Method for selecting powder disc ceramic shot blasting angle and coverage rate

Abstract

The application provides a powder disc ceramic shot peening angle and coverage selection method, comprising the following steps: step one, determining shot peening parameters, and determining a shot peening angle and a surface coverage range according to the shot peening parameters; step two, establishing a shot peening strengthening finite element model according to the shot peening parameters; step three, verifying the shot peening strengthening finite element model in step two through actual shot peening data; step four, obtaining the influence law of the shot peening angle on residual stress and surface roughness through the shot peening strengthening finite element model verified in step three, and simultaneously, obtaining the influence law of the shot peening coverage on residual stress and surface roughness through the shot peening strengthening finite element model verified in step three; step five, establishing a shot peening strengthening life model according to the stress analysis results of the powder disc and the results of step four, and obtaining the optimal shot peening angle and the optimal shot peening coverage according to the shot peening strengthening life model. The application can be used to guide powder disc processing and improve the fatigue life of parts.

Description

Technical Field

[0001] This specification relates to the field of aero-engine wheel technology, specifically to a method for selecting the angle and coverage of a powder disc ceramic shot peening. Background Technology

[0002] Shot peening is a typical and widely used surface strengthening technique that improves the fatigue life of parts by introducing residual stress and refining surface grains. Many parameters affect the effectiveness of shot peening, including: shot diameter, shot type, peening angle, shot velocity, and shot coverage.

[0003] Currently, the surface strengthening effect of shot peening relies on theoretical research. In order to quantitatively analyze the surface strengthening effect of shot peening, it is necessary to establish the correspondence between shot peening and the surface state of the part. By introducing surface state parameters into the low-cycle fatigue life analysis model, a low-cycle fatigue life analysis model that considers the influence of shot peening can be established. Summary of the Invention

[0004] In view of this, embodiments of this specification provide a method for selecting the angle and coverage of shot peening for powder disc ceramics, in order to guide powder disc processing and improve the fatigue life of parts.

[0005] The technical solution of this invention is as follows: A method for selecting the angle and coverage of shot peening of a powder disc ceramic, comprising:

[0006] Step 1: Determine the shot peening parameters, and based on these parameters, determine the shot peening angle and surface coverage range.

[0007] Step 2: Establish a finite element model for shot peening based on the shot peening parameters;

[0008] Step 3: Verify the shot peening strengthening finite element model from Step 2 using actual shot peening data;

[0009] Step 4: Using the qualified shot peening finite element model verified in Step 3, obtain the influence law of shot peening angle on residual stress and surface roughness. At the same time, using the qualified shot peening finite element model verified in Step 3, obtain the influence law of shot peening coverage on residual stress and surface roughness.

[0010] Step 5: Based on the stress analysis results of the powder disk and the results of Step 4, establish the shot peening strengthening SPS-MC life model, and obtain the optimal shot peening angle and the optimal shot peening coverage based on the shot peening strengthening SPS-MC life model.

[0011] Further, step two specifically involves: using an explicit dynamic algorithm to establish a three-dimensional multi-shot peening strengthening finite element model of shot peening velocity, shot peening angle, and shot peening coverage.

[0012] Further, step three specifically involves: extracting the average stress of each layer along the depth direction in the shot-peened area and comparing it with the average stress of each layer along the depth direction extracted by electrolytic peeling after actual shot peening. If the error between the finite element simulation results of the maximum average residual compressive stress and surface stress concentration factor of the shot-peened layer and the actual shot peening results is less than 10%, then the shot peening strengthening finite element model is effective.

[0013] Furthermore, step four includes: using the formula σ(α)=(k1α+b1)σ 02 The influence of shot peening angle on surface residual stress is obtained, where σ(α) is the surface residual stress under different shot peening angles α, and k1 and b1 are coefficients obtained by least squares fitting.

[0014] Furthermore, step four includes: using the formula K(α)=a²α 2 +b2α+c2 is used to obtain the influence law of shot peening angle on surface roughness, where K(α) is the surface stress concentration factor under different shot peening angles α, and a2, b2, c2 are coefficients obtained by least squares fitting.

[0015] Furthermore, step four also includes:

[0016] Establish the functional relationship between shot peening coverage p and surface residual stress σ(p): σ(p)=(k3p+b3)σ 0.2 ;

[0017] According to the formula σ(α)=(k1α+b1)σ 0.2 The functional relationship is σ(p)=(k3p+b3)σ 0.2 A functional relationship between the shot peening angle α, shot peening coverage p, and surface residual stress σ(α, p) is established by fitting: σ(α, p) = (k1α + b1)(k3p + b3)σ 0.2 / (150k3+b3), where k3 and b3 are coefficients obtained by fitting using the least squares method.

[0018] Furthermore, step four also includes:

[0019] Establish the functional relationship between shot peening coverage p and surface roughness K(p): K(p) = k4p + b4;

[0020] According to the formula K(α)=a2α 2 The relationship between the shot peening angle α, shot peening coverage p, and surface stress concentration factor K(α, p) is established by fitting the formula K(p) = k4p + b4 and the functional relationship K(p) = (a2α + b2 + c2 + k4 + c2 + k4 + c2 + k4 + c4 + b2 + c2 + c2 + k4 + c4 + c2 ... 2+b2α+c2)(k4p+b4) / (150k4+b4), where k4 and b4 are coefficients obtained by least squares fitting.

[0021] Furthermore, step five specifically involves establishing a shot peening SPS-MC life model based on the residual surface stress σ(α, p) and surface stress concentration factor K(α, p) after shot peening.

[0022]

[0023] Furthermore, according to the formula To obtain the optimal shot peening angle and the optimal shot peening coverage.

[0024] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above-mentioned technical solutions adopted in the embodiments of this specification include at least the following: the present invention can introduce surface state parameters into the low-cycle fatigue life analysis model and establish a low-cycle fatigue life analysis model that considers the influence of shot peening process. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a flowchart illustrating an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram illustrating the variation of surface residual stress / yield strength with shot peening angle;

[0028] Figure 3 This is a schematic diagram showing the variation of surface stress concentration factor with shot peening angle;

[0029] Figure 4 This is a schematic diagram illustrating the variation of surface residual stress / yield strength with shot peening coverage.

[0030] Figure 5 This is a schematic diagram showing the variation of surface stress concentration coefficient with shot peening coverage. Detailed Implementation

[0031] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0032] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] like Figures 1 to 5 As shown, this embodiment of the invention provides a method for selecting the angle and coverage of shot peening for powder disc ceramics, specifically including the following steps:

[0034] Determine the shot peening parameters. For the powder disc, select ceramic shot. The diameter of the ceramic shot is 0.15mm to 0.45mm. The main shot peening parameters to focus on are the shot peening angle, shot peening velocity, and shot peening coverage.

[0035] A finite element model for shot peening was established. A three-dimensional multi-shot peening finite element model was established using Abaqus software and an explicit dynamic algorithm, considering shot peening velocity v, shot peening angle α, and shot peening coverage p. Shot peening kinetic energy is a comprehensive reflection of shot peening velocity v and shot peening angle α. The kinetic energy depends on the component of the shot peening velocity in the normal direction to the shot-peened surface (v×cos(α)). In this invention, the shot peening velocity v is kept constant, and the influence of shot peening angle α on surface residual stress and surface coverage p is obtained.

[0036] Determine the shot peening angle and surface coverage range. Shot peening kinetic energy E = nmv 2 ×(cos(α)) 2 / 2 (n is the number of projectiles, m is the mass of a single projectile), taking the shot peening velocity v as constant, and the shot peening angle α in the range of [0°, 90°], the smaller the shot peening angle α, the greater the kinetic energy of a single projectile. However, when the shot peening angle is 0°, the kinetic energy of a single projectile is the maximum. Only half of the projectiles retain their initial kinetic energy, while the other projectiles lose kinetic energy due to mutual collisions. Therefore, when the shot peening angle α = 45°, the shot peening kinetic energy E = nmv 2 / 4; When the shot peening angle α=0°, the shot peening kinetic energy E≥nmv 2 / 4, the shot peening angle α is generally taken as [0°, 45°]; the shot peening coverage p is taken as [100%, 200%].

[0037] Verification of the finite element model for shot peening strengthening. For the three-dimensional multi-shot shot peening strengthening finite element model, the average stress of each layer along the depth direction in the shot-peened area is extracted and compared with the average stress of each layer along the depth direction extracted by electrolytic peeling after actual shot peening. If the error between the finite element simulation results of the maximum average residual compressive stress and the surface stress concentration factor of the shot peening peeling layer and the actual shot peening results is within 10%, then the shot peening strengthening finite element model is effective.

[0038] The influence of shot peening angle on surface residual stress was investigated. Simulations were used to obtain the surface residual stress σ(α) under different shot peening angles α with a shot peening coverage of 150%. A functional relationship between shot peening angle α and surface residual stress σ(α) was established by fitting, where k1 and b1 are coefficients obtained by least squares fitting.

[0039] σ(α)=(k1α+b1)σ 0.2 (1)

[0040] The influence of shot peening angle on surface roughness was determined. The influence of shot peening angle on surface roughness is manifested as the surface stress concentration factor. The surface stress concentration factor K(α) was obtained by simulation under different shot peening angles α with a shot peening coverage of 150%. A functional relationship between shot peening angle α and surface stress concentration factor K(α) was established by fitting, where a2, b2, and c2 are coefficients obtained by least squares fitting.

[0041] K(α)=a2α 2 +b²α+c² (2)

[0042] The influence of shot peening coverage on residual stress was investigated. Simulations were used to obtain the surface residual stress σ(p) at a shot peening angle of 5° and different shot peening coverage ρ. A functional relationship between shot peening coverage ρ and surface residual stress σ(p) was established as σ(p)=(k3p+b3)σ 0.2 In the formula, k3 and b3 are coefficients obtained by least squares fitting. Based on step 5, a functional relationship between the shot peening angle α, shot peening coverage p, and surface residual stress σ(α, p) is established through fitting.

[0043] σ(α,p)=(k1α+b1)(k3p+b3)σ 0.2 / (150k3+b3) (3)

[0044] The influence of shot peening coverage on surface roughness was investigated. Simulations were used to obtain the surface roughness K(p) at a shot peening angle of 5° and different shot peening coverage p. A functional relationship between shot peening coverage p and surface roughness K(p) was established using the formula K(p) = k4p + b4, where k4 and b4 are coefficients obtained by least squares fitting. Based on step 6, a functional relationship between shot peening angle α, shot peening coverage p, and surface stress concentration factor K(α, p) was established using the formula.

[0045] K(α, p) = (a²α) 2 +b2α+c2)(k4p+b4) / (150k4+b4) (4)

[0046] Stress analysis of the powder peening disk. The stress of the powder peening disk was analyzed using the finite element method to obtain the strain amplitude ε at the location of maximum stress in the shot peening area. a and mean stress σ m .

[0047] A shot peening SPS-MC lifetime model (considering residual stress, surface roughness, and mean stress modified Manson-Coffin model) is established. Introducing the effects of surface residual stress σ(α, p) and surface stress concentration factor K(α, p) after shot peening, the established shot peening SPS-MC lifetime model is as follows:

[0048]

[0049] Obtain the optimal shot peening angle and shot peening coverage. Based on the shot peening enhanced SPS-MC life model, i.e., formula (5), with life N as a function and shot peening angle α and shot peening coverage p as independent variables, calculate the derivatives of shot peening angle α and shot peening coverage p respectively. When the derivatives are all zero, the corresponding shot peening angle α and shot peening coverage p are the optimal shot peening angle and shot peening coverage. The derivative results are shown in formula (6).

[0050]

[0051] The beneficial effects of this invention are as follows:

[0052] First, based on the simulation results of the three-dimensional multi-shot peening finite element model, a bivariate quadratic function relationship between surface residual stress and shot peening angle and shot peening coverage is established, as well as a bivariate cubic function relationship between surface stress concentration factor and shot peening angle and shot peening coverage. Then, the surface residual stress and surface stress concentration factor are introduced into the SPS-MC life model to establish the shot peening-SPS-MC life model. Finally, by differentiating the surface residual stress and surface stress concentration factor using the shot peening-SPS-MC life model, the optimal shot peening angle and shot peening coverage of the powder disk shot peening zone are obtained to guide powder disk processing and improve the fatigue life of parts.

[0053] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for selecting a powder disc ceramic shot peening angle and coverage, characterized by, include: Step 1: Determine the shot peening parameters, and determine the shot peening angle and surface coverage range based on the shot peening parameters; Step 2: Establish a finite element model for shot peening strengthening based on the shot peening parameters; Step 3: Verify the shot peening strengthening finite element model in Step 2 using actual shot peening data; Step 4: Obtain the influence of shot peening angle on residual stress and surface roughness using the qualified shot peening finite element model verified in Step 3. At the same time, obtain the influence of shot peening coverage on residual stress and surface roughness using the qualified shot peening finite element model verified in Step 3. Step 5: Based on the stress analysis results of the powder disk and the results of Step 4, establish the shot peening strengthening SPS-MC life model, and obtain the optimal shot peening angle and the optimal shot peening coverage based on the shot peening strengthening SPS-MC life model. The step four includes: obtaining the influence law of shot peening angle on surface residual stress by formula wherein, is the surface residual stress under different shot peening angles is the surface residual stress under different shot peening angles is the coefficient obtained by least square fitting. The influence law of shot peening angle on surface roughness is obtained by formula , wherein, is the surface stress concentration coefficient under different shot peening angles, , and is a coefficient obtained by least square fitting. A function relationship between shot peening coverage p and surface residual stress is established ; According to the formula and the functional relationship formula The function relationship formula of shot angle , shot coverage p and surface residual stress is established , wherein is the coefficient obtained by least square fitting; A function relationship between shot peening coverage p and surface roughness R a is established ;​ According to the formula and the functional relationship formula Fitting to establish the shot angle , shot coverage and the function of the surface stress concentration coefficient The function formula , wherein is the coefficient obtained by least square fitting; The step five is specifically: according to the surface residual stress after shot peening And surface stress concentration coefficient Establishing the shot peening SPS-MC life model .

2. The powder disc ceramic shot peening angle and coverage selection method of claim 1, wherein, Step two specifically involves: using an explicit dynamics algorithm to establish a three-dimensional multi-shot peening strengthening finite element model of shot peening velocity, shot peening angle, and shot peening coverage.

3. The powder disc ceramic shot peening angle and coverage selection method of claim 1, wherein, Step three specifically involves: extracting the average stress of each layer along the depth direction in the shot-peened area and comparing it with the average stress of each layer along the depth direction extracted by electrolytic peeling after actual shot peening. If the error between the maximum average residual compressive stress and the surface stress concentration factor of the shot-peened layer in the finite element simulation results and the actual shot peening results is less than 10%, then the shot peening strengthening finite element model is effective.

4. The powder disc ceramic shot peening angle and coverage selection method of claim 1, wherein, According to the formula The optimal shot angle and the optimal shot coverage are obtained.

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