Method and device for calculating residual stress field of laser shock and shot peening composite strengthened surface layer

Abstract

The invention relates to the technical field of aero-engines, and provides a method and a device for calculating a residual stress field of a laser shock and shot peening composite strengthened surface layer, and the method comprises the following steps: building a tenon finite element model; strengthening a micro-motion contact area of the tenon finite element model based on a first strengthening process to obtain a first residual stress field; performing stress rebound analysis on the first residual stress field to obtain a first steady-state stress-strain field; strengthening the micro-motion contact region based on a second strengthening process and the first steady-state stress-strain field to obtain a target residual stress field; and performing stress rebound analysis on the target residual stress field to obtain the residual stress field of the composite reinforced surface layer. The method comprises the following steps: performing strengthening and stress rebound analysis on a micro contact area of a tenon finite element model through laser shock or shot peening strengthening to obtain a first steady-state stress-strain field; and strengthening is performed based on shot blasting or laser shock strengthening, a residual stress field is obtained by combining a first steady-state stress-strain field and stress rebound analysis, and a theoretical basis for technological parameter optimization is provided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engine, and particularly relates to a laser shock and shot peening composite strengthening surface residual stress field calculation method and device. BACKGROUND

[0002] The rotating components such as aero-engine blades and disks are key core parts of an aero-engine (for example, a turbofan engine). Once the aero-engine blades / disk fail, the engine will stop, which will endanger safety. When the aero-engine blades serve in an extreme environment condition integrating high speed, high pressure and complex vibration (or high temperature environment), fatigue failure will occur due to defects in surface integrity, and finally micro-cracks in the fatigue danger area of the blades will expand, and even the blades will be broken. The existing data shows that more than 80% of the fatigue cracks in the aero-engine blades originate from surface processing defects or damages. Therefore, good surface treatment and strengthening process are used to control the surface integrity, which is the key to improving the fatigue life of the aero-engine blades and ensuring reliable operation of the aero-engine for a long time.

[0003] At present, in the manufacturing process of the tenon of the aero-engine blade, the laser shock and shot peening composite strengthening process is widely used to improve the anti-fretting fatigue performance. However, in the composite strengthening process of the blade tenon, it is difficult to accurately predict the residual stress distribution after the composite strengthening, which leads to the difficulty in optimizing the process parameters. Therefore, how to calculate the residual stress field of the laser shock and shot peening composite strengthening is an important topic to be solved in the industry at present. SUMMARY

[0004] The present application provides a laser shock and shot peening composite strengthening surface residual stress field calculation method and device, which solves the defect that the residual stress after the composite strengthening is difficult to accurately predict in the prior art, can accurately calculate the residual stress field of the laser shock and shot peening composite strengthening surface, and provides a theoretical basis for process parameter optimization.

[0005] The present application provides a laser shock and shot peening composite strengthening surface residual stress field calculation method, which comprises the following steps: establishing a tenon finite element model; strengthening a fretting contact area of the tenon finite element model based on a first strengthening process to obtain a first residual stress field; performing stress rebound analysis on the first residual stress field to obtain a first steady-state stress and strain field; strengthening the fretting contact area of the tenon finite element model based on a second strengthening process and the first steady-state stress and strain field to obtain a target residual stress field; wherein the first strengthening process is one of laser shock strengthening and shot peening strengthening, and the second strengthening process is the other one of laser shock strengthening and shot peening strengthening; Performing stress rebound analysis on the target residual stress field to obtain the residual stress field of the composite strengthened surface layer.

[0006] According to the laser shock and shot peening composite strengthening surface layer residual stress field calculation method provided by the application, the micro-motion contact area of the tenon finite element model is strengthened based on the first strengthening process to obtain a first residual stress field, which comprises the following steps: The micro-motion contact area of the tenon finite element model is strengthened based on laser shock to obtain the laser energy absorption depth and distribution of the micro-motion contact area. Based on the laser energy absorption depth and distribution, the stress field caused by laser shock is determined. After the laser shock of the micro-motion contact area is completed, the stress field distribution of the surface of the micro-motion contact area is determined as the first residual stress field.

[0007] According to the laser shock and shot peening composite strengthening surface layer residual stress field calculation method provided by the application, the micro-motion contact area of the tenon finite element model is strengthened based on laser shock, which comprises the following steps: Determine the strengthening path based on the position of the micro-motion contact area. Control the laser shock strengthening to travel according to the strengthening path to strengthen the micro-motion contact area.

[0008] According to the laser shock and shot peening composite strengthening surface layer residual stress field calculation method provided by the application, the micro-motion contact area of the tenon finite element model is strengthened based on the second strengthening process and the first steady-state stress-strain field to obtain a target residual stress field, which comprises the following steps: Import the first steady-state stress-strain field into the tenon finite element model to obtain a tenon finite element model with the first steady-state stress-strain field. Strengthen the tenon finite element model with the first steady-state stress-strain field based on the second strengthening process to obtain the target residual stress field.

[0009] According to the laser shock and shot peening composite strengthening surface layer residual stress field calculation method provided by the application, the micro-motion contact area of the tenon finite element model is strengthened based on the second strengthening process and the first steady-state stress-strain field to obtain a target residual stress field, which comprises the following steps: Strengthen the tenon finite element model based on the second strengthening process to obtain a second residual stress field. Superimpose the second residual stress field and the first steady-state stress-strain field to obtain the target residual stress field.

[0010] According to the laser shock and shot peening composite strengthening surface layer residual stress field calculation method provided by the application, the first residual stress field is subjected to stress rebound analysis to obtain a first steady-state stress-strain field, which comprises the following steps: introducing the first residual stress field into a finite element analysis software; based on the static force rebound principle, obtaining a stable stress-strain field; determining the stable stress-strain field as a first steady-state stress-strain field.

[0011] According to the laser shock and shot peening composite strengthening surface residual stress field calculation method provided by the application, after the residual stress field of the composite strengthened surface is obtained, the method further comprises: based on the residual stress field of the composite strengthened surface, adjusting the process parameters of the laser shock strengthening and / or the process parameters of the shot peening strengthening.

[0012] According to the laser shock and shot peening composite strengthening surface residual stress field calculation method provided by the application, the material in the tenon finite element model is set as a J-C constitutive model.

[0013] The application further provides a laser shock and shot peening composite strengthening surface residual stress field calculation device, comprising: a establishing module, configured to establish a tenon finite element model; a first obtaining module, configured to strengthen a micro-motion contact area of the tenon finite element model based on a first strengthening process, and obtain a first residual stress field; a second obtaining module, configured to perform stress rebound analysis on the first residual stress field, and obtain a first steady-state stress-strain field; a third obtaining module, configured to strengthen the micro-motion contact area of the tenon finite element model based on a second strengthening process and the first steady-state stress-strain field, and obtain a target residual stress field; wherein the first strengthening process is one of laser shock strengthening and shot peening strengthening, and the second strengthening process is the other of laser shock strengthening and shot peening strengthening; a fourth obtaining module, configured to perform stress rebound analysis on the target residual stress field, and obtain a residual stress field of a composite strengthened surface.

[0014] The application further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the laser shock and shot peening composite strengthening surface residual stress field calculation method as described above when executing the computer program.

[0015] The laser shock and shot combined strengthening surface residual stress field calculation method provided by the application, the micro-motion contact area of the tenon finite element model is strengthened by laser shock strengthening or shot strengthening, the first residual stress field is obtained, and the first stable stress and strain field is obtained after stress rebound analysis; then the micro-motion contact area of the finite element model is strengthened based on shot strengthening or laser shock strengthening, and the target residual stress field is obtained in combination with the first stable stress and strain field, and the residual stress field of the blade tenon combined strengthening surface is calculated after stress rebound analysis, thereby providing a theoretical basis for optimizing the laser shock and shot combined strengthening process parameters. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0017] Figure 1 is one of the flowcharts of the laser shock and shot combined strengthening surface residual stress field calculation method provided by the application.

[0018] Figure 2 is the second flowchart of the laser shock and shot combined strengthening surface residual stress field calculation method provided by the application.

[0019] Figure 3 is the third flowchart of the laser shock and shot combined strengthening surface residual stress field calculation method provided by the application.

[0020] Figure 4 is the fourth flowchart of the laser shock and shot combined strengthening surface residual stress field calculation method provided by the application.

[0021] Figure 5 is one of the stress distribution nephograms of the laser shock strengthening tenon micro-motion contact area provided by the application.

[0022] Figure 6 is the second stress distribution nephogram of the laser shock strengthening tenon micro-motion contact area provided by the application.

[0023] Figure 7 is the third stress distribution nephogram of the laser shock strengthening tenon micro-motion contact area provided by the application.

[0024] Figure 8 is the fourth stress distribution nephogram of the laser shock strengthening tenon micro-motion contact area provided by the application.

[0025] Figure 9is the stress distribution nephogram of the laser shock peening tenon micro-motion contact area provided by the application.

[0026] Figure 10 is the stress distribution nephogram of the laser shock peening tenon micro-motion contact area provided by the application.

[0027] Figure 11 is the stress distribution nephogram of the laser shock peening tenon micro-motion contact area provided by the application.

[0028] Figure 12 is the stress distribution nephogram of the laser shock peening tenon micro-motion contact area provided by the application.

[0029] Figure 13 is the stress distribution nephogram of the laser shock peening tenon micro-motion contact area provided by the application.

[0030] Figure 14 is the stress distribution nephogram of the laser shock peening tenon micro-motion contact area provided by the application.

[0031] Figure 15 is the stress distribution nephogram of the laser shock peening tenon micro-motion contact area provided by the application.

[0032] Figure 16 is the stress distribution nephogram of the laser shock peening tenon micro-motion contact area provided by the application.

[0033] Figure 17 is the stress distribution nephogram of the laser shock peening tenon micro-motion contact area provided by the application.

[0034] Figure 18 is the stress distribution nephogram of the laser shock peening tenon micro-motion contact area provided by the application.

[0035] Figure 19 is the stress distribution nephogram of the laser shock peening tenon micro-motion contact area provided by the application.

[0036] Figure 20 is the stress distribution nephogram of the laser shock peening tenon micro-motion contact area provided by the application.

[0037] Figure 21 is the stress distribution nephogram of the laser shock peening tenon micro-motion contact area provided by the application.

[0038] Figure 22 is the stress distribution nephogram of the laser shock peening tenon micro-motion contact area provided by the application.

[0039] Figure 23 is the stress distribution nephogram of the laser shock peening tenon micro-motion contact area provided by the application.

[0040] Figure 24 is the stress distribution nephogram of the mortise micro-motion contact area under the laser shock and shot peening composite reinforcement provided by the application.

[0041] Figure 25 is the structural schematic diagram of the mortise simulation piece provided by the application.

[0042] Figure 26 is the schematic diagram of the relationship between the surface position and the residual stress provided by the application.

[0043] Figure 27 is the schematic diagram of the relationship between the depth position and the residual stress provided by the application.

[0044] Figure 28 is the structural schematic diagram of the laser shock and shot peening composite reinforcement surface residual stress field calculation device provided by the application.

[0045] Figure 29 is the structural schematic diagram of the electronic device provided by the application.

[0046] The reference signs: 10, mortise simulation piece; 11, micro-motion plane. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical scheme and advantages of the application clearer, the technical scheme in the application will be described clearly and completely below in combination with the drawings in the application. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0048] The laser shock and shot peening composite reinforcement surface residual stress field calculation method of the application will be described below. Figures 1-27 The laser shock and shot peening composite reinforcement surface residual stress field calculation method of the application will be described below.

[0049] Figure 1 One of the flow schematic diagrams of the laser shock and shot peening composite reinforcement surface residual stress field calculation method provided by the embodiments of the application is shown as Figure 1 The calculation method comprises the following steps: Step 100, establishing a mortise finite element model.

[0050] Step 200, strengthening the micro-motion contact area of the mortise finite element model based on a first reinforcement process, to obtain a first residual stress field.

[0051] Step 300, performing stress rebound analysis on the first residual stress field, to obtain a first steady-state stress and strain field.

[0052] Step 400, strengthening the micro-motion contact area of the tenon finite element model based on the second strengthening process and the first steady-state stress-strain field, to obtain a target residual stress field.

[0053] Step 500, stress rebound analysis is performed on the target residual stress field to obtain a residual stress field of the composite strengthened surface layer.

[0054] The first strengthening process is one of laser shock peening and shot peening, and the second strengthening process is the other of laser shock peening and shot peening.

[0055] Laser shock peening is a surface strengthening technique that uses a high-energy laser beam to act on the surface of the material, producing high temperature and high pressure mechanical-thermal coupling effects, causing plastic deformation of the surface layer material, thereby introducing residual compressive stress.

[0056] Shot peening, on the other hand, uses high-speed moving pellets to impact the surface of the material, causing plastic deformation of the surface layer and forming residual compressive stress.

[0057] Laser shock peening has a high strain rate and a deep influence layer, while shot peening has high uniformity and hardening rate. The tenon micro-motion fatigue is a combined damage form of wear and fatigue, however, single laser shock or shot peening is difficult to meet the high requirements of the surface strengthening of the tenon of the aero-engine blade. Combining the advantages of both can introduce a deeper residual compressive stress and a hardening layer on the surface of the material. The severe plastic deformation of the material surface leads to grain refinement and the generation of a large number of high-density dislocations, thereby further improving the micro-motion fatigue performance of the material.

[0058] It should be noted that the laser shock and shot peening introduce residual stress in the material surface layer is one of the main factors to improve the material fretting fatigue life, and the research found that the influence law of residual stress on fatigue and fretting fatigue is: laser shock peening can more effectively inhibit the initiation and early propagation of fatigue cracks, and the anti-fretting fatigue performance is stronger; the residual compressive stress is released with the increase of the number of fretting fatigue cycles, and the release rate is closely related to the position and the direction of the fretting fatigue crack propagation, and the release degree of the residual stress is more obvious within 0.5mm of the material surface layer, and the release degree of the residual stress along the direction of the fretting fatigue crack is the highest. And through the study on the change of the surface layer residual stress of the untreated sample in the process of fretting fatigue, it is found that: the residual compressive stress will be generated in the surface layer of the material in the process of fretting fatigue, and the level of these residual compressive stress has directional characteristics, and the level of the residual stress generated along the direction of the fretting fatigue is higher; with the increase of the fatigue load cycle, the level of the residual stress first increases to a maximum value, and then decreases. It is found that the fracture of the original specimen (untreated sample), the shot peening specimen and the laser shock peening specimen after the fretting fatigue test is observed, and the results show that: under the action of high fatigue load, the crack initiation points of the three kinds of specimens are all in the surface of the fretting contact area; when the fatigue load decreases, the fatigue crack initiation point may appear in the subsurface near the maximum tensile stress. In the fretting fatigue test of the surface strengthening treated specimen under low fatigue load, the crack initiation point is not in the fretting spot area, which may be due to the residual compressive stress introduced by the surface strengthening inhibits the surface crack initiation and early propagation caused by fretting, so that the crack initiation is converted to be caused by ordinary fatigue, so that the crack initiation point appears in the point of the maximum tensile stress in the subsurface. Therefore, it is necessary to obtain the residual stress field of the fretting contact area of the blade tenon after laser shock and shot peening composite strengthening through numerical simulation calculation, so as to provide technical support for the anti-fretting fatigue design of the tenon. Based on this, the tenon finite element model is established, the numerical simulation calculation of laser shock and shot peening composite strengthening is carried out, and the steady-state residual compressive stress field of the fretting contact area of the tenon after laser shock and shot peening composite strengthening is obtained.

[0059] Specifically, a tenon finite element model is established, the fretting contact area of the tenon finite element model is strengthened based on laser shock, a first residual stress field is obtained, stress rebound analysis is performed on the first residual stress field, and a first steady-state stress and strain field is obtained; then the fretting contact area of the finite element model is strengthened based on shot peening, and the first steady-state stress and strain field is combined to obtain a target residual stress field, and stress rebound analysis is performed on the target residual stress field, so that the residual stress field of the blade tenon composite strengthening surface layer is calculated, thereby providing a theoretical basis for optimizing the process parameters of laser shock and shot peening composite strengthening. It should be noted that shot peening can be performed first to obtain a first residual stress field, and then laser shock peening can be performed to obtain a target residual stress field.

[0060] The laser shock and shot peening composite strengthening surface residual stress field calculation method provided by the embodiment of the application strengthens the micro-motion contact area of the tenon finite element model through laser shock strengthening or shot peening strengthening, obtains a first residual stress field, and obtains a first steady stress-strain field after stress rebound analysis; then, the micro-motion contact area of the finite element model is strengthened based on shot peening strengthening or laser shock strengthening, and the target residual stress field is obtained in combination with the first steady stress-strain field, and the residual stress field of the blade tenon composite strengthened surface is calculated after stress rebound analysis, thereby providing a theoretical basis for optimizing laser shock and shot peening composite strengthening process parameters.

[0061] In an embodiment of the application, step 100 can include the following content: Based on the action mechanism of laser shock and shot peening strengthening, a three-dimensional finite element model of the tenon is established, which is the tenon finite element model.

[0062] Optionally, the material in the tenon finite element model is set as a J-C constitutive model.

[0063] It can be understood that the tenon adopts a titanium alloy material, and the tenon finite element model adopts a Johnson-Cook (J-C) constitutive model to describe the dynamic mechanical behavior of the titanium alloy, which comprehensively considers strain hardening, strain rate effect and temperature softening effect.

[0064] In the embodiment, the tenon finite element model mainly includes the following parts: Material model: a J-C elastic-plastic material model is adopted to consider the nonlinear deformation behavior of the material, and specific material parameters of the titanium alloy, such as the elastic modulus and the yield strength, are introduced.

[0065] Load model: laser shock strengthening and shot peening strengthening are modeled respectively, and the time-space coupling effect is considered.

[0066] Boundary condition: the bottom surface of the tenon is set as a fixed boundary condition, and the contact surface of the tenon and the disc is set as a strengthening area (i.e., the micro-motion contact area).

[0067] It can be understood that the finite element software (Advanced Simulation for Engineering and Sciences, ABAQUS) is used to calculate the transient stress-strain distribution of the tenon surface, and the transient stress-strain result is imported into ABAQUS for static rebound calculation to obtain the stable stress-strain field after strengthening. It should be noted that the transient stress-strain distribution is the residual stress of the tenon surface after strengthening, and the residual stress field obtained after the entire micro-motion contact area of the tenon is strengthened is taken as the transient stress-strain result.

[0068] In one embodiment of the present application, the mechanism of laser shock peening is the rapid absorption of laser energy, which creates a mechanical-thermal coupling effect of high temperature and high pressure on the material surface. The laser shock peening process can be divided into the following stages: Laser energy absorption: the laser beam interacts with the material surface, and the laser energy is absorbed by the material and converted into heat energy.

[0069] High temperature and high pressure loading: the laser energy is released in a very short time, resulting in extremely high temperature and pressure on the material surface.

[0070] Shock wave generation: the high pressure load propagates through the material, forming a shock wave, causing plastic deformation of the surface layer material.

[0071] Residual stress introduction: after the shock wave subsides, residual compressive stress is generated in the surface layer of the material.

[0072] Optionally, as shown in Figure 2 Step 200 can include the following steps: Step 210, based on laser shock, strengthening the micro-motion contact area of the tenon finite element model, obtaining the laser energy absorption depth and distribution of the micro-motion contact area.

[0073] Step 220, based on the laser energy absorption depth and distribution, determining the stress field caused by laser shock.

[0074] Step 230, after completing the laser shock of the micro-motion contact area, the stress field distribution on the surface of the micro-motion contact area is determined as the first residual stress field.

[0075] It can be understood that the laser beam is incident on the micro-motion contact area of the tenon finite element model, the laser energy absorption depth and distribution of the surface layer of the tenon finite element model are calculated through laser-material interaction, and the stress field caused by laser shock is calculated combined with the temperature field and the thermal expansion characteristics of the material. After completing the laser shock of the entire micro-motion contact area, the stress field distribution on the surface of the micro-motion contact area is determined as the first residual stress field.

[0076] In one embodiment of the present application, in step 210, based on laser shock, the micro-motion contact area of the tenon finite element model is strengthened, which can include the following contents: Determine the strengthening path based on the position of the micro-motion contact area; control the laser shock peening to travel along the strengthening path to strengthen the micro-motion contact area.

[0077] As shown in Figure 25As shown, the tenon finite element model is designed according to the blade root tenon structure, the tenon and the wheel disc contact surface are taken as the fretting contact area, the fretting contact area is divided into a plurality of laser strengthening areas, the strengthening path is planned according to the position of the fretting contact area, and the laser shock peening is controlled to march according to the strengthening path, so that the plurality of laser strengthening areas are strengthened one by one, thereby completing the strengthening of the fretting contact area.

[0078] As shown in the examples, Figures 5 to 19 As shown, the laser shock peening is performed on the fretting contact area, the fretting contact area is divided into a left region, a middle region and a right region arranged in sequence along the horizontal direction, and the laser shock peening is performed on the fretting contact area every 20 ns (nanoseconds). As shown in the examples, Figures 5 to 9 As shown, the laser shock peening is performed on the left region of the fretting contact area from top to bottom; as shown in the examples, Figures 10 to 14 As shown, the laser shock peening is performed on the right region of the fretting contact area from top to bottom; as shown in the examples, Figures 15 to 19 As shown, the laser shock peening is performed on the middle region of the fretting contact area from top to bottom. It should be noted that the stress field distribution diagram of the tenon surface layer can be obtained after each laser shock, and the residual stress distribution in the surface and depth directions is shown in the stress field distribution diagram; after the laser shock of the entire fretting contact area is completed, the stress field distribution of the surface of the fretting contact area corresponding to the last laser shock is taken as the first residual stress field, that is, Figure 19 The stress field distribution is determined as the first residual stress field.

[0079] Further, the step 300 can include the following contents: The first residual stress field is introduced into the finite element analysis software; based on the static elastic recovery principle, a stable stress-strain field is obtained; and the stable stress-strain field is determined as the first stable stress-strain field.

[0080] It can be understood that after the laser shock is completed, the first residual stress field is introduced into ABAQUS for static elastic recovery analysis, the residual stress distribution of the surface layer of the fretting contact area is calculated, and the residual stress distribution is taken as the first stable stress-strain field.

[0081] In an embodiment of the present application, the mechanism of shot peening is the impact deformation of high-speed shot particles on the material surface. The shot peening process can be divided into the following stages: Shot impact: high-speed moving shot particles impact the material surface, causing local plastic deformation.

[0082] Stress wave generation: during the impact process, stress waves are generated on the material surface, causing deformation of the surface layer material.

[0083] Residual stress introduction: after the impact is completed, the surface layer of the material retains residual compressive stress.

[0084] Further, the composite strengthening is laser shock peening and shot peening, the action mechanism of the composite strengthening is the synergistic effect of the two strengthening modes, the laser shock provides the mechanical-thermal coupling effect of high temperature and high pressure, the shot peening provides the impact deformation effect, and the combination of the two strengthening processes can significantly improve the residual compressive stress density of the surface layer and the subsurface layer of the titanium alloy blade tenon and optimize the distribution of the residual stress.

[0085] Optionally, as shown in Figure 3 Step 400 can include the following steps: Step 410, introducing the first steady-state stress-strain field into the tenon finite element model to obtain the tenon finite element model with the first steady-state stress-strain field.

[0086] Step 420, strengthening the tenon finite element model with the first steady-state stress-strain field based on the second strengthening process to obtain the target residual stress field.

[0087] It can be understood that the first steady-state stress-strain field is introduced into the tenon finite element model to obtain the tenon finite element model with the first steady-state stress-strain field, the tenon finite element model with the first steady-state stress-strain field is strengthened by shot peening to obtain the target residual stress field, and the target residual stress field is introduced into ABAQUS for static force rebound calculation to obtain the residual stress field of the composite strengthened surface layer.

[0088] Examples, as shown in Figures 20 to 23 The shot peening is performed on the micro-motion contact area; wherein, Figure 20 is an output high-speed moving shot, Figure 21 is the contact of the high-speed moving shot with the micro-motion contact area, Figure 22 is the impact of the high-speed moving shot with the material surface of the micro-motion contact area, Figure 23 is the rebound of the shot after the impact, and the stress field distribution diagram of the tenon surface layer is obtained, and the residual stress distribution in the surface and depth directions is shown in the stress field distribution diagram.

[0089] In another embodiment of the present application, step 400 can include the following content: Strengthening the tenon finite element model based on the second strengthening process to obtain the second residual stress field; superimposing the second residual stress field and the first steady-state stress-strain field to obtain the target residual stress field.

[0090] It can be understood that the tenon finite element model during shot peening should consider the influence of the speed, angle, particle size and coverage of the shot on the impact effect, calculate the surface layer plastic deformation and stress field distribution caused by shot peening impact, and take it as the second residual stress field, superimpose the second residual stress field and the first steady-state stress-strain field to obtain the target residual stress field, as shown in Figure 24and the steady-state residual stress distribution of the surface layer is calculated by introducing the target residual stress field into ABAQUS after the shot peening is completed, and the steady-state residual stress distribution is taken as the residual stress field of the composite strengthened surface layer; Figure 24 Fig. a shows the springback process, and Fig. b shows the residual stress field of the composite strengthened surface layer.

[0091] In an embodiment of the present application, as shown in Fig. 1, after step 500, the calculation method further comprises the following steps: Figure 4 Step 600: adjusting the process parameters of laser shock peening and / or the process parameters of shot peening based on the residual stress field of the composite strengthened surface layer.

[0092] For example, the blade tenon is made of titanium alloy, which has high strength, high toughness and good corrosion resistance. However, the engine blade tenon needs to bear complex loads during operation, including centrifugal force, vibration load, stress concentration, etc., and is prone to fatigue failure. Therefore, laser shock and shot peening are used for composite strengthening of the surface of the blade tenon. In the process of composite strengthening of the titanium alloy blade tenon, the residual stress distribution of the surface layer is difficult to accurately predict, which leads to instability of material performance and difficulty in optimizing process parameters. Therefore, in this embodiment, a tenon finite element model is established, the mechanism of laser shock and shot peening is combined, the residual stress field of the surface layer is calculated, and the process parameters of laser shock and shot peening are optimized based on the residual stress distribution of the surface layer. By optimizing the composite strengthening process parameters, the hardness, wear resistance and fatigue strength of the surface of the titanium alloy blade tenon can be significantly improved, which provides theoretical support for actual engineering applications.

[0093] It can be understood that based on the residual stress field of the composite strengthened surface layer, the process parameters of laser shock peening can be optimized, the process parameters of shot peening can be optimized, or the process parameters of laser shock peening and the process parameters of shot peening can be simultaneously optimized.

[0094] In this embodiment, optimizing the process parameters of laser shock and shot peening can include laser energy density, laser shock time, shot particle size, shot particle injection speed and impact sequence.

[0095] In an embodiment of the present application, the accuracy of the residual stress field of the composite strengthened surface layer is verified by an experimental device, which comprises the following: The tenon simulation piece 10 is designed according to the blade root tenon structure, and the material is titanium alloy (Ti-6Al-4V). The tenon simulation piece is designed according to the blade root tenon structure, and the tenon contact surface with the disc is taken as the micro-motion plane 11, which is the micro-motion contact area.

[0096] Laser shock equipment: a high-energy pulse laser such as a Nd:YAG laser is used.​

[0097] Shot peening equipment: Use shot peening equipment to control the speed and particle size of the shot.

[0098] Stress measurement equipment: Use X-ray stress measurement equipment, such as XRD (X-ray diffraction), to measure the residual stress distribution on the surface.

[0099] The working process of the experimental device in this embodiment: Laser shock test: According to the process parameters (set laser energy density, shock time, etc.), the surface of the micro-motion contact area of ​​the titanium alloy tenon simulation part is laser shock strengthened.

[0100] Shot peening experiment: Based on laser shock peening, the surface of the micro-contact area of ​​the titanium alloy tenon simulation part was shot peened.

[0101] Stress measurement: Use X-ray stress measurement equipment to measure the residual stress distribution on the surface of the composite reinforced micro-contact area, such as Figure 26 and Figure 27 As shown; Figure 26 In the figure, the horizontal axis is the surface position, the unit is mm (millimeter), and the vertical axis is the residual stress, the unit is MPa (megapascal); Figure 27 In the figure, the horizontal axis is the depth position, the unit is μm (micrometer), and the vertical axis is the residual stress, the unit is MPa (megapascal).

[0102] like Figure 26 As shown in Figure 2, the experimental data and simulation data have a high degree of overlap. Figure 26 In , a represents experimental data and b represents simulation data; Figure 27 As shown in Figure 2, the trends of the experimental data and the simulation data are basically consistent, both showing that the residual stress gradually decreases with increasing depth. Figure 27 In the equation, c represents experimental data and d represents simulation data; Figure 26 and Figure 27 It can be seen that the simulation results are highly consistent with the experimental data in terms of overall trend and magnitude, thus verifying the reliability of the calculation method of this embodiment. It should be noted that the simulation data is the residual stress field of the composite reinforced surface layer obtained after executing steps 100 to 500 of this embodiment; the experimental data is the residual stress distribution of the surface layer of the micro-contact area measured during the above experimental process.

[0103] The following describes the device for calculating the residual stress field of the surface layer subjected to laser shock and shot peening composite strengthening provided by the present invention. The device for calculating the residual stress field of the surface layer subjected to laser shock and shot peening composite strengthening described below and the method for calculating the residual stress field of the surface layer subjected to laser shock and shot peening composite strengthening described above can be referred to in correspondence with each other.

[0104] like Figure 28As shown, the laser shock and shot combined strengthening surface layer residual stress field calculation device includes a establishing module 2810, a first obtaining module 2820, a second obtaining module 2830, a third obtaining module 2840, and a fourth obtaining module 2850; wherein: The establishing module 2810 is configured to establish a tenon finite element model.

[0105] The first obtaining module 2820 is configured to strengthen the micro-motion contact area of the tenon finite element model based on a first strengthening process, to obtain a first residual stress field.

[0106] The second obtaining module 2830 is configured to perform stress rebound analysis on the first residual stress field, to obtain a first steady-state stress-strain field.

[0107] The third obtaining module 2840 is configured to strengthen the micro-motion contact area of the tenon finite element model based on a second strengthening process and the first steady-state stress-strain field, to obtain a target residual stress field; wherein the first strengthening process is one of laser shock strengthening and shot strengthening, and the second strengthening process is the other of laser shock strengthening and shot strengthening.

[0108] The fourth obtaining module 2850 is configured to perform stress rebound analysis on the target residual stress field, to obtain a residual stress field of a combined strengthening surface layer.

[0109] Figure 29 An example of a schematic diagram of a physical structure of an electronic device is shown in FIG. 1. Figure 29 As shown, the electronic device can include a processor 2910, a communications interface 2920, a memory 2930, and a communications bus 2940, wherein the processor 2910, the communications interface 2920, and the memory 2930 can communicate with each other through the communications bus 2940. The processor 2910 can invoke a logical instruction in the memory 2930 to execute a laser shock and shot combined strengthening surface layer residual stress field calculation method, which includes: establishing a tenon finite element model; strengthening the micro-motion contact area of the tenon finite element model based on a first strengthening process, to obtain a first residual stress field; performing stress rebound analysis on the first residual stress field, to obtain a first steady-state stress-strain field; strengthening the micro-motion contact area of the tenon finite element model based on a second strengthening process and the first steady-state stress-strain field, to obtain a target residual stress field; wherein the first strengthening process is one of laser shock strengthening and shot strengthening, and the second strengthening process is the other of laser shock strengthening and shot strengthening; and performing stress rebound analysis on the target residual stress field, to obtain a residual stress field of a combined strengthening surface layer.

[0110] In addition, the logic instructions in the memory 2930 described above can be implemented in the form of a software function unit and sold or used as an independent product, which can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the parts that contribute to the prior art or parts of the technical solutions can be embodied in the form of a software product, which is stored in a storage medium, including a plurality of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the embodiments of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various program code storage media.

[0111] In another aspect, the present application also provides a computer program product, the computer program product comprising a computer program, the computer program being stored in a non-transitory computer readable storage medium, and the computer program being executable by a processor to cause a computer to perform the laser shock and shot peening combined strengthening surface residual stress field calculation method provided by the above-mentioned methods, the method comprising: establishing a tenon finite element model; strengthening the micro-motion contact area of the tenon finite element model based on a first strengthening process to obtain a first residual stress field; performing stress rebound analysis on the first residual stress field to obtain a first steady stress and strain field; strengthening the micro-motion contact area of the tenon finite element model based on a second strengthening process and the first steady stress and strain field to obtain a target residual stress field; wherein the first strengthening process is one of laser shock peening and shot peening, and the second strengthening process is the other of laser shock peening and shot peening; and performing stress rebound analysis on the target residual stress field to obtain a residual stress field of a combined strengthening surface.

[0112] In another aspect, the present application also provides a non-transitory computer readable storage medium having a computer program stored thereon, the computer program being executable by a processor to implement the laser shock and shot peening combined strengthening surface residual stress field calculation method provided by the above-mentioned methods, the method comprising: establishing a tenon finite element model; strengthening the micro-motion contact area of the tenon finite element model based on a first strengthening process to obtain a first residual stress field; performing stress rebound analysis on the first residual stress field to obtain a first steady stress and strain field; strengthening the micro-motion contact area of the tenon finite element model based on a second strengthening process and the first steady stress and strain field to obtain a target residual stress field; wherein the first strengthening process is one of laser shock peening and shot peening, and the second strengthening process is the other of laser shock peening and shot peening; and performing stress rebound analysis on the target residual stress field to obtain a residual stress field of a combined strengthening surface.

[0113] The device embodiments described above are merely illustrative, wherein the units illustrated as separate components can or can not be physically separated, and the components illustrated as units can or can not be physical units, i.e., can be located in one place, or can be distributed to multiple network units. Part or all of the modules can be selected to achieve the purposes of the embodiments according to actual needs. Those skilled in the art can understand and implement without creative labor.

[0114] Through the description of the above embodiments, those skilled in the art can clearly understand that the embodiments can be realized by means of software and the necessary general hardware platform, and of course can also be realized by hardware. Based on such understanding, the above technical solutions can be embodied in the form of software products, and the computer software products can be stored in a computer readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and include a plurality of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute the methods of the embodiments or some parts of the embodiments.

[0115] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for calculating the residual stress field of the surface layer strengthened by laser shock and shot peening, characterized in that: include: Establish a finite element model of the tenon; Strengthening the fretting contact area of ​​the tenon finite element model based on a first strengthening process to obtain a first residual stress field; Performing stress rebound analysis on the first residual stress field to obtain a first steady-state stress-strain field; Strengthening the micro-contact area of ​​the tenon finite element model based on the second strengthening process and the first steady-state stress-strain field to obtain a target residual stress field; wherein the first strengthening process is one of laser shock peening and shot peening, and the second strengthening process is the other of laser shock peening and shot peening; A stress rebound analysis is performed on the target residual stress field to obtain the residual stress field of the composite strengthened surface layer.

2. The method for calculating the residual stress field of the surface layer after laser shock and shot peening composite strengthening according to claim 1 is characterized in that: The step of strengthening the micro-motion contact area of ​​the tenon finite element model based on the first strengthening process to obtain a first residual stress field includes: Strengthening the micro-motion contact area of ​​the tenon finite element model based on laser shock, and obtaining the laser energy absorption depth and distribution of the micro-motion contact area; determining a stress field caused by the laser shock based on the laser energy absorption depth and distribution; After the laser shock treatment of the micro-motion contact area is completed, the stress field distribution on the surface of the micro-motion contact area is determined as a first residual stress field.

3. The method for calculating the residual stress field of the surface layer after laser shock and shot peening composite strengthening according to claim 2 is characterized in that: The strengthening of the micro-motion contact area of ​​the tenon finite element model based on laser shock comprises: determining a strengthening path based on the position of the micro-motion contact area; The laser shock peening is controlled to proceed along the strengthening path to strengthen the micro-motion contact area.

4. The method for calculating the residual stress field of the surface layer after laser shock and shot peening composite strengthening according to claim 1 is characterized in that: The step of strengthening the micro-contact area of ​​the tenon finite element model based on the second strengthening process and the first steady-state stress-strain field to obtain a target residual stress field includes: Importing the first steady-state stress and strain field into the tenon finite element model to obtain the tenon finite element model having the first steady-state stress and strain field; The tenon finite element model with the first steady-state stress and strain field is strengthened based on the second strengthening process to obtain the target residual stress field.

5. The method for calculating the residual stress field of the surface layer after laser shock and shot peening composite strengthening according to claim 1 is characterized in that: The step of strengthening the micro-contact area of ​​the tenon finite element model based on the second strengthening process and the first steady-state stress-strain field to obtain a target residual stress field includes: Strengthening the tenon finite element model based on the second strengthening process to obtain a second residual stress field; The second residual stress field and the first steady-state stress and strain field are superimposed to obtain a target residual stress field.

6. The method for calculating the residual stress field of the surface layer after laser shock and shot peening composite strengthening according to claim 1 is characterized in that: The performing stress rebound analysis on the first residual stress field to obtain a first steady-state stress-strain field includes: Importing the first residual stress field into finite element analysis software; Based on the static rebound principle, a stable stress and strain field is obtained; The stable stress-strain field is determined as a first steady-state stress-strain field.

7. The method for calculating the residual stress field of the surface layer by laser shock and shot peening composite strengthening according to any one of claims 1 to 6, characterized in that: After obtaining the residual stress field of the composite strengthened surface layer, the method further comprises: Based on the residual stress field of the composite strengthened surface layer, the process parameters of the laser shock strengthening and / or the process parameters of the shot peening are adjusted.

8. The method for calculating the residual stress field of the surface layer by laser shock and shot peening composite strengthening according to any one of claims 1 to 6, characterized in that: The material in the tenon finite element model is set as the JC constitutive model.

9. A device for calculating residual stress field of surface layer strengthened by laser shock and shot peening, characterized in that: include: Establish a module for establishing a finite element model of the tenon; A first obtaining module is used to strengthen the micro-contact area of ​​the tenon finite element model based on a first strengthening process to obtain a first residual stress field; A second obtaining module is used to perform stress rebound analysis on the first residual stress field to obtain a first steady-state stress and strain field; a third obtaining module, configured to strengthen the micro-motion contact area of ​​the tenon finite element model based on a second strengthening process and the first steady-state stress-strain field to obtain a target residual stress field; wherein the first strengthening process is one of laser shock peening and shot peening, and the second strengthening process is the other of laser shock peening and shot peening; The fourth obtaining module is used to perform stress rebound analysis on the target residual stress field to obtain the residual stress field of the composite strengthened surface layer.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method for calculating the residual stress field of the surface layer strengthened by laser shock and shot peening as described in any one of claims 1 to 8 is implemented.

Images