Underwater laser shock remanufacturing method and system

Abstract

The invention discloses an underwater laser shock remanufacturing method and system, and belongs to the field of underwater laser shock remanufacturing, and the method comprises the following steps: establishing a workpiece three-dimensional defect model according to a defect detection signal; a double-layer dynamic water body isolation structure is formed in the model area through a coaxial laminar flow nozzle and a sandwich laminar flow nozzle; controlling laser energy and pulse width in the isolation area according to workpiece materials and defect parameters to perform impact repair; real-time closed-loop regulation and control are performed according to feedback signals of the CCD high-speed camera and the ultrasonic sensor so as to maintain stable water film thickness and laser focus position; and after repairing is completed, graded pressure relief and density detection are executed. The system is composed of a central control system, a laser generator, a multi-axis mechanical arm, a sensing assembly and a double-layer nozzle structure. According to the scheme, stable transmission and accurate control of laser shock energy in a complex underwater environment are realized, and the repair consistency and the process stability are improved.

Description

Technical Field

[0001] This invention belongs to the field of underwater laser shock remanufacturing, and particularly relates to an underwater laser shock remanufacturing method and system. Background Technology

[0002] With the widespread application of high-strength metallic materials in equipment manufacturing, shipbuilding, energy, and marine engineering, surface cracks, pitting, and structural degradation often occur during service due to stress corrosion, fatigue damage, or impact wear. To restore the mechanical properties of components and extend their service life, laser shock peening and remanufacturing technology has been extensively studied. Existing underwater repair methods mainly include three types: wet methods, dry chamber methods, and localized dry methods. Wet methods directly utilize water as a confinement layer, resulting in simple equipment structures, but they are susceptible to bubble disturbances and water flow fluctuations. Dry chamber methods achieve gas-liquid isolation by establishing a sealed air chamber, but the chamber is bulky, costly, and complex to operate. Localized dry methods form an air isolation layer in a localized area using a small drainage hood, which improves environmental interference, but has poor adaptability to complex curved surfaces and deep-water environments, and insufficient isolation stability.

[0003] Existing underwater repair methods still have the following problems in practical applications: First, the water isolation method has poor stability, and the morphology of the isolation layer is easily affected by external fluid disturbances and water depth changes, resulting in laser energy transmission attenuation and focus shift, thereby reducing impact accuracy; Second, existing devices generally lack multi-parameter closed-loop control, and cannot coordinate multiple physical parameters such as laser energy, water pressure, and focus pose in real time, resulting in uneven impact layer density and poor repair consistency; Third, existing systems have difficulty maintaining a constant water film thickness and laser incident angle in complex curved surfaces or deep water environments, resulting in insufficient process stability and limiting the promotion and application of this technology. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides an underwater laser shock remanufacturing method and system, comprising:

[0005] The defect area on the workpiece surface is determined based on the defect detection signal, and a three-dimensional defect model is established based on the spatial coordinates of the defect area.

[0006] Based on the three-dimensional model, a dynamic water isolation zone is established in the underwater environment, and the laser system is controlled to perform impact repair according to the state of the isolation zone.

[0007] The termination and evaluation procedure will be executed based on the detection signal after the repair is completed.

[0008] Optionally, in the step of determining the defect area on the workpiece surface based on the defect detection signal, the defect signals on the workpiece surface and inside are collected by an ultrasonic flaw detector, and the equivalent size of the defect is determined based on the signal strength and waveform characteristics. When the equivalent size of the defect is less than a preset threshold, the three-dimensional modeling step is entered.

[0009] Optionally, in the step of establishing a three-dimensional defect model based on the spatial coordinates of the defect area, the ultrasonic rangefinder is used to collect surface distance data of the defect area, a three-dimensional geometric model of the repair area is constructed based on the collected data, and the radius of curvature parameter is output for laser path planning.

[0010] Optionally, after the three-dimensional defect model is established, the repair area is pre-processed according to the surface information of the model. The pre-processing includes cleaning the surface with deionized high-pressure water jet and uniformly coating a laser absorption layer after cleaning to form a uniform absorption interface suitable for laser action.

[0011] Optionally, in the step of establishing a dynamic water isolation zone in the underwater environment based on the three-dimensional model, annular high-pressure deionized water is sprayed by a sandwich laminar flow nozzle to displace the external water, while axial high-pressure deionized water is sprayed by a coaxial laminar flow nozzle to displace the water on the workpiece surface, thereby forming a stable deionized water film constraint layer on the workpiece surface.

[0012] Optionally, during the establishment of the dynamic isolation zone in the water body, the water pressure relationship between the interlayer laminar flow nozzle and the coaxial laminar flow nozzle is determined according to the water depth compensation factor and the pressure coupling coefficient, and the injection pressure is adjusted by the feedback signals of the flow meter and the shut-off valve to maintain the steady state of the isolation zone.

[0013] Optionally, in the step of controlling the laser system to perform impact repair based on the state of the isolated area, the laser pulse energy, pulse width and frequency are determined according to the three-dimensional defect model and the workpiece material, the laser focus position is calibrated in real time according to the image data fed back by the CCD high-speed camera, and the laser focusing lens is adjusted by a multi-axis robotic arm to maintain vertical incidence.

[0014] On the other hand, the present invention also provides an underwater laser shock remanufacturing system, comprising:

[0015] The central control system is used to receive signals from various sensors and adjust the operating instructions of the laser energy module, water pressure control module, and robot posture module in real time.

[0016] A laser generator is used to produce laser pulses;

[0017] A multi-axis robotic arm is used to adjust the position and angle of the laser impact; a laser transmission channel is used to transmit laser pulses to the protective cover;

[0018] The protective cover, rigidly connected to the multi-axis robotic arm via an adapter plate, is used to create a localized environment;

[0019] Deionized water source, used to provide high-pressure deionized water;

[0020] Deionized water pressure injection device, used to generate high-pressure deionized water;

[0021] Water flow transmission channel, used to transport high-pressure deionized water;

[0022] Flow meters and shut-off valves are used to control water flow.

[0023] A multi-station rotary chuck system, located inside a protective cover, is used to clamp sensing devices and drive them to rotate around the Z-axis.

[0024] A CCD high-speed camera, ultrasonic flaw detector, and ultrasonic rangefinder are integrated into the circumference of a rotating chuck for monitoring the condition of the workpiece.

[0025] Coaxial laminar flow nozzles and sandwich laminar flow nozzles are used to form a water film constraint layer on the surface of a workpiece;

[0026] The central control system controls the laser generator to generate laser pulses based on the location and size of the defects determined by the ultrasonic flaw detector, and adjusts the laser impact position and angle through a multi-axis robotic arm. At the same time, it dynamically calibrates the coaxiality between the laser focus and the workpiece rotation center based on the image of the water film center area obtained by the CCD high-speed camera.

[0027] On the other hand, the present invention also provides an electronic device including a memory, a processor, and a computing program stored in the memory and executable on the processor, wherein the processor implements the method when executing the computing program.

[0028] On the other hand, the present invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method.

[0029] Compared with the prior art, the present invention has the following advantages and technical effects:

[0030] This invention achieves stable energy transfer and dynamic focus calibration during laser shock processes in underwater environments by constructing a dynamic water isolation structure based on a double-layer laminar flow nozzle and combining it with real-time closed-loop control using multiple sensors. This scheme can automatically adjust the water film thickness and jet pressure according to changes in surface curvature and water depth, maintaining a stable isolation layer shape and effectively avoiding energy attenuation and incident deviation. Simultaneously, the central control system coordinates the control of laser energy, water pressure, and orientation, resulting in more uniform density in the impact area. This improves the precision and consistency of remanufacturing and significantly enhances the stability of underwater laser shock processes in complex environments. Attached Figure Description

[0031] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0032] Figure 1 This is a schematic diagram of the method flow according to an embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of the system structure according to an embodiment of the present invention;

[0034] Figure 3 This is a first schematic diagram of the internal structure of the underwater laser protective cover according to an embodiment of the present invention;

[0035] Figure 4 This is a second schematic diagram of the internal structure of the underwater laser protective cover according to an embodiment of the present invention;

[0036] The components include: 1. Central control system; 2. Laser generator; 3. Multi-axis robotic arm; 4. Laser transmission channel; 5. Protective cover; 6. Deionized water source; 7. Deionized water pressure jet device; 8. Water flow transmission channel; 9. Flow meter; 10. Shut-off valve; 11. Adapter plate; 12. Multi-station rotary chuck system; 13. CCD high-speed camera; 14. Ultrasonic flaw detector; 15. Ultrasonic rangefinder; 16. Coaxial laminar flow nozzle; 17. Sandwich laminar flow nozzle. Detailed Implementation

[0037] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0038] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0039] Example 1

[0040] like Figure 1 As shown, this embodiment provides an underwater laser shock remanufacturing method, including:

[0041] The defect area on the workpiece surface is determined based on the defect detection signal, and a three-dimensional defect model is established based on the spatial coordinates of the defect area.

[0042] Based on the three-dimensional model, a dynamic water isolation zone is established in the underwater environment, and the laser system is controlled to perform impact repair according to the state of the isolation zone.

[0043] The termination and evaluation procedure will be executed based on the detection signal after the repair is completed.

[0044] Specifically, it includes: (a) Impact zone pretreatment: the location and size of the workpiece defect are determined by an ultrasonic flaw detector. When the equivalent size D of the defect is less than or equal to the critical threshold, the subsequent process is executed; after the location is determined, the curved contour of the defect location is scanned by an ultrasonic rangefinder and a three-dimensional model is established; the surface of the repair area is cleaned by high-pressure water jet and coated with a laser absorption layer.

[0045] (b) Establishment of dynamic isolation zone: High-pressure deionized water is supplied by the interlayer laminar flow nozzle to drain the ambient water. At the same time, high-pressure deionized water is supplied by the coaxial laminar flow nozzle inside the protective cover to drain the water on the workpiece surface. A deionized water film is then placed on the workpiece surface as a constraint layer to establish a dynamic water isolation zone.

[0046] (c) Laser Shock: Laser parameters are determined based on defect size and workpiece material; a laser repair path is planned based on 3D modeling; laser pulses are emitted, and real-time closed-loop control is performed during the laser shock process; images of the central area of ​​the water film are acquired using a CCD high-speed camera and transmitted to the central control system for void feature identification and analysis; according to the planned path, when a curved surface appears, the laser focusing lens is rotated to maintain perpendicular incidence, and the surface tilt angle is... When the size is too large, it is dynamically adjusted by a multi-axis robot;

[0047] (d) Termination procedure: Execute the graded depressurization procedure to shut off the high-pressure water source; use ultrasonic flaw detection to test the density of the impact layer.

[0048] Furthermore, the critical threshold for the defect size described in step (a) is set at 100 μm, and defects exceeding this threshold size are ignored during impact.

[0049] The laser absorption layer in step (a) is an aluminum foil or a black paint coating with a thickness of 30-100 μm.

[0050] Furthermore, in step (b), the pressure range of the high-pressure deionized water is 50-300 MPa, and the flow rate is controlled at 10-15 L / min.

[0051] Furthermore, the relationship between the water pressure of the sandwich laminar flow nozzle and the coaxial laminar flow nozzle in step (b) is expressed by the following formula:

[0052] ;

[0053] in The water pressure of the jacketed nozzle (MPa). Where is the water pressure of the coaxial nozzle (MPa), K is the pressure coupling coefficient, and α is the water depth compensation factor. The water depth of the device.

[0054] The relationship between the interlayer laminar flow nozzle and the ambient water pressure in step (b) is as follows:

[0055] ;

[0056] in, For environmental water pressure, The radius of curvature of the repair surface is ρ, the density of the interlayer jet is v, the jet exit velocity is σ, and the surface tension coefficient is σ.

[0057] In step (b), the thickness of the water film is controlled by the central controller, using the following formula:

[0058] ;

[0059] in It is the base thickness coefficient, which characterizes the overall wetting properties of the material surface under planar working conditions; The curvature attenuation intensity factor quantifies the attenuation intensity of the surface effect on the water film. The curvature sensitivity coefficient determines the rate at which the water film decays as the curvature changes; For jet pressure, Let be the radius of curvature.

[0060] The implementation of the parameters in the formula is as follows: the P value is controlled by a pressure sensor closed loop; the R value is obtained by scanning the curvature of the surface with an ultrasonic rangefinder before laser impact; the A, B, and C parameters need to be calibrated by technicians through experiments to obtain more accurate coefficient values. For example, when dealing with a nickel-based alloy convex surface (R=5mm) under a working condition of 200MPa: the calculated δ=24.0μm is obtained, and the controller adjusts the nozzle flow rate to 132L / min.

[0061] In step (c), the laser uses 532nm green light with a single pulse energy range of 1.5 J-8.0 J and a pulse width of 10-20ns.

[0062] In step (c), the surface inclination angle is ,in For the surface inclination angle, For the surface normal vector, For the nozzle axis vector, when Adjustment To and parallel.

[0063] Step (c) includes real-time closed-loop control: determining the cause of water film rupture based on the void characteristics in the center of the water film identified by the CCD, and then making overall adjustments accordingly.

[0064] Furthermore, in step (c), the cause of water film rupture is determined based on the void characteristics in the center of the water film identified by the CCD, including the following countermeasures: For the thermo-coupling effect, if the pulse energy E > 4.0J, the water pressure is increased by 8% 50μs in advance, and the high pressure is maintained for 200μs after the pulse ends; For the fluid dynamic imbalance problem, the central controller performs dynamic water pressure compensation with a period of 10ms.

[0065] This embodiment also includes a water pressure safety verification process, and the coaxial water film thickness: ;

[0066] Interlayer water pressure setting (water depth H=10m): ;

[0067] Flow control: Coaxial nozzle 12.5L / min — corresponding pressure 220MPa;

[0068] ;

[0069] ;

[0070] The laser shock process includes:

[0071] The angle of inclination of the curved surface is ,in For the surface inclination angle, For the surface normal vector, Nozzle axis vector

[0072] when Adjustment To and parallel;

[0073] Water film integrity monitoring: CCD is triggered to capture images with each pulse to identify the rupture rate: when the rupture rate is >5%, the water pressure is increased by 6.5% (e.g., 150→160MPa); when the rupture rate is >15%, the system is immediately stopped and the self-cleaning program is started.

[0074] Example 2

[0075] like Figure 2-4 As shown, this embodiment provides an underwater laser shock remanufacturing apparatus, comprising:

[0076] The system comprises: 1. Central control system; 2. Laser generator; 3. Multi-axis robotic arm; 4. Laser transmission channel; 5. Protective cover; 6. Deionized water source; 7. Deionized water pressure jet device; 8. Water flow transmission channel; 9. Flow meter; 10. Shut-off valve; 11. Adapter plate; 12. Multi-station rotary chuck system; 13. CCD high-speed camera; 14. Ultrasonic flaw detector; 15. Ultrasonic rangefinder; 16. Coaxial laminar flow nozzle; 17. Sandwich laminar flow nozzle. The laser generator 2 is connected to the top of the protective cover 5 via the laser transmission channel 4. The protective cover 5 is rigidly connected to the multi-axis robotic arm 3 via the adapter plate 11. The protective cover 5 contains a multi-station rotary chuck system 12, which clamps and drives the sensing device to rotate around the Z-axis. The multi-station rotary chuck system 12 is equipped with a monitoring... The measurement system integrates a CCD high-speed camera 13, an ultrasonic flaw detector 14, and an ultrasonic rangefinder 15 around the rotary chuck; the central axis of the multi-station rotary chuck system 12 is connected to the laser generator 2, with the laser port surrounding the coaxial laminar flow nozzle 16; the protective cover 5 has a double-layer design, with a sandwich laminar flow nozzle 15 inside the interlayer; the coaxial laminar flow nozzle 16 and the sandwich laminar flow nozzle 17 are connected to a high-pressure deionized water source 7 through a water flow transmission channel 8; the water flow transmission channel is equipped with a flow meter 9 and a shut-off valve 10; the central controller 1 receives signals from various sensors and adjusts the operation instructions of the laser energy module, water pressure control module, and robot posture module in real time, and dynamically calibrates the coaxiality by comparing the coordinate deviation between the laser focus and the workpiece rotation center through the visual positioning module.

[0077] The protective cover 5 adopts a titanium alloy double-layer shell structure. The outer cavity is connected to the laminar flow nozzle 17 to form an annular water curtain channel (φ300mm), and the top of the inner cavity integrates a coaxial laminar flow nozzle 16. The laser transmission channel 4 is equipped with a cooling pipe to maintain a constant temperature environment of 20±2℃. The multi-station rotary chuck system 12 achieves 360° continuous underwater rotation through a magnetohydrodynamic seal. It has three sets of monitoring units evenly distributed around its circumference: a CCD high-speed camera 13 equipped with a 532nm filter system and a frame rate of 5000fps; an ultrasonic flaw detector 14 using a 128-element phased array probe with a resolution of 0.05mm; and an ultrasonic rangefinder 15 with a transmission frequency of 10MHz and a ranging accuracy of ±0.02mm. The coaxial laminar flow nozzle 16 has an outlet diameter of 3mm, a cone angle of 8°, and forms a uniform water film (thickness 28.7μm) at a distance of 20mm from the workpiece surface. The focusing lens servo system achieves ±5° tilt angle compensation (response time <50ms).

[0078] On the other hand, this embodiment also provides an electronic device, including a memory, a processor, and a computing program stored in the memory and executable on the processor, wherein the processor implements the method when executing the computing program.

[0079] On the other hand, this embodiment also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method.

[0080] The above are merely preferred embodiments 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 scope of the technology 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 method for underwater laser shock remanufacturing, characterized in that, include: The defect area on the workpiece surface is determined based on the defect detection signal, and a three-dimensional defect model is established based on the spatial coordinates of the defect area. Based on the three-dimensional model, a dynamic water isolation zone is established in the underwater environment, and the laser system is controlled to perform impact repair according to the state of the isolation zone. The termination and evaluation procedure will be executed based on the detection signal after the repair is completed.

2. The method according to claim 1, characterized in that, In the step of determining the defect area on the workpiece surface based on the defect detection signal, the defect signals on the surface and inside of the workpiece are collected by an ultrasonic flaw detector, and the equivalent size of the defect is determined according to the signal strength and waveform characteristics. When the equivalent size of the defect is less than a preset threshold, the three-dimensional modeling step is entered.

3. The method according to claim 1, characterized in that, In the step of establishing a three-dimensional defect model based on the spatial coordinates of the defect area, the surface distance data of the defect area is collected by an ultrasonic rangefinder, a three-dimensional geometric model of the repair area is constructed based on the collected data, and the curvature radius parameter is output for laser path planning.

4. The method according to claim 1, characterized in that, After the three-dimensional defect model is established, the repair area is pre-processed according to the surface information of the model. The pre-processing includes cleaning the surface with deionized high-pressure water jet and uniformly coating a laser absorption layer after cleaning to form a uniform absorption interface suitable for laser action.

5. The method according to claim 1, characterized in that, In the step of establishing a dynamic water isolation zone in the underwater environment based on the three-dimensional model, annular high-pressure deionized water is sprayed by a sandwich laminar flow nozzle to displace the external water, while axial high-pressure deionized water is sprayed by a coaxial laminar flow nozzle to displace the water on the workpiece surface, thereby forming a stable deionized water film constraint layer on the workpiece surface.

6. The method according to claim 1, characterized in that, During the establishment of the dynamic isolation zone in the water body, the water pressure relationship between the interlayer laminar flow nozzle and the coaxial laminar flow nozzle is determined according to the water depth compensation factor and the pressure coupling coefficient. The injection pressure is adjusted by the feedback signals of the flow meter and the shut-off valve to maintain the steady state of the isolation zone.

7. The method according to claim 1, characterized in that, In the step of controlling the laser system to perform impact repair based on the state of the isolated area, the laser pulse energy, pulse width and frequency are determined according to the three-dimensional defect model and the workpiece material. The laser focus position is calibrated in real time according to the image data fed back by the CCD high-speed camera, and the laser focusing lens is adjusted by the multi-axis robotic arm to maintain vertical incidence.

8. The underwater laser shock remanufacturing system according to any one of claims 1-7, characterized in that, include: The central control system is used to receive signals from various sensors and adjust the operating instructions of the laser energy module, water pressure control module, and robot posture module in real time. A laser generator is used to produce laser pulses; A multi-axis robotic arm is used to adjust the position and angle of the laser impact; a laser transmission channel is used to transmit laser pulses to the protective cover; The protective cover, rigidly connected to the multi-axis robotic arm via an adapter plate, is used to create a localized environment; Deionized water source, used to provide high-pressure deionized water; Deionized water pressure injection device, used to generate high-pressure deionized water; Water flow transmission channel, used to transport high-pressure deionized water; Flow meters and shut-off valves are used to control water flow. A multi-station rotary chuck system, located inside a protective cover, is used to clamp sensing devices and drive them to rotate around the Z-axis. A CCD high-speed camera, ultrasonic flaw detector, and ultrasonic rangefinder are integrated into the circumference of a rotating chuck for monitoring the condition of the workpiece. Coaxial laminar flow nozzles and sandwich laminar flow nozzles are used to form a water film constraint layer on the surface of a workpiece; The central control system controls the laser generator to generate laser pulses based on the location and size of the defects determined by the ultrasonic flaw detector, and adjusts the laser impact position and angle through a multi-axis robotic arm. At the same time, it dynamically calibrates the coaxiality between the laser focus and the workpiece rotation center based on the image of the water film center area obtained by the CCD high-speed camera.

9. An electronic device comprising a memory, a processor, and a computing program stored in the memory and executable on the processor, characterized in that, When the processor executes the computing program, it implements the method of any one of claims 1-7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the method of any one of claims 1-7.

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