CN202305480U - Storage tank bottom plate corrosion detection system based on ultrasonic Lamb wave - Google Patents

Storage tank bottom plate corrosion detection system based on ultrasonic Lamb wave Download PDF

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CN202305480U
CN202305480U CN2011203547661U CN201120354766U CN202305480U CN 202305480 U CN202305480 U CN 202305480U CN 2011203547661 U CN2011203547661 U CN 2011203547661U CN 201120354766 U CN201120354766 U CN 201120354766U CN 202305480 U CN202305480 U CN 202305480U
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plate
detection
storage tank
sensor array
circuit board
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何存富
郑阳
吴斌
周进节
李杨
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Beijing University of Technology
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Beijing University of Technology
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Abstract

The utility model relates to a storage tank bottom plate corrosion detection system based on an ultrasonic Lamb wave, belonging to the technical field of nondestructive detection of pressure containers. The storage tank bottom plate corrosion detection system is characterized in that: an upper computer (1) is connected with and controls an arbitrary function generation plate card (2); the arbitrary function generation plate card (2) is connected with a power amplifier (3); the power amplifier (3) is connected with a multi-channel changeover switch (4); the multi-channel changeover switch (4) is connected with a signal separator (7); the signal separator (7) is connected with a detection sensor array and a multi-channel data acquisition plate card (9); and the multi-channel data acquisition plate card (9) is connected to the upper computer (1) and is used for transmitting the acquired signal to the upper computer. According to the storage tank bottom plate corrosion detection system based on the ultrasonic Lamb wave, a margin plate can be detected on line without emptying a storage tank or lifting liquid level; and for offline detection of a center plate, compared with other detection methods, the detection of a whole steel plate can be finished by once excited reception, so that the storage tank bottom plate corrosion detection system is fast and high-efficiency.

Description

Storage tank bottom plate corrosion detection system based on ultrasonic Lamb wave
Technical field
The utility model belongs to the Nondestructing Detection of Pressure Vessels technical field, is specifically related to a kind of ultrasonic Lamb wave Dynamic Non-Destruction Measurement that utilizes and realizes the system that the storage tank bottom plate corrosion detects.
Background technology
Large-scale petroleum storing tank is widely used in commercial production and national strategy oil reserve.In the long service process, large-scale storage tank is corroded by many factor affecting easily, causes crude oil leakage and structural failure.And mostly the material of storage tank stores is inflammable and explosive or poisonous oil product; Self-capacity is big; Tend to cause fire, explosion accident in case lose efficacy, and brought enormous economic loss not only can for oil gas industry, and may cause great personnel casualty accidents and serious environmental to pollute.
Storage tank bottom plate corrosion at present regularly detects method commonly used has ultrasound wave, ray, infiltration, magnetic, leakage field and acoustic emission detection etc.Other method all need be opened a jar offline inspection except that acoustic emission detection, promptly stop using storage tank, batch turning, opens and replace clear Xian, the testing staff is got into carry out each item in the jar to detect, and these detection methods all is a detection, and waste time and energy, it is higher to detect cost.And ray detection is harmful, and it is abominable that magnetic detects operating mode.Though acoustic emission detection is a kind of online measuring technique, before detection, should reduce the storage medium liquid level, raise liquid level again during detection, carry out pressurize in 85%, 95% and 100% liquid level respectively, the corrosion default place on the base plate will produce acoustic emission signal.These signals are received by the low frequency sensor of equidistant placement at the storage tank bottom plate edge, adopt any three sensors realization location on the circumference again.The testing process complicated and time consumption, and be subject to influence of environmental noise, because it is a kind of passive sound detection technology, can only monitor active defective simultaneously, can't predict for depositing corrosion default.
Patent " method for detecting guide waves of the steel storage tank bottom plate " (patent No.: 200810240571) adopt wedge type transducer; Certain beam direction is arranged; Can only manually change successively the detection side to, the duplicate detection process realizes the detection to base plate, detection efficiency is low.Simultaneously, edge placement one coil sensor there is no need along the storage tank place, because complicated scattering and wave mode conversion will take place in the commissure Lamb ripple, the echoed signal of passing through weld seam can't be used for testing process.
(patent No.: 200910238113) described formation method depends on two important prerequisites to patent " based on the non-destructive detection method for plate-structure lamb wave of virtual focusing of transducer array ": the dispersion curve of (1) accurate Calculation plate structure; (2) all sensors must have same emission and receiving sensitivity in the array; (3) eliminate the breast picture and need reference signal (obtaining its reference signal through Theoretical Calculation or when plate is complete in advance).The method can't be used for the detection of storage tank bottom plate; Reason is following: at first; The storage tank bottom plate complex structure, and because its meeting load fluid etc., at present; Do not have good its dispersion curve of method accurate Calculation, this just makes that utilizing in the above-mentioned patent wavenumber domain to carry out ripple packs tightly the method that contracts and can't realize; Secondly, in the actual detected process,, thereby can't have same emission and receiving sensitivity because detection system and sensor can not have on all four performance; Once more, because the complicacy of storage tank bottom plate structure, be difficult to accurately obtain the reference signal of Theoretical Calculation, and the detection method storage tank that is used for being on active service more, can't obtain the reference signal of plate when complete.
The utility model content
The purpose of the utility model be to overcome the detection efficiency that has had detection means low, detect the not enough shortcoming of practicality; With the Lamb ripple storage tank bottom plate corrosion condition is detected; Be exactly to utilize a kind of low frequency (detection and location that the zeroth order of 80kHz~1MHz) symmetry mode (S0 mode) Lamb ripple is realized the storage tank bottom plate corrosion specifically; The excitation of adopting a kind of circumferential consistent Electromagnetic Acoustic Transducer that encourages and receive S0 mode Lamb ripple to carry out signal receives; Utilization array total focus algorithm is embodied as picture to defect distribution, and testing process is divided margin plate on-line detecting system and center plate off-line checking system two parts.
The technical scheme of the utility model; Specifically see Fig. 1, device comprises: host computer 1, arbitrary function generation integrated circuit board 2, power amplifier 3, hyperchannel change-over switch 4, detecting sensor array, demultiplexer 7, prime amplifier 8 and multi-channel data acquisition integrated circuit board 9.Connect control arbitrary function generation integrated circuit board 2 by host computer 1; Arbitrary function generation integrated circuit board 2 links to each other with power amplifier 3; Power amplifier 3 links to each other with hyperchannel change-over switch 4, and hyperchannel change-over switch 4 links to each other with demultiplexer 7, and demultiplexer 7 links to each other with detecting sensor array and multi-channel data acquisition integrated circuit board 9; Multi-channel data acquisition integrated circuit board 9 is connected into host computer 1, and multi-channel data acquisition integrated circuit board 9 is transferred to host computer with the signal that collects.
Described detecting sensor array comprises linear sensor array 5 and ring-like sensor array 6.
Described detecting sensor array adopts Electromagnetic Acoustic Transducer, is connected with prime amplifier 8 between demultiplexer 7 and the multi-channel data acquisition integrated circuit board 9.
Wherein, the linear sensor array 5 that is used for the margin plate detection is positioned over the part that margin plate exceeds tube wall, and the width that exceeds is about 10-15cm; The ring-like sensor array 6 that is used for the center plate detection is positioned in the middle of the center plate, sees Fig. 2, shown in Figure 3.
Use the detection method of above-mentioned storage tank bottom plate corrosion detection system based on ultrasonic Lamb wave, comprise the steps:
Step 1: confirm to detect mode, frequency and group velocity: storage tank bottom plate is regarded as free plate,, draws out corresponding dispersion curve (like Figure 10, Figure 11) by dispersion equation according to its thickness and material parameter.The Lamb ripple dimension of choosing S0 mode detects mode, and the wave structure that frequency is lower than each Frequency point of S0 mode of 1MHz is analyzed.Through choosing the group velocity dispersion curve rate of change frequency band analyst coverage (like the 0-500kHz among Figure 11) of dwindling wave structure research slowly; To each Frequency point of this frequency band wave structure figure (like Figure 12) that draws, choose displacement field distribution among the wave structure figure the thickness of slab direction linearly the Frequency point of (or near linear) as detecting frequency f 0At last, corresponding group velocity dispersion curve finds the detection frequency f 0Pairing group velocity, used in order to calculating afterwards.
Step 2: turn to grid with the geometric configuration of seized structure is discrete, with the center point coordinate (x of grid m, y n) represent each grid (x, y represent horizontal and vertical grouping, and m, n represent the horizontal ordinate of grid behind the specified coordinate initial point).The placement sensor array, line style placement sensor array is adopted in the detection of margin plate, is arranged on the margin plate in the wallboard outside, and ring-like array is adopted in the detection of center plate, is arranged in the center position of plate; The coordinate of each sensor in the survey record array.
Step 3: adopting a kind of centre frequency is f 0By 5 cycle sine wave signals of the Gaussian window modulation signal after through the chirp conversion as pumping signal, and be T with the sensor serial number in the sensor array i(i=1,2...n, n are number of sensors in this group sensor array), the order that increases progressively by passing through of linear array wherein, ring-like array is then being specified T 1Increase progressively by counterclockwise order behind the sensor; From T 1Sensor begins, and all the sensors encourages successively, and in each process of motivation, all sensors receives signal simultaneously.Obtain original n * n and organize time-domain signal, every group of signal is that an excitation receives S Ij, footmark i represents the stimulus sensor numbering, and footmark j represents the receiving sensor numbering;
Step 4: original detection signal is carried out inverse transformation, the useful detection signal of demodulation from the chirp signal, promptly centre frequency is f 0The detection signal that receives after in plate, propagating of 5 cycle sine wave signals by Gaussian window modulation, then signal is carried out bandpass filtering, obtain signal matrix H Ij
Step 5: formula is satisfied in wave propagation: l=c gT wherein l is the wave propagation distance, c gBe the group velocity of ripple, t is the wave propagation time.Can calculate the wave propagation distance according to each known sensor locus thus, and then confirm the time delay matrix of each focus point, according to the time-delay matrix from signal matrix H IjIn obtain the amplitude matrix A of corresponding time point Ij
Step gathers six: coordinate (x m, y n) the color value C of grid of representative MnProvide by following formula:
C mn=∑A ij
With C MnFurther be mapped as RGB or gray-scale value and can obtain the defect distribution image of whole plate.
The utility model is with respect to already present detection method, and its advantage mainly is, and the first, the method for the utility model need not to empty storage tank or carries out liquid surface lifting, can carry out online detection to margin plate; The second, the utility model method need not to get into tank inside and can realize the detection to storage tank bottom plate margin plate corrosion situation on the margin plate of transducer arrangements outside storage tank shell; The 3rd, the utility model method can detect the defective of base plate upper and lower surfaces simultaneously in testing process, i.e. corrosion default on base plate and fluid surface of contact and base plate and the sand bedding course surface of contact; The 4th, for the offline inspection of center plate, compared to other detection method, the utility model method once encourages reception can accomplish the detection of a monoblock steel plate, rapidly and efficiently; The 5th, the utility model method does not have consistent contact condition to requiring sensor, does not require the consistance of sensor and each passage of hardware yet, can be advantageously applied to engineering reality, and detection influenced by neighbourhood noise less.These characteristics are that other detection method is not available.
Description of drawings:
Fig. 1 detection system installation drawing;
Fig. 2 margin plate detecting sensor array installation site synoptic diagram
Fig. 3 center plate detecting sensor array installation site synoptic diagram
Fig. 4 sensor array detects the storage tank bottom plate synoptic diagram
5 cycle sinusoidal signals of Fig. 5 Gaussian window modulation
Fig. 6 chirp signal
Fig. 7 chirp signal spectrum
Fig. 8 total focus imaging algorithm synoptic diagram
Fig. 9 signal processing flow figure
The phase velocity dispersion curve of the steel plate of the thick 11mm of Figure 10
The group velocity dispersion curve of the steel plate of the thick 11mm of Figure 11
Wave structure figure and displacement field distribution plan in the steel plate of the thick 11mm of Figure 12 during S0 mode 50kHz
Among the figure, 1-upper computer software, 2-arbitrary function generation integrated circuit board, 3-power amplifier, 4-hyperchannel change-over switch; 5-linear array sensor, 6-annular array sensor, 7-demultiplexer, 8-prime amplifier; 9-multi-channel data acquisition integrated circuit board, 10-center plate, 11-margin plate, 12-wallboard.
Embodiment
With a kind of 10*10 4The pontoon-deck-tank detection describes for example.
The margin plate of this kind oil tank is of a size of: 21 * 2000 * 6350mm 3, sheet material is 12MnNiVR, center plate is of a size of: 11 * 2800 * 13800mm 3, sheet material is Q235-B.
Draw margin plate and middle amplitude-frequency rate less than the dispersion curve in the 1MHz scope.Select the Lamb ripple of low frequency (in the 1MHz), zeroth order symmetry mode (S0 mode) to detect.Lamb ripple compared to other mode and frequency band it is advantageous that: at first, the S0 mode Lamb ripple frequency dispersion degree in this frequency range is very little, thereby makes bearing accuracy higher; Secondly, the S0 modal waves structural plane intrinsic displacement in this scope almost is evenly distributed along steel plate thickness, makes to detect the corrosion default on the whole thickness of slab is all kept very high sensitivity; Once more, detect mode A0 mode compared to another kind Lamb ripple commonly used, S0 mode in-plane displacement accounts for absolute leading; Acoplanarity displacement is very little; Thereby receive the influence of upper strata load (fluid) and lower floor's bitumen sand cushion hardly, thus can ignore upper strata fluid and lower floor's bitumen sand cushion in the theoretical models, make and detect and signal analysis becomes very succinct; And the group velocity of A0 mode is altered a great deal by the influence of load, is not easy to utilize it to detect.The dispersion curve of the thick center plate of 11mm as shown in Figure 8.
In this frequency range, the wave structure of S0 mode is analyzed, find out in-plane displacement along thickness evenly distribute or approximate equally distributed frequency as detecting frequency.Wave structure figure and displacement field distribution plan in the steel plate of thick 11mm as shown in Figure 9 during S0 mode 50kHz.From then on figure can know, in-plane displacement is approximate linearly along the thickness direction distribution during 50kHz, and its group velocity variation slowly, and the frequency dispersion degree is little, the full middle requirement that detects.From dispersion curve, find out S0 mode group velocity corresponding under this frequency.Group velocity under this frequency also can be utilized two sensors, adopts the mode of sharp receipts, in plate, records.
This example is selected a kind of circumferential consistent Electromagnetic Acoustic Transducer that encourages, receives S0 mode Lamb ripple for use.The detection of margin plate is adopted linear or near line shape placement sensor array, and circular array is adopted in the detection of center plate.Number of sensors is not limit in the array; General sensor number is many more, can obtain imaging effect preferably more, but the increase of sensor number will increase hardware cost and computing velocity; So the selection of sensor number should be lacked on the basis that guarantees imaging effect as far as possible.But no matter how the sensor number in line style and the circular array changes, and all testing processes are just the same.Select the reason of line style and circular array: at first, the shape of these two kinds of arrays can guarantee under the same situation of imaging resolution that the sensor number is few as far as possible, saves hardware cost and computing time greatly; Secondly, during online detections of CONSIDERING EDGE plate, need be installed on sensor array outside the jar; The restriction of installing space makes sensor array to place along jar outside listrium; Thereby array is approximately line style, is not strict line style even it is pointed out that array; For example under the situation of arc, signal Processing and imaging process are just the same.At last, circular array is when in commission former detects, and array is placed the center of plate, will guarantee with the sensor to be that all directions at center all have imaging effect preferably like this.Adopting ten sensors to form array in this example detects.
Pumping signal adopts a kind of chirp signal, shown in Fig. 5 (b).Can obtain the sine wave signal in 5 cycles of Gaussian window modulation after this chirp signal process inverse transformation.Utilize the chirp signal can in pumping signal, comprise bigger energy, detect distance and will obviously improve.If n sensor arranged in the array, as shown in Figure 6, is numbered T i(i=1,2...n), the order that linear array increases progressively by passing through, ring-like array is then being specified T 1Increase progressively by counterclockwise order behind the sensor and number.The excitation of signal and gatherer process are: from T 1The sensor beginning, all the sensors encourages successively, and in each process of motivation, all sensors receives signal simultaneously.At this moment will obtain original n * n and organize time-domain signal, every group of signal is that an excitation receives S Ij, footmark i represents the stimulus sensor numbering, and footmark j represents the receiving sensor numbering, like S 13Be sensor T 1Excitation T 3Receive.
Signal Processing and imaging process.Original detection signal is carried out inverse transformation, and the useful detection signal of demodulation carries out bandpass filtering to signal then from the chirp signal, obtains signal matrix H Ij, turn to each grid with the geometric configuration of detection architecture is discrete, with grid element center point coordinate (x m, y n) represent each grid.Under the situation of known each sensor locus, calculate the time delay matrix of each focus point, from signal matrix H IjIn obtain the amplitude matrix A of corresponding time point Ij, all amplitude phase adductions are mapped as color value, define the color at grid place for this reason.After institute is accomplished color calculation a little, can accomplish imaging processing to total.

Claims (4)

1. based on the storage tank bottom plate corrosion detection system of ultrasonic Lamb wave, comprising: host computer (1), arbitrary function generation integrated circuit board (2), power amplifier (3), hyperchannel change-over switch (4), detecting sensor array, demultiplexer (7), prime amplifier (8) and multi-channel data acquisition integrated circuit board (9); It is characterized in that: connect control arbitrary function generation integrated circuit board (2) by host computer (1); Arbitrary function generation integrated circuit board (2) links to each other with power amplifier (3); Power amplifier (3) links to each other with hyperchannel change-over switch (4); Hyperchannel change-over switch (4) links to each other with demultiplexer (7); Demultiplexer (7) links to each other with detecting sensor array and multi-channel data acquisition integrated circuit board (9), and multi-channel data acquisition integrated circuit board (9) is connected into host computer (1), and multi-channel data acquisition integrated circuit board (9) is transferred to host computer with the signal that collects.
2. the storage tank bottom plate corrosion detection system based on ultrasonic Lamb wave according to claim 1 is characterized in that: described detecting sensor array comprises linear sensor array (5) and ring-like sensor array (6).
3. the storage tank bottom plate corrosion detection system based on ultrasonic Lamb wave according to claim 1; It is characterized in that: described detecting sensor array adopts Electromagnetic Acoustic Transducer, is connected with prime amplifier (8) between demultiplexer (7) and the multi-channel data acquisition integrated circuit board (9).
4. the storage tank bottom plate corrosion detection system based on ultrasonic Lamb wave according to claim 1 is characterized in that: the linear sensor array (5) that is used for the margin plate detection is positioned over the part that margin plate exceeds tube wall, and the width that exceeds is about 10-15cm; The ring-like sensor array (6) that is used for the center plate detection is positioned in the middle of the center plate.
CN2011203547661U 2011-09-21 2011-09-21 Storage tank bottom plate corrosion detection system based on ultrasonic Lamb wave Active CN202305480U (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102539528A (en) * 2011-09-21 2012-07-04 北京工业大学 System and method for detecting corrosion of storage tank base plate based on ultrasonic Lamb wave
CN103293223A (en) * 2013-03-04 2013-09-11 江苏省特种设备安全监督检验研究院镇江分院 Characteristic guided wave based butt weld nondestructive testing system
CN103308609A (en) * 2013-06-26 2013-09-18 哈尔滨工业大学 Lamb wave mode control method based on electromagnetic ultrasonic emission transducer
CN103323525A (en) * 2013-05-21 2013-09-25 广东电网公司电力科学研究院 Nonlinear ultrasound system used for detecting super austenitic stainless steel inter-granular corrosion
CN110470742A (en) * 2019-04-25 2019-11-19 西安交通大学 A kind of accurate detecting method of channel bend defect

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102539528A (en) * 2011-09-21 2012-07-04 北京工业大学 System and method for detecting corrosion of storage tank base plate based on ultrasonic Lamb wave
CN103293223A (en) * 2013-03-04 2013-09-11 江苏省特种设备安全监督检验研究院镇江分院 Characteristic guided wave based butt weld nondestructive testing system
CN103323525A (en) * 2013-05-21 2013-09-25 广东电网公司电力科学研究院 Nonlinear ultrasound system used for detecting super austenitic stainless steel inter-granular corrosion
CN103308609A (en) * 2013-06-26 2013-09-18 哈尔滨工业大学 Lamb wave mode control method based on electromagnetic ultrasonic emission transducer
CN103308609B (en) * 2013-06-26 2015-05-20 哈尔滨工业大学 Lamb wave mode control method based on electromagnetic ultrasonic emission transducer
CN110470742A (en) * 2019-04-25 2019-11-19 西安交通大学 A kind of accurate detecting method of channel bend defect
CN110470742B (en) * 2019-04-25 2020-06-19 西安交通大学 Accurate detection method for defects of pipeline elbow

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