CN-121994928-A - Ultrasonic detection and damage assessment method and system for curved composite material component

CN121994928ACN 121994928 ACN121994928 ACN 121994928ACN-121994928-A

Abstract

The invention relates to an ultrasonic detection and damage assessment method and system for a curved composite material member, which comprise the steps of collecting three-dimensional point cloud data of a damaged area on the surface of the curved composite material member, constructing a detection path point sequence, controlling an industrial robot and an ultrasonic phased array to synchronously move and scan according to time, collecting ultrasonic A scanning signals and position and posture information of the tail end of the robot, deriving and calculating three-dimensional space coordinates of reflection points in the curved composite material member according to the position and posture, constructing an initial three-dimensional damaged point cloud, setting a segmentation threshold value to construct an initial segmented damaged point cloud, improving a traditional DBSCAN clustering algorithm to perform clustering segmentation to obtain point clouds of each independent damaged area, and voxeizing the point clouds of the independent damaged area into a three-dimensional voxel model to realize quantitative damage assessment. The invention realizes the automation and high-precision three-dimensional damage detection and evaluation of complex curved surface components, and effectively solves the problems that the traditional ultrasonic detection method depends on manual operation, has poor adaptability, and has non-visual detection results.

Inventors

HU JUNSHAN
WANG LIANGXIANG
YANG JINCHENG
Xie Donglun
Tao Haolan
SU XINGTAO
TIAN WEI

Assignees

南京航空航天大学

Dates

Publication Date: 20260508
Application Date: 20260121

Claims (10)

1. The ultrasonic detection and damage evaluation method for the curved composite material member is characterized by comprising the following steps of: s1, an industrial robot collects three-dimensional point cloud data of a surface damage area of a curved surface composite material component, and a scanning direction is determined and a detection path point sequence is generated through preprocessing, layering slicing, feature point extraction and B spline curve fitting; S2, controlling the industrial robot to move along the detection path point sequence, synchronously scanning a damaged area along a scanning direction by utilizing an ultrasonic phased array, collecting ultrasonic A scanning signals at each sampling moment, simultaneously recording the position and posture information of the tail end of the robot at each sampling moment, and constructing a synchronous data set which takes the sampling moment as an index and contains the ultrasonic A scanning signals and the position and posture information of the tail end of the robot; the robot tail end pose information comprises three-dimensional space coordinates and a pose rotation matrix of the industrial robot tail end; S3, calculating three-dimensional space coordinates of the center of the ultrasonic probe and sound beam direction vectors thereof based on the terminal pose information of the robot in the synchronous data set, calculating three-dimensional space coordinates of each reflection point in the curved composite material member by combining the material sound velocity of the curved composite material member and the sound wave flight time in the acquired ultrasonic A scanning signal, and performing color mapping and rendering according to the corresponding ultrasonic echo amplitude values at each reflection point to generate initial three-dimensional damage point cloud; S4, setting a segmentation threshold based on ultrasonic echo amplitude statistics characteristics of a non-damaged area of the curved composite material member, and primarily separating damage and background of an initial three-dimensional damage point cloud to obtain an initial segmentation damage point cloud; S5, improving a traditional DBSCAN clustering algorithm by taking the similarity of ultrasonic echo amplitude between points as a constraint condition for the initial segmentation damage point cloud to obtain an improved DBSCAN algorithm, and carrying out clustering segmentation on the initial segmentation damage point cloud to obtain point clouds of each independent damage region; S6, carrying out voxelization treatment on the point clouds of the independent damaged areas after clustering segmentation, converting the discrete point clouds into a regular three-dimensional voxel model, and accurately calculating the characterization parameters of each independent damaged area based on the three-dimensional voxel model to realize quantitative damage assessment of the curved surface composite material component.
2. The ultrasonic detection and damage assessment method for curved composite material members according to claim 1, wherein the specific process of step S1 comprises the following steps: S11, acquiring three-dimensional point cloud data by an industrial robot as an original point cloud, performing statistical outlier removal and voxel grid downsampling pretreatment on the original point cloud, improving data quality and reducing calculation complexity, and obtaining a pretreated point cloud; s12, extracting a main direction of the preprocessed point cloud by adopting a principal component analysis algorithm, establishing a local scanning coordinate system for scanning, and determining a scanning direction and a stepping direction; S13, generating a group of parallel planes at fixed intervals along the stepping direction, slicing the preprocessed point cloud in a layered manner, and extracting a contour point set formed by intersecting each layer of slice with the point cloud as a candidate path point; s14, performing B spline curve fitting on the candidate path points, and resampling the same arc length along the fitted B spline curve to obtain uniformly distributed path points; s15, solving the surface normal vector of each path point, and sequencing the path points according to an arch-shaped scanning strategy to generate an ordered detection path point sequence.
3. The ultrasonic detection and damage assessment method for a curved composite material member according to claim 2, wherein the method comprises the steps of: For each path point, searching K nearest neighbor points in the preprocessed point cloud, fitting the path point and the K nearest neighbor points into a local plane by adopting a least square method, and calculating the normal vector of the local plane as the surface normal vector of the path point; The detection path point sequence comprises coordinates of each path point and a surface normal vector of each path point.
4. The ultrasonic detection and damage assessment method for curved composite material members according to claim 1, wherein the step S2 comprises: And triggering the transmission and the reception of the probe of the ultrasonic phased array at fixed time intervals to acquire ultrasonic A scanning signals.
5. The ultrasonic detection and damage assessment method for curved composite material members according to claim 1, wherein the specific process of step S3 comprises the following steps: S31, acquiring the offset distance from the center of the ultrasonic probe to the tail end of the industrial robot, and performing pose transformation based on the pose information of the tail end of the robot to obtain the three-dimensional space coordinate of the center of the ultrasonic probe; s32, multiplying the attitude rotation matrix at the tail end of the industrial robot with the unit vector to obtain a sound beam direction vector of the center of the ultrasonic probe; S33, processing ultrasonic A scanning signals to obtain sound wave flight time and ultrasonic echo amplitude of each part of a damaged area, and calculating by combining the material sound velocity of the curved surface composite material member to obtain damage depth; S34, adding the damage depth and the coupling water layer thickness, vectorizing based on the sound beam direction vector, and then superposing to the three-dimensional space coordinate of the center of the ultrasonic probe to obtain the three-dimensional space coordinate of the imaging point corresponding to each aperture of the ultrasonic phased array, namely the three-dimensional space coordinate of each reflection point in the curved composite material component; and S35, calculating RGB values of each imaging point according to the corresponding ultrasonic echo amplitude values of each reflecting point, and rendering to generate an initial three-dimensional damage point cloud.
6. The ultrasonic detection and damage assessment method for curved composite material members according to claim 1, wherein the specific process of step S4 comprises the following steps: S41, selecting a reference point cloud in a non-damaged area of the curved composite material member, and calculating the statistical characteristics of ultrasonic echo amplitude values of all points in the reference point cloud, wherein the statistical characteristics of the ultrasonic echo amplitude values comprise the mean value and standard deviation of the ultrasonic echo amplitude values; S42, setting a segmentation threshold based on the statistical characteristics of ultrasonic echo amplitude values of each point in the reference point cloud, wherein the segmentation threshold is set in the following manner: ; Wherein, the Representing a segmentation threshold; 、 respectively representing the mean value and standard deviation of the ultrasonic echo amplitude; Is an experience coefficient; s43, traversing each point in the initial three-dimensional damage point cloud, reading an ultrasonic echo amplitude corresponding to each point, comparing the ultrasonic echo amplitude with a segmentation threshold value, judging the point as a damage candidate point if the ultrasonic echo amplitude is greater than the segmentation threshold value, and judging the point as a background point if the ultrasonic echo amplitude is greater than the segmentation threshold value; S44, constructing a set by using all the damage candidate points, and outputting the set as a primary segmentation damage point cloud, wherein the primary segmentation damage point cloud comprises three-dimensional space coordinates and ultrasonic echo amplitude values of the damage candidate points and is used for subsequent clustering.
7. The ultrasonic detection and damage assessment method for curved composite material members according to claim 1, wherein the specific process of step S5 comprises the following steps: s51, setting initial parameters of an improved DBSCAN algorithm, including a neighborhood radius, a minimum neighborhood point number and an ultrasonic echo amplitude similarity tolerance, and simultaneously marking all points in the initial segmentation damage point cloud as unvisited; S52, selecting an unaccessed point from the initial segmentation damage point cloud Marking as accessed, reading ultrasonic echo amplitude, and searching all and points Is not greater than the neighborhood radius and is equal to the point Points where the absolute value of the difference between the ultrasonic echo amplitudes is not greater than the ultrasonic echo amplitude similarity tolerance constitute points Is an active neighborhood set of (1) ; S53, judging the effective neighborhood set If the number of points in the set neighborhood point is not less than the set minimum neighborhood point, if so, the point is selected Classified as core points and added to a new cluster Then in the form of dots Is a core point based on the effective neighborhood set Clustering is performed If not, then point Temporarily classifying the points as noise points, and returning to the step S52 to select the next point which is not accessed; S54, repeating the processes of the steps S52 to S53 until all points in the initial segmentation damage point cloud are marked as accessed and classified, outputting all generated clusters, and completing the clustering segmentation process, wherein each cluster represents an independent damage area segmented by a cluster, so as to form an independent damage area point cloud.
8. The method for ultrasonic inspection and damage assessment of curved composite material member according to claim 7, wherein in step S53, the point-of-use is performed Is a core point based on the effective neighborhood set Clustering is performed Comprises the following steps: s531, from the effective neighborhood set Is not selected to be classified points Query point Whether or not it has been accessed; S532, if it is If not accessed, go to step S5321, if yes Step S5322 is performed if the user has accessed the device; S5321 marking points For accessed, the points are constructed with the same seek conditions of step S52 Is an active neighborhood set of (1) Judgment point Is an active neighborhood set of (1) Whether the number of the points in the set minimum neighborhood point is not smaller than the set minimum neighborhood point: if yes, then point Also classified as core point joining clusters At the same time point Is an active neighborhood set of (1) Merging points Is an active neighborhood set of (1) Returning to step S531 to select the next unclassified point Up to a valid neighborhood set All points in (a) are classified; if not, go to step S5322; s5322, read Point If the information of (1) Not adding any cluster, then the point Classifying as boundary points and adding clusters If it is If clusters have been added, the process returns to step S531 to select the next unclassified point Up to a valid neighborhood set All points in (a) have been classified.
9. An ultrasonic detection and damage assessment system for a curved composite material member, which is used for applying the ultrasonic detection and damage assessment method for the curved composite material member according to any one of claims 1-8, and is characterized by comprising an industrial robot, a multifunctional end effector and an upper computer; The industrial robot is a motion component part in the system and is used for driving the multifunctional end effector to carry out ultrasonic detection and feeding back the position and posture information of the tail end of the robot; The multifunctional end effector is arranged on an end flange of the industrial robot and is used for carrying out point cloud scanning and ultrasonic detection on a curved composite material component, and comprises an ultrasonic detection module (1), a coupling module (2), a flexible floating module (3), a point cloud scanning module (4) and a flange connection module (5); the upper computer is used for integrally controlling the industrial robot and the end effector to complete path planning, data acquisition, imaging and damage assessment.
10. The ultrasonic inspection and damage assessment system for curved composite members of claim 9, wherein: the ultrasonic detection module (1) is used for executing the transceiving of ultrasonic signals and acquiring ultrasonic detection data of the curved composite material component; the coupling module (2) is used for providing a coupling environment between the ultrasonic probe and the curved composite material member to be detected; The flexible floating module (3) is used for realizing the self-adaptive fitting of the detection end and the curved composite material member; The point cloud scanning module (4) is used for acquiring profile data of the curved composite material component; the flange connection module (5) is used for combining the ultrasonic detection module (1), the coupling module (2), the flexible floating module (3) and the point cloud scanning module (4) into a whole and is connected with the tail end flange of the industrial robot.

Description

Ultrasonic detection and damage assessment method and system for curved composite material component Technical Field The invention relates to the technical field of nondestructive testing, in particular to an ultrasonic testing and damage evaluation method and system for a curved composite material component. Background In recent years, composite materials are increasingly used in the fields of aerospace, rail transit and the like because of the advantages of high specific stiffness, strength, light weight characteristics, remarkable fracture resistance and the like. However, unlike metal components, the composite components have weaker interlayer strength, are susceptible to damage forms such as delamination, voids, debonding and the like during manufacturing, assembly and service, become crack propagation sources under the action of complex alternating load, weaken the comprehensive mechanical properties of the components, and seriously endanger service safety. Therefore, the interior of the composite material is required to be subjected to timely and accurate nondestructive inspection by means of ultrasonic detection and other methods to eliminate potential safety hazards, but the composite material structural member is complex in preparation process and various in structure, and higher requirements are put on ultrasonic nondestructive inspection and damage evaluation technologies. The traditional ultrasonic nondestructive testing technology mostly adopts a fixed scanning device or manual operation, and is difficult to realize high-precision three-dimensional imaging and damage evaluation on complex curved surface components. In the traditional technology, the synchronization of the ultrasonic echo signals and the scanning position is mostly dependent on a mechanical encoder or a preset path planning, and the problems of poor adaptability of complex curved surfaces, non-visual detection results, dependence on manual experience in damage assessment and the like exist. Therefore, there is a need for an ultrasound detection and lesion assessment method that is highly accurate, adaptive and automated. Disclosure of Invention Aiming at the defects of the prior art, the invention provides the ultrasonic detection and damage evaluation method and system for the curved surface composite material component, which solve the problems that the traditional ultrasonic nondestructive detection technology is difficult to realize high-precision three-dimensional imaging and damage evaluation of the complex curved surface component, the complex curved surface has poor adaptability, the detection result is not visual, the damage evaluation depends on manual experience and the like, and can realize the self-adaptive ultrasonic detection of the complex curved surface component and accurately evaluate the damage condition. In order to achieve the technical aim, the invention provides the following technical scheme that the ultrasonic detection and damage assessment method for the curved composite material component comprises the following steps: s1, an industrial robot collects three-dimensional point cloud data of a surface damage area of a curved surface composite material component, and a scanning direction is determined and a detection path point sequence is generated through preprocessing, layering slicing, feature point extraction and B spline curve fitting; S2, controlling the industrial robot to move along the detection path point sequence, synchronously scanning a damaged area along a scanning direction by utilizing an ultrasonic phased array, collecting ultrasonic A scanning signals at each sampling moment, simultaneously recording the position and posture information of the tail end of the robot at each sampling moment, and constructing a synchronous data set which takes the sampling moment as an index and contains the ultrasonic A scanning signals and the position and posture information of the tail end of the robot; the robot tail end pose information comprises three-dimensional space coordinates and a pose rotation matrix of the industrial robot tail end; S3, calculating three-dimensional space coordinates of the center of the ultrasonic probe and sound beam direction vectors thereof based on the terminal pose information of the robot in the synchronous data set, calculating three-dimensional space coordinates of each reflection point in the curved composite material member by combining the material sound velocity of the curved composite material member and the sound wave flight time in the acquired ultrasonic A scanning signal, and performing color mapping and rendering according to the corresponding ultrasonic echo amplitude values at each reflection point to generate initial three-dimensional damage point cloud; S4, setting a segmentation threshold based on ultrasonic echo amplitude statistics characteristics of a non-damaged area of the curved composite material member, and primarily separating damage and ba