Laser shock peening method based on zonal iterative dual constraint

Abstract

The application discloses a laser shock peening method based on partition iteration double constraint, and relates to the technical field of laser processing. The method comprises the following steps: dividing a to-be-processed surface area of a to-be-processed component into a plurality of subareas, and setting laser shock points in each subarea; performing partition iteration double constraint traversal shock; in each iteration, firstly randomly disturbing the macro processing sequence of all subareas, then selecting one point from the unshocked points of each subarea, arranging the selected points according to the disturbed subarea sequence to form a shock subsequence of the current iteration; repeating the iteration until all the points are traversed to form a first layer of shock strengthening layer; and continuously repeating the superposition until a preset shock layer number is reached. The application can significantly inhibit the anisotropy of residual stress and the edge effect, and realize uniform strengthening.

Description

Technical Field

[0001] This invention relates to the field of laser processing technology, and in particular to a laser shock enhancement method based on partitioned iterative dual constraints. Background Technology

[0002] Laser shock peening (LSP) is an advanced surface modification technology that significantly improves the fatigue resistance, wear resistance, and corrosion resistance of metallic materials by introducing residual compressive stress fields and gradient nanostructures into the surface layer. In practical applications, to ensure processing efficiency, a specific spot overlap rate (such as 50%) and a "Z"-shaped spot path (i.e., the spot scans back and forth along a straight line to form a Z-shaped trajectory) are typically used for point-by-point and row-by-row overlapping processing.

[0003] However, conventional "Z"-shaped laser path methods have the following inherent defects in the strengthening process, especially for high-performance machining of thin-walled parts such as aero-engine blades: Residual stress edge effect: The inherent characteristics of the laser spot sequence and the lack of external material equilibrium stress at the component edges lead to residual tensile stress near the starting edge of the LSP and residual compressive stress near the ending edge. Residual stress anisotropy: The "Z"-shaped scanning method results in residual compressive stress parallel to the scanning direction being much greater than that perpendicular to it, leading to an uneven distribution of the residual stress field. Bending deformation of thin-walled parts: The uneven distribution of residual stress easily causes overall bending deformation of thin-walled parts, resulting in partial release of residual compressive stress and significantly reducing the strengthening effect.

[0004] While existing technologies can alleviate the aforementioned problems to some extent by changing the scanning direction (XY or YX mode), employing a scanning sequence from the center to the boundary, or using simple random scanning, significant shortcomings remain: regardless of the "Z"-shaped mode, residual tensile stress exists at the center of the processed area; simple random scanning may cause localized short-term impact concentration, failing to guarantee overall uniformity, and the effect of suppressing residual stress anisotropy is limited. Therefore, a novel laser shock peening method is urgently needed that can actively and uniformly control the residual stress field while suppressing anisotropy and bending deformation. Summary of the Invention

[0005] The purpose of this invention is to provide a laser shock strengthening method based on partitioned iterative dual constraints to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides a laser shock strengthening method based on partitioned iterative dual constraints, comprising the following steps: dividing the surface area of ​​the component to be processed into multiple sub-regions, and setting several laser shock points in each sub-region; performing partitioned iterative dual constraint traversal shock: taking the sub-region as the basic processing unit, in each iteration, firstly, the macroscopic processing order of all the sub-regions is randomly shuffled; then, micro-point position constraints are performed, the micro-point position constraints including selecting one laser shock point from the un-shuffled points of each sub-region; finally, the selected laser shock points are arranged according to the shuffled sub-region order to form the shock sub-sequence of this iteration; repeating the iteration until all the laser shock points are traversed to form a first shock strengthening layer; on top of the first shock strengthening layer, repeatedly performing the partitioned iterative dual constraint traversal shock, superimposing to form subsequent shock strengthening layers, until a preset number of shock layers is reached.

[0007] Preferably, the surface area to be processed is divided into N×M sub-regions of equal area, where N and M are both positive integers; each sub-region is provided with a×b laser impact points, where a and b are both positive integers.

[0008] Preferably, the total number of iterations is equal to the total number of laser impact points within a single sub-region.

[0009] Preferably, the random shuffling of the macroscopic processing order is performed independently once per iteration, and the arrangement order of the sub-regions is different in each iteration.

[0010] Preferably, the micro-point positioning constraint is to select one laser impact point from the unimpacted points in each sub-region according to a preset rule in each iteration.

[0011] Preferably, the partitioned iterative dual-constraint traversal impact generates a global impact path sequence through a dynamic path planning module, and the industrial robotic arm controls the laser to perform laser impact on the surface of the component to be processed according to the global impact path sequence.

[0012] Preferably, the component to be processed is a thin-walled component.

[0013] Preferably, the laser shock peening process parameters include laser wavelength, pulse energy, spot diameter, spot overlap rate, pulse width, and repetition frequency.

[0014] Preferably, the sub-region division size and the number of laser impact points are quantitatively matched and optimized based on the material, shape, size, and target strengthening effect of the component to be processed.

[0015] Preferably, an absorbent layer is applied to the surface of the component to be processed, and a constraint layer is provided above the absorbent layer.

[0016] Compared with the prior art, the present invention has the following advantages and technical effects: The laser shock peening method based on partitioned iterative dual constraints provided by this invention decomposes a large processing area into multiple sub-regions through the synergistic effect of macroscopic partitioning and microscopic iteration. It forces the laser beam to follow a deterministic homogenization rule of "taking a point from each sub-region in each round" at both the macroscopic and microscopic levels, breaking the ordered or locally random patterns of traditional "Z"-shaped paths and simple random scanning. This invention effectively suppresses residual stress anisotropy, eliminates edge effects and bending deformation, achieving a highly uniform strengthening effect. It offers high processing reliability and strong process flexibility, making it particularly suitable for small, precision, thin-walled parts with extremely high uniformity requirements, and providing a new path for automated intelligent processing. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention.

[0018] Figure 1 This is a process flow diagram of the laser shock homogenization strengthening method based on partitioned iterative dual constraints of the present invention.

[0019] Figure 2 This is a visualization of the laser shock uniform strengthening process path sequence of 4×4 partitioned iterative dual constraints in an embodiment of the present invention.

[0020] Figure 3 This is a comparison of the surface curvature of 2mm thick AR, LSP, and RLSP-4 samples in the embodiments of the present invention.

[0021] Figure 4 This is a comparison diagram of the residual stress in the X and Y directions of the samples under different laser shock peening processes in the embodiments of the present invention.

[0022] Figure 5 The electrochemical impedance spectroscopy of 2 mm thick AR, LSP and RLSP-4 samples in the embodiments of the present invention is shown.

[0023] Figure 6 This is a comparison diagram of the degree of bending deformation in the X and Y directions of RLSP-4 samples of different thicknesses in the embodiments of the present invention.

[0024] Figure 7 This is a comparison diagram of the residual stress in the X and Y directions of a 3mm thick sample under different laser shock strengthening processes in an embodiment of the present invention.

[0025] Figure 8 This is a comparison diagram of the residual stress in the X and Y directions of a 5mm thick sample under different laser shock strengthening processes in an embodiment of the present invention.

[0026] Figure 9 The electrochemical impedance spectroscopy of the 3 mm thick AR, LSP, and RLSP-4 samples in the embodiments of the present invention is shown.

[0027] Figure 10 The electrochemical impedance spectroscopy of 5 mm thick AR, LSP and RLSP-4 samples in the embodiments of the present invention is shown. Detailed Implementation

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. The described embodiments are merely some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0029] like Figure 1 As shown, this invention provides a laser shock strengthening method based on partitioned iterative dual constraints, comprising the following steps: dividing the surface area of ​​the component to be processed into multiple sub-regions, and setting several laser shock points in each sub-region; performing partitioned iterative dual constraint traversal shock: taking the sub-region as the basic processing unit, in each iteration, firstly, the macroscopic processing order of all sub-regions is randomly shuffled; then, micro-point constraints are performed, which include selecting one laser shock point from the un-shuffled points in each sub-region; finally, the selected laser shock points are arranged according to the shuffled sub-region order to form the shock sub-sequence of this iteration; repeating the iteration until all laser shock points are traversed to form the first shock strengthening layer; above the first shock strengthening layer, repeatedly performing partitioned iterative dual constraint traversal shock, superimposing to form subsequent shock strengthening layers, until a preset number of shock layers is reached.

[0030] By dividing the surface area of ​​the component to be processed into multiple sub-regions and setting several laser shock points in each sub-region, and combining the macroscopic sequence constraint and microscopic point positioning constraint of the partitioned iterative double-constraint traversal shock, the orderly superposition mode of residual stress can be completely changed, making the residual compressive stress values ​​in all directions tend to be consistent, thereby significantly suppressing the anisotropy of residual stress. At the same time, through multiple iterations and global traversal, the thermal influence of each layer of shock is evenly distributed throughout the processing area, avoiding excessive stress concentration at the starting or ending edge, thereby effectively suppressing edge effects and the overall bending deformation of thin-walled parts.

[0031] The scheme is further optimized by dividing the surface area to be processed into N×M sub-regions of equal area, where N and M are both positive integers; each sub-region is set with a×b laser impact points, where a and b are both positive integers.

[0032] The above settings enable precise gridding of large-area processing areas, providing clear spatial units and point coordinates for subsequent dual-constraint traversal impacts, thus ensuring the uniformity and controllability of the processing process.

[0033] The scheme was further optimized so that the total number of iterations was equal to the total number of laser impact points in a single sub-region.

[0034] With the above settings, it can be ensured that after all iterations are completed, all laser impact points in each sub-region are traversed only once, thereby ensuring that every part of the entire surface area to be processed is subjected to the exact same number of impacts, achieving absolute uniformity of the strengthening effect.

[0035] To further optimize the scheme, the random shuffling of the macroscopic processing order is performed independently in each iteration, and the arrangement order of the sub-regions is different in each iteration.

[0036] By randomly shuffling the macroscopic processing order of sub-regions in each iteration, the execution order of different sub-regions in each iteration is different. This effectively avoids the regular and continuous superposition of residual stress induced by shock waves in a certain fixed direction, making the stress accumulation effect in different directions tend to be balanced, and further suppressing the anisotropy of residual stress.

[0037] To further optimize the scheme, the micro-point positioning constraint is to select a laser impact point from the unimpacted points in each sub-region according to a preset rule in each iteration.

[0038] By selecting a laser impact point from the unimpacted points in each sub-region according to a preset rule in each iteration, micro-homogeneous selection within the sub-region is achieved, ensuring that different points within the same sub-region are uniformly selected in different rounds, thereby guaranteeing the uniformity of the probability and order of impact on each point at the micro-scale.

[0039] To further optimize the scheme, the partitioned iterative double-constraint traversal impact is generated by a dynamic path planning module to produce a global impact path sequence, and the industrial robotic arm controls the laser to perform laser impact on the surface of the component to be processed according to the global impact path sequence.

[0040] By generating a global impact path sequence through a dynamic path planning module, and controlling the laser to perform laser impact according to the sequence by an industrial robotic arm, the automated and intelligent execution of dual-constraint traversal impact can be achieved, which greatly improves processing efficiency and path execution accuracy, and provides key technical support for flexible manufacturing enhanced by laser impact.

[0041] The plan was further optimized so that the component to be processed is a thin-walled part.

[0042] By applying the method of this invention to thin-walled parts, bending deformation and anisotropy problems that are prone to occur in thin-walled parts during laser shock strengthening can be effectively suppressed. It is particularly suitable for surface strengthening of thin-walled components such as aero-engine blades and gas turbine blades, which have extremely high requirements for dimensional accuracy and performance uniformity.

[0043] Further optimization of the scheme involves laser shock peening process parameters including laser wavelength, pulse energy, spot diameter, spot overlap rate, pulse width, and repetition frequency.

[0044] By optimizing process parameters such as laser wavelength, pulse energy, spot diameter, spot overlap rate, pulse width, and repetition frequency, the impact intensity and range of action can be flexibly adjusted according to different materials and performance requirements. This, combined with the dual constraint path of partitioned iteration, achieves the best strengthening effect.

[0045] The scheme was further optimized by quantitatively matching and optimizing the sub-region division size and the number of laser impact points based on the material, shape, size of the component to be processed, and the target strengthening effect.

[0046] By quantitatively matching and optimizing the sub-region division size and the number of laser impact points based on the material, shape, size, and target strengthening effect of the component to be processed, the method of the present invention has extremely strong process flexibility and adaptability. It can perform customized path planning for different application scenarios and performance requirements, and maximize the uniform strengthening advantage of dual-constraint traversal impact.

[0047] To further optimize the solution, an absorbent layer is applied to the surface of the component to be processed, and a constraint layer is set above the absorbent layer.

[0048] By attaching an absorption layer to the surface of the component to be processed to absorb laser energy and generate high-pressure plasma, and setting a constraint layer above the absorption layer to constrain plasma expansion and prolong the shock wave action time, the peak pressure and energy utilization rate of laser shock enhancement can be effectively improved. Combined with the dual constraint traversal path, the strengthening effect and uniformity can be further improved.

[0049] The laser shock peening method based on partitioned iterative dual constraints provided by this invention has the following overall implementation process: First, the surface of the component to be processed is pre-treated; then, according to the material and shape of the component, the surface area to be processed is divided into N×M equal-area sub-regions, and the laser shock points in each sub-region are located by coordinates; next, using the sub-region as the basic processing unit, a partitioned iterative dual constraint traversal strategy is executed. In each iteration, the macroscopic processing order of all sub-regions is randomly shuffled, and then a point is selected from the remaining un-impacted points in each sub-region. The selected point is arranged according to the shuffled sub-region order to form an impact sub-sequence. This process is repeated until all points are traversed, forming the first impact strengthening layer; then, the second, third, and even more layers of dual constraint traversal impact are superimposed on this layer until the preset total number of layers is reached; finally, uniform strengthening of the entire surface area to be processed is completed. This invention, through the synergistic effect of "macro-regional partitioning" and "micro-iteration," decomposes a large-area processing region into multiple sub-regions and forces the laser beam to follow a deterministic homogenization rule of "taking a point from each sub-region in each round" at both the macro and micro levels. This completely breaks the ordered stress superposition mode of the traditional "Z"-shaped path and the uncontrollability of simple random scanning. It can obtain a highly uniform residual compressive stress field at both the macro and micro scales, significantly suppressing the anisotropy of residual stress, eliminating edge effects and bending deformation, and realizing high-quality, isotropic, and uniform strengthening of thin-walled components. This effectively improves their service performance, such as fatigue resistance, wear resistance, and corrosion resistance.

[0050] Example This embodiment uses a thin-walled 2Cr12 martensitic stainless steel sample with geometric dimensions of 36mm×36mm×2mm as the object to further describe the present invention in detail.

[0051] Operating Procedures: Before processing, the sample surface is pretreated by grinding the surface using silicon carbide (SiC) sandpaper in sequence with grit sizes of 180, 400, and 800. The ground sample is then ultrasonically cleaned in anhydrous ethanol for 10 minutes to thoroughly remove surface oil and oxide films. After pretreatment, a square processing area of ​​25.5 mm × 25.5 mm is marked on the sample surface.

[0052] This embodiment develops a dynamic path planning algorithm that uses a partitioned iterative dual-constraint strategy to perform gridded division and path reconstruction of the processing area. Specifically, the algorithm first divides the square processing area into 16 equal-area grid sub-regions of 4×4, and further sets 16 discrete laser impact points of 4×4 in each sub-region, for a total of 256 impact points globally. When generating the impact sequence, the algorithm performs 16 iterations (the total number of iterations equals the total number of impact points in a single sub-region). In each iteration, the macroscopic execution order of these 16 sub-regions is completely shuffled through a randomization mechanism (macroscopic order constraint). Then, within each sub-region, a point is independently selected from its remaining unimpacted points according to a preset rule (microscopic point selection constraint). Finally, the selected points are arranged according to the shuffled sub-region order to form the impact sub-sequence of this iteration. This mechanism ensures that each iteration selects one point from each sub-region, achieving both macroscopic path constraints between sub-regions and microscopic point constraints within sub-regions. Through 16 iterations, all 256 points are traversed in a single pass, ultimately generating a globally partitioned iterative dual-constraint impact path sequence. The sequence is visualized as follows... Figure 2 As shown.

[0053] After completing the shock sequence planning, the pretreated samples were installed in the YS120-R200A laser shock strengthening equipment. A 0.1mm thick black tape was applied to the surface of the sample to be processed as a flexible energy-absorbing layer, and a robotic arm constraining medium spraying device sprayed laminar flowing water onto the sample surface to form a 1mm thick water film as a constraint layer. The core process parameters for laser shock strengthening were set as follows: laser wavelength 1064nm, pulse energy 3J, spot diameter 3mm, spot overlap rate 50%, pulse width 16ns, and repetition frequency 2Hz. After starting the equipment, the high-precision industrial robotic arm and laser were controlled to strictly follow the above-mentioned partitioned iterative double-constraint path sequence, performing a single laser shock at each point to complete the strengthening process of the sample. The sample prepared by this process was named RLSP-4 sample. As a comparison, the sample processed using the same process parameters but with the path changed to a traditional "Z"-shaped point-by-point overlapping path was named LSP sample, while the original sample that underwent the same pretreatment but was not laser strengthened was named AR sample.

[0054] After the strengthening process was completed, the macroscopic bending chord height of the three samples was measured using a digital radius gauge, both parallel to the conventional laser propulsion direction (X direction) and perpendicular to it (Y direction). The results are as follows: Figure 3The test results show that the chord height of the AR sample approaches 0 mm in both directions; the traditional LSP sample, due to the uneven stress release caused by the "Z"-shaped path, exhibits significant anisotropic bending, with its chord heights in the X and Y directions increasing to 0.124 mm and 0.097 mm, respectively, and the bending difference between the two directions reaching as high as 0.027 mm. In contrast, the RLSP-4 sample prepared using the process of this embodiment shows a significantly reduced chord height in the X direction to 0.092 mm and a chord height in the Y direction to 0.096 mm, with a bending difference between the two directions of only 0.004 mm. This result indicates that the dual-constraint ergonomic strategy of this invention eliminates the macroscopic stress imbalance caused by the superposition of continuous laser beams, significantly suppresses bending deformation of thin-walled parts parallel to the scanning direction, and achieves isotropic deformation.

[0055] The residual stress field of the surface layer was tested using an X-350A X-ray stress diffractometer along two measurement lines in the X and Y directions. Five measurement points were selected at equal intervals along each measurement line. The results are as follows: Figure 4 Test results show that, on the X-direction measurement line, the traditional "Z"-type LSP treatment, due to the ordered and repeated superposition of stress around the periphery of a single laser beam in the direction of travel, causes the average difference in residual compressive stress in both directions to drastically increase from -8.2 MPa in the AR sample to -46.0 MPa, exhibiting severe residual stress anisotropy. Furthermore, the stress difference shows a clear progressive characteristic and edge effect from the starting point to the ending point. However, after using the RLSP-4 process, this difference is significantly reduced to -19.2 MPa, with no progressive boundary abrupt changes throughout the entire measurement line. Similarly, on the Y-direction measurement line, the average difference in residual stress in both directions of the traditional LSP sample is as high as -44.2 MPa, while the RLSP-4 sample successfully reduces this difference to -9.0 MPa, a reduction of 35.2 MPa.

[0056] In this embodiment, electrochemical impedance spectroscopy (EIS) tests were performed on AR, LSP, and RLSP-4 samples in 3.5 wt.% NaCl solution. The test results are as follows: Figure 5 As shown in the figure, impedance spectroscopy data indicate that, compared to the original AR sample without laser strengthening, the capacitive arc radius of both the LSP and RLSP-4 samples treated with laser shock peening significantly increased. This directly proves that laser shock peening can effectively improve the corrosion resistance of 2Cr12 martensitic stainless steel. Furthermore, under two different impact paths, the RLSP-4 sample prepared using the process in this embodiment showed a more significant increase in capacitive arc radius compared to the LSP sample with the traditional "Z"-shaped path, exhibiting the best electrochemical corrosion resistance among all tested samples.

[0057] In summary, the traditional "Z"-shaped progressive scanning path severely exacerbates the anisotropy of residual stress and macroscopic deformation imbalance in thin-walled components, thereby weakening their service modification effect. The laser shock peening process based on a partitioned iterative dual-constraint strategy proposed in this invention can effectively suppress macroscopic bending deformation and residual stress anisotropy in thin-walled components. While effectively reducing stress release, it retains high-amplitude residual compressive stress, thus providing strong process and data support for achieving high-quality uniform strengthening and corrosion-resistant modification of the surface of thin-walled metal components.

[0058] This embodiment further investigated the bending deformation behavior of thin-walled 2Cr13 martensitic stainless steel specimens with thicknesses of 3 mm and 5 mm. The results are as follows: Figure 6 As shown in the figure, the test results indicate that after partitioned iterative double-constraint laser shock peening (RLSP-4) treatment, the bending deformation in the X and Y directions of 3mm and 5mm thick samples is basically the same, indicating that this process can effectively suppress the anisotropy of deformation in thin-walled parts of different thicknesses. Furthermore, as the sample thickness increases from 3mm to 5mm, the overall bending deformation of the sample shows a further decreasing trend. This verifies that, under the premise of effectively suppressing deformation anisotropy using the RLSP-4 process, increasing the matrix thickness can provide stronger stiffness support, thus facilitating further control of macroscopic deformation.

[0059] The surface residual stress of 3mm and 5mm thick samples was also measured, and the results are as follows: Figure 7 and Figure 8As shown, for a 3mm thick specimen, after the traditional "Z"-type LSP treatment, the average difference in residual stress in both directions along the X-direction measurement line increased significantly from -1.8MPa for the AR specimen to -22.4MPa, exhibiting a clear edge effect that decreases from the starting point to the ending point. However, after using the RLSP-4 process, this average difference was reduced to -15MPa, the bidirectional anisotropy was significantly weakened, and the distribution was stable along the entire measurement line. On the Y-direction measurement line, the average difference in both directions of the traditional LSP was significantly increased to -26.6MPa compared to the AR specimen, while the RLSP-4 specimen successfully reduced this difference to -7.6MPa (an absolute reduction of 19.0MPa). For a 5mm thick sample, after conventional LSP treatment, the average difference in residual stress along the X and Y directions increased dramatically from 2MPa and -0.4MPa for the AR sample to -46.6MPa and -54.8MPa, respectively, indicating enhanced anisotropy. However, after using the RLSP-4 process, the difference in residual stress along the X and Y directions was significantly reduced to -5MPa and -9.2MPa, respectively, representing a reduction in anisotropy of 41.6MPa and 45.6MPa compared to conventional LSP. These data demonstrate that regardless of substrate thickness, conventional line-by-line scanning paths exacerbate the anisotropy of surface residual stress due to the continuous unidirectional superposition of energy. In contrast, the RLSP-4 process of this invention exhibits excellent stress field homogenization control across the entire spectrum.

[0060] The electrochemical impedance spectroscopy results of the 3 mm and 5 mm thick samples in 3.5 wt.% NaCl solution are as follows: Figure 9 and Figure 10 As shown in the figure. The results all indicate that, compared with their original AR samples, the capacitive arc radii of the LSP and RLSP-4 samples after laser shock treatment are significantly increased. Furthermore, at the same thickness, the capacitive arc radius of the RLSP-4 sample reaches its maximum value, exhibiting the best electrochemical corrosion resistance. From the longitudinal comparison of thickness evolution, compared with the 2 mm thick sample, the capacitive arc radii of both the 3 mm thick LSP and RLSP-4 samples are increased; while the capacitive arc radius of the 5 mm thick sample shows a further significant expansion compared to the 3 mm thick sample.

[0061] Based on the above analysis of the thickness effect on macroscopic deformation and microscopic stress, the mechanism is as follows: while increasing the matrix thickness can improve the stiffness of the component and reduce deformation, traditional line-by-line scanning still cannot eliminate the anisotropy caused by unidirectional energy stacking. The RLSP-4 process proposed in this invention can break the continuous superposition of energy at different thicknesses. While effectively suppressing deformation and stress anisotropy, it also produces a synergistic effect with increased thickness, maximizing the retention of high-amplitude, uniformly distributed residual compressive stress. Therefore, regardless of the thickness of the thin-walled component, processing with the RLSP-4 process can achieve the largest capacitive arc radius and the best corrosion resistance, further establishing the significant technical advantages of this process in improving the corrosion resistance and uniform strengthening of thin-walled parts of different specifications.

[0062] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention 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 the present invention should be included within the scope of protection of the present invention.

Claims

1. A laser shock peening method based on a partitioned iterative dual constraint, characterized in that, Includes the following steps: The surface area of ​​the component to be processed is divided into multiple sub-regions, and several laser impact points are set in each sub-region. The partitioned iterative double-constraint traversal impact is performed as follows: taking the sub-region as the basic processing unit, in each iteration, the macroscopic processing order of all the sub-regions is first randomly shuffled; then, micro-point position constraints are applied, which include selecting one laser impact point from the unimpacted points of each sub-region; finally, the selected laser impact points are arranged according to the shuffled sub-region order to form the impact sub-sequence of this iteration. The iteration is repeated until all the laser impact points are traversed to form the first impact reinforcement layer. On the first impact reinforcement layer, the partitioned iteration double constraint traversal impact is repeated to form subsequent impact reinforcement layers until the preset number of impact layers is reached.

2. The laser shock strengthening method based on partitioned iterative dual constraints according to claim 1, characterized in that, The surface area to be processed is divided into N×M sub-regions of equal area, where N and M are both positive integers; each sub-region is provided with a×b laser impact points, where a and b are both positive integers.

3. The laser shock strengthening method based on partitioned iterative dual constraints according to claim 1, characterized in that, The total number of iterations is equal to the total number of laser impact points within a single sub-region.

4. The laser shock strengthening method based on partitioned iterative dual constraints according to claim 1, characterized in that, The random shuffling of the macroscopic processing order is performed independently once per iteration, and the arrangement order of the sub-regions is different in each iteration.

5. The laser shock strengthening method based on partitioned iterative dual constraints according to claim 1, characterized in that, The micro-point positioning constraint is to select one laser impact point from the unimpacted points in each sub-region according to a preset rule in each iteration.

6. The laser shock strengthening method based on partitioned iterative dual constraints according to claim 1, characterized in that, The partitioned iterative dual-constraint traversal impact generates a global impact path sequence through a dynamic path planning module, and the industrial robotic arm controls the laser to perform laser impact on the surface of the component to be processed according to the global impact path sequence.

7. The laser shock strengthening method based on partitioned iterative dual constraints according to claim 1, characterized in that, The component to be processed is a thin-walled part.

8. The laser shock strengthening method based on partitioned iterative dual constraints according to claim 1, characterized in that, The parameters of laser shock peening process include laser wavelength, pulse energy, spot diameter, spot overlap rate, pulse width, and repetition frequency.

9. The laser shock strengthening method based on partitioned iterative dual constraints according to claim 1, characterized in that, The sub-region division size and the number of laser impact points are quantitatively matched and optimized based on the material, shape, size, and target strengthening effect of the component to be processed.

10. The laser shock strengthening method based on partitioned iterative dual constraints according to claim 1, characterized in that, An absorbent layer is applied to the surface of the component to be processed, and a constraint layer is provided above the absorbent layer.

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