LEVELS OF TOPOGRAPHY IN MECHANICS OF PRECISION JOINTS

Characterizing even very smooth surfaces it is necessary to take into account multilevel structure of topography. By methods of stylus profi lometry and atomic force microscopy (AFM) roughness of hard magnetic d isk substrates textured under different regimes was measured. It is sh own that the methods reflect various levels of roughness with overlapp ing ranges of wave lengths. Quantitative parameters for each roughness level suitable for the subsequent modeling of an actual contact zone were determined. To reduce influence of the roughness' long-wave compo nents on the relief parameters at a small-scale level, computer proces sing of the AFM-images was performed. For the description of the actua l contact area hybrid two-level model was offered. The Greenwood-Willi amson scheme using the profilometry data and complemented by the accou nt of superficial forces influence was used at a microlevel. Computer simulation of a contact on a database of AFM-image of a surface was us ed at submicrolevel. Influence of the contact area discreteization at a microlevel on a degree of submicroasperities deformation was taken i nto account. Visualization of the real contact area was performed. Dis tinctions in the operational characteristics of surfaces depending on their texturing modes was shown. (C) 1998 Elsevier Science Ltd.