasonic testing, and ultrasonic testing. Each method is based on a different detection principle and has its own advantages and disadvantages in practical applications.

[0004] (1) Infrared thermal imaging detection technology

[0005] Infrared thermal imaging detection technology is based on infrared physics and uses the difference in temperature field distribution between the debonded area and the intact area of ​​the bonded structure surface when subjected to thermal excitation to determine the location of debonding damage. Its advantages include the ability to perform large-area rapid detection of various damage types, intuitive image display, and no need to contact the workpiece. Its disadvantages include significant influence from environmental temperature factors, relatively difficult qualitative analysis of defects, and low quantitative accuracy of defects.

[0006] (2) X-ray detection technology

[0007] X-ray detection technology utilizes the different absorption rates of X-rays in intact and damaged areas of the bonded structure, resulting in different degrees of X-ray attenuation at the receiving end. However, the attenuation coefficient of debonded tank linings changes little, and due to their enclosed structure, it is difficult to achieve radiographic transmission.

[0008] (3) Nonlinear ultrasonic testing

[0009] Nonlinear ultrasonic testing is mainly used to detect the early stage of micro-deadhesion. It relies on the nonlinear acoustic phenomena generated when ultrasound waves pass through micro-damage, such as harmonics and waveform distortion, to obtain relevant information about the early damage and evaluate it. The disadvantage of this method is the high cost of the testing equipment.

[0010] (5) Linear ultrasonic testing

[0011] Traditional ultrasonic testing is based on the principle that different materials or media have different acoustic impedances. When ultrasonic waves act on different media, they will produce phenomena such as reflection and scattering. When defects are generated in a material, the amplitude and phase of the emitted ultrasonic waves change. The defects are evaluated by measuring the echo amplitude, etc. Traditional ultrasonic testing methods are mostly used for macroscopic and large-sized defects, with moderate testing costs. In addition, they can be combined with the positioning information of mechanical devices to achieve C-scan imaging of internal defects, making the test results more intuitive.

[0012] Currently, traditional ultrasonic testing of tank sidewall quality mainly employs the ultrasonic contact method, which can use coupling agents such as machine oil and paste, along with automated crawlers for automatic scanning. However, due to the rough surface of the tank and poor coupling between the ultrasonic probe and the wall, the intensity of the ultrasonic signal incident on the tank wall varies significantly. Furthermore, the wall thickness and curvature vary at different locations within the tank, resulting in too many interfering factors when using traditional methods to evaluate the bonding quality based on the ultrasonic echo amplitude at the bonding surface. This severely impacts the evaluation of lining debonding. Therefore, further improvements are needed. Summary of the Invention

[0013] The technical problem to be solved by the present invention is to provide an ultrasonic detection method for debonding of the inner lining of the curved side wall of storage tank, which can improve the debonding effect of the inner lining.

[0014] The technical solution adopted by the present invention to solve the above-mentioned technical problem is: an ultrasonic detection method for debonding of the inner lining of the curved side wall of a storage tank, characterized by comprising the following steps:

[0015] Step 1: Manufacture a stepped test block made of the same material as the storage tank to be tested. The thickness of each step of the test block from low to high is hn, h-n+1, ​​...h, h+1, ...h+n; where h is the wall thickness of the storage tank to be tested, n is an integer, and hn>0.

[0016] Step 2: Place the ultrasonic probe on top of the test block, use the ultrasonic probe to probe each step of the test block, obtain the detection signal corresponding to each step of the test block, and record the maximum amplitude of the interface wave and the maximum amplitude of the bottom wave in the detection signal corresponding to each step of the test block.

[0017] Step 3: Set the relationship to be fitted as y = f(x), where f(.) is the function to be fitted. Take the thickness of each step of the test block as the x value and the maximum amplitude of the interface wave of each step of the test block as the y value. Substitute different x values ​​and corresponding y values ​​into the relationship to be fitted to obtain the first relationship y = f1(x) satisfied by the maximum amplitude of the interface wave, where f1(.) is the fitted first function.

[0018] In addition, the thickness of each step of the test block is taken as the x value, and the maximum amplitude of the bottom wave of each step of the test block is taken as the y value. Different x values ​​and corresponding y values ​​are substituted into the relationship to be fitted, and the second relationship y = f2(x) satisfied by the maximum amplitude of the bottom wave is obtained by fitting. f2(.) is the fitted second function.

[0019] Step 4: Use an ultrasonic probe to perform a full scan of the area to be tested inside the tank, and obtain the maximum amplitude WI of the interface wave at each location in the area to be tested. h(p,q) Maximum amplitude of bottom wave WB h(p,q) And the thickness value h(p,q); p,q are the positions of the detected area in the planar dimension;

[0020] Step 5: Calculate the average thickness of all components in the detected area, and substitute this average thickness as the x-value into the first relational expression to calculate the maximum amplitude Y of the first interface wave. I Furthermore, by substituting the average thickness as x into the second equation, the maximum amplitude Y of the first bottom wave was calculated. B ;

[0021] Step 6: Substitute the thickness values ​​at each location in the detected area from Step 4 into the first relational expression to obtain the ideal maximum amplitude Y of the interface wave at each location in the detected area. I (p,q), and simultaneously substitute the thickness values ​​at each location in the detected area from step 4 into the second relational expression to obtain the ideal maximum amplitude Y of the bottom wave at each location in the detected area. B (p,q); Map the ideal maximum amplitude of the interface wave and the ideal maximum amplitude of the bottom wave at each location in the detected area to obtain the mapped maximum amplitude of the interface wave W′I at each location in the detected area. h(p,q) The maximum amplitude W′B of the bottom wave after mapping to each location in the detected area. h(p,q) ;

[0022]

[0023] Step 7: Calculate the bonding quality evaluation index S = W′I h(p,q) / W′B h(p,q) Or S = W'B h(p,q) / W′I h(p,q) The bonding quality evaluation index is compared with the preset bonding quality evaluation index threshold to obtain the debonding result of the tested area.

[0024] As an improvement, the specific control logic for step 7 is as follows:

[0025] When S = W′I h(p,q) / W′B h(p,q) When, determine W′Ih(p,q) / W′B h(p,q) Is it less than or equal to the preset first adhesion quality evaluation index threshold? If a is the first coefficient and a > 1, then the detected area is determined to be detached; otherwise, the detected area is determined to be non-detached.

[0026] When S = W′B h(p,q) / W′I h(p,q) When, determine W′B h(p,q) / W′I h(p,q) Is it greater than or equal to the preset threshold for the second bonding quality evaluation index? If b is the second coefficient and 0 < b < 1, then the detected area is determined to be detached; otherwise, the detected area is determined to be detached.

[0027] The second preferred embodiment of the present invention is: an ultrasonic testing method for the debonding of the inner lining of the curved sidewall of a storage tank, characterized by comprising the following steps:

[0028] Step a: Use an ultrasonic probe to perform a full scan of the curved sidewall of the tank to be tested, obtain the detection signals corresponding to each position, and record the maximum amplitude of the interface wave and the maximum amplitude of the bottom wave in each detection signal.

[0029] Step b: Set the relationship to be fitted as y = f(x), where f(.) is the function to be fitted. Take the thickness of each position in the full scan in step a as the x value, and the maximum amplitude of the interface wave in each detection signal as the y value. Substitute different x values ​​and corresponding y values ​​into the relationship to be fitted to obtain the third relationship y = f3(x) satisfied by the maximum amplitude of the interface wave, where f3(.) is the fitted third function. In addition, take the thickness of each position in the full scan in step a as the x value, and the maximum amplitude of the bottom wave in each detection signal as the y value. Substitute different x values ​​and corresponding y values ​​into the relationship to be fitted to obtain the fourth relationship y = f4(x) satisfied by the maximum amplitude of the bottom wave, where f4(.) is the fitted fourth function.

[0030] Step c: Use an ultrasonic probe to perform a full scan of the area to be tested inside the tank, and obtain the maximum amplitude WI of the interface wave at each location in the area to be tested. h(p,q) Maximum amplitude of bottom wave WB h(p,q) And the thickness value h(p,q); p,q are the positions of the detected area in the planar dimension;

[0031] Step d: Calculate the average thickness of all components in the detected area, and substitute this average thickness as the x-value into the third relational expression to calculate the maximum amplitude Y′ of the second interface wave. IFurthermore, by substituting the average thickness as the x-value into the fourth relation, the maximum amplitude Y′ of the second bottom wave was calculated. B ;

[0032] Step e: Substitute the thickness values ​​at each location in the detected area from step d into the third relational expression to obtain the ideal maximum amplitude value Y′ of the interface wave at each location in the detected area. I (p,q), and simultaneously substitute the thickness values ​​at each location in the detected area from step d into the fourth relational expression to obtain the ideal maximum amplitude Y′ of the bottom wave at each location in the detected area. B (p,q); Map the ideal maximum amplitude of the interface wave and the ideal maximum amplitude of the bottom wave at each location in the detected area to obtain the mapped maximum amplitude of the interface wave W″I at each location in the detected area. h(p,q) The maximum amplitude of the bottom wave after mapping to each location in the detected area, W″B h(p,q) ;

[0033]

[0034] Step f: Calculate the bonding quality evaluation index S1 = W″I h(p,q) / W″B h(p,q) Or S1 = W″B h(p,q) / W″I h(p,q) The bonding quality evaluation index is compared with the preset bonding quality evaluation index threshold to obtain the debonding result of the tested area.

[0035] Preferably, the specific control logic for step f is as follows:

[0036] When S1 = W″I h(p,q) / W″B h(p,q) When, determine W″I h(p,q) / W″B h(p,q) If the value is less than or equal to mean(S1) + r*σ(S1), where mean(S1) is the average of all S1 values, r is the third constant coefficient, and σ(S1) is the standard deviation of all S1 values, then the detected area is determined to be debonded; otherwise, the detected area is determined not to be debonded.

[0037] When S1 = W″B h(p,q) / W″I h(p,q) When, determine W″B h(p,q) / W″I h(p,q) If the value is greater than or equal to mean(S1)-r*σ(S1), then the detected area is determined to be detached; otherwise, the detected area is determined not to be detached.

[0038] Preferably, the value of r is 3.

[0039] Preferably, the formula to be fitted changes according to the different near-field regions N of the ultrasonic probe in the material of the tank to be tested, and the formula for calculating N is:

[0040]

[0041] Where D is the crystal diameter of the ultrasonic probe, f is the frequency of the ultrasonic probe, and C is the velocity of sound in the material of the tank to be tested.

[0042] Preferably, the relationship to be fitted falls into the following three categories:

[0043] When h ≤ N, y = f(x) = A + Bx + Cx 2 +Dx 3 A, B, C, and D are constant terms, linear terms, quadratic terms, and cubic terms, respectively, and A, B, C, and D are all constants.

[0044] When N < h ≤ k*N, y = f(x) = Ee -Fx E and F are both constants; k is a preset value;

[0045] When h > k*N, y = f(x) = G / x, where G is a constant.

[0046] Preferably, the value of k is 3.

[0047] Compared with existing technologies, the advantages of this invention are as follows: By manufacturing a stepped test block with the same material as the tank to be tested, and using an ultrasonic probe to detect the test block, or by directly using ultrasound to perform a full scan of the curved sidewall of the tank to be tested, the relationship between the maximum amplitude of the interface wave and the thickness, and the relationship between the maximum amplitude of the bottom wave and the thickness can be calibrated. Based on the calibrated relationships, the influence of surface curvature changes and poor coupling on the tested structure can be corrected, and finally, the bonding quality of the lining can be quantitatively evaluated. Therefore, this method is easy to automate, convenient to operate, and highly automated. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the ultrasonic detection signal in an embodiment of the present invention. Detailed Implementation

[0049] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0050] Example 1:

[0051] An ultrasonic testing method for detecting debonding of the inner lining of curved sidewalls in storage tanks includes the following steps:

[0052] Step 1: Manufacture a stepped test block made of the same material as the storage tank to be tested. The thickness of each step of the test block from low to high is hn, h-n+1, ​​...h, h+1, ...h+n; where h is the wall thickness of the storage tank to be tested, n is an integer; hn>0.

[0053] Step 2: Place the ultrasonic probe on top of the test block, use the ultrasonic probe to probe each step of the test block, obtain the detection signal corresponding to each step of the test block, and record the maximum amplitude of the interface wave and the maximum amplitude of the bottom wave in the detection signal corresponding to each step of the test block.

[0054] Step 3: Set the relationship to be fitted as y = f(x), where f(.) is the function to be fitted. Take the thickness of each step of the test block as the x value and the maximum amplitude of the interface wave of each step of the test block as the y value. Substitute different n values ​​and the corresponding y values ​​into the relationship to be fitted to obtain the first relationship y = f1(x) satisfied by the maximum amplitude of the interface wave, where f1(.) is the first fitted function.

[0055] In addition, the thickness of each step of the test block is taken as the x value, and the maximum amplitude of the bottom wave of each step of the test block is taken as the y value. Different x values ​​and corresponding y values ​​are substituted into the relationship to be fitted, and the second relationship y = f2(x) satisfied by the maximum amplitude of the bottom wave is obtained by fitting. f2(.) is the fitted second function.

[0056] Step 4: Use an ultrasonic probe to perform a full scan of the area to be tested inside the tank, and obtain the maximum amplitude WI of the interface wave at each location in the area to be tested. h(p,q) Maximum amplitude of bottom wave WB h(p,q) And the thickness value h(p,q); p,q are the positions of the detected area in the planar dimension;

[0057] Step 5: Calculate the average thickness of all components in the detected area, and substitute this average thickness as the x-value into the first relational expression to calculate the maximum amplitude Y of the first interface wave. I Furthermore, by substituting the average thickness as x into the second equation, the maximum amplitude Y of the first bottom wave was calculated. B ;

[0058] Step 6: Substitute the thickness values ​​at each location in the detected area from Step 4 into the first relational expression to obtain the ideal maximum amplitude Y of the interface wave at each location in the detected area. I (p,q), and simultaneously substitute the thickness values ​​at each location in the detected area from step 4 into the second relational expression to obtain the ideal maximum amplitude of the bottom wave at each location in the detected area; map the ideal maximum amplitude of the interface wave at each location in the detected area to obtain the mapped maximum amplitude of the interface wave at each location in the detected area. The maximum amplitude of the bottom wave after mapping to each location in the detected area

[0059]

[0060] Step 7: Calculate the bonding quality evaluation index S = W′I h(p,q) / W′B h(p,q) Or S = W'B h(p,q) / W′I h(p,q) The bonding quality evaluation index is compared with the preset bonding quality evaluation index threshold to obtain the debonding result of the tested area.

[0061] The specific control logic is as follows:

[0062] When S = W′I h(p,q) / W′B h(p,q) When, determine W′I h(p,q) / W′B h(p,q) Is it less than or equal to the preset first adhesion quality evaluation index threshold? If a is the first coefficient and a > 1, then the detected area is determined to be detached; otherwise, the detected area is determined not to be detached. In this embodiment, the value range of a is a∈[1,1.2].

[0063] When S = W′B h(p,q) / W′I h(p,q) When, determine W′B h(p,q) / W′I h(p,q) Is it greater than or equal to the preset threshold for the second bonding quality evaluation index? b is the second coefficient and 0 < b < 1. If so, the detected area is determined to be detached; otherwise, the detected area is determined to be detached. In this embodiment, the value range of b is b∈[0.8,1].

[0064] In this embodiment, the formula to be fitted changes according to the different near-field regions N of the ultrasonic probe in the material of the tank to be tested. The formula for calculating N is:

[0065]

[0066] Where D is the diameter of the wafer used in the ultrasonic probe, in mm; f is the frequency of the ultrasonic probe, in MHz; and C is the velocity of sound in the material of the tank under test. In this embodiment, the material of the tank under test is steel, so C is approximately 5900 × 10⁻⁶. 3 mm / s, the standard probe frequencies are 2, 2.5, 5, 10… (unit: MHz), and the probe diameters are 5, 8, 10, 15, 20, 40, 50… (unit: mm);

[0067] In this embodiment, accurate sound speed calculation is required. The formula for calculating C is:

[0068]

[0069] Among them, WB h-i WI represents the maximum amplitude of the bottom wave in the detection signal corresponding to a step with thickness hi in the test block. h-i The maximum amplitude of the interface wave in the detection signal corresponding to the step with thickness hi in the test block is denoted as .

[0070] In this embodiment, the relationship to be fitted is divided into the following three cases:

[0071] When h ≤ N, y = f(x) = A + Bx + Cx 2 +Dx 3 A, B, C, and D are constant terms, linear terms, quadratic terms, and cubic terms, respectively, and A, B, C, and D are all constants.

[0072] When N < h ≤ k*N, y = f(x) = Ee -Fx E and F are both constants; k is a preset value; in this embodiment, k is 3; in this case, the total number of steps of the test block is preferably 3 or 5, then the value of n is 1 or 2 accordingly;

[0073] When h > k*N, y = f(x) = G / x, where G is a constant.

[0074] In this embodiment, the ultrasonic vertical incident method is used to detect the debonding of the inner lining on the curved side. When the ultrasonic wave is incident on the sidewall, it will receive interface waves, defect waves, and bottom waves, such as... Figure 1 As shown, all interface wave / defect wave / bottom wave amplitudes refer to the maximum amplitude of the waveform.

[0075] To facilitate understanding of the ultrasonic testing method in this invention, this embodiment uses a storage tank wall thickness of h = 40 mm, an ultrasonic probe with a frequency of 5 MHz and a diameter of 10 mm as an example for illustration. Therefore, h satisfies the following condition: N < h ≤ 3*N, then y = f(x) = Ee -Fx ;

[0076] A stepped steel specimen was fabricated, with the thicknesses of each step ranging from 38, 39, 40, 41, to 42 mm. The maximum amplitude values ​​of the interface waves in the detection signals corresponding to each step were obtained as 0.67, 0.61, 0.55, 0.50, and 0.45, respectively. These values ​​were then substituted into the equation y = f(x) = Ee. -Fx E is calculated I =30, F I=0.1; Additionally, the maximum amplitude values ​​of the bottom wave in the detection signals corresponding to each step of the test block are obtained as 0.54, 0.48, 0.43, 0.39, and 0.35. Substituting these values ​​into y = f(x) = Ee -Fx E is calculated B =35, F B =0.11;

[0077] Accurate calculation of the sound velocity yields the corrected sound velocity in the steel material.

[0078] After completing the above calibration and sound velocity calibration, ultrasonic testing is performed on the tank to be tested. The tank is generally a spherical or cylindrical tank with a certain curvature on its surface. A phased array ultrasonic probe (linear or area array) can be used, or a conventional single or array straight probe can be used. A phased array probe consists of multiple chips, while a single conventional probe generally consists of a single crystal. Taking a single ultrasonic chip (crystal) as an example, because the surface of the tank has a certain curvature and is relatively rough or uneven, the single ultrasonic chip (crystal) makes point contact with the surface of the tank in a localized area.

[0079] Ultrasonic probe-generated ultrasonic waves travel through the following path analysis: The ultrasonic waves are emitted from the probe, enter the coupling agent (water), and then enter the steel wall of the tank to be tested. When they encounter the steel / plastic (rubber) interface, the ultrasonic waves are reflected, pass through the steel, enter the coupling agent, and then return to the probe.

[0080] First, the wall thickness is measured using ultrasonic testing technology. When the ultrasonic probe moves across the surface of the tank, it receives interface waves and bottom waves. Based on the time t corresponding to the maximum amplitude of the bottom wave and the maximum amplitude of the interface wave, the time difference between them is calculated. Multiplying this difference by the calibrated sound velocity of the steel material yields the sidewall thickness value.

[0081] Then, the debonding determination is performed according to the specific implementation methods in steps 4 to 7.

[0082] Example 2:

[0083] Unlike Example 1, this example does not require the fabrication of test blocks; instead, ultrasonic waves are used to perform a full scan of the curved sidewalls of the tank under test.

[0084] The ultrasonic testing method for detecting debonding of the inner lining of the curved sidewall of a storage tank in this embodiment includes the following steps:

[0085] Step a: Use an ultrasonic probe to perform a full scan of the curved sidewall of the tank to be tested, obtain the detection signals corresponding to each position, and record the maximum amplitude of the interface wave and the maximum amplitude of the bottom wave in each detection signal.

[0086] Step b: Set the relationship to be fitted as y = f(x), where f(.) is the function to be fitted. Take the thickness of each position in the full scan in step a as the x value, and take the maximum amplitude of the interface wave in each detection signal as the y value. Substitute the different x values ​​and the corresponding y values ​​into the relationship to be fitted to obtain the third relationship y = f3(x) satisfied by the maximum amplitude of the interface wave, where f3(.) is the fitted third function.

[0087] In addition, the thickness of each position in the full scan in step a is taken as the x value, and the maximum amplitude of the bottom wave in each detection signal is taken as the y value. Different x values ​​and corresponding y values ​​are substituted into the relationship to be fitted, and the fourth relationship y = f4(x) satisfied by the maximum amplitude of the bottom wave is obtained by fitting. f4(.) is the fitted fourth function.

[0088] Step c: Use an ultrasonic probe to perform a full scan of the area to be tested inside the tank, and obtain the maximum amplitude WI of the interface wave at each location in the area to be tested. h(p,q) Maximum amplitude of bottom wave WB h(p,q) And the thickness value h(p,q); p,q are the positions of the detected area in the planar dimension;

[0089] Step d: Calculate the average thickness of all components in the detected area, and substitute this average thickness as the x-value into the third relational expression to calculate the maximum amplitude Y′ of the second interface wave. I Furthermore, by substituting the average thickness as the x-value into the fourth relation, the maximum amplitude Y′ of the second bottom wave was calculated. B ;

[0090] Step e: Substitute the thickness values ​​at each location in the detected area from step d into the third relational expression to obtain the ideal maximum amplitude value Y′ of the interface wave at each location in the detected area. I (p,q), and simultaneously substitute the thickness values ​​at each location in the detected area from step d into the fourth relational expression to obtain the ideal maximum amplitude Y′ of the bottom wave at each location in the detected area. B (p,q); Map the ideal maximum amplitude of the interface wave and the ideal maximum amplitude of the bottom wave at each location in the detected area to obtain the mapped maximum amplitude of the interface wave W″I at each location in the detected area. h(p,q) The maximum amplitude of the bottom wave after mapping to each location in the detected area, W″B h(p,q) ;

[0091]

[0092] Step f: Calculate the bonding quality evaluation index S1 = W″I h(p,q) / W″B h(p,q) Or S1 = W″B h(p,q) / W″I h(p,q) The bonding quality evaluation index is compared with the preset bonding quality evaluation index threshold to obtain the debonding result of the tested area.

[0093] The specific control logic is as follows:

[0094] When S1 = W″I h(p,q) / W″B h(p,q) When, determine W″I h(p,q) / W″B h(p,q) If the value is less than or equal to mean(S1) + r*σ(S1), where mean(S1) is the average of all S1 values, r is the third constant coefficient, and σ(S1) is the standard deviation of all S1 values, then the detected area is determined to be debonded; otherwise, the detected area is determined not to be debonded. In this embodiment, the value of r is 3.

[0095] When S1 = W″B h(p,q) / W″I h(p,q) When, determine W″B h(p,q) / W″I h(p,q) If the value is greater than or equal to mean(S1)-r*σ(S1), then the detected area is determined to be detached; otherwise, the detected area is determined not to be detached.

[0096] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An ultrasonic testing method for detecting debonding of the inner lining of curved sidewalls of storage tanks, characterized in that... Includes the following steps: Step 1: Manufacture a stepped test block made of the same material as the storage tank to be tested. The thickness of each step of the test block from low to high is hn, h-n+1, ​​...h, h+1, ...h+n; where h is the wall thickness of the storage tank to be tested, n is an integer, and hn>0. Step 2: Place the ultrasonic probe on top of the test block, use the ultrasonic probe to probe each step of the test block, obtain the detection signal corresponding to each step of the test block, and record the maximum amplitude of the interface wave and the maximum amplitude of the bottom wave in the detection signal corresponding to each step of the test block. Step 3: Set the relationship to be fitted as y = f(x), where f(.) is the function to be fitted. Take the thickness of each step of the test block as the x value and the maximum amplitude of the interface wave of each step of the test block as the y value. Substitute different x values ​​and corresponding y values ​​into the relationship to be fitted to obtain the first relationship y = f1(x) satisfied by the maximum amplitude of the interface wave, where f1(.) is the fitted first function. In addition, the thickness of each step of the test block is taken as the x value, and the maximum amplitude of the bottom wave of each step of the test block is taken as the y value. Different x values ​​and corresponding y values ​​are substituted into the relationship to be fitted, and the second relationship y = f2(x) satisfied by the maximum amplitude of the bottom wave is obtained by fitting. f2(.) is the fitted second function. Step 4: Use an ultrasonic probe to perform a full scan of the area to be tested inside the tank, and obtain the maximum amplitude WI of the interface wave at each location in the area to be tested. h(p,q) Maximum amplitude of bottom wave WB h(p,q) And the thickness value h(p,q); p,q are the positions of the detected area in the planar dimension; Step 5: Calculate the average thickness of all components in the detected area, and substitute this average thickness as the x-value into the first relational expression to calculate the maximum amplitude Y of the first interface wave. I Furthermore, by substituting the average thickness as x into the second equation, the maximum amplitude Y of the first bottom wave was calculated. B ; Step 6: Substitute the thickness values ​​at each location in the detected area from Step 4 into the first relational expression to obtain the ideal maximum amplitude Y of the interface wave at each location in the detected area. I (p,q), and simultaneously substitute the thickness values ​​at each location in the detected area from step 4 into the second relational expression to obtain the ideal maximum amplitude Y of the bottom wave at each location in the detected area. B (p,q); Map the ideal maximum amplitude of the interface wave and the ideal maximum amplitude of the bottom wave at each location in the detected area to obtain the mapped maximum amplitude of the interface wave W′I at each location in the detected area. h(p,q) The maximum amplitude W′B of the bottom wave after mapping to each location in the detected area. h(p,q) ; Step 7: Calculate the bonding quality evaluation index S = W′I h(p,q) / W′B h(p,q) Or S = W'B h(p,q) / W′I h(p,q) The bonding quality evaluation index is compared with the preset bonding quality evaluation index threshold to obtain the debonding result of the tested area.

2. The ultrasonic testing method according to claim 1, characterized in that: The specific control logic for step 7 is as follows: When S = W′I h(p,q) / W′B h(p,q) When, determine W′I h(p,q) / W′B h(p,q) Is it less than or equal to the preset first adhesion quality evaluation index threshold? If a is the first coefficient and a > 1, then the detected area is determined to be detached; otherwise, the detected area is determined to be non-detached. When S = W'B h(p,q) / W′I h(p,q) When, determine W′B h(p,q) / W′I h(p,q) Is it greater than or equal to the preset threshold for the second bonding quality evaluation index? If b is the second coefficient and 0 < b < 1, then the detected area is determined to be detached; otherwise, the detected area is determined to be detached.

3. An ultrasonic testing method for debonding of the inner lining of curved sidewalls of storage tanks, characterized in that... Includes the following steps: Step a: Use an ultrasonic probe to perform a full scan of the curved sidewall of the tank to be tested, obtain the detection signals corresponding to each position, and record the maximum amplitude of the interface wave and the maximum amplitude of the bottom wave in each detection signal. Step b: Set the relationship to be fitted as y = f(x), where f(.) is the function to be fitted. Take the thickness of each position in the full scan in step a as the x value, and take the maximum amplitude of the interface wave in each detection signal as the y value. Substitute the different x values ​​and the corresponding y values ​​into the relationship to be fitted to obtain the third relationship y = f3(x) satisfied by the maximum amplitude of the interface wave, where f3(.) is the fitted third function. In addition, the thickness of each position in the full scan in step a is taken as the x value, and the maximum amplitude of the bottom wave in each detection signal is taken as the y value. Different x values ​​and corresponding y values ​​are substituted into the relationship to be fitted, and the fourth relationship y = f4(x) satisfied by the maximum amplitude of the bottom wave is obtained by fitting. f4(.) is the fitted fourth function. Step c: Use an ultrasonic probe to perform a full scan of the area to be tested inside the tank, and obtain the maximum amplitude WI of the interface wave at each location in the area to be tested. h(p,q) Maximum amplitude of bottom wave WB h(p,q) And the thickness value h(p,q); p,q are the positions of the detected area in the planar dimension; Step d: Calculate the average thickness of all components in the detected area, and substitute this average thickness as the x-value into the third relational expression to calculate the maximum amplitude Y′ of the second interface wave. I Furthermore, by substituting the average thickness as the x-value into the fourth relation, the maximum amplitude Y′ of the second bottom wave was calculated. B ; Step e: Substitute the thickness values ​​at each location in the detected area from step d into the third relational expression to obtain the ideal maximum amplitude value Y′ of the interface wave at each location in the detected area. I (p,q), and simultaneously substitute the thickness values ​​at each location in the detected area from step d into the fourth relational expression to obtain the ideal maximum amplitude Y′ of the bottom wave at each location in the detected area. B (p,q); Map the ideal maximum amplitude of the interface wave and the ideal maximum amplitude of the bottom wave at each location in the detected area to obtain the mapped maximum amplitude of the interface wave W″I at each location in the detected area. h(p,q) The maximum amplitude of the bottom wave after mapping to each location in the detected area, W″B h(p,q) ; Step f: Calculate the bonding quality evaluation index S1 = W″I h(p,q) / W″B h(p,q) Or S1 = W″B h(p,q) / W″I h(p,q) The bonding quality evaluation index is compared with the preset bonding quality evaluation index threshold to obtain the debonding result of the tested area.

4. The ultrasonic testing method according to claim 3, characterized in that: The specific control logic for step f is as follows: When S1 = W″I h(p,q) / W″B h(p,q) When, determine W″I h(p,q) / W″B h(p,q) If the value is less than or equal to mean(S1) + r*σ(S1), where mean(S1) is the average of all S1 values, r is the third constant coefficient, and σ(S1) is the standard deviation of all S1 values, then the detected area is determined to be debonded; otherwise, the detected area is determined not to be debonded. When S1 = W″B h(p,q) / W″I h(p,q) When, determine W″B h(p,q) / W″I h(p,q) If the value is greater than or equal to mean(S1)-r*σ(S1), then the detected area is determined to be detached; otherwise, the detected area is determined not to be detached.

5. The ultrasonic testing method according to claim 4, characterized in that: The value of r is 3.

6. The ultrasonic testing method according to any one of claims 1 to 5, characterized in that: The formula to be fitted varies depending on the near-field region N of the ultrasonic probe in the material of the tank to be tested. The formula for calculating N is: Where D is the crystal diameter of the ultrasonic probe, f is the frequency of the ultrasonic probe, and C is the velocity of sound in the material of the tank to be tested.

7. The ultrasonic testing method according to claim 6, characterized in that: The relationship to be fitted falls into the following three categories: When h ≤ N, y = f(x) = A + Bx + Cx 2 +Dx 3 A, B, C, and D are constant terms, linear terms, quadratic terms, and cubic terms, respectively, and A, B, C, and D are all constants. When N < h ≤ k*N, y = f(x) = Ee -Fx E and F are both constants; k is a preset value; When h > k*N, y = f(x) = G / x, where G is a constant.

8. The ultrasonic testing method according to claim 7, characterized in that: The value of k is 3.

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