Characterisation of the 3D waviness and roughness motifs

The surface summits and their waviness envelope constitute the boundary surface of contact area during the tribological life of solids. The form, scale and orientation of the three-dimensional motifs play an important role on flatness behaviour of engineered surfaces, contact mechanics, adherence, friction, lubrication and leakage problems. The basic idea of this work considers that the three-dimensional motifs of the surface are a key elements of surface topography in regard to different field of tribology. The 2D motif is defined as the part of profile which associates tow peaks separated a deep valley (pit). The extension of the 2D motif definition to the 3D morphology needs the simultaneous assessment of waviness and roughness. The approach developed in this work is based on a geomorphologic definition of 3D motif. The approach is improved by a new algorithm of waviness envelope construction and a morphologic filter using the waviness envelope as a low-frequency surface of filtering.