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CN-122017032-A - Ultrasonic nondestructive testing flaw detection method and system for welding seam of building steel structure

CN122017032ACN 122017032 ACN122017032 ACN 122017032ACN-122017032-A

Abstract

The invention discloses a method and a system for ultrasonic nondestructive testing and flaw detection of a welding seam of a building steel structure, and belongs to the technical field of welding seam detection; the method comprises the steps of extracting a noise amplitude sequence in a non-welding area to construct a noise statistics table, driving an ultrasonic array probe to respectively generate a full matrix echo data set and a plane wave echo data set according to a scanning gesture table, mapping the full matrix echo data set and the plane wave echo data set into a full focusing image and a plane wave superposition image, calculating amplitude difference to generate a fusion weight map, generating a fusion image based on the fusion weight map, executing area segmentation by using the noise statistics table, and extracting a defect boundary coordinate table. According to the invention, by adopting the technical scheme of laser point cloud guiding probe posture, dual-mode imaging fusion and self-adaptive noise segmentation, high-precision, automatic identification and objective quantitative evaluation of internal defects of welding seams can be realized.

Inventors

  • SUN FEI

Assignees

  • 淄博职业技术大学

Dates

Publication Date
20260512
Application Date
20260415

Claims (10)

  1. 1. The ultrasonic nondestructive testing flaw detection method for the welding line of the building steel structure is characterized by comprising the following steps: Acquiring laser point cloud data of a weld surface, selecting local neighborhood points to perform plane fitting, calculating a local normal direction, converting a probe inclination angle, and generating a scanning attitude table; Controlling an ultrasonic array probe to move to a non-welding area outside a weld joint to be detected to acquire echo waveforms, intercepting a structural scattering signal segment between a start wave and a bottom wave to extract a noise amplitude sequence, calculating an amplitude histogram and an accumulation proportion by using the noise amplitude sequence, and generating a noise statistics table; driving an ultrasonic array probe to perform point-by-point positioning according to a scanning gesture table, performing array element successive emission and full channel receiving, and storing according to point position numbers to generate a full matrix echo data set; Driving an ultrasonic array probe to perform point-by-point positioning according to a scanning attitude table, performing multi-angle plane wave transmission and full-channel reception, and storing according to point position numbers to generate a plane wave echo data set; mapping the full matrix echo data set to generate a full focusing image, mapping the plane wave echo data set to generate a plane wave superposition image, and calculating amplitude difference of the full focusing image and the plane wave superposition image to generate a fusion weight map; And performing weighted summation on the full-focus image and the plane wave superposition image based on the fusion weight map to generate a fusion image, performing region segmentation on the fusion image by using a noise statistics table, extracting a connected region boundary, and generating a defect boundary coordinate table.
  2. 2. The ultrasonic non-destructive inspection method for a weld joint of a steel structure of a building of claim 1, wherein generating a scan gesture table comprises: performing statistical outlier filtering processing on the laser point cloud data on the surface of the welding seam to remove noise points, and performing uniform grid downsampling processing to construct a sparse point cloud coordinate set; Traversing the sparse point cloud coordinate set, respectively constructing candidate neighborhood points with different orders of magnitude, performing least square plane fitting, selecting a least fitting residual error, and extracting a method vector as a local normal direction; Calculating the geometric included angle between the local normal direction and the vertical axis of the point cloud coordinate system, mapping and converting the geometric included angle into a probe inclination angle, and performing association storage on the sparse point cloud coordinate set and the probe inclination angle to generate a scanning gesture table.
  3. 3. The ultrasonic non-destructive inspection method of a structural steel structure weld joint of claim 1, wherein generating a noise statistics table comprises: Controlling the ultrasonic array probe to move to a non-welding area outside the weld joint to be detected, exciting ultrasonic pulses and collecting echo waveforms; Identifying a starting wave peak value and a bottom wave peak value of the echo waveform by traversing the time axis data of the echo waveform, extracting waveform data by using a time coordinate index of the starting wave peak value and the bottom wave peak value, and generating a noise amplitude sequence; Dividing the noise amplitude sequence into discrete amplitude intervals, counting the number of sampling points falling into each interval to generate an amplitude histogram, performing step-by-step accumulation calculation on the amplitude histogram to generate an accumulation proportion, and constructing a noise statistics table.
  4. 4. The ultrasonic non-destructive inspection method of a structural steel structure weld according to claim 3, wherein generating a noise amplitude sequence comprises: Dividing the time axis data of the echo waveform into a near-field searching interval and a far-field searching interval, locking a local maximum value in the near-field searching interval to serve as a starting wave peak value, and locking a global maximum value in the far-field searching interval to serve as a bottom wave peak value; and respectively extracting time coordinate indexes by using the initial wave peak value and the bottom wave peak value as a interception starting point and an interception end point, extracting middle-section waveform data by using the interception starting point and the interception end point, and executing absolute value operation to generate a noise amplitude sequence.
  5. 5. The method of ultrasonic non-destructive inspection of a weld joint of a steel structure of construction of claim 1, wherein generating a full matrix echo dataset comprises: sequentially analyzing the space coordinates and the probe inclination angle in the scanning attitude table, generating a multi-axis motion control instruction, driving the ultrasonic array probe to move and attaching to the current target scanning point position; activating an ultrasonic array probe to execute single array element alternate excitation action, and simultaneously controlling all array elements to execute synchronous acquisition action to construct a single-frame full-matrix data packet; And extracting point numbers from the scanning posture table, establishing an index mapping relation between the point numbers and Shan Zhen full-matrix data packets, performing serialization additional storage, and generating a full-matrix echo data set.
  6. 6. The method of ultrasonic non-destructive inspection of a weld joint of a steel structure of construction of claim 1, wherein generating a plane wave echo dataset comprises: reading coordinate parameters in the scanning attitude table, driving the ultrasonic array probe to move and locate to the current scanning point, and setting a plane wave transmitting angle; Traversing the plane wave transmitting angle to calculate the array element transmitting delay time, controlling the ultrasonic array probe to execute simultaneous excitation according to the transmitting delay time, and controlling all array elements to execute full-channel receiving to acquire echo data; And reading the point position numbers by using the scanning attitude table, executing association marks on the echo data and the point position numbers, and writing the association marks into a storage medium to generate a plane wave echo data set.
  7. 7. The ultrasonic nondestructive inspection method for a welded seam of a steel structure of a building according to claim 1, wherein calculating the difference in amplitude for the fully focused image and the plane wave superimposed image to generate a fusion weight map comprises: Discretizing the detection area, mapping and filling amplitude data to discrete nodes based on a full matrix echo data set and a plane wave echo data set, and generating a full focusing image and a plane wave superposition image; and performing matrix subtraction operation by using the full-focus image and the plane wave superimposed image to obtain an amplitude residual matrix, and performing inversion mapping on the amplitude residual matrix to generate a fusion weight map.
  8. 8. The method of ultrasonic non-destructive inspection of a weld joint of a steel structure of construction of claim 7, wherein mapping and filling amplitude data into discrete nodes comprises: dividing a two-dimensional coordinate plane based on the detection area, performing grid division on the two-dimensional coordinate plane according to the step length of the spatial resolution, and defining grid crossing points as discrete nodes; And calculating the acoustic wave propagation path time based on the discrete nodes, extracting waveform amplitude values from the full matrix echo data set and the plane wave echo data set according to the acoustic wave propagation path time, and executing delay superposition operation to fill the discrete nodes.
  9. 9. The ultrasonic non-destructive inspection method of a structural steel structure weld joint of claim 1, wherein generating a defect boundary coordinate table comprises: respectively performing pixel-level multiplication and numerical superposition on the full-focus image and the plane wave superposition image by using the fusion weight map to generate a fusion image; searching a segmentation reference value in a noise statistics table according to a preset noise confidence ratio, performing threshold segmentation on the fused image, extracting a pixel set with amplitude intensity exceeding the segmentation reference value, and forming a defect communication area; and identifying the outline pixels of the outermost layer according to the defect communication area, extracting the space position coordinates according to the outline pixels of the outermost layer, and sequentially arranging the space position coordinates to generate a defect boundary coordinate table.
  10. 10. An ultrasonic nondestructive inspection system for a welding seam of a steel structure of a building, for realizing the ultrasonic nondestructive inspection method for the welding seam of the steel structure of the building according to any one of claims 1 to 9, comprising: The point cloud attitude generation module is used for acquiring laser point cloud data of the surface of the welding seam, selecting local neighborhood points to execute plane fitting, calculating local normal directions and converting probe inclination angles to generate a scanning attitude table; the noise statistics construction module is used for controlling the ultrasonic array probe to move to a non-welding area outside a weld joint to be detected to acquire echo waveforms, intercepting a structural scattering signal segment between a start wave and a bottom wave to extract a noise amplitude sequence, calculating an amplitude histogram and an accumulation proportion by using the noise amplitude sequence, and generating a noise statistics table; The full matrix echo acquisition module is used for driving the ultrasonic array probe to perform point-by-point positioning according to the scanning gesture table, performing array element successive transmission and full channel reception, storing according to the point position number, and generating a full matrix echo data set; The plane wave echo acquisition module is used for driving the ultrasonic array probe to perform point-by-point positioning according to the scanning attitude table, performing multi-angle plane wave emission and full-channel reception, storing according to the point position numbers, and generating a plane wave echo data set; The dual-imaging weight generation module is used for mapping the full-matrix echo data set to generate a full-focusing image, mapping the plane wave echo data set to generate a plane wave superposition image, and calculating amplitude difference of the full-focusing image and the plane wave superposition image to generate a fusion weight map; And the fusion segmentation boundary output module is used for performing weighted summation on the full-focus image and the plane wave superposition image based on the fusion weight map to generate a fusion image, performing region segmentation on the fusion image by utilizing the noise statistics table, extracting the boundary of the connected region and generating a defect boundary coordinate table.

Description

Ultrasonic nondestructive testing flaw detection method and system for welding seam of building steel structure Technical Field The invention belongs to the technical field of weld joint detection, and particularly relates to an ultrasonic nondestructive testing flaw detection method and system for a welding joint of a building steel structure. Background The building steel structure is widely applied to modern building engineering due to good strength and durability. As a core bearing structure of modern building engineering, the quality of welding seams of a building steel structure directly determines structural safety and durability. Ultrasonic nondestructive detection is a mainstream technology for detecting weld defects, wherein ultrasonic phased array detection is widely used for identifying welding defects such as cracks, slag inclusion, air holes and the like by virtue of the advantages of visual imaging, high detection efficiency and the like. The current conventional ultrasonic phased array detection method mainly relies on manual setting of detection parameters and scanning by means of fixed beam angles, and partial improvement scheme can be combined with workpiece surface morphology data to carry out beam parameter compensation, so that basic defect detection and preliminary evaluation can be realized. However, in practical engineering application, the problems of corrosion-resistant coating, rust, oxide scale, uneven roughness and the like often exist on the surface of a welding seam of a steel structure, which can cause poor coupling effect of an ultrasonic probe, energy loss of sound beams and unstable echo signals, meanwhile, the existing method adopts a single imaging mode, high resolution and high signal to noise ratio are difficult to consider, defect detail and deep defect detection capability are limited, threshold segmentation depends on manual experience or fixed reference values, subjectivity is strong, the interference of material noise is easy, and finally tiny defect omission detection and complex defect misjudgment are caused, so that high-precision and objective defect quantitative assessment cannot be realized. Disclosure of Invention In order to solve the problems, the invention provides the ultrasonic nondestructive testing flaw detection method and system for the welding seam of the building steel structure, and the technical scheme of laser point cloud guiding probe posture, dual-mode imaging fusion and self-adaptive noise segmentation is adopted, so that the high-precision, automatic identification and objective quantitative evaluation of the internal defects of the welding seam can be realized. The above object can be achieved by the following scheme: the ultrasonic nondestructive testing flaw detection method for the welding line of the building steel structure comprises the following steps: Acquiring laser point cloud data of a weld surface, selecting local neighborhood points to perform plane fitting, calculating a local normal direction, converting a probe inclination angle, and generating a scanning attitude table; Controlling an ultrasonic array probe to move to a non-welding area outside a weld joint to be detected to acquire echo waveforms, intercepting a structural scattering signal segment between a start wave and a bottom wave to extract a noise amplitude sequence, calculating an amplitude histogram and an accumulation proportion by using the noise amplitude sequence, and generating a noise statistics table; driving an ultrasonic array probe to perform point-by-point positioning according to a scanning gesture table, performing array element successive emission and full channel receiving, and storing according to point position numbers to generate a full matrix echo data set; Driving an ultrasonic array probe to perform point-by-point positioning according to a scanning attitude table, performing multi-angle plane wave transmission and full-channel reception, and storing according to point position numbers to generate a plane wave echo data set; mapping the full matrix echo data set to generate a full focusing image, mapping the plane wave echo data set to generate a plane wave superposition image, and calculating amplitude difference of the full focusing image and the plane wave superposition image to generate a fusion weight map; And performing weighted summation on the full-focus image and the plane wave superposition image based on the fusion weight map to generate a fusion image, performing region segmentation on the fusion image by using a noise statistics table, extracting a connected region boundary, and generating a defect boundary coordinate table. Preferably, generating the scan gesture table includes: performing statistical outlier filtering processing on the laser point cloud data on the surface of the welding seam to remove noise points, and performing uniform grid downsampling processing to construct a sparse point cloud coordinate set; Traversi