An optimization method for the process of controlling the shape of laser shock peening of blades

Abstract

The present invention provides an optimization method for the shape control process of laser shock peening of blades. First, a three-dimensional mesh model of the blade is generated using HyperMesh modeling software, the three-dimensional mesh model of the blade is calculated by Abaqus software, analyzed and controlled for software loop calculation using Matlab software, and a set of regional parameters of the three-dimensional mesh model of the blade with a deformation amount less than the characteristic deformation amount is obtained. On this basis, the shape control process processing parameters are designed by the response surface method and the blade is processed. The deformation amount of the blade after shape control processing is obtained through reverse engineering, the processing parameters are regressed and fitted, and the shape control process processing parameters with the smallest deformation amount are obtained. Further, the blade deformation amounts are compared within the set of regional parameters to obtain the shape control process regional parameters with the smallest blade deformation amount, thereby completing the optimization of the shape control process of laser shock peening of the blade, which can not only improve the fatigue life and corrosion resistance of the blade, but also meet the precision manufacturing requirements of aerospace industrial workpieces.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser strengthening, and particularly relates to an optimization method for the shape control process of laser shock peening of blades. Background Technique

[0002] Laser shock processing (LSP) is to irradiate the surface of a metal material with a high-energy pulsed laser beam, resulting in the formation of a high-pressure plasma (GPa level) on the absorption protection layer on the surface of the metal material. At the same time, due to the confinement effect of the confinement layer, the high-pressure plasma forms a high-pressure shock wave that propagates directionally into the metal material. When the peak pressure of the shock wave is higher than the dynamic yield strength of the material, it will cause severe plastic deformation on the material surface layer and form a relatively high residual compressive stress. This surface strengthening method can significantly improve the structural fatigue characteristics, wear resistance, and stress corrosion performance of the material.

[0003] Laser shock processing technology is used for the strengthening treatment of components such as compressor blades and turbine blades of aeroengines to improve the service life and service reliability of the blades. However, during the actual process of laser shock peening of blades, the blades are extremely prone to large deformations and distortions, which will affect the service state and mechanical properties of the blades during actual service. And the method of mechanical straightening will not only increase the input cost, but may also cause secondary damage to the blades.

[0004] At present, there is no public disclosure regarding the formulation and optimization of the shape control process during the laser strengthening of blades. Summary of the Invention

[0005] The purpose of the present invention is to provide an optimization method for the shape control process of laser shock peening of blades, so as to solve the problem in the prior art that there is a lack of an optimization method for the shape control process during the laser strengthening of blades.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] An optimization method for the shape control process of laser shock peening of blades, comprising the following steps:

[0008] S1: Obtain and record the initial three-dimensional data A of the blade by using a coordinate measuring machine, and the three-dimensional data is the contour curves of the blade back and blade basin at different positions of the blade;

[0009] Select a laser shock peening area on the blade, set the width a of the strengthening area, select a shape control process area on the blade, and set the area geometric parameters and area position parameters of the shape control process area. The area geometric parameters include the first distance x0 and the second distance y0, and the area position parameters include the first distance to the edge x1 and the second distance to the edge y1; Import the strengthening area width a, the first distance x0, the second distance y0, the first distance to the edge x1, and the second distance to the edge y1 into the HyperMesh modeling software to generate a three-dimensional mesh model of the blade;

[0010] S2: Import the three-dimensional mesh model of the blade into the Abaqus software, assign analysis parameters to the elements of the three-dimensional mesh model of the blade and calculate the analysis parameters to obtain the deformation amount of the three-dimensional mesh model of the blade after shape control processing;

[0011] S3: Import the deformation amount of the three-dimensional mesh model of the blade into the Matlab software for analysis and loop calculation. Determine whether the deformation amount is less than the characteristic deformation amount. If the determination is yes, output the corresponding area parameters and re-execute step S1 until the area parameters meet the termination condition. If the determination is no, directly re-execute step S1 until the area parameters meet the termination condition to obtain a set of shape control process area parameters for which the deformation amount of the three-dimensional mesh model of the blade is less than the characteristic deformation amount;

[0012] S4: Design the processing parameters of the shape control process through the response surface method for the set of area parameters, and perform shape control processing on the blade to obtain the blade after shape control processing;

[0013] S5: Use a coordinate measuring instrument to obtain the three-dimensional data A1 of the blade after shape control processing, and compare it with the initial three-dimensional data A of the blade through reverse engineering to obtain the deformation amount of the blade after shape control processing;

[0014] S6: Perform regression fitting on the processing parameters according to the deformation amount of the blade after shape control processing, analyze the obtained regression equation, and calculate the shape control process processing parameters with the minimum deformation amount;

[0015] S7: Compare the blade deformation amounts within the set of area parameters according to the shape control process processing parameters with the minimum deformation amount to obtain the shape control process area parameters with the minimum blade deformation amount, that is, complete the optimization of the shape control process.

[0016] Preferably, in step S1, the first distance x0 is the width distance of the shape control process area, the second distance y0 is the length distance of the shape control process area, the first distance to the edge x1 is the distance from the long side of the shape control process area to the laser shock peening area on the blade, and the second distance to the edge y1 is the distance from the wide side of the shape control process area to the tip of the blade.

[0017] Preferably, the analysis parameters in step S2 include material parameters and load parameters. Among them, the material parameters include density, elastic modulus, Poisson's ratio, and yield strength; the load parameters include displacement and pre-set compressive stress; the deformation amount is the maximum deformation amount at the most severely deformed position of the three-dimensional blade mesh model; the deformation amount of the three-dimensional blade mesh model after shape control processing is the maximum deformation amount at the most severely deformed position of the three-dimensional blade mesh model.

[0018] Preferably, the characteristic deformation amount in step S3 is the allowable deformation amount of the blade without affecting its use, and the termination condition is the allowable processing area of the blade, that is, the area other than the laser shock peening area.

[0019] Preferably, the processing parameters of the shape control process in step S4 include laser energy, spot diameter, and overlap rate.

[0020] Preferably, in step S5, according to the deformation amount of the blade obtained after shape control processing, regression fitting is performed on the processing parameters, and the obtained regression equation is analyzed to calculate the processing parameters of the shape control process with the minimum deformation amount.

[0021] Preferably, in step S5, multiple regression analysis is performed on the deformation amount of the blade to obtain regression equations respectively characterizing the relationships between the deformation amount of the blade and laser energy, spot diameter, and overlap rate.

[0022] Preferably, in step S1, the first distance x0 ≥ 10 mm, the second distance y0 ≥ 10 mm, the first distance to the edge x1 ≥ 0, and the second distance to the edge y1 ≥ 0.

[0023] Advantages of the present invention:

[0024] The present invention provides an integration of simulation calculation and actual processing. A three-dimensional blade mesh model is generated using HyperMesh modeling software, the three-dimensional blade mesh model is calculated by Abaqus software, analyzed using Matlab software, and the software loop calculation is controlled to obtain a set of regional parameters where the deformation amount of the three-dimensional blade mesh model is less than the characteristic deformation amount. On this basis, the processing parameters of the shape control process are designed by the response surface method and the blade is processed. The deformation amount of the blade after shape control processing is obtained through reverse engineering, regression fitting is performed on the processing parameters to obtain the processing parameters of the shape control process with the minimum deformation amount. Further, the deformation amounts of the blades are compared within the set of regional parameters to obtain the regional parameters of the shape control process with the minimum deformation amount of the blade, thereby completing the optimization of the shape control process, improving the anti-fatigue performance of the blade, and meeting the requirements of precision manufacturing. Description of the Drawings

[0025] Figure 1 is a flowchart of an optimization method for a blade laser shock peening shape control process of the present invention;

[0026] Figure 2 It is a schematic diagram of the parameters of the shape control machining area of the titanium alloy blade in the embodiment of the present invention. Detailed implementation manners

[0027] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this invention will be more complete and comprehensive, and will fully convey the concept of the example embodiments to those skilled in the art. The features or characteristics described may be combined in any suitable manner in one or more embodiments.

[0028] As Figure 1 shown in the flowchart of an optimization method for a blade laser shock peening shape control process, an optimization method for a blade laser shock peening shape control process includes the following steps:

[0029] S1: Obtain and record the initial three-dimensional data A of the blade using a coordinate measuring machine, where the three-dimensional data is the contour curves of the blade back and blade basin at different positions of the blade;

[0030] As Figure 2 shown, select the inlet edge area and the exhaust edge area of the blade body or the blade back as the laser shock peening area, set the width a of the strengthening area, select the shape control process area, and set the area geometric parameters and area position parameters of the shape control process area. The area geometric parameters include the first distance x0 and the second distance y0, and the area position parameters include the first distance to the edge x1 and the second distance to the edge y1; the first distance x0 is the width distance of the shape control process area, the second distance y0 is the length distance of the shape control process area, the first distance to the edge x1 is the distance from the long side of the shape control process area to the laser shock peening area on the blade, and the second distance to the edge y1 is the distance from the wide side of the shape control process area to the blade tip;

[0031] Import the strengthening area width a, the first distance x0, the second distance y0, the first distance to the edge x1, and the second distance to the edge y1 into the HyperMesh modeling software to generate a three-dimensional mesh model of the blade;

[0032] S2: Import the three-dimensional mesh model of the blade into the Abaqus software, assign analysis parameters to the elements of the three-dimensional mesh model of the blade and calculate the analysis parameters to obtain the deformation amount of the three-dimensional mesh model of the blade after shape control machining; the analysis parameters include material parameters and load parameters. Among them, the material parameters include density, elastic modulus, Poisson's ratio, and yield strength; the load parameters include displacement and pre-set compressive stress; the deformation amount of the three-dimensional mesh model of the blade after shape control machining is the maximum deformation amount at the position where the deformation of the three-dimensional mesh model of the blade is the most serious.

[0033] S3: The deformation amount of the three-dimensional blade grid model is imported into Matlab software for analysis and loop calculation to determine whether the deformation amount is less than the characteristic deformation amount. If the determination result is yes, the corresponding area parameters are output, and step S1 is executed again until the area parameters meet the termination condition. If the determination result is no, step S1 is directly executed again until the area parameters meet the termination condition, and a set of shape control process area parameters with the deformation amount of the three-dimensional blade grid model less than the characteristic deformation amount is obtained.

[0034] The characteristic deformation amount is the allowable deformation amount of the blade, and the termination condition is the allowable processing area of the blade. The allowable deformation amount refers to the deformation amount of the blade without affecting its use, and the allowable processing area refers to other areas except the laser shock peening area.

[0035] S4: The area parameter set is used to design the processing parameters of the shape control process through the response surface method. The processing parameters of the shape control process include laser energy, spot diameter, and overlap rate, and the blade is subjected to shape control processing to obtain the blade after shape control processing.

[0036] S5: A three-coordinate measuring instrument is used to obtain the three-dimensional data A1 of the blade after shape control processing, and it is compared with the initial three-dimensional data A of the blade through reverse engineering to obtain the deformation amount of the blade after shape control processing.

[0037] S6: According to the deformation amount of the blade after shape control processing, the processing parameters are regressively fitted, and the obtained regression equation is analyzed to calculate the shape control process processing parameters with the minimum deformation amount.

[0038] S7: According to the shape control process processing parameters with the minimum deformation amount, the blade deformation amounts are compared within the area parameter set to obtain the shape control process area parameters with the minimum blade deformation amount, that is, the optimization of the shape control process is completed.

[0039] Embodiment

[0040] S1: Taking the bottom plane of the blade tenon as the reference plane, a three-coordinate measuring instrument with a ruby measuring head of Φ1.5mm is used to measure the profiles of the blade back and blade basin at positions 20mm, 40mm, 60mm, 75mm, 85mm, 90mm, and 94mm away from the reference plane. The number of measurement coordinate points for each profile is between 30 and 36, and 14 profile curves are obtained to form and record the initial three-dimensional data A of the blade.

[0041] The laser shock peening area is the inlet and exhaust edge areas of the blade body and the blade back. The width of the strengthening area a = 5mm. The shape control process area is within the non-laser shock peening area on the blade back. The area parameters are divided into area geometric parameters x0, y0 and area position parameters x1, y1. Initial values are assigned to the area parameters according to the size of the blade. Among them, the area geometric parameters x0 ≥ 10mm, y0 ≥ 10mm, and the area position parameters x1 ≥ 0, y1 ≥ 0. As Figure 2 shown, use the HyperMesh modeling software to generate a three-dimensional mesh model of the blade containing the laser shock peening area and the shape control process area. Since the blade shape is relatively complex, tetrahedral meshes are used.

[0042] S2. The material is TC4 titanium alloy. The full side is constrained at the blade tenon position. A pre-stress of 300MPa is preset in the laser shock peening treatment area, and a pre-stress of 300MPa is preset in the shape control process area. The area with the largest deformation of the blade three-dimensional mesh model is the exhaust edge area at the blade tip.

[0043] S3. The characteristic deformation amount is 0.15mm. The termination condition is x1 = 0 or x1 + x0 = w0 - 2a. The number of area parameters with a deformation amount less than 0.15mm in the blade three-dimensional mesh model is 2 through MATLAB screening. w0 is the blade width.

[0044] S4. Set 3 for each process parameter. Determine the laser energy and spot diameter according to the empirical formula. Generally, the laser energy increment is 0.2J - 1J, and the spot diameter increment is generally 0.2mm - 0.6mm. The overlapping rates are 25%, 50% and 75% respectively, and the number of impacts is 1 time. The processing parameters of three factors and three levels designed according to the response surface method are shown in Table 1 below, where 12 are analysis factors and 5 are central tests to estimate errors.

[0045] Table 1 Processing parameter table of three factors and three levels

[0046] Serial number Laser energy (J) Spot diameter (mm) Lap rate 1 7.4 3.4 50％ 2 6.6 3.4 50％ 3 7.4 2.6 50％ 4 6.6 2.6 50％ 5 7.4 3 75％ 6 6.6 3 75％ 7 7.4 3 25％ 8 6.6 3 25％ 9 7 3.4 75％ 10 7 2.6 75％ 11 7 3.4 25％ 12 7 2.6 25％ 13 7 3 50％ 14 7 3 50％ 15 7 3 50％ 16 7 3 50％ 17 7 3 50％

[0047] S5. Compare with the initial three-dimensional data A of the blade through the reverse engineering software Geomagic Design. The area with the largest deformation of the blade is the exhaust edge area at the blade tip.

[0048] S6. Take the obtained blade deformation amount as the dependent variable, and the laser energy, spot diameter and overlapping rate as the independent variables. Perform regression fitting on the experimental results to obtain a mathematical model with multiple degrees of freedom. Analyze it to obtain the shape control process parameters with the smallest blade deformation amount, that is, under the process parameters of laser energy 6.8J, spot diameter 2.8mm, and overlapping rate 50%, the deformation amounts of the blades under two area parameters are the lowest.

[0049] S7. Complete the optimization of the shape control process.

[0050] In summary, a three-dimensional mesh model of the blade is generated using the HyperMesh modeling software, the three-dimensional mesh model of the blade is calculated by the Abaqus software, the Matlab software is used for analysis and to control the software loop calculation, a set of regional parameters where the deformation amount of the three-dimensional mesh model of the blade is less than the characteristic deformation amount is obtained. On this basis, the processing parameters of the shape control process are designed by the response surface method and the blade is processed. The deformation amount of the blade after shape control processing is obtained through reverse engineering, the processing parameters are regressed and fitted, the processing parameters of the shape control process with the minimum deformation amount are obtained, and further, the deformation amounts of the blades are compared within the set of regional parameters to obtain the regional parameters of the shape control process with the minimum deformation amount of the blade, thus completing the optimization of the shape control process.

[0051] Other embodiments of the present invention will be readily apparent to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include known common knowledge or conventional technical means in the technical field not disclosed by the present invention. The specification and examples are only to be considered as exemplary, and the true scope and spirit of the present invention are pointed out by the appended claims.

Claims

1. An optimization method for a leaf laser shock peening shape control process, characterized in that It includes the following steps: S1: Obtain and record the initial three-dimensional data A of the blade using a coordinate measuring machine. The three-dimensional data are the contour curves of the blade back and blade basin at different positions of the blade; Select the laser shock peening area on the blade, set the width a of the strengthening area, select the shape control process area on the blade, and set the area geometric parameters and area position parameters of the shape control process area. The area geometric parameters include the first distance x0 and the second distance y0, and the area position parameters include the first distance to the edge x1 and the second distance to the edge y1; Import the width a of the strengthening area, the first distance x0, the second distance y0, the first distance to the edge x1, and the second distance to the edge y1 into the HyperMesh modeling software to generate a three-dimensional mesh model of the blade; S2: Import the three-dimensional mesh model of the blade into the Abaqus software, assign analysis parameters to the elements of the three-dimensional mesh model of the blade and calculate the analysis parameters to obtain the deformation amount of the three-dimensional mesh model of the blade after shape control processing; S3: Import the deformation amount of the three-dimensional mesh model of the blade into the Matlab software for analysis and iterative calculation. Determine whether the deformation amount is less than the characteristic deformation amount. If the determination is yes, output the corresponding area parameters and re-execute step S1 until the area parameters meet the termination condition. If the determination is no, directly re-execute step S1 until the area parameters meet the termination condition to obtain a set of shape control process area parameters for which the deformation amount of the three-dimensional mesh model of the blade is less than the characteristic deformation amount; S4: Design the processing parameters of the shape control process through the response surface method based on the set of area parameters, and perform shape control processing on the blade to obtain the blade after shape control processing; S5: Obtain the three-dimensional data A1 of the blade after shape control processing using a coordinate measuring machine, and compare it with the initial three-dimensional data A of the blade through reverse engineering to obtain the deformation amount of the blade after shape control processing; S6: Perform regression fitting on the processing parameters according to the deformation amount of the blade after shape control processing, analyze the obtained regression equation, and calculate the shape control process processing parameters with the minimum deformation amount; S7: Compare the blade deformation amounts within the set of area parameters according to the shape control process processing parameters with the minimum deformation amount to obtain the shape control process area parameters with the minimum blade deformation amount, that is, complete the optimization of the shape control process.

2. The optimization method of a blade laser shock peening shape control process according to claim 1, characterized in that: In step S1, the first distance x0 is the width distance of the shape control process area, the second distance y0 is the length distance of the shape control process area, the first distance to the edge x1 is the distance from the long side of the shape control process area to the laser shock peening area on the blade, and the second distance to the edge y1 is the distance from the wide side of the shape control process area to the blade tip.

3. The optimization method of a blade laser shock peening shape control process according to claim 1, characterized in that: In step S2, the analysis parameters include material parameters and load parameters. Among them, the material parameters include density, elastic modulus, Poisson's ratio, and yield strength; the load parameters include displacement and pre-set compressive stress; the deformation amount is the maximum deformation amount at the position where the three-dimensional mesh model of the blade is most severely deformed; the deformation amount of the three-dimensional mesh model of the blade after shape control processing is the maximum deformation amount at the position where the three-dimensional mesh model of the blade is most severely deformed.

4. The optimization method of a blade laser shock peening shape control process according to claim 1, characterized in that: The characteristic deformation amount in the step S3 is the allowable deformation amount of the blade without affecting its use, and the termination condition is the allowable machining area of the blade, that is, the area other than the laser shock peening area.

5. The optimization method of a blade laser shock peening shape control process according to claim 1, characterized in that: The processing parameters of the shape control process in the step S4 include laser energy, spot diameter, and overlapping rate.

6. The optimization method of a blade laser shock peening shape control process according to claim 1, characterized in that: In the step S6, a multiple regression analysis is performed on the deformation amount of the blade to obtain regression equations respectively characterizing the relationships between the deformation amount of the blade, laser energy, spot diameter, and overlapping rate.

7. An optimization method for a blade laser shock peening shape control process according to claim 1 or 2, characterized in that: In the step S1, the first distance x0 ≥ 10 mm, the second distance y0 ≥ 10 mm, the first distance to the edge x1 ≥ 0 mm, and the second distance to the edge y1 ≥ 0 mm.

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