Multi-energy-level X-ray and auxiliary sensor fused stress concentration area rapid positioning and screening system and multi-energy-level X-ray and auxiliary sensor fused stress concentration area rapid positioning and screening method

Abstract

The invention discloses a multi-energy-level X-ray and auxiliary sensor fused stress concentration area rapid positioning and screening system and method, and relates to the cross technical field of a nondestructive testing technology and material mechanical property evaluation. The system integrates a macroscopic positioning mechanism, a detection unit, an auxiliary sensor array, a non-contact micro-load exciter, a micro-intervention unit and other modules, and follows the closed-loop logic of active excitation-collaborative perception-data fusion-accurate quantification-in-situ verification. The method comprises the following steps: acquiring multi-source data by combining acoustic excitation with multiple sensors, and generating a suspicious area map through D-S evidence theory fusion; the stress gradient is accurately analyzed through multi-energy-level X-rays; and finally, the micro-intervention unit executes stress release and retest verification. The system breaks through the bottlenecks of low efficiency, blind positioning and single function of the traditional technology, realizes rapid, accurate and integrated detection and regulation of the stress concentration area of the large component, and is suitable for the scenes of high-speed rail bogies, aero-engine parts and the like.

Description

Technical Field

[0001] This invention relates to the interdisciplinary field of nondestructive testing technology and material mechanical property evaluation, specifically a rapid location and screening system and method for stress concentration areas by integrating multi-level X-rays and auxiliary sensors. Background Technology

[0002] In industrial production and equipment operation and maintenance, residual stress and stress concentration areas inside metal components are key factors leading to fatigue failure, crack initiation and propagation, seriously threatening the operational safety of equipment. X-ray stress testing technology, as a mature non-destructive testing technique, is widely used in the field of material mechanical property evaluation due to its advantages of high precision and non-destructiveness.

[0003] However, traditional X-ray stress testing technology has three major bottlenecks: First, it adopts a single-point measurement mode, which is extremely inefficient. For large components, comprehensive screening of stress concentration areas requires a lot of time, making it difficult to meet the rapid testing needs of industrial sites. Second, it lacks macroscopic positioning capabilities. The testing process relies on the operator's experience to select points, which is unreliable and prone to missed or false detections. Third, the testing and verification processes are disconnected. It can only complete stress measurement but cannot verify the test results in real time or effectively intervene in dangerous stress concentration areas, making it difficult to form a complete technical closed loop.

[0004] In existing technologies, some solutions attempt to combine X-ray detection with other non-destructive testing methods, but most are merely simple technology stacking, failing to achieve true data fusion and collaborative operation. For example, some systems are equipped with both infrared thermal imagers and X-ray detectors, but they operate independently, and the data is not effectively fused and analyzed. This fails to fully leverage the synergistic advantages of multimodal sensing and still cannot solve the problems of low efficiency, blind positioning, and limited functionality inherent in traditional technologies. Consequently, they cannot meet the urgent needs of industrial sites for rapid, accurate, and integrated stress detection.

[0005] Based on this, a rapid localization and screening system and method for stress concentration areas by fusing multi-level X-rays with auxiliary sensors is now provided, which can eliminate the drawbacks of existing systems. Summary of the Invention

[0006] The purpose of this invention is to provide a rapid localization and screening system and method for stress concentration areas by fusing multi-level X-rays with auxiliary sensors, in order to solve the problems in the prior art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A rapid location and screening system for stress concentration areas that integrates multi-level X-rays and auxiliary sensors, including macroscopic positioning components, detection components, micro-intervention components, support and safety components, and a non-contact micro-load exciter; The non-contact micro-load exciter applies a global transient excitation to a stationary workpiece to stimulate the thermoelastic effect characterizing the stress state. The macroscopic positioning component is used to carry an end effector for positioning in three-dimensional space; The detection component is used to achieve accurate measurement; The micro-intervention component is used to perform in-situ micro-area processing to achieve stress release and effect verification; The support and safety components are used to fix and position the workpiece to be tested, ensuring the stability of the workpiece during the testing process; The non-contact micro-load exciter is a wide-area acoustic exciter, which is fixedly installed on the inner wall of the electromagnetic shield of the support and safety components, and the excitation range covers the effective working area of ​​the stage.

[0008] Based on the above technical solutions, the present invention also provides the following optional technical solutions: In one alternative: the macroscopic positioning component includes a three-axis gantry and a six-axis robotic arm. The three-axis gantry is mounted on a platform to provide a wide-range, high-rigidity XYZ-axis motion platform. The six-axis robotic arm is mounted on the motion slider of the three-axis gantry and can provide flexible multi-angle postures, carrying end-effectors for positioning.

[0009] In one alternative: the detection component includes an integrated detection probe, which is held at the end of a six-axis robotic arm by an electromagnetic clamp, the electromagnetic clamp having a vibration damping layer module inside; The integrated detection probe integrates an auxiliary sensor module and an X-ray stress detection core. The auxiliary sensor module includes a high-resolution 3D vision camera, an infrared thermal imager, and an ultrasonic transceiver. The X-ray stress detection core includes a micro-focusing X-ray tube mounted on a phase change material heat sink, an electric multi-leaf collimator for dynamically adjusting the X-ray beam size, and a CMOS detector for precise measurement.

[0010] In one alternative: the non-contact micro-load exciter's excitation range covers the effective working area of ​​the stage, the working frequency range is 50Hz-1000Hz, and the rated power is less than 10W.

[0011] In one alternative: the micro-intervention component includes a motion track independent of the three-axis gantry and a micro-intervention robotic arm running on the motion track, the end of which carries a micro-force-sensing drill bit holder for performing in-situ micro-area machining.

[0012] In one alternative: the support and safety assembly includes an electromagnetic shield and a stage, the stage being used to fix and position the workpiece to be tested, and the electromagnetic shield being used to provide an electromagnetic compatibility environment.

[0013] This invention also discloses a rapid localization and screening system and method for stress concentration areas by fusing multi-level X-rays with auxiliary sensors, comprising the following steps: S1: 3D topography scanning and baseline establishment: The six-axis robotic arm, equipped with a high-resolution 3D vision camera, performs non-contact scanning of the workpiece on the stage along a preset path, generating a high-precision three-dimensional point cloud model of the workpiece. This establishes a unified global coordinate system and spatial reference for the entire system, automatically identifying geometric discontinuities such as welds, concave corners, and notches, and marking them as "geometrically suspicious areas." S2: Synchronous monitoring of acoustic excitation and infrared thermal imaging: The control system triggers a non-contact micro-load exciter to operate for 1-3 seconds in the frequency range of 100-500Hz, thereby exciting the entire workpiece to generate micron-level vibration. S3: Ultrasonic surface wave pinpoint measurement: The ultrasonic transceiver is moved to the surface of the "geometric suspicious area" and the "hot spot suspicious area". Acoustic coupling is achieved through an external automatic coupling agent supply device. The surface wave propagation speed is measured and compared with the stress-free reference area. Areas where the speed change exceeds the threshold are marked as "sound speed suspicious areas". S4: Data Fusion and Map Generation The control system runs fusion algorithms such as DS evidence theory to overlay and calculate the probability of the "suspicious areas" from the three sensors onto a unified three-dimensional model, generating a "stress concentration suspicious area probability map". This map marks 1 to N high-probability areas and their coordinates on the three-dimensional model with different colors and gives the detection priority. S5: Intelligent Path Planning and Positioning Based on the "probability map of suspicious areas" and the shortest path principle, the control system automatically tracks the movement trajectory of the six-axis robotic arm. The robotic arm, carrying the X-ray detection core, moves to the highest priority suspicious area. Using the 3D model established in step S1, the robotic arm's posture is automatically adjusted to ensure that the X-ray beam is perpendicular to the workpiece surface. S6: Multi-level X-ray stress measurement: A two-step measurement method, from fast to precise, is adopted: Rapid screening: The motorized multi-leaf collimator is switched to the large spot mode, and the X-ray tube is rapidly switched between several voltages such as 30kV and 40kV. Only a few ψ angles are measured, and the presence of stress anomalies and gradient trends in the area can be quickly assessed within 10-20 seconds. Precise quantification: If the screening result is abnormal, the collimator immediately switches to the small spot mode, performs a complete sin²ψ method measurement at the point of highest stress, and uses multiple tube voltages to obtain diffraction data at different depths; Output the precise surface stress value, principal stress direction, and stress distribution σ(z) at this point with respect to depth; The robotic arm then moves automatically to the next suspicious area according to the planned path, repeating steps S5 and S6 until all high-probability areas have been measured. S7: Micro-intervention decision-making: When the control system determines that the stress value at a certain measurement point exceeds the preset safety threshold, it will prompt the operator or automatically generate a micro-intervention command. At this time, the main robotic arm carrying the X-ray detection core will return to a safe position. S8: Micro-hole fabrication and stress relief: The control system schedules an independent micro-intervention robotic arm to move along its motion path to the target coordinates. The micro-force sensor drill bit holder on the micro-intervention robotic arm performs micro-hole machining and monitors the feed force in real time to prevent drill breakage. S9: Effect Verification; After the micro-intervention is completed, the six-axis robotic arm returns to the point with the X-ray detection core to perform a rapid stress measurement. By comparing stress data before and after drilling, the stress release rate was calculated. A significant release rate verified the accuracy of the initial detection and simultaneously completed stress control.

[0014] In one alternative approach: In step S2, within 5-10 seconds before the excitation begins, during the excitation process, and after the excitation stops, the infrared thermal imager continuously captures a sequence of temperature field images of the workpiece surface at a high frame rate. By analyzing the thermal sequence images, the temperature change rate of each pixel is calculated. Force concentration areas, due to their high vibration energy consumption, will exhibit a slower cooling rate or a higher temperature rise than their surroundings, thus being identified as "suspected hot spot areas". Compared with the prior art, the beneficial effects of the present invention are as follows: This invention employs a detection strategy of "macroscopic rapid screening + microscopic precise quantification". It uses an auxiliary sensor array to perform rapid full-field scanning of the workpiece, intelligently generating a limited number of high-probability stress concentration suspicious areas. Then, it schedules the X-ray stress detection core to perform precise quantitative measurements only on these key areas, minimizing the number of points for the most time-consuming X-ray fine measurement. Compared with the traditional point-by-point inspection mode, the detection efficiency is improved by several times.

[0015] This invention constructs a collaborative sensing system based on the "geometry-thermal-acoustic" multi-physics coupling principle. By fusing multi-source data through the DS evidence theory algorithm, the detection results of different sensors are cross-validated. The overall confidence level of a region that shows anomalies in three dimensions—morphology, thermal, and acoustic—is determined to be a stress concentration area is increased by an order of magnitude. This fundamentally overcomes the defects of single sensors being susceptible to interference, misjudgment, or missed detection, and achieves a qualitative leap in positioning reliability.

[0016] This invention integrates multiple functions such as detection, positioning, verification, and control. It can not only quickly locate and accurately measure stress concentration areas, but also perform in-situ micro-processing on dangerous stress concentration areas through independent micro-intervention units to achieve stress release. The release effect is verified through retesting, forming a complete technical closed loop and solving the problem of disconnect between detection and verification in traditional technologies.

[0017] The system of this invention adopts a non-contact detection and intervention method, which can realize in-situ detection of large components without disassembly, thus reducing detection costs. It is applicable to the detection of residual stress and stress concentration areas of various metal components such as high-speed rail bogies and aero-engine parts, and can meet the urgent needs of industrial sites for rapid, accurate and integrated stress detection, and has broad application prospects. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the present invention.

[0019] Figure 2 This is a flowchart of the rapid pre-location and suspicious area generation process of the present invention.

[0020] Figure 3 This is a flowchart of the precise quantitative and in-situ verification control process of the present invention.

[0021] Figure label annotations: 1 Three-axis gantry, 2 Electromagnetic shield, 3 High-resolution 3D vision camera, 4 Six-axis robotic arm, 5 Harmonic reducer, 6 Electromagnetic clamp, 7 Programmable high voltage generator, 8 Micro-intervention robotic arm, 9 Motion track, 10 Stage, 11 CMOS detector, 12 Micro-focusing X-ray tube, 13 Electric multi-leaf collimator, 14 Infrared thermal imager, 15 Phase change material heat dissipation base, 16 Ultrasonic transceiver, 17 Vibration damping partition module, 18 Non-contact micro-load exciter. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0023] In one embodiment, such as Figure 1-3As shown, the stress concentration area rapid positioning and screening system integrating multi-level X-ray and auxiliary sensors includes a macro positioning component, a detection component, a micro-intervention component, a support and safety component, and a non-contact micro-load exciter 18. The non-contact micro-load exciter 18 applies a global transient excitation to a stationary workpiece to stimulate the thermoelastic effect characterizing the stress state. The macroscopic positioning component is used to carry an end effector for positioning in three-dimensional space; The detection component is used to achieve accurate measurement; The micro-intervention component is used to perform in-situ micro-area processing to achieve stress release and effect verification; The support and safety components are used to fix and position the workpiece to be tested, ensuring the stability of the workpiece during the testing process; The non-contact micro-load actuator 18 is a wide-area acoustic actuator, which is fixedly installed on the inner wall of the electromagnetic shield 2 of the support and safety components, and the excitation range covers the effective working area of ​​the stage 10.

[0024] The above embodiments disclose a rapid location and screening system for stress concentration areas by fusing multi-level X-rays with auxiliary sensors. Its specific working principle and process are as follows: (I) Rapid Location and Screening System for Stress Concentration Zones It includes macroscopic positioning components, detection components, non-contact micro-load exciter, micro-intervention components, and support and safety components. These components work together to achieve intelligent detection and closed-loop control of stress concentration areas.

[0025] The macroscopic positioning component is used to carry the end effector for precise positioning in three-dimensional space, and includes a three-axis gantry 1 and a six-axis robotic arm 4. The three-axis gantry 1 is mounted above the stage 10, providing a large-range, high-rigidity XYZ-axis motion platform, enabling rapid movement of the detection component within a large spatial range; the six-axis robotic arm 4 is mounted on the motion slider of the three-axis gantry 1, and has flexible multi-angle attitude adjustment capabilities, which can precisely adjust the attitude of the detection component to ensure detection accuracy.

[0026] The detection component is an integrated detection probe, which is held at the end of a six-axis robotic arm 4 by an electromagnetic clamp 6 equipped with a vibration damping layer module 17. The vibration damping layer module 17 can effectively reduce the impact of vibration during the movement of the robotic arm on the detection accuracy.

[0027] The integrated detection probe integrates an auxiliary sensor module and an X-ray stress detection core, enabling rapid pre-positioning and accurate measurement.

[0028] Auxiliary sensor module: for rapid pre-positioning, including a high-resolution 3D vision camera 3, an infrared thermal imager 14, and an ultrasonic transceiver 16. The high-resolution 3D vision camera 3 can acquire high-precision three-dimensional topographic data of the workpiece, establish a global spatial coordinate reference, and automatically identify areas with high geometric stress concentration coefficients, such as notches, weld toes, and variable cross-sections; the infrared thermal imager 14, under synchronous excitation by a non-contact micro-load exciter, detects micro-area thermoelastic effects caused by stress concentration and locks down areas of energy anomalies; the ultrasonic transceiver 16, based on the acoustoelastic effect, evaluates near-surface mechanical property anomalies by measuring changes in surface wave velocity.

[0029] The core components of X-ray stress detection, used for precise measurement, include a micro-focusing X-ray tube 12 on a phase change material heat sink 15, an electrically driven multi-leaf collimator 13 for dynamically adjusting the X-ray beam size, and a CMOS detector 11. The micro-focusing X-ray tube 12 generates a high-precision X-ray beam to excite the workpiece lattice and produce diffraction signals. The phase change material heat sink 15 effectively dissipates heat, ensuring stable operation of the X-ray tube. The electrically driven multi-leaf collimator 13 dynamically adjusts the X-ray beam size, enabling switching between rapid screening with a large beam and precise quantitative measurement with a small beam. The CMOS detector 11 rapidly acquires X-ray diffraction patterns, enabling rapid calculation of stress values.

[0030] The non-contact micro-load actuator 18 is a wide-area acoustic actuator, which is fixedly installed on the inner wall of the electromagnetic shield 2 of the support and safety components. The excitation range covers the effective working area of ​​the stage 10. The actuator operates in the frequency range of 50Hz-1000Hz, has a rated power of less than 10W, and can apply global transient low-frequency vibration to the workpiece to excite the thermoelastic effect characterizing the stress state, providing a physical basis for the detection of the auxiliary sensor module.

[0031] The micro-intervention component is used to perform in-situ micro-area machining, achieving stress release and effect verification. It includes a motion track 9 independent of the three-axis gantry 1 and a micro-intervention robotic arm 8 running on the track. The end effector of the micro-intervention robotic arm 8 carries a micro-force-sensing drill bit holder, which can perform micro-hole machining operations. The micro-force sensing function can monitor the feed force in real time to prevent drill breakage and ensure the safety and reliability of the machining process.

[0032] The support and safety components include a stage 10 and an electromagnetic shield 2. The stage 10 is used to fix and position the workpiece to be tested, ensuring the stability of the workpiece during the testing process. The electromagnetic shield 2 provides an electromagnetic compatibility environment to avoid the influence of external electromagnetic interference on the testing equipment, and also prevents X-ray leakage, ensuring the safety of the operators. The macroscopic positioning components, testing components, auxiliary sensor modules, non-contact micro-load exciter, and micro-intervention components are all integrated within the electromagnetic shield 2, forming an integrated testing platform.

[0033] The control and data processing module is the core control unit of the system. It is configured to execute collaborative control processes, enabling the orderly operation of each module and the fusion processing of data. Specifically, it includes the following steps: Data acquisition: Drive the macro positioning component to enable the integrated detection probe to scan the workpiece. During this process, the non-contact micro-load exciter is triggered to work simultaneously, and the infrared thermal imager 14 is controlled to acquire dynamic thermal sequence images of the workpiece surface. At the same time, the high-resolution 3D vision camera 3 and the ultrasonic transceiver 16 are controlled to acquire morphology and sound velocity data respectively.

[0034] Data fusion: Based on the collected dynamic thermal sequence images, topographic data, and sound velocity data, the DS evidence theory algorithm is used for fusion calculation to generate a probability map of suspected stress concentration areas covering the workpiece surface. The DS evidence theory algorithm can quantify and synthesize the degree of support from different sensors for the proposition that "this point is a stress concentration area," thereby improving the reliability of positioning.

[0035] Precise Measurement: Based on the probability map of suspected stress concentration areas, the path of the six-axis robotic arm 4 is planned, and the X-ray stress detection core is moved to each suspected area in sequence. By controlling the electric multi-leaf collimator 13 to switch the spot size and adjusting the voltage of the micro-focusing X-ray tube 12, a seamless connection is achieved from rapid screening with large spots to precise quantitative measurement with small spots, and the stress gradient at different depths is obtained.

[0036] Micro-intervention and verification: When the measured stress value at a certain point exceeds the preset threshold, an independent micro-intervention component is dispatched to move to that point, perform micro-hole processing to achieve stress release, and control the X-ray stress detection core to return for retesting to verify the stress release effect, forming a complete technical closed loop.

[0037] (II) Methods for rapid location and screening of stress concentration areas: Based on the above system, the present invention also provides a method for rapid location and screening of stress concentration areas, comprising the following steps: S1: Rapid pre-positioning controls the auxiliary sensor module to quickly scan the workpiece, simultaneously triggering the non-contact micro-load exciter. A high-resolution 3D vision camera 3 scans and generates a high-precision 3D point cloud model of the workpiece, automatically identifying geometric discontinuities and marking them as "geometrically suspicious areas." An infrared thermal imager 14 acquires dynamic thermal sequence images during and before / after the exciter's operation, analyzing the temperature change rate of each pixel. Stress concentration areas, due to high vibration energy consumption, slow cooling rates, or higher temperature rises, are marked as "hot spot suspicious areas." An ultrasonic transceiver 16 moves to the "geometrically suspicious areas" and "hot spot suspicious areas," achieving acoustic coupling through an automatic coupling agent supply device. The surface wave propagation speed is measured, and areas where the speed change exceeds a threshold (e.g., ±0.5%) are marked as "sound speed suspicious areas."

[0038] The DS evidence theory algorithm is used to perform multi-source data fusion calculation on the relevant data of "geometric suspicious area", "hot spot suspicious area" and "sound velocity suspicious area" to generate a probability map of stress concentration suspicious areas covering the surface of the workpiece. The map marks high probability areas and their coordinates with different colors on the three-dimensional model and gives the detection priority.

[0039] S2: Precise measurement. Based on the probability map of suspected stress concentration areas and the shortest path principle, the movement trajectory of the six-axis robotic arm 4 is automatically planned, and the macroscopic positioning component is controlled to move the X-ray stress detection core to each suspected area sequentially. Using the 3D model established in step S1, the robotic arm posture is automatically adjusted to ensure that the X-ray beam is perpendicular to the workpiece surface.

[0040] A two-step measurement method, from fast to precise, is adopted: First, the motorized multi-leaf collimator 13 switches to the large spot mode, and the X-ray tube rapidly switches between multiple voltages such as 30kV and 40kV, measuring only a few ψ angles to quickly assess whether there is stress anomaly and gradient trend in the area within 10-20 seconds; if the screening result is abnormal, the collimator immediately switches to the small spot mode, performs a complete sin²ψ method measurement (multiple ψ angles) at the point of highest stress, and uses multiple tube voltages to obtain diffraction data at different depths.

[0041] Based on Bragg's law, the sin²ψ method, and the principle of depth profile analysis, the stress value and stress distribution with depth are calculated. Bragg's law is used to determine the conditions for X-ray diffraction in a crystal, and its formula is 2dsinθ=nλ (d is the interplanar spacing, θ is the diffraction angle, λ is the X-ray wavelength, and n is the diffraction order). By measuring the change in interplanar spacing under different incident angles, and combining it with the strain calculation formula ε=(d-d0) / d0=-cotθ0*(θ-θ0) (d0 and θ0 are reference values ​​in the stress-free state), the strain is calculated. Then, according to the sin²ψ method stress calculation formula σ=[E / (1+ν)]* ε / The stress value is calculated using (sin²ψ) (where E is Young's modulus and ν is Poisson's ratio). By solving the weighted average stress under different tube voltages, and combining the X-ray attenuation model and the Tikhonov regularized inversion algorithm, the stress distribution σ(z) with depth is analyzed.

[0042] S3: When the verification and control and data processing module determines that the stress value at a certain measurement point exceeds the preset safety threshold (such as 70% of the material yield strength), it prompts the operator or automatically generates a micro-intervention command, and the main robotic arm carrying the X-ray detection core returns to the safe position.

[0043] The independent micro-intervention robotic arm 8 moves along its motion track 9 to the target coordinates. The micro-force sensing drill bit holder performs micro-hole machining (e.g., Ø0.5mm, 1mm depth) and monitors the feed force in real time to prevent drill breakage. After the micro-intervention is completed, the six-axis robotic arm 4 returns to the point with the X-ray detection core to perform a rapid stress measurement. By comparing the stress data before and after drilling, the stress release rate is calculated. If the release rate is significant (e.g., >20%), the accuracy of the initial detection is verified, and stress regulation is completed, forming a complete "detection-positioning-verification-regulation" technical closed loop.

[0044] Example 1: In-service maintenance of key welds on high-speed railway bogies Inspection target: Key load-bearing welds on the side beams of the bogie of a certain type of high-speed train. The material is high-strength low-alloy steel, and in-situ inspection is required.

[0045] Testing process: S1: Rapid pre-positioning (on-site time: approximately 20 minutes) 3D Vision Scanning: The six-axis robotic arm 4, carrying a high-resolution 3D vision camera 3, scans a weld area approximately two meters long, generating a high-precision three-dimensional point cloud model of the workpiece. The software automatically identifies three areas (A, B, C) with poor geometric shape at the weld toe and obvious undercut, marking them as "geometrically suspicious areas".

[0046] Infrared thermal imaging screening: The non-contact micro-load exciter 18 is triggered to work in the frequency range of 100-500Hz for 1-3 seconds to excite the workpiece to generate micron-level vibration; the infrared thermal imager 14 continuously captures temperature field sequence images at a high frame rate of 30Hz before, during and after excitation, and for 5-10 seconds after stopping. Analysis reveals an abnormally clear strip-shaped hot spot near area B, with a cooling rate about 40% slower than the surrounding area, which is marked as a "hot spot suspicious area".

[0047] Ultrasonic surface wave measurement: The robotic arm was controlled to move the ultrasonic transceiver 16 to the "geometric suspicion area" and the "hot spot suspicion area" to measure the surface wave propagation speed. No obvious abnormal sound speed area was found.

[0048] Data fusion: The DS evidence theory algorithm is used to fuse the data. Region B has both "geometric defects" and "hot spot anomalies" characteristics and is marked as the highest priority detection point, while regions A and C are secondary priority.

[0049] S2: Precise Measurement (On-site time: approximately 15 minutes / point) Positioning and Survey: The robotic arm carrying the X-ray probe was precisely moved to the center of the hot spot in area B. The motorized multi-leaf collimator 13 was switched to the Ø3mm large spot mode. The X-ray tube was rapidly switched between 30kV and 40kV voltages. It was initially estimated that the stress in this area exceeded 300MPa and there was a large gradient.

[0050] Precise quantification: The collimator was switched to the Ø0.5mm small spot mode, and a complete sin²ψ method measurement (7 ψ angles) was performed at the center of the hot spot. Stress depth distribution was analyzed using multi-level analysis at 25kV, 30kV, 35kV, and 40kV. Final measurement results: The surface stress was +385MPa (tensile stress). Within a depth of 0.1mm, the stress rapidly decreased to approximately 250MPa. This stress value is close to the material's fatigue strength limit, indicating a high risk of fatigue crack initiation.

[0051] S3: Micro-intervention and validation (On-site time: approximately 10 minutes) Micro-intervention execution: The micro-intervention robotic arm 8 is scheduled to move to the target coordinates to perform micro-hole machining with a diameter of Ø0.5mm and a depth of 1.0mm, and the feed force is monitored in real time.

[0052] Effect verification: After drilling, the X-ray probe returned to the point for rapid retesting. The stress value dropped from 385MPa to 155MPa, and the stress release rate reached 60%, verifying the accuracy of the initial test and completing stress control.

[0053] Example 2: Risk Assessment of Stress Concentration and Microcrack Initiation in the Tenon Groove of High-Pressure Turbine Blades for Aero-Engines The object of inspection: the tenon and groove of the first stage blade of a high-pressure turbine of a certain type of commercial aero-engine, which mates with the turbine disk. The material is a nickel-based high-temperature alloy.

[0054] Detection process: S1: Rapid pre-positioning (time per blade: 25 minutes) 3D visual topography measurement: High-resolution 3D vision camera 3 takes full-size point cloud of the tooth root of the tenon groove. The software automatically analyzes the machining deviation of the tooth root contour radius and finds that the actual fillet radius of the first tooth root of the tenon groove of blades No. 3, 5 and No. 7 is about 0.05mm smaller than the design value (R0.5mm) and the surface roughness Ra value is slightly higher, which is marked as "geometric doubt area".

[0055] Infrared thermal imaging load spectrum mapping: Utilizing the residual heat after the engine's last test run, in a constant temperature and dust-free workshop, the high-sensitivity 14 continuously monitored the cooling blade tenons and found a linear low-temperature band with a length of about 1.5 mm at the root of the first tooth of the tenon groove of blade No. 5, which was marked as a "hot spot suspected area".

[0056] Ultrasonic surface wave measurement: The ultrasonic transceiver 16 was moved to the above-mentioned suspicious area to measure the surface wave velocity, and no obvious abnormalities were found.

[0057] Data fusion: The target area of ​​blade No. 5 simultaneously meets the conditions of "geometric defect" and "load concentration" and is marked as the detection point of "highest risk level".

[0058] S2: Precise Measurement (Time: 20 minutes) Positioning and Measurement: The robotic arm, carrying a miniature X-ray probe, precisely aligned a Ø0.1mm micro-spot with the "linear low-temperature zone" at the root of the fifth blade using 3D vision guidance. Measurements were performed at three energy levels (25kV, 30kV, and 35kV) and multiple ψ angles. Measurement Results: The surface stress was +625MPa (tensile stress). At a depth of 0.05mm, the stress was still as high as +580MPa, with a gentle gradient, far exceeding the material's high-cycle fatigue limit (10^7 cycles, ±550MPa).

[0059] S3: Micro-intervention and validation (Time: 15 minutes) Verification micro-intervention: With the consent of the manufacturer's representative, a micro drill bit is used to perform verification hole machining with a diameter of 0.2 mm and a depth of 0.15 mm.

[0060] Stress release verification: After drilling, the stress was measured again and dropped from 625MPa to 210MPa, with a release rate of 66%, confirming the existence of an extremely high non-uniform concentrated stress field at this point.

[0061] Microscopic analysis: Scanning electron microscopy analysis of the trace amount of chips obtained by micro-drilling revealed multiple dislocation pile-ups and early slip bands at this point, which are precursors to fatigue crack initiation.

[0062] Using the principle calculation method: 1. Multi-sensor data fusion algorithm (for rapid pre-positioning) Principle: Using DS evidence theory or fuzzy integrals, information from sensors with different physical properties, such as infrared, vision, and ultrasound, is fused. The degree of support of each sensor for the proposition that "this point is a stress concentration area" is quantified and synthesized, and finally a comprehensive "stress concentration probability distribution map" is output.

[0063] Formula example (Simplified model of DS evidence theory): Let U To identify the frame, where A B represents "a stress concentration area". It represents "no".

[0064] For each sensor s (Such as an infrared thermal imager), it assigns a basic probability assignment function m to a region. satisfy: in It indicates "uncertainty".

[0065] The fusion rule for two sensors (such as infrared and ultrasound) is as follows:

[0066] Among them, K It is a normalization constant used to exclude the influence of conflicting evidence.

[0067] Ultimately, m was chosen. The area with the highest stress value is designated as a potential stress concentration zone.

[0068] 2. Principles and Formulas for Calculating Multi-Level X-ray Stress Principle: Based on Bragg's law and sin²ψ The method calculates stress by measuring the change in interplanar spacing at different incident angles. Multiple energy levels (different voltages) imply different penetration depths, thus yielding stress gradients.

[0069] Core formula: 3. Bragg's Law: Where, d It is the interplanar spacing, θ It is the diffraction angle, λ It is the wavelength of X-rays.

[0070] 4. Strain calculation: Among them, d0 and θ0 It is the reference value for the stress-free state, ψ and φ It measures the direction angle.

[0071] 5. Stress calculation (sin²ψ method): Among them, E It is Young's modulus, ν It is Poisson's ratio. This is determined by linear fitting of sin²ψ. The stress σ can be calculated from the slope.

[0072] 6. Depth Contour Analysis: By solving for different tube voltages Weighted average stress under By combining the X-ray attenuation model, stress as a function of depth can be inverted. Distribution This is a typical inverse problem solution, which can be achieved through... Solving using regularization and other methods:

[0073] Among them It is the weight function matrix. It is a smoothing operator, and α' is a regularization parameter.

[0074] 7. The thermoelastic effect principle of infrared thermal imaging stress localization Principle: Under adiabatic or near-adiabatic conditions, materials undergo temperature changes during elastic deformation (thermoelastic effect). The strain energy density is high in stress concentration areas, resulting in more significant temperature change signals.

[0075] Formula (thermoelastic effect):

[0076] in:

[0077]

[0078]

[0079]

[0080]

[0081]

[0082] By monitoring the distribution of ΔT under cyclic loading or instantaneous excitation, stress concentration areas can be located.

[0083] Principle of Ultrasonic Surface Wave Stress Detection Principle: Stress (strain) affects the acoustoelastic constant inside a material, thereby changing the propagation speed of ultrasonic waves, especially surface waves.

[0084] Formula (acoustic elasticity effect):

[0085] (This is a simplified form; the specific formula varies depending on the waveform and boundary conditions.) in:

[0086]

[0087]

[0088]

[0089]

[0090]

[0091] 8. Intelligent path planning algorithm (for improving efficiency) Principle: The process of finding stress concentration points is modeled as a sequential decision problem. Using algorithms such as Bayesian optimization or reinforcement learning, the next best measurement point is intelligently selected based on existing measurement data and prior sensor information, so as to find the true stress concentration area with the fewest number of measurements.

[0092] Formula example (Bayesian optimization): Define a data acquisition function, as desired for improvement:

[0093] Among them It is an unknown stress concentration function. This is the current optimal measurement point. This is existing data.

[0094] The algorithm selects at each step to make ' The largest point Measurements are performed to achieve an efficient global search.

[0095] Theoretical basis and calculation formula The theoretical basis for X-ray stress measurement is crystal diffraction and elasticity. This is the physical basis for accurate stress measurement.

[0096] 9. Bragg's Law Principle: The conditions under which X-rays diffract in a crystal.

[0097] formula:

[0098] In the formula:

[0099]

[0100]

[0101]

[0102] 10. Lattice strain calculation Principle: Calculate lattice strain by observing changes in the diffraction angle.

[0103] formula:

[0104] In the formula:

[0105]

[0106]

[0107]

[0108] 11. Stress calculation using the sin²ψ method Principle: In polycrystalline materials, the stress and strain in a specific direction (φ) have a linear relationship with the change of sin²ψ.

[0109] formula:

[0110] For simplicity, it is often written as:

[0111] In the formula:

[0112]

[0113]

[0114]

[0115]

[0116] 12. Principle of Multi-Level Deep Analysis Principle: X-rays of different energies have different penetrating abilities, and their measurement signal is a weighted average of the stress distribution σ(z) with depth.

[0117] formula:

[0118] The system controls the X-ray tube to operate at different voltages to obtain weighted average stress data at different penetration depths, and analyzes the stress distribution σ(z) with depth based on the X-ray attenuation model and regularized inversion algorithm.

[0119] In the formula:

[0120]

[0121]

[0122] Theoretical basis of infrared thermal imaging positioning: thermoelastic effect Principle: Under adiabatic or near-adiabatic conditions, the elastic deformation of isotropic materials will cause temperature changes.

[0123] formula:

[0124] In the formula:

[0125]

[0126]

[0127]

[0128]

[0129]

[0130] Application: Under cyclic loading or instantaneous excitation, the stress concentration area has the largest stress amplitude and its ΔT is also the most significant, thus appearing as a "hot spot" or "cold spot" on the thermography.

[0131] The theoretical basis of ultrasonic surface wave localization: acoustic elastic effect Principle: Stress changes the elastic constant of a material, which in turn affects the propagation speed of ultrasound waves within it.

[0132] Formula (for surface waves propagating along direction 3, affected by σ3 stress):

[0133] In the formula:

[0134]

[0135]

[0136]

[0137]

[0138] Data fusion and decision theory foundations: Evidence theory Principle: Mathematically synthesize the degree of support from different sensors for the same proposition ("this point is a stress concentration area").

[0139] The basic probability assignment function of DS evidence theory is used: For the recognition framework (H: is a stress concentration area, H: is not): Each sensor i is assigned a basic probability value. satisfy:

[0140] The fusion rule for two sensors (such as infrared 1 and ultrasound 2) is as follows:

[0141] In the formula, the denominator is the normalization constant K, which is used to eliminate conflicts between pieces of evidence.

[0142] application: The higher the value, the more reliable it is to be identified as a stress concentration area.

[0143] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A multi-level X-ray and auxiliary sensor fusion stress concentration area rapid positioning and screening system, characterized in that, It comprises a macro positioning assembly, a detection assembly, a micro intervention assembly, a support and safety assembly, and a non-contact micro load exciter (18); The non-contact micro load exciter (18) applies global transient excitation to the static workpiece to excite thermal-elastic effect representing stress state; The macro positioning assembly is used to carry the end tool for positioning in three-dimensional space; The detection assembly is used to realize accurate measurement; The micro intervention assembly is used to perform in-situ micro area processing to realize stress release and effect verification; The support and safety assembly is used to fix and position the workpiece to be tested to ensure the stability of the workpiece during detection; The non-contact micro load exciter (18) is a wide-area acoustic wave exciter, which is fixedly installed on the inner side wall of the electromagnetic shield (2) of the support and safety assembly, and the excitation range covers the effective working area of the worktable (10).

2. The multi-level X-ray and auxiliary sensor fusion stress concentration zone rapid positioning and screening system according to claim 1, characterized in that, The macro positioning assembly comprises a three-axis gantry (1) and a six-axis mechanical arm (4), the three-axis gantry (1) is erected on the worktable (10) to provide a large-range, high-rigidity XYZ axial motion platform, and the six-axis mechanical arm (4) is installed on the moving slider of the three-axis gantry (1) to provide a flexible multi-angle posture and carry the end tool for positioning.

3. The multi-level X-ray and auxiliary sensor fusion stress concentration zone rapid positioning and screening system according to claim 1, characterized in that, The detection assembly comprises an integrated detection probe, which is held by the six-axis mechanical arm (4) at the end through an electromagnetic clamp (6), and a damping separation module (17) is arranged in the electromagnetic clamp (6); The integrated detection probe is internally integrated with an auxiliary sensor module and an X-ray stress detection core, the auxiliary sensor module comprises a high-resolution 3D vision camera (3), an infrared thermal imager (14) and an ultrasonic transceiver (16), and the X-ray stress detection core comprises a micro-focus X-ray tube (12) installed on a phase change material heat dissipation base (15), an electric multi-leaf collimator (13) for dynamically adjusting the size of an X-ray beam spot and a CMOS detector (11) for accurate measurement.

4. The multi-level X-ray and auxiliary sensor fusion stress concentration zone rapid positioning and screening system according to claim 1, characterized in that, The non-contact micro load exciter (18) has an excitation range covering the effective working area of the worktable (10), a working frequency range of 50-1000 Hz, and a rated power of less than 10 W.

5. The multi-level X-ray and auxiliary sensor fusion stress concentration zone rapid positioning and screening system according to claim 1, characterized in that, The micro intervention assembly comprises a moving track (9) independent of the three-axis gantry (1) and a micro intervention mechanical arm (8) running on the moving track (9), the micro intervention mechanical arm (8) carries a micro force sensing drill bit holder at the end for performing in-situ micro area processing.

6. The multi-level X-ray and auxiliary sensor fusion stress concentration zone rapid positioning and screening system according to claim 1, characterized in that, The support and safety assembly comprises an electromagnetic shield (2) and a worktable (10), the worktable (10) is used to fix and position the workpiece to be tested, and the electromagnetic shield (2) is used to provide an electromagnetic compatible environment.

7. A method for rapid positioning and screening of stress concentration areas based on the system of any one of claims 1-6, characterized in that, The steps include: S1: 3D topography scanning and reference establishment: The six-axis robot (4) carries a high-resolution 3D vision camera (3) to perform non-contact scanning of the workpiece on the worktable (10) along a preset path, generating a high-precision three-dimensional point cloud model of the workpiece, establishing a unified global coordinate system and spatial reference for the entire system, and automatically identifying geometric discontinuities such as welds, corners, and gaps, marking them as "geometric suspicious areas"; S2: Synchronous monitoring of acoustic excitation and infrared thermal imaging: The control system triggers the non-contact micro-load exciter (18) to work in the frequency range of 100-500Hz for 1-3 seconds, exciting the entire workpiece to produce micron-level vibrations; S3: Ultrasonic surface wave point measurement: The ultrasonic transceiver (16) is controlled to move to the surface of the "geometric suspicious area" and "thermal spot suspicious area", achieve acoustic coupling through an external automatic coupling agent supply device, and measure the surface wave propagation speed. The speed is compared with the stress-free reference area, and the area where the speed changes exceeds the threshold is marked as "acoustic speed suspicious area"; S4: Data fusion and atlas generation: The control system runs DS evidence theory fusion algorithm to superimpose and calculate the "suspicious area" list from the three sensors on the unified three-dimensional model, generating a "stress concentration suspicious area probability atlas". The atlas marks 1~N high probability areas and their coordinates on the three-dimensional model with different colors, and gives the detection priority; S5: Intelligent path planning and positioning: The control system automatically adjusts the motion trajectory of the six-axis robot (4) according to the "suspicious area probability atlas" and the shortest path principle. The robot carries the X-ray detection core to the highest priority suspicious area, adjusts the robot posture automatically based on the 3D model established in step S1, and ensures that the X-ray beam is perpendicular to the workpiece surface; S6: Multi-energy level X-ray stress measurement: Two-step measurement method from fast to accurate: Fast screening: The motorized multi-leaf collimator (13) switches to large spot mode, the X-ray tube quickly switches at several voltages such as 30kV and 40kV, only a few ψ angles are measured, and the area is quickly evaluated within 10-20 seconds to determine whether there is stress anomaly and gradient trend; Accurate quantification: If the screening result is abnormal, the collimator immediately switches to small spot mode, aligns the highest stress point for complete sin²ψ method measurement, and uses multiple tube voltages to obtain diffraction data at different depths; Output the accurate surface stress value, principal stress direction, and stress distribution σ(z) with depth of the point; Then the robot moves to the next suspicious area according to the planned path, repeats steps S5 and S6, and measures all high probability areas; S7: Micro-intervention decision: When the control system determines that the stress value of a measurement point exceeds the preset safety threshold, it will prompt the operator or automatically generate a micro-intervention instruction. At this time, the main robot carrying the X-ray detection core retreats to a safe position; S8: Micro-hole machining and stress release: The control system dispatches the independent micro-intervention robot (8) to move to the target coordinate along its motion trajectory (9), and the micro-force sensing drill holder on the micro-intervention robot (8) performs micro-hole machining and real-time monitoring of the feed force to prevent the drill from breaking; S9: Effect verification; After the micro-intervention is completed, the six-axis robot (4) carries the X-ray detection core back to the point again to perform a rapid stress measurement; By comparing the stress data before and after drilling, the stress release rate is calculated, and the accuracy of the initial detection is verified if the release rate is significant, and the stress regulation is completed at the same time.

8. The method of claim 7, wherein the stress concentration zone is a region of the body that is subjected to a high level of stress. In step S2, the infrared thermal imager (14) continuously shoots the surface temperature field sequence images of the workpiece at a high frame rate within 5-10 seconds before the excitation starts, during the excitation, and after the excitation stops. By analyzing the thermal sequence images, the temperature change rate of each pixel point is calculated. The force concentration area will show a slower cooling rate or a higher temperature rise than the surrounding area due to large vibration energy consumption, so it is identified as a "thermal spot suspicious area".

Images