Constructional element surface e.g. cylinder bearing surface, characterizing method for internal-combustion engine, involves determining parameter for characterization of roughness of surface from stochastic structure portion

摘要

The method involves measuring a topography of an area of a surface to be characterized and dividing the measured topography into a deterministic and a stochastic structure portion. The parameter for the characterization of a roughness of the surface is determined from the stochastic structure portion, where the parameter comprises a spectral density function of the stochastic structure portion and a middle point curvature of surface points of the stochastic structure portion. A variance of the roughness distribution is determined from the spectral density function.