Engineering surface topography analysis using an extended discrete modal decomposition

Abstract

Surface topography is a crucial link to connect precision manufacturing processes and product performance. Discrete modal decomposition (DMD) is recently developed filtering method for surface topography analysis, which projects the engineering surface onto a series of modal basis. Comparing with traditional filtering methods, DMD method is well applied to various engineering surfaces with holes effectively without end effect. However, each decomposed mode of DMD has not been mapped to the surface components, which lacks physical dimensions. Hence, a novel extended discrete modal decomposition (EDMD) is proposed to achieve the multi-scale engineering surface topography analysis in this paper. The proposed EDMD method including data transforming, surface inverse modeling, extended discrete modal decomposition and quantitative evaluation. Gaussian filter, robust Gaussian regression filter, spline filter and extended tetrolet transform are used as comparisons of the proposed method in numerical simulations. The EDMD method perform well both in continuous and discontinuous engineering surfaces, which overcomes the border distortion especially for discontinuous engineering surfaces and complements the physical dimension of each decomposed mode. Three real engineering surface case studies illustrate the proposed EDMD method is effective and applicable.