• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2019, Vol. 55 ›› Issue (21): 118-126.doi: 10.3901/JME.2019.21.118

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Study of Synthesis and Properties of Anisotropic Fractal Surfaces

ZHANG Ling, ZHENG Guolei, YANG Rongrong   

  1. School of Mechanical Engineering and Automation, Beihang University, Beijing 100191
  • Received:2019-01-23 Revised:2019-06-09 Online:2019-11-05 Published:2020-01-08

Abstract: For modeling of anisotropic fractal surfaces, a novel synthesis method named by synthetic dimension method is proposed, which is based on discrete Fourier transform and aroused by the nominal dimension Dx,Dy. By contrasting nominal dimension with computed dimension values that are obtained by the derived power spectrum formula of surface's profiles and the concomitant numerical calculation, the method proves to be useful. Further, relationships between nominal dimensions with power distribution and roughness of the generated fractal surface and surface profiles in x, y direction are discussed. On the one hand, through analyzing of surface's profile power spectrum, profile's cumulative power ratio is introduced to describe power distribution, by which the qualitative understanding of effects of nominal dimensions on profile's power can be promoted, and the relation between profile's frequency with power distribution under the impact of the dimensions is also explained quantitatively. On the other hand, taking energy analysis as an entrance, connections of nominal dimensions with surface and profile roughness are established. Meanwhile, according to the conservation of energy principle, relationships of the profile roughness Rqx,Rqy and the surface roughness Sq are revealed. The results show that smaller Dx or Dy induces a higher low-frequency energy ratio in corresponding direction, and vice versa, however, the total profile's powers in x and y direction always equal, and increase with Dx and Dy. In addition, Dx, Dy only affect the absolute roughness values of Sq,Rqx and Rqy by causing roughness increase with them, not the relative relation of Rqx and Rqy.

Key words: fractal surface, discrete Fourier transform, synthetic dimension method, nominal dimension, profile's power distribution, roughness

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