An improved FFT method for shot peening surface reconstruction

Abstract

Shot peening is the efficient method for metal surface modification and performance improvement. However, there is still no effective way to establishing the mathematical model for shot peening surface reconstruction, resulting in restricting the correlation study between shot peening surface properties and morphology. The difficulty of shot peening surface reconstruction lies in how to accurately characterize the roughness surface height and texture features. Therefore, a novel method of generating non-Gaussian sequences with specified height roughness parameters is proposed in this paper. Fast Fourier transform (FFT) method gets improved combined with the new method, which overcome the predicament that the unimproved FFT cannot ensure the height features in the reconstructed shot peening surfaces. In addition, a new autocorrelation function in shot peening surfaces is proposed to accurately characterize the reconstructed surface texture. The experimental results show that with the improved FFT method and the new autocorrelation function introduced to shot peening surface reconstruction, the maximum error of the seven height roughness parameters in the reconstructed surface is 2.201%. And the texture features and height distribution of the reconstructed surface are in good agreement with the measured surface.