Visualized high-efficiency simulation evaluation method for stone chip resistance of automobile coating

Abstract

The application provides a visual high-efficiency simulation evaluation method for stone chip resistance of automobile coating. The method is based on simulation results of single particle impact on coating sample at different impact speeds and impact angles, constructs a two-dimensional interpolation function of coating damage area and a coating damage grade determination table, calculates impact position, impact speed and impact angle of particles in standard test of stone chip resistance of automobile coating, calculates impact damage area of each particle, obtains impact damage grade of each particle by using the coating damage grade table, and uniformly represents the impact position, damage area and damage grade of each particle on the coating sample by using post-processing software, so as to realize evaluation of the whole damage of automobile coating under visual conditions, compare with the stone chip resistance diagram in the standard test, and obtain the overall damage parameters of the automobile coating. The application eliminates the defect of poor test repeatability and solves the difficulty of simulation of the whole process of the standard test.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of simulation evaluation of automobile coating stone chip resistance, in particular to a visual simulation evaluation method for automobile coating stone chip resistance. BACKGROUND

[0002] The stone chip resistance of automobile coating has always been an important part of the technical requirements of automobile exterior coating. Currently, the test of the stone chip resistance of automobile coating is mainly based on experiments. The existing standard test of the stone chip resistance of automobile coating is mainly divided into two systems: the German DIN system and the American SAE system. There is no special test standard in China, and major automobile companies often choose the two test standard systems from abroad to test the stone chip resistance. However, the test method is costly and has poor repeatability, so major automobile companies have been looking for a more efficient and feasible evaluation method for the stone chip resistance of automobile coating (Wang, N. X., Zhang, X. Y., & Du, Y. F. (2012). Automobile body coating stone chip resistance test and evaluation method. Automobile technology and materials, 3, 1-5.).

[0003] With the rapid development of computer technology, numerical simulation technology is increasingly favored by automobile researchers. Currently, there is no relevant simulation method applied to the study of the stone chip resistance of automobile coating. The main reason is that in the standard test of the stone chip resistance of automobile coating, a large number of particles impact the coating sample under the drive of high-pressure gas, and the test time is about 7-10 seconds, which results in a huge finite element model size and a super-long simulation time for the simulation of the multi-particle impact of automobile coating. In addition, the damage phenomenon of the coating is also complex, and it is almost impossible to simulate the whole process of the stone chip resistance of automobile coating with the existing computer technology.

[0004] By analyzing the whole process of multi-particle impact on the coating sample, if the superimposed effect of particle impact is not considered, it can be regarded as a combination of single-particle impact. Currently, Chen et al. proposed a method of interpolating the damage area of multiple particle impact on the coating and summing up the coating area to evaluate the stone chip resistance of automobile coating (Zang, M. Y., Zou, C. Q., & Chen, L. (2022, February 8). A high-efficiency simulation evaluation method and system for the stone chip resistance of automobile coating. Guangdong, CN114021406A.). However, the total damage area of the coating sample cannot be used as an evaluation index for the stone chip resistance. The existing two test standard systems evaluate the stone chip resistance of the coating by comparing the damaged coating sample with the standard stone chip resistance diagram, which is a direct and overall damage phenomenon evaluation. Therefore, a visual simulation method for the stone chip resistance of automobile coating is needed. SUMMARY

[0005] The application provides a visual high-efficiency simulation evaluation method for stone chip resistance of automobile coating, which is based on simulation results of single particle impact on a coating sample at different impact speeds and impact angles, and builds a two-dimensional interpolation function of coating damage area and a coating damage level determination table with impact speed and impact angle as independent variables without considering the superposition of particle impacts.

[0006] The application achieves the purpose at least by one of the following technical solutions.

[0007] A visual high-efficiency simulation evaluation method for stone chip resistance of automobile coating comprises the following steps.

[0008] S1, a finite element model of a single particle of a certain mass normally impacting a coating sample is established for simulation, and the damage area of the coating and the damage level of the coating are obtained, and the simulation results are compared with test phenomena to verify the effectiveness of the simulation model.

[0009] S2, the impact speed and impact angle of the particle are gradient-divided, and impact damage simulation at different speeds and different angles is performed to obtain the coating damage area and the coating damage level under multiple groups of impact speed and impact angle.

[0010] S3, multiple groups of single particle impact damage simulation results are taken as discrete data points, and the impact speed and impact angle are taken as independent variables to build a two-dimensional interpolation function of the coating damage area and a coating damage level determination table.

[0011] S4, a fluid-particle coupling calculation method is used to obtain the impact point position, impact speed and impact angle of each particle in the standard test of stone chip resistance of automobile coating.

[0012] S5, the impact speed and impact angle of each particle obtained in step S4 are sequentially brought into the coating damage area function and the coating damage level determination table in step S3 to obtain the coating damage area and the coating damage level of each particle.

[0013] S6, the impact position of each particle obtained in step S4 and the coating damage area and coating damage level of each particle obtained in step S5 are uniformly characterized on the coating sample, and a visual automobile coating multi-particle simulation result is obtained;

[0014] S7, the visual automobile coating multi-particle simulation result obtained in step S6 is directly compared with the stone impact resistance performance diagram in the standard test of automobile coating stone impact resistance performance, and the analysis and evaluation of the overall damage of the automobile coating under the visual condition are realized.

[0015] Further, in step S1, when a single particle impacts the coating sample perpendicularly, a quarter normal impact finite element model is established by using the symmetry of the structure and the load, the damage area of the coating and the damage level of the coating are obtained by finite element simulation, and the simulation result is compared with the test result. The coating damage level is consistent and the coating damage area error is not more than 10%, and the finite element model is determined to be effective. If the coating damage level is inconsistent or the coating damage area error exceeds 10%, adjust the coating material and parameters of the finite element model, and perform finite element simulation again, and compare with the test result until the finite element model is effective.

[0016] Further, in step S2, when a single particle impacts the coating sample obliquely, a half oblique impact finite element model is established according to the symmetry of the structure and the load, the coating material and parameters of the finite element model are kept unchanged, and the damage area of the coating and the damage level of the coating under oblique impact are obtained by finite element simulation.

[0017] Further, in step S2, the impact speed is gradient divided within the set speed range, and the quarter normal impact model is used to perform normal impact simulation at different impact speeds, and the coating damage area and the coating damage level under each impact speed are counted.

[0018] Within a set angle range, the impact angle is gradient divided, and then the impact speed is gradient divided under each specific impact angle. The half oblique impact model is used to perform oblique impact simulation at different impact angles and different impact speeds, and the corresponding coating damage area and coating damage level are counted.

[0019] Further, in step S2, the coating damage area is calculated according to the area of a circle with the impact center as the center and the distance from the impact center to the coating damage edge as the radius;

[0020] The damage level of the coating is determined according to the deepest coating exposed by the coating damage area. The coating includes varnish layer, color paint layer, middle coating layer, electrophoretic layer and substrate from surface to deepest part.

[0021] Further, in step S3, the impact speed is set as the x variable, the impact angle is set as the y variable, and the damage area of the coating is set as the z variable, and a two-dimensional interpolation function is created by using a plurality of single particle impact damage simulation results as discrete data.

[0022] Further, in step S3, the damage level of the coating is a typical discontinuous quantity, and a relationship between the impact speed, the impact angle and the damage level of the coating is established by using a decision table, the impact speed is set as the x variable of the decision table, the impact angle is set as the y variable of the decision table, and the damage level of the coating is set as the z variable of the decision table, and a coating damage level decision table is constructed according to a plurality of single particle impact damage simulation results as basic data.

[0023] Further, in step S4, the impact point position, the impact speed and the impact angle of each particle in the multi-particle impact coating sample can be obtained by fluid-particle coupling calculation, and the particle impacts the surface of the coating sample, so the impact point coordinates are two-dimensional plane coordinates, and the symmetry center of the coating sample is the coordinate origin.

[0024] Further, in step S5, the impact speed and the impact angle of each particle are substituted into the two-dimensional interpolation function of the damage area of the coating to obtain the impact damage area of each particle, and the impact speed and the impact angle of each particle are substituted into the coating damage level decision table to obtain the impact damage level of each particle.

[0025] Further, in step S6, the coating sample is drawn by using post-processing software, the impact point coordinates of each particle and the corresponding coating damage area and coating damage level are uniformly represented on the coating sample to realize the visual evaluation of the overall damage of the automobile coating, and the overall damage parameters of the automobile coating are obtained by comparing with the stone chip resistance performance diagram in the standard test.

[0026] Compared with the prior art, the present application has the following advantages and technical effects: the present application considers two important damage characteristics of the automobile coating under impact, namely the damage area of the coating and the damage level of the coating, and displays the overall damage phenomenon of the coating sample after impact in a visual manner, which avoids the defects of poor test repeatability, solves the problems of large calculation amount of numerical simulation of the stone chip resistance performance of the automobile coating and difficult engineering application, and the simulation results obtained by the method can be directly compared with the stone chip resistance performance diagram in the standard test to intuitively evaluate the stone chip resistance performance of the automobile coating, and the engineering application value is higher. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 A flow chart of a visual automobile coating stone chip resistance performance efficient simulation evaluation method in the embodiment of the present application is shown in the figure.

[0028] Figure 2This is a schematic diagram of a quarter-finite element model of a single particle of automotive coating impact in an embodiment of the present invention.

[0029] Figure 3 This is a schematic diagram of a half-finite element model of a single-particle tilted impact of an automotive coating in an embodiment of the present invention.

[0030] Figure 4 This is a two-dimensional interpolation function surface plot of the coating damage area in an embodiment of the present invention;

[0031] Figure 5 This is a diagram of the coating determination table program code in Embodiment 1 of the present invention;

[0032] Figure 6 This is a schematic diagram of the simulation results of multi-particle impact damage to automotive coatings in Embodiment 1 of the present invention;

[0033] Figure 7 This is a schematic diagram of the simulation results of multi-particle impact damage to automotive coatings in Embodiment 2 of the present invention;

[0034] Figure 8 This is a two-dimensional interpolation function surface plot of the coating damage area in Embodiment 3 of the present invention;

[0035] Figure 9 This is a schematic diagram of the simulation results of multi-particle impact damage to automotive coatings in Embodiment 3 of the present invention. Detailed Implementation

[0036] The implementation flowchart of the present invention is as follows: Figure 1 As shown, in order to make the objectives, technical solutions and advantages of the present invention clearer, the specific implementation of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0037] Example 1:

[0038] In this embodiment, taking the simulation of the stone chip resistance performance of automotive coatings based on the American SAE J400 standard test conditions as an example, the method of the present invention does not consider the influence of particle shape. Therefore, in this embodiment, the impact particles are uniformly regarded as standard spheres, and the implementation of the present invention will be further explained in detail.

[0039] A highly efficient simulation evaluation method for visualizing the stone chip resistance of automotive coatings includes the following steps:

[0040] S1. Establish a finite element model of a single particle normal impact coating sample of a certain mass and simulate it to obtain the damage area and damage level of the coating. Compare the simulation results with the experimental phenomena to verify the effectiveness of the simulation model.

[0041] When the single particle impacts the coating sample, a quarter of the normal impact finite element model is established by using the symmetry of the structure and load, and the coating damage area and the coating damage level are obtained by finite element simulation, and are compared with the test results. The simulation results and the test results are consistent in coating damage level and the coating damage area error is not more than 10%, which determines that the finite element model is effective. If the coating damage level is inconsistent or the coating damage area error exceeds 10%, the coating material and parameters of the finite element model are adjusted, and the finite element simulation is performed again, and is compared with the test results until the finite element model is effective.

[0042] Through investigation, it is known that in the SAE J400 standard test, the particle speed range accelerated by the high pressure acceleration tube is 7-12 m / s, the impact angle is between 60°-90°, the impact speed is divided into 6 values with a gradient of 1 m / s, and the impact angle is divided into 4 angle values with an interval of 10°, so 24 groups of single particle impact damage simulation of automobile coating are required, and the scheme is shown in Table 1.

[0043] Table 1 Single particle impact damage simulation scheme of automobile coating

[0044]

[0045]

[0046] In order to improve the calculation efficiency of numerical simulation, according to the symmetry of the structure and load of the particle-coating impact simulation model, a 1 / 4 finite element model is built for single particle normal impact condition as shown in Figure 2 , a 1 / 2 finite element model is built for single particle inclined impact condition as shown in Figure 3 ; in the simulation of particle impact coating, the deformation of the particle can be ignored, and at the same time, in order to improve the calculation efficiency, the particle can be set as a rigid body; the material physical parameters of each group remain the same, only the impact speed and impact angle are changed, 24 groups of single particle impact damage simulation of automobile coating are carried out, the coating damage area and the coating damage level of each simulation group are counted, and the results are listed in Table 2.

[0047] Table 2 Single particle impact damage simulation results of automobile coating

[0048]

[0049] S2, the impact speed and impact angle of the particle are gradient divided, and impact damage simulation of different speeds and different angles is carried out respectively, and the coating damage area and the coating damage level under multiple impact speeds and impact angles are obtained;

[0050] When the single particle impact coating sample is tilted, a half-tilted impact finite element model is established according to the symmetry of the structure and the load, the coating material and parameters of the finite element model are kept unchanged, and the coating damage area and coating damage level under the tilt impact are obtained by finite element simulation.

[0051] Within the set speed range, the impact speed is gradiently divided, the quarter normal impact model is used to perform normal impact simulation of different impact speeds, and the coating damage area and coating damage level under each impact speed are counted;

[0052] Within the set angle range, the impact angle is gradiently divided, and then the impact speed is gradiently divided under each specific impact angle, the half-tilted impact model is used to perform tilt impact simulation of different impact angles and different impact speeds, and the corresponding coating damage area and coating damage level are counted.

[0053] The coating damage area is calculated according to the area of a circle with the impact center as the center and the distance from the impact center to the coating damage edge as the radius;

[0054] The coating damage level is determined according to the deepest coating exposed by the coating damage area, and the coating from the surface to the deepest part includes varnish layer, color paint layer, middle coating layer, electrophoretic layer and substrate in turn.

[0055] S3, using multiple groups of single particle impact damage simulation results as discrete data points, impact speed and impact angle as independent variables to construct a two-dimensional interpolation function with coating damage area as dependent variable and a coating damage level determination table;

[0056] The impact speed is set as the x variable, the impact angle is set as the y variable, and the coating damage area is set as the z variable, and a two-dimensional interpolation function is created using multiple groups of single particle impact damage simulation results as discrete data.

[0057] The coating damage level is a typical discontinuous quantity, and the relationship between the impact speed, the impact angle and the coating damage level is established by using a determination table, the impact speed is used as the x variable of the determination table, the impact angle is used as the y variable of the determination table, and the coating damage level is the determination result defined as the z variable, and a coating damage level determination table is constructed according to multiple groups of single particle impact damage simulation results as basic data.

[0058] The impact speed of the particle is used as the x variable, the impact angle is used as the y variable, and the coating damage area is used as the z variable, 24 groups of coating damage areas under different impact speeds and different impact angles obtained are used as discrete data, an interpolation function tool in a commercial mathematical software matlab is used to construct a two-dimensional interpolation function of the coating damage area z=f(x,y), and a function surface graph is as shown in Figure 4The obtained 24 groups of different impact speed and different impact angle of the coating damage level are summarized to build a coating damage level judgment table, as shown in Table 3, and the judgment rules of the coating damage judgment table are written into a program using the conditional judgment statement in the commercial mathematical software matlab, and the program code page is as shown in Figure 5 The judgment is convenient for the next step.

[0059] Table 3 Coating damage level judgment table

[0060] It should be noted that the two-dimensional interpolation function of the coating damage area in the embodiment is interpolated using the interpolation method, that is, the use range of the interpolation function is limited to the impact speed and impact angle in the embodiment, and the coating damage level judgment table is also the same.

[0061] S4, using the fluid and particle coupling calculation method to obtain the impact point position, impact speed and impact angle of each particle in the standard test of the stone impact resistance of the automobile coating;

[0062] Through the fluid and particle coupling calculation, the impact point position, impact speed and impact angle of each particle in the multi-particle impact coating sample can be obtained, and the particle impacts the surface of the coating sample, so the impact point coordinates are two-dimensional plane coordinates, and the symmetry center of the coating sample is the coordinate origin.

[0063] S5, the impact speed and impact angle of each particle obtained in step S4 are sequentially brought into the coating damage area function and the coating damage level judgment table in step S3 to obtain the coating damage area and the coating damage level of each particle;

[0064] The impact speed and impact angle of each particle are substituted into the two-dimensional interpolation function of the coating damage area to obtain the impact damage area of each particle, and the impact speed and impact angle of each particle are brought into the coating damage level judgment table to obtain the impact damage level of each particle.

[0065] Based on the fluid and particle calculation method, the impact point position, impact speed and impact angle of each particle in the SAE J400 standard test are obtained, the symmetry center of the coating sample is taken as the origin, the width direction is taken as the x axis, and the length direction is taken as the y axis. A two-dimensional rectangular coordinate system is established to represent the position coordinates of the impact point. There are 183 particles in the whole impact process. The two-dimensional interpolation function z=f(x,y) of the coating damage area is used to calculate the coating damage area of the 183 particles. The coating damage level of the 183 particles is determined by using the coating judgment table program code, and the results are counted into a table. Table 4 shows the impact information of part of 40 particles.

[0066] Table 4 Impact information and simulation results of each particle in the impact process obtained by fluid and particle coupling calculation

[0067]

[0068] S6, the impact position of each particle obtained in step S4 and the coating damage area and coating damage level of each particle obtained in step S5 are uniformly represented on the coating sample to obtain a visual automobile coating multi-particle simulation result;

[0069] The coating sample is drawn using post-processing software, the impact point coordinates of each particle and the corresponding coating damage area and coating damage level are uniformly represented on the coating sample, the overall damage of the automobile coating is evaluated under the visual condition, and the overall damage parameters of the automobile coating are obtained by comparing with the stone chip resistance performance diagram in the standard test.

[0070] S7, the visual automobile coating multi-particle simulation result obtained in step S6 is directly compared with the stone chip resistance performance diagram in the standard test of automobile coating stone chip resistance performance, and the overall damage of the automobile coating is analyzed and evaluated under the visual condition.

[0071] When representing the coating damage area, the impact point coordinates of each particle are taken as the center of the circle, the coating damage area is converted into a circular area for drawing, different numbers are used to represent the damage level of the coating, and the commercial software matlab is used to realize the visualization of the multi-particle impact damage simulation result, as shown in Figure 6 Finally, the damage parameters of the automobile coating are 1.5

[0072] Example 2

[0073] The implementation steps of this example are the same as those of example 1, except that the division gradient of the particle impact angle is adjusted. In the example, the impact angle of the particles is mostly concentrated between 80-90°, and the coating damage level caused by the particle impact is greatly affected by the impact angle, so in this example, the impact angle is divided according to an interval of 5° between 80-90°, and a new coating damage level determination table is obtained as shown in Table 5. The impact point coordinates of each particle and the corresponding coating damage area and coating damage level are uniformly represented on the coating sample as shown in Figure 7

[0074] Table 5 Coating damage level determination table

[0075] Example 3

[0076] ​The implementation steps of the embodiment are the same as those of Example 1, except that a three-time spline method is used to construct a two-dimensional interpolation function of the coating damage area. The impact speed of the particle is taken as the x variable, the impact angle is taken as the y variable, and the damage area of the coating is taken as the z variable. The damage areas of the coating under 24 different impact speeds and impact angles are taken as discrete data, and a three-time spline interpolation function tool in the commercial software matlab is used to construct a two-dimensional interpolation function z = f(x, y) of the coating damage area. The function surface graph is shown in Figure 8 The impact point coordinates of each particle and the corresponding coating damage area and coating damage grade in the embodiment are uniformly represented on the coating sample as shown in Figure 9

[0077] The above embodiments of the present application are merely examples for clearly illustrating the present application, and are not intended to limit the embodiments of the present application. Based on the above description, other different forms of changes or variations can be made by those of ordinary skill in the art. All the embodiments need not be exhausted here. Any modification, equivalent replacement and improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the claims of the present application.

[0078] In summary, the present application simultaneously considers two important damage characteristics of the automobile coating when the coating is impacted, namely the damage area of the coating and the damage grade of the coating, and visually displays the overall damage phenomenon of the coating sample after being impacted. The simulation result can be directly compared with the stone impact resistance performance graph in the standard test, which not only avoids the defect of poor test repeatability, but also solves the problems of large calculation amount of numerical simulation of the stone impact resistance of the automobile coating and difficult engineering application, thereby providing a visual and high-efficiency simulation method for evaluating the stone impact resistance of the automobile coating.​

Claims

1. A highly efficient simulation evaluation method for the visual stone chip resistance of automotive coatings, characterized in that, Includes the following steps: S1. Establish a finite element model of a single particle normal impact coating sample of a certain mass and simulate it to obtain the damage area and damage level of the coating. Compare the simulation results with the experimental phenomena to verify the effectiveness of the simulation model. S2. Divide the impact velocity and impact angle of the particles into gradients, and perform impact damage simulations at different velocities and angles to obtain the coating damage area and coating damage level under multiple impact velocities and impact angles. S3. Using multiple sets of single-particle impact damage simulation results as discrete data points, and impact velocity and impact angle as independent variables, a two-dimensional interpolation function with coating damage area as dependent variable and a coating damage level determination table are constructed. S4. Use fluid-particle coupling calculation method to obtain the impact point location, impact velocity and impact angle of each particle in the standard test of the stone chip resistance of automotive coatings. S5. Substitute the impact velocity and impact angle of each particle obtained in step S4 into the coating damage area function and coating damage level determination table in step S3 to obtain the coating damage area and coating damage level of each particle. S6. The impact position of each particle obtained in step S4, the coating damage area and coating damage level of each particle obtained in step S5 are uniformly represented on the coating sample to obtain visualized multi-particle simulation results of automotive coating. S7. Directly compare the visualized multi-particle simulation results of the automotive coating obtained in step S6 with the stone impact resistance performance diagram in the standard test of automotive coating stone impact resistance performance, so as to realize the analysis and evaluation of the overall damage of automotive coating under visualization conditions.

2. The highly efficient simulation evaluation method for visualizing the stone chip resistance of automotive coatings according to claim 1, characterized in that, In step S1, when a single particle is impacted in the normal direction, a quarter-normal impact finite element model is established using the symmetry of the structure and load. The damage area and damage level of the coating are obtained through finite element simulation and compared with the test results. If the coating damage level is consistent with the test results and the coating damage area error does not exceed 10%, the finite element model is deemed to be effective. If the coating damage level is inconsistent or the coating damage area error exceeds 10%, adjust the coating material and parameters of the finite element model, re-perform the finite element simulation, and compare it with the experimental results until the finite element model is valid.

3. The highly efficient simulation evaluation method for visualizing the stone chip resistance of automotive coatings according to claim 1, characterized in that, In step S2, when a single particle is tilted and impacted, a half-tilted impact finite element model is established based on the symmetry of the structure and load. The coating material and parameters of the finite element model are kept unchanged, and finite element simulation is performed to obtain the coating damage area and coating damage level under tilted impact.

4. The highly efficient simulation evaluation method for visualizing the stone chip resistance of automotive coatings according to claim 1, characterized in that, In step S2, within the set speed range, the impact speed is divided into gradients, and the normal impact simulation at different impact speeds is performed using a quarter-normal impact model. The coating damage area and coating damage level at each impact speed are statistically analyzed. Within a set angle range, the impact angle is divided into gradients, and then the impact velocity is divided into gradients at each specific impact angle. The half-tilt impact model is used to simulate tilted impacts at different impact angles and velocities, and the corresponding coating damage area and coating damage level are statistically analyzed.

5. The highly efficient simulation evaluation method for the visual stone chip resistance of automotive coatings according to claim 2, characterized in that, In step S1, the area of ​​coating damage is calculated based on the area of ​​a circle with the impact center as the center and the distance from the impact center to the edge of coating damage as the radius. The damage level of the coating is determined according to the deepest part of the coating exposed by the damaged area. The coating consists of the clear coat, color coat, intermediate coat, electrophoretic coat, and substrate in sequence from the surface to the deepest part.

6. The highly efficient simulation evaluation method for visualizing the stone chip resistance of automotive coatings according to claim 1, characterized in that, In step S3, the impact velocity is set as the x variable, the impact angle as the y variable, and the damaged area of ​​the coating as the z variable. A two-dimensional interpolation function is created using multiple sets of single-particle impact damage simulation results as discrete data.

7. The highly efficient simulation evaluation method for visualizing the stone chip resistance of automotive coatings according to claim 1, characterized in that, In step S3, the damage level of the coating is a typical discontinuous quantity. The relationship between impact velocity, impact angle and coating damage level is established using a decision table. Impact velocity is used as the x variable in the decision table, impact angle is used as the y variable in the decision table, and the damage level of the coating is defined as the z variable based on the decision result. The coating damage level decision table is constructed based on multiple sets of single-particle impact damage simulation results.

8. The highly efficient simulation evaluation method for visualizing the stone chip resistance of automotive coatings according to claim 1, characterized in that, In step S4, the impact point position, impact velocity and impact angle of each particle in the multi-particle impact coating sample can be obtained through fluid-particle coupling calculation. Since the particles impact the surface of the coating sample, the impact point coordinates are two-dimensional plane coordinates, and the center of symmetry of the coating sample is the origin of the coordinate system.

9. The highly efficient simulation evaluation method for visualizing the stone chip resistance of automotive coatings according to claim 1, characterized in that, In step S5, the impact velocity and impact angle of each particle are substituted into the two-dimensional interpolation function of the coating damage area to obtain the impact damage area of ​​each particle. The impact velocity and impact angle of each particle are then substituted into the coating damage level determination table to obtain the impact damage level of each particle.

10. The highly efficient simulation evaluation method for the visual stone chip resistance of automotive coatings according to claim 1, characterized in that, In step S6, the coating sample is drawn using post-processing software. The impact point coordinates of each particle, as well as the corresponding coating damage area and coating damage level, are uniformly represented on the coating sample to achieve a comprehensive evaluation of the automotive coating damage under visualization conditions. The results are compared with the stone impact resistance performance diagram in the standard test to obtain the overall damage parameters of the automotive coating.

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