Fractal Dimension Prediction Model of Coating Damage Surface by Wind-sand Erosion

In this paper, the fractal dimension prediction model of coating damage surface by wind-sand erosion was established, and the erosion damage surface morphology was reconstructed, which provides the basis for the study of coating wind-sand erosion damage surface morphology. The sand erosion damage test of polyurethane anticorrosive topcoat coating was carried out, the impact model of multi-particle was established, particle impact damage area and distribution probability were solved by using the Hertz contact theory. By described the evolution law of surface damage, the iterative relationship of the increase of damage area was obtained. And combined with the theory of fractal distribution, the fractal dimension of damaged surface was solved. Finally, analyzes the influence of different parameters on the theoretical model, The theoretical model was used to reconstruct the surface morphology of erosion damage, predict the fractal dimension of damage surface, and compared it with experimental results. In the erosion experiment, with the increase of erosion time and angle, the random and evenly distributed damage areas will overlap and connect with each other, and the fractal dimension will also increase. The surface fractal dimension has a maximum value, and the single-particle impact damage area under oblique angle is a comet. In the theoretical model, the larger the dominant particle size, the slower the initial growth rate of the fractal dimension. The larger the impact damage area, the faster the growth rate of the fractal dimension. The larger the damage scale factor, the larger the maximum value of the fractal dimension. The larger the damage area before erosion, the larger the initial fractal dimension. Comparing the theoretical model with the experimental results, the damage evolution law of the reconstructed damage surface morphology was similar to the experimental results, and the cosine similarity of surface topography and the correlation coefficient of fractal dimension were both greater than 0.9. By analyzing the characteristics of solid particle erosion and experimental results, it was found that wind-sand erosion is a nonlinear feedback dynamic system, and coating erosion surface morphology has iterative damage evolution process. Based on this, the fractal dimension prediction model of coating wind-sand erosion damage surface was established. The wind-sand flow parameters can be used to effectively predict the fractal dimension of the damage surface and reconstruct the damage surface morphology under different erosion time. The predicted results of the theoretical model have a high similarity with the experimental results, which can provide a basis for the study of the surface morphology of wind-sand erosion damage. © 2022, Chongqing Wujiu Periodicals Press. All rights reserved.