阅读说明：本技术 用于检测大型储罐底板腐蚀缺陷的检测方法 (Detection method for detecting corrosion defects of large storage tank bottom plate ) 是由 杨进 孙臣臣 白永忠 屈定荣 邱枫 黄贤滨 于 2019-10-17 设计创作，主要内容包括：本发明公开了一种用于检测大型储罐底板腐蚀缺陷的检测方法,所述检测方法包括：在底板中部设置多个超声波传感器构成的传感器布置区,通过控制各个超声波传感器发射时刻的时延,使多个超声波传感器发出的超声导波同时到达同一检测点；收到回波后,对信号进行处理定位出缺陷位置。本发明的有益技术效果是：提出了一种用于检测大型储罐底板腐蚀缺陷的检测方法,该检测方法可以使超声导波的检测范围得到有效拓展,并且可通过盲信号分离算法剔除回波中的干扰信号,使我们能够准确地定位出缺陷位置。(The invention discloses a detection method for detecting corrosion defects of a bottom plate of a large storage tank, which comprises the following steps: a sensor arrangement area formed by a plurality of ultrasonic sensors is arranged in the middle of the bottom plate, and ultrasonic guided waves sent by the plurality of ultrasonic sensors reach the same detection point at the same time by controlling the time delay of the emission time of each ultrasonic sensor; after receiving the return signals, processing the signals to locate the defect position. The beneficial technical effects of the invention are as follows: the detection method can effectively expand the detection range of ultrasonic guided waves, and can remove interference signals in echoes through a blind signal separation algorithm, so that the defect position can be accurately positioned.)

1. A detection method for detecting corrosion defects of a bottom plate of a large storage tank is characterized by comprising the following steps: the detection method comprises the following steps:

1) arranging a plurality of ultrasonic sensors in the middle of the bottom plate, recording the area surrounded by the ultrasonic sensors as a sensor arrangement area, wherein the size of the sensor arrangement area is far smaller than that of the bottom plate; the ultrasonic sensor is a transmitting-receiving integrated ultrasonic sensor; the arrangement form of the plurality of ultrasonic sensors is selected from the following three ways: in the first mode, a plurality of ultrasonic sensors form a plurality of circular rings, the radiuses of the different circular rings are different, and the circular rings are concentric; in the second mode, a plurality of ultrasonic sensors form a cross-shaped array; in a third mode, a plurality of ultrasonic sensors form a square matrix;

recording the geometric center of the sensor arrangement area as a circle center; recording the moment of sending the ultrasonic guided waves by the ultrasonic sensor as the launching moment; by controlling the time delay of each emission moment, the ultrasonic guided waves emitted by the plurality of ultrasonic sensors can reach the same position at the same time, and the position is marked as a detection point; recording the distance from the detection point to the circle center as a detection radius; arranging a plurality of detection points on the periphery of the sensor arrangement area, and recording the plurality of detection points with the same detection radius as a detection group; a plurality of detection points governed by a single detection group are uniformly distributed along the circumferential direction of the circle center;

2) during detection, the detection operation is carried out on the plurality of detection groups one by one; when a single detection group is detected, a plurality of detection points are detected one by one; when a single detection point is detected, the time delay of each emission moment is controlled, so that the ultrasonic guided waves emitted by the multiple ultrasonic sensors reach the corresponding detection point at the same time, and then after the multiple ultrasonic sensors receive the corresponding return waves, the next detection point is continuously detected;

3) after receiving the echoes, processing the echoes received by the ultrasonic sensor by adopting a blind signal separation algorithm based on ICA independent component analysis, eliminating interference signals in the echoes to obtain effective signals related to the structural defects, and then processing the effective signals by adopting a TOF flight time algorithm to position the defect positions.

Technical Field

The invention relates to a storage tank structure health detection technology, in particular to a detection method for detecting corrosion defects of a large storage tank bottom plate.

Background

The large-scale storage tank is an important infrastructure of industries such as petroleum and chemical industry, and needs to be regularly subjected to structural health detection in order to ensure the safe operation of the large-scale storage tank;

the storage tank bottom plate is one of the important components of storage tank, and in the long-term in-service process, the storage tank bottom plate inevitably can appear structural defect under the effect of multiple factor, to the large-scale storage tank bottom plate that the diameter reaches hundred meters, if adopt traditional nondestructive test technique to detect, the cost is higher, and is inefficient.

Ultrasonic guided waves have the advantages that the technical scheme that the ultrasonic guided waves are used for detecting defects of the storage tank bottom plate exists in the prior art, but for the storage tank bottom plate with the large diameter, in order to reduce the influence of attenuation on the detection range, the prior art usually adopts low-frequency guided wave excitation to detect, and although the detection range is ensured by the detection mode, small defects possibly existing in the plate cannot be detected; on the other hand, when ultrasonic guided waves are propagated in the bottom plate, scattering occurs at the welding seam, and the large-sized storage tank bottom plate cannot be manufactured by using a whole steel plate due to large area and can only be welded by adopting a plurality of steel plates, so that the welding seam inside the large-sized storage tank bottom plate has more welding seams, the scattering caused by the welding seam is more, signal analysis is difficult, and defect information cannot be well fed back to a sensor network, so that the positions of defects cannot be accurately identified and positioned; the ultrasonic sensor array is arranged outside the storage tank edge plate, so that the online detection of the edge plate can be realized, and the storage tank does not need to be emptied or the liquid level is reduced; for the off-line detection of the medium-amplitude plate, compared with other detection methods, a single sensor is excited, and a plurality of sensors are used for receiving and completing the detection of a whole steel plate, however, the detection mode can only detect the corrosion defect of the current single steel plate, and the defect detection under the interference of the welding seam condition is not considered, because the echo signal and the defect signal of the welding seam are easily mixed together in the time domain and are difficult to distinguish; the conventional detection mode and the later-stage signal processing of the ultrasonic guided wave phased array cannot effectively eliminate the influence of weld echoes in all directions, so that the corrosion defect can only be detected on a single current steel plate.

Disclosure of Invention

Aiming at the problems in the background art, the invention provides a detection method for detecting the corrosion defect of a bottom plate of a large-scale storage tank, which is innovative in that: the detection method comprises the following steps:

1) arranging a plurality of ultrasonic sensors in the middle of the bottom plate, recording the area surrounded by the ultrasonic sensors as a sensor arrangement area, wherein the size of the sensor arrangement area is far smaller than that of the bottom plate; the ultrasonic sensor is a transmitting-receiving integrated ultrasonic sensor; the arrangement form of the plurality of ultrasonic sensors is selected from the following three ways: in the first mode, a plurality of ultrasonic sensors form a plurality of circular rings, the radiuses of the different circular rings are different, and the circular rings are concentric; in the second mode, a plurality of ultrasonic sensors form a cross-shaped array; in a third mode, a plurality of ultrasonic sensors form a square matrix;

recording the geometric center of the sensor arrangement area as a circle center; recording the moment of sending the ultrasonic guided waves by the ultrasonic sensor as the launching moment; by controlling the time delay of each emission moment, the ultrasonic guided waves emitted by the plurality of ultrasonic sensors can reach the same position at the same time, and the position is marked as a detection point; recording the distance from the detection point to the circle center as a detection radius; arranging a plurality of detection points on the periphery of the sensor arrangement area, and recording the plurality of detection points with the same detection radius as a detection group; a plurality of detection points governed by a single detection group are uniformly distributed along the circumferential direction of the circle center;

2) during detection, the detection operation is carried out on the plurality of detection groups one by one; when a single detection group is detected, a plurality of detection points are detected one by one; when a single detection point is detected, the time delay of each emission moment is controlled, so that the ultrasonic guided waves emitted by the multiple ultrasonic sensors reach the corresponding detection point at the same time, and then after the multiple ultrasonic sensors receive the corresponding return waves, the next detection point is continuously detected;

3) after receiving the echoes, processing the echoes received by the ultrasonic sensor by adopting a blind signal separation algorithm based on ICA independent component analysis, eliminating interference signals in the echoes to obtain effective signals related to the structural defects, and then processing the effective signals by adopting a TOF flight time algorithm to position the defect positions.

The principle of the invention is as follows: when a single detection point is detected, because a large number of ultrasonic guided waves simultaneously reach the same detection point, the amplitude of an echo can be greatly enhanced, so that the problem that the amplitude of the echo is weak after long-distance conduction can be effectively solved, and the influence of attenuation on the detection range is avoided; on the other hand, because a large number of welding seams exist in the bottom plate and various boundaries are added, a large number of interference signals caused by the welding seams and the boundaries exist in the echo signals, and the inventor finds that the interference signals are similar to the multipath effect in the radar field through analysis, so the invention thinks that the interference signals in the echo can be processed by adopting a blind signal separation algorithm commonly used in the radar field, the interference signals in the echo are eliminated, and finally effective signals related to the structural defects can be obtained; and finally, processing the effective signal by using a common TOF flight time algorithm to locate the defect position.

Considering that a blind signal separation algorithm and a TOF (time of flight) algorithm based on ICA (independent component analysis) are both the prior art, details of specific implementation of the blind signal separation algorithm and the TOF algorithm are not repeated herein;

the beneficial technical effects of the invention are as follows: the detection method can effectively expand the detection range of ultrasonic guided waves, and can remove interference signals in echoes through a blind signal separation algorithm, so that the defect position can be accurately positioned.

Drawings

FIG. 1 is a schematic diagram of the arrangement position of ultrasonic sensors according to the present invention (the ultrasonic sensors are arranged in a square matrix in the figure);

FIG. 2 is a schematic diagram showing the distribution positions of ultrasonic sensors arranged in concentric rings;

FIG. 3 is a schematic diagram showing the distribution positions of ultrasonic sensors arranged in a cross-shaped array;

the names corresponding to each mark in the figure are respectively: ultrasonic sensor 1, weld 2.

Detailed Description

A detection method for detecting corrosion defects of a bottom plate of a large storage tank is innovative in that: the detection method comprises the following steps:

1) arranging a plurality of ultrasonic sensors in the middle of the bottom plate, recording the area surrounded by the ultrasonic sensors as a sensor arrangement area, wherein the size of the sensor arrangement area is far smaller than that of the bottom plate; the ultrasonic sensor is a transmitting-receiving integrated ultrasonic sensor; the arrangement form of the plurality of ultrasonic sensors is selected from the following three ways: in the first mode, a plurality of ultrasonic sensors form a plurality of circular rings, the radiuses of the different circular rings are different, and the circular rings are concentric; in the second mode, a plurality of ultrasonic sensors form a cross-shaped array; in a third mode, a plurality of ultrasonic sensors form a square matrix;

recording the geometric center of the sensor arrangement area as a circle center; recording the moment of sending the ultrasonic guided waves by the ultrasonic sensor as the launching moment; by controlling the time delay of each emission moment, the ultrasonic guided waves emitted by the plurality of ultrasonic sensors can reach the same position at the same time, and the position is marked as a detection point; recording the distance from the detection point to the circle center as a detection radius; arranging a plurality of detection points on the periphery of the sensor arrangement area, and recording the plurality of detection points with the same detection radius as a detection group; a plurality of detection points governed by a single detection group are uniformly distributed along the circumferential direction of the circle center;

2) during detection, the detection operation is carried out on the plurality of detection groups one by one; when a single detection group is detected, a plurality of detection points are detected one by one; when a single detection point is detected, the time delay of each emission moment is controlled, so that the ultrasonic guided waves emitted by the multiple ultrasonic sensors reach the corresponding detection point at the same time, and then after the multiple ultrasonic sensors receive the corresponding return waves, the next detection point is continuously detected;

3) after receiving the echoes, processing the echoes received by the ultrasonic sensor by adopting a blind signal separation algorithm based on ICA independent component analysis, eliminating interference signals in the echoes to obtain effective signals related to the structural defects, and then processing the effective signals by adopting a TOF flight time algorithm to position the defect positions.